MC33812, Multifunctional Ignition And Injector Driver - Data Sheet

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Keywords

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Transcript

Document Number: MC33812
Rev. 6.0, 4/2016
NXP Semiconductors
Data sheet: Technical DataMultifunctional Ignition and Injector
Driver
The 33812 is an engine control analog power IC intended for motorcycle and
other single/dual cylinder small engine control applications. The IC consists of
three integrated low-side drivers, one pre-driver, a +5.0 V, voltage pre-regulator,
an MCU watchdog circuit, an ISO 9141 K-Line interface, and a parallel interface
for MCU communication. The three low-side drivers are provided for driving a fuel
injector, a lamp or LED, and a relay or other load. The pre-driver is intended to
drive either an Insulated Gate Bipolar Transistor (IGBT) or a bipolar Darlington
transistor to control an ignition coil. This device is powered by SMARTMOS
technology.
Features:
• Designed to operate over the range of ~4.7 V  VPWR  36 V
• Fuel injector driver - Current Limit - 4.0 A typical
• Ignition pre-driver can drive IGBT or Darlington bipolar junction transistors
• Ignition pre-driver has independent high and low-side outputs
• Relay driver - current limit - 4.0 A typical
• Lamp driver- current limit - 1.5 A typical
• All external outputs protected against short to battery, overcurrent
• Ignition and other drivers protected against overtemperature
• Interfaces directly to MCU using 5.0 V parallel interface
• VCC voltage pre-regulator provides +5.0 V power for the MCU
• MCU Power On RESET generator
• MCU watchdog timer circuit with parallel refresh/time setting line
• Independent fault annunciation outputs for ignition, injector and relay drivers
• ISO-9141 K-Line transceiver for communicating diagnostic messages
Figure 1. Simplified application diagram
SMALL ENGINE CONTROL IC
33812
Applications:
• Single cylinder engine control
• Dual cylinder engine control
EK Pb-FREE SUFFIX
98ASA10556D
32 Pin SOICW EP
MRX
33812
VBAT
LAMPOUT
MCU
RESET
ROUT
RELAY OR
MIL
VBAT
RESET
VCC
MTX
INJIN
VCCSENS
DGND
+5 V
IGNIN
IGNOUTH
ISO9141 ISO9141
IGNFB
VCCREF
INJOUT
INJECTOR
VBAT
VBAT
GPIO
RXD
TXD
PGND1,2
WD_INH
TM_EN, TEST2
GPIO
GPIO WDRFSH
INJFLT
IGNFLT
GPIO
GPIO
LAMPIN
RINGPIO
GPIO
VBAT
IGNSUP
PNP
IGNOUTL
(IGBT DRIVER SHOWN)
OTHER LOAD
VPWR
Note: Surge Voltage protection recommended on VPWR
GPIO RELFLT
+5 V
VPWR© 2016 NXP B.V.
Figure 2. Simplified application diagram (Darlington mode)
MRX
33812
VBAT
LAMPOUT
MCU
RESET
ROUT
RELAY OR
MIL
VBAT
RESET
VCC
MTX
INJIN
VCCSENS
DGND
+5 V
IGNIN
IGNOUTH
ISO9141 ISO9141
IGNFB
VCCREF
INJOUT
INJECTOR
VBAT
VBAT
GPIO
RXD
TXD
PGND1,2
WD_INH
TM_EN, TEST2
GPIO
GPIO WDRFSH
INJFLT
IGNFLT
GPIO
GPIO
LAMPIN
RINGPIO
GPIO
VBAT
IGNSUP
PNP
IGNOUTL
(DARLINGTON
OTHER LOAD
+5 V
GPIO RELFLT
+5 V
VPWR
DRIVER SHOWN)
2 NXP Semiconductors
33812
Table of Contents
1 Orderable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Internal block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 Pinout diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2 Static electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.3 Dynamic electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1 Functional pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6 Functional device operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.1 Operational modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.2 Injector driver operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.3 Ignition pre-driver operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.4 Relay driver operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.5 Lamp driver operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.6 LAMPOUT fault detection features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.7 Over/undervoltage shutdown strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.8 Watchdog timer operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.9 ISO-9141 transceiver operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7 Typical applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.1 Low-voltage operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.2 Low-side injector driver voltage clamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
8 Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
8.1 Package dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
NXP Semiconductors 3
33812
1 Orderable parts
Table 1. Orderable part variations
Part number Temperature (TA) Package Notes
MC33812EK -40 °C to 125 °C 98ASA10556D, 32-pin SOICW-EP (1)
Notes
1. For Tape and Reel, add an R2 suffix to the part number.
4 NXP Semiconductors
33812
2 Internal block diagram
Figure 3. Simplified internal block diagram
VPWR, VCC
Oscillator
INJIN
VPWR
IGNIN
~50 µA
~50 µA
LOGIC CONTROL
Gate Control
Current Limit
Temperature Limit
Short Protection
Open det. on Injector
+ RS
lLimit
VClamp

Relay and
~75µA
INJOUT
VCCREF
Band Gap
PARALLEL
CONTROL
undervoltage
POR, overvoltage
V10.0 Analog
V2.5 Logic
Bias
ROUT
VCCSENS
+ RS
lLimit
VClamp

Gate Control
Current Limit
Temperature Limit
Short Protection
ISO9141
CONTROLLER
MRX
MTX
LAMPOUT
VCC
ISO9141
~50 µA
~50 µA
Lamp Output
Ignition
IGNSUP
Predriver
IGNFB
GND
TEST3
TEST1
PGND1
PGND2
DGND
IGNFLT
WATCHDOGRESET
VCC
INJFLT
LAMPIN
WDRFSH
RIN
~50 µA
VCC
~50 µA
VCC
~50 µA
~50 µA
~50 µA
IGNOUTH
Short
Protection IGNOUTL
Injector Output
TEST2
WD_INH
VCC
~50 µA
~50 µA
RELFLT
VCC
~50 µA
(Open Drain)
TM_EN
~50 µA
*Note: Pull-up and pull-down current sources are ~50 µA unless otherwise noted
NXP Semiconductors 5
33812
3 Pin connections
3.1 Pinout diagram
Figure 4. Pin connections
Table 2. Pin definitions
Pin Pin name Pin function Formal name Description
1 IGNOUTL Output Ignition Output Low Low-side output to drive Gate/Base of IGBT/Bipolar Darlington
2 IGNOUTH Output Ignition Output High High-side output to drive Gate/Base of IGBT/Bipolar Darlington
3 IGNSUP Input Ignition Output Supply Tie to +5.0 V for Darlington, tie to the VPWR supply for IGBT output device
4 IGNFB Input Feedback from Source Voltage feedback from source of Ignition driver transistor through 10:1 voltage divider
5 ISO9141 Input/Output ISO9141 K-Line Bidirectional Serial Data Signal
The ISO9141 pin is VPWR level IN/OUT signal connected to external ECU Tester
using ISO9141 protocol.The output is open drain and the Input is a ratiometric VPWR
level threshold comparator
6 VCCSENS Input Voltage Sense from VCC Feedback to internal VCC regulator from external pass transistor
7 VCCREF Output VCC Reference Base drive Base drive voltage for external PNP pass transistor
8 VPWR Supply Input Main Voltage Supply Input VPWR is the main voltage supply Input for the device. Connected to +12 volt battery (It should have reverse battery protection and transient suppression)
9 RESET Output Reset Output to MCU Logic Level Reset signal used to reset the MCU when the watchdog circuit times out, during undervoltage conditions on VCC and for initial power up and power down
10 INJFLT Output Injector Fault Logic Level output to MCU indicating any fault in the injector circuit
11 RELFLT Output Relay Fault Logic Level output to MCU indicating any fault in the relay circuit
12 IGNFLT Output Ignition Fault Logic Level output to MCU indicating any fault in the ignition circuit
13 INJIN Input Injector Parallel Input Logic Level input from the MCU to control the injector driver output
14 RIN Input Relay Parallel Input Logic Level Parallel input to activate RELAY output, ROUT
15 LAMPIN Input LAMP Parallel Input Logic Level Parallel input to activate the malfunction indicator lamp output, LAMP
16 IGNIN Input Ignition Parallel Input Logic Level Input from MCU controlling the ignition coil current flow and spark.
17 MTX Input ISO9141 MCU Data Input Input logic level ISO9141 data from the MCU to the ISO9141 IN/OUT pin
18 MRX Output Low-side Driver Output Output logic level ISO9141 data to the MCU from the ISO9141 IN/OUT pin
19 WDRFSH Input Watchdog Refresh Logic level input from MCU to refresh the watchdog circuit to prevent RESET
20 TM_EN Input Test Mode Enable Used by NXP test engineering, tie to Gnd in operation
GND
IGNOUTL
IGNOUTH
IGNSUP
IGNFB
ISO9141
VCCSENS
VCCREF
VPWR
RESET
INJFLT
RELFLT
IGNFLT
INJIN
RIN
LAMPIN
IGNIN
TEST3
TEST2
TEST1
WD_INH
N.C.
INJOUT
PGND1
DGND
LAMPOUT
PGND2
ROUT
N.C.
TM_EN
WDRFSH
MRX
MTX
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
Transparent Top View
6 NXP Semiconductors
33812
21 N.C. Unused ------- Unused pin, leave open
22 ROUT Output Relay Driver Output Low-side relay driver output driven by parallel input RIN
23 PGND2 Ground Power Ground 2 Ground for RELAY driver output
24 LAMPOUT Output Warning Lamp Output Low-side driver output for MIL (warning lamp) driven by parallel input LAMPIN
25 DGND Ground Supply Ground Tied to ground plane, used for ground for all low power signals
26 PGND1 Ground Power Ground 1 Ground for INJOUT injector driver output
27 INJOUT Output Injector Driver Output Low-side driver output for Injector driven by parallel input INJIN
28 N.C. Unused ------- Unused pin, leave open
29 WD_INH Input Watch Dog Inhibit Normally tied to GND, if tied high through a pull-up, it inhibits RESET from a watchdog timeout
30 TEST1 Input Test 1 MUST be tied to GND
31 TEST2 Input Test 2 MUST be tied to GND
32 TEST3 Input Test 3 MUST leave OPEN
EP GND Ground Substrate Ground Should be tied to DGND
Table 2. Pin definitions
Pin Pin name Pin function Formal name Description
NXP Semiconductors 7
33812
4 Electrical characteristics
4.1 Maximum ratings
Table 3. Maximum ratings
All voltages are with respect to ground, unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage
to the device.
Symbol Rating Value Unit Notes
VPWR VPWR Supply Voltage -0.3 to 45 VDC
(2)
VIL Logic Input Voltage (MTX, INJIN, IGNIN, WDRFSH, LAMPIN, RIN) -0.3 to VCC VDC
VINJOUT
VRELOUT
Injector and RELAY Low-side Driver Drain Voltage (VINJOUT)
-0.3 to VCLAMP_INJ
-0.3 to VCLAMP_REL
VDC
LAMPOUT Lamp Low-side Driver Drain Voltage (LAMPOUT) -0.3 to VCLAMP_LAMP VDC
ECLAMP_INJ_SP
ECLAMP_REL_SP
Output Clamp Energy (INJOUT and ROUT) (Single Pulse)
TJUNCTION = 150 °C, IOUT = 1.5 A
100 mJ
ECLAMP_INJ_CP
ECLAMP_REL_CP
Output Clamp Energy (INJOUT and ROUT) (Continuous operation)
TJUNCTION = 125 °C, IOUT = 1.0 A, (Max. frequency is 70 Hz, Maximum Duty
Cycle 90%)
100 mJ
IOCC_MAX Output Continuous Current (INJOUT and ROUT) TJUNCTION = 150 °C 2.0 A
ECLAMP_LAMP_SP
Output Clamp Energy (LAMPOUT) (Single Pulse) - TJUNCTION = 150 °C,
IOUT = 0.5 A
35 mJ
VESD1
VESD2
VESD3
VESD4
ESD Voltage
• Human Body Model
• Machine Model
• Charge Device Model (Corner pins)
• Charge Device Model
±2000
±200
±750
±500
V (3)
THERMAL RATINGS
TA
TJ
TC
Operating Temperature
• Ambient
• Junction
• Case
-40 to 125
-40 to 150
-40 to 125
C
TSTG Storage Temperature -55 to 150 C
PD Power Dissipation (TA  25C) 1.7 W
(6)
TSOLDER Peak Package Reflow Temperature During Solder Mounting Note 5 C (4), (5)
RJA
RJL
RJC
Thermal Resistance
• Junction-to-Ambient
• Junction- to-Lead
• Junction-to-Flag
75
8.0
1.2
C/W
Notes
2. Exceeding these limits may cause malfunction or permanent damage to the device.
3. ESD testing is performed in accordance with the Human Body Model (HBM) (CZAP = 100 pF, RZAP = 1500 ), the Machine Model (MM)
(CZAP = 200 pF, RZAP = 0 ), and the Charge Device Model (CDM), Robotic (CZAP = 4.0 pF).
4. Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may cause
malfunction or permanent damage to the device.
5. NXP’s Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow Temperature and
Moisture Sensitivity Levels (MSL), Go to www.nxp.com, search by part number [e.g. remove prefixes/suffixes and enter the core ID to view all
orderable parts (i.e. MC33xxxD enter 33xxx), and review parametrics.
6. This parameter is guaranteed by design, but is not production tested.
8 NXP Semiconductors
33812
4.2 Static electrical characteristics
Table 4. Static electrical characteristics
Characteristics noted under conditions of 7.0 V  VPWR  18 V, -40 C  TC  125 C, unless otherwise noted. Where applicable, typical
values reflect the parameter’s approximate average value with VPWR = 14 V, TA = 25 C.
Symbol Characteristic Min. Typ. Max. Unit Notes
POWER INPUT (VPWR)
VPWR (FO)
VPWR (FP)
Supply Voltage (measured at VPWR pin)
• Fully Operational
• Full Parameter Specification
4.7
7.0


36
18
V (7)
IVPWR (ON) Supply Current - All Outputs Disabled (Normal Mode) – 10.0 14.0 mA
VPWR(OV) VPWR Overvoltage Shutdown Threshold Voltage 36.5 39 42 V
(8)
VPWR(OV-HYS) VPWR Overvoltage Shutdown Hysteresis Voltage 0.5 1.5 3.0 V
VPWR(UV) VPWR Undervoltage Shutdown Threshold Voltage 3.0 3.7 4.4 V
(8)
VPWR(UV-HYS) VPWR Undervoltage Shutdown Hysteresis Voltage 100 200 300 mV
VOLTAGE REGULATOR OUTPUTS (VCCREF, VCCSENS)
VSENS
VCCSENS (VCC) Output Voltage (measured with external output PNP
(FZT753 typical) transistor and 500 Load on VCCSENS) 4.9 5.0 5.1 V
IVCCREF VCCREF Output Current – -5.0 – mA (9)
IVCCCL VCCREF Current Limit 5.0 15 20 mA
VOCE Output Capacitance External (ceramic, low ESR recommended) 2.2 – – F
IVCCSENS VCCSENS Input Current – 50 1000 A
REGLINE_VCC
Line Regulation (external output PNP transistor and 500 Load on
VCCSENS) – 2 25 mV
REGLOAD_VCC
Load Regulation (external output PNP transistor and 500  Load on
VCCSENS) – 2 25 mV
VDROPOUT Dropout Voltage (Minimal Input/Output Voltage at full load) – 46 200 mV
RESETUV_VCC VCC Undervoltage RESET Threshold Voltage 4.5 4.7 4.9 V
LOW-SIDE DRIVER (INJOUT AND ROUT)
VOUT (FLT-TH)
Output Fault Detection Voltage Threshold
Outputs programmed OFF (Open Load, Injector/Relay)
Outputs programmed ON (Short to Battery)
2.0 2.5 3.0 V (10)
I(OFF)OCO
Output OFF Open Load Detection Current (Injector/Relay)
• VDRAIN = 18 V, Outputs Programmed OFF
40 75 150 A
RDS (ON)-INJ/REL
RDS (ON)-INJ/REL
RDS (ON)-INJ/REL
Drain-to-Source ON Resistance
• IOUT =1.0 A, TJ = 125°C, VPWR =14 V
• IOUT =1.0 A, TJ = 25°C, VPWR =14 V
• IOUT =1.0 A, TJ = -40°C, VPWR =14 V




0.25
0.2
0.4



IOUT (LIM)-INJ/REL Output Self Limiting Current 3.0 – 6.0 A
VCLAMP_INJ/REL Output Clamp Voltage - ID = 20 mA 48 53 58 V
Notes
7. Overvoltage thresholds minimum and maximum include hysteresis
8. Undervoltage thresholds minimum and maximum include hysteresis, for disabling outputs only, RESET based on VCC undervoltage
9. This parameter is guaranteed by design, however is not production tested.
10. Output fault detect thresholds are the same for output open and shorts.
NXP Semiconductors 9
33812
LOW-SIDE DRIVER (INJOUT AND ROUT) (CONTINUED)
IOUT (LKG)-INJ
Output Leakage Current (INJOUT)
• VDRAIN = 24 V, (Note: open load detection current can’t be
disabled)
– – 1.0 mA
IOUT (LKG)-REL
Output Leakage Current (ROUT)
• VDRAIN = 24 V, (Note: open load detection current can’t be
disabled)
– – 1.0 mA
TLIM-INJ/REL Overtemperature Shutdown 155 – 190 C (11)
TLIM (HYS)-INJ/REL Overtemperature Shutdown Hysteresis 5.0 10 15 C (11)
LOW-SIDE DRIVER (LAMPOUT)
RDS (on)LAMP
Drain-to-Source ON Resistance
• IOUT = 300 mA, TJ = 150 C, VPWR = 14 V
– – 1.0 
IOUT (LIM)-LAMP Output Self Limiting Current 1.0 – 2.5 A
VCLAMP-LAMP Output Clamp Voltage - ID = 20 mA 48 53 58 V
IOUT (LKG)-LAMP
Output Leakage Current
• VDRAIN = 24 V, (Note: no open load detection current)
– – 20 A (11)
VOUT (FLT-TH)-
LAMP
Output Fault Detection Voltage Threshold
Outputs programmed ON (short to battery) 2.0 2.5 3.0 V
(11)
TLIM-LAMP Overtemperature Shutdown 155 – 190 C (11)
TLIM (HYS)-LAMP Overtemperature Shutdown Hysteresis 5.0 10 15 C (11)
IGNITION (IGBT/DARLINGTON) DRIVER PARAMETERS (IGNOUTL, IGNOUTH, IGNFB, IGNSUP)
RDS_L(on)
Drain-to-Source ON Resistance
(IGNOUTL Output, Gate/Base Drive Turn Off Resistance) 150 300 400 
RDS_H(on)
Drain-to-Source ON Resistance
(IGNSUP to IGNOUTH Output, Gate/Base Drive Turn On Resistance) – 70 90 
I GATEDRIVE_H Ignition Output High Source Current (IGNOUTH) 40 50 – mA
PD_IGNOUTH Ignition Output High (IGNOUTH) Device Power Dissipation – – 300 mW
(12)
VIGNFB_OUT
(FLT-TH)
Output Fault Detection Voltage Threshold
(At IGNFB pin, not at input of 10:1 Voltage Divider)
Output programmed OFF (Open Load)
Output programmed ON (Short to Battery)
100 250 400 mV (13)
IFBX(FLT-SNS)
Feedback Sense Current (FBx Input Current), FBx = 2.0 V, Output
Programmed OFF – – 1.0 A
VIGNSUP_IGBT
VIGNSUP_DARL
IGNSUP Voltage for:
• IGBT
• Darlington


VPWR
5.0
VPWR_MAX
VCC_MAX
V (13)
TLIM-IGNOUTH,L Overtemperature Shutdown on IGNOUTH and IGNOUTL 155 – 190 C (13)
TLIM (HYS)-
IGNOUTH,L
Overtemperature Shutdown Hysteresis on IGNOUTH and IGNOUTL 5.0 10 15 C (13)
Notes
11. This parameter is guaranteed by design, however is not production tested.
12. These parameters are guaranteed by design.
13. This parameter is guaranteed by design, however it is not production tested.
Table 4. Static electrical characteristics (continued)
Characteristics noted under conditions of 7.0 V  VPWR  18 V, -40 C  TC  125 C, unless otherwise noted. Where applicable, typical
values reflect the parameter’s approximate average value with VPWR = 14 V, TA = 25 C.
Symbol Characteristic Min. Typ. Max. Unit Notes
10 NXP Semiconductors
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ISO9141 TRANSCEIVER PARAMETERS (ISO9141)
VIL_ISO Input Low Voltage at ISO I/O pin – – 0.3xVPWR V
VIH_ISO Input High Voltage at ISO I/O pin 0.7*VPWR – – V
VHYST_ISO Input Hysteresis at ISO I/O pin
0.15xVPW
R – –
VOL_ISO Output Low Voltage at ISO I/O pin – – 0.2xVPWR V
VOH_ISO Output High Voltage at ISO I/O pin 0.8xVPWR – – V
ILIM_ISO Output Current Limit at ISO I/O pin (MTX = 0) 50 100 150 mA
CL_ISO Load Capacitance at ISO I/O pin 0.01 3.0 10 nF (14)
DIGITAL OUTPUTS (MRX, IGNFLT, RELFLT, INJFLT)
VOH Output Logic High Voltage Level (at IOH =1.0 mA load) 0.8 x VCC – VCC + 0.2 V
VOL Output Logic Low Voltage Level (at IOL =1.0 mA load) GND – 0.1 x VCC V
DIGITAL OUTPUT (RESET)
RRESET Resistance of Internal pull-down resistor on open drain RESET pin 100 – 500 k
DIGITAL INPUTS (MTX, INJIN, IGNIN, LAMPIN, WDRFSH, RIN, WD_INH)
VIH Input Logic High Voltage Thresholds 0.7 x VCC – VCC + 0.3 V
VIL Input Logic Low Voltage Thresholds GND - 0.3 – 0.2 x VCC V
VIHYS Input Logic Voltage Hysteresis 0.5 – 1.5 V
CIN Input Logic Capacitance – – 20 pF
(15)
ILOGIC_PD Input Logic Pull-down Current (all except MTX) - 0.8 V to 5.0 V 30 50 100 A
ILOGIC_PU Input Logic Pull-up Current (MTX only) - 0.8 V to 5.0 V -30 -50 -100 A
Notes
14. This parameter is guaranteed by design, however it is not production tested.
15. These parameters are guaranteed by design.
Table 4. Static electrical characteristics (continued)
Characteristics noted under conditions of 7.0 V  VPWR  18 V, -40 C  TC  125 C, unless otherwise noted. Where applicable, typical
values reflect the parameter’s approximate average value with VPWR = 14 V, TA = 25 C.
Symbol Characteristic Min. Typ. Max. Unit Notes
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4.3 Dynamic electrical characteristics
Table 5. Dynamic electrical characteristics
Characteristics noted under conditions of 7.0 V  VPWR  18 V, -40 C  TC  125 C, unless otherwise noted. Where applicable, typical
values reflect the parameter’s approximate average value with VPWR = 14 V, TA = 25 C.
Symbol Characteristic Min. Typ. Max. Unit Notes
POWER INPUT
tUV
Required Low State Duration on VPWR for Undervoltage Detect
VPWR  VPWR_UV
1.0 – – s (16)
WATCHDOG TIMER
WDMAX Maximum Time Value Watchdog can be loaded with – – 10 s
WDLOAD Maximum WDRFSH Pulse Width to load full Watchdog time value – – 1.0 ms
WDRFSHMIN Minimum Pulse Width on WDRFSH to refresh Watchdog timer 1.0 – – s
WDRESET Reset Pulse Width when Watchdog times out 100 – – s
ISO9141 TRANSCEIVER
ISOBR Typical ISO9141 Data Rate – 10 – kbps (16)
tTXDF Turn OFF Delay MTX Input to ISO Output – – 2.0 s
tRXDF, tRXDR Turn ON/OFF Delay ISO Input to MRX Output – – 1.0 s
tRXR, tRXF Rise and Fall Time MRX Output (measured from 10% to 90%) – – 1.0 s
tTXR, tTXF Maximum Rise and Fall Time MTX Input (measured from 10% to 90%) – – 1.0 s (16)
LAMP DRIVER
tOC(BLANK) Inrush Current Blanking Time (LAMPOUT only) 5.0 7.0 9.0 ms
tRETRY_LAMP
LAMPOUT, Automatic Retry Timer During Short to Battery Fault
Condition 7.0 10 13 ms
DIGITAL LOGIC OUTPUTS
t R (DLO) INJFLT, IGNFLT Output Signal Rise Time – 100 200 ns
(16)
t F (DLO) INJFLT, IGNFLT Output Signal Fall Time – 100 200 ns (16)
INJECTOR AND RELAY DRIVER
tSC Output ON Current Limit Fault Filter Timer 30 60 90 µs
t(OFF)OC
Output OFF Open Circuit Fault Filter Timer (INJECTOR and RELAY
Driver) 100 – 400 µs
t SR(RISE) Output Slew Rate - Rise - ZLOAD = 14 VLOAD = 14 V 1.0 5.0 10 V/s
t SR(FALL) Output Slew Rate - Fall - ZLOAD = 14 , VLOAD = 14 V 1.0 5.0 10 V/s
IGNITION PRE-DRIVER
t(OFF)OC Output OFF Open Circuit Fault Filter Timer 100 – 400 µs
t(ON)(SC) Output ON Short-circuit to Battery Fault Detection Timer 30 60 90 µs
Notes
16. This parameter is guaranteed by design, however is not production tested.
12 NXP Semiconductors
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5 Functional description
5.1 Functional pin description
5.1.1 Supply input (VPWR)
The VPWR pin is battery input to the 33812 IC. A POR/LVI sub-circuit monitors this input's voltage level. The VPWR pin requires external
reverse battery and transient protection.
5.1.2 Output (VCCREF)
The VCCREF output pin is used to drive an external 5.0 V regulator PNP bipolar pass transistor.
5.1.3 Input (VCCSENS)
The VCCSENS pin is used to monitor the +5.0 Volts from the external pass transistor’s output. A POR is performed when the voltage on
the VCCSENS pin goes from 0 to VCC.
5.1.4 Digital ground (DGND)
The DGND pin provides ground reference for the digital inputs and outputs. The VCC supply is referenced to the DGND pin.
5.1.5 PGND1 and PGND2
The PGNDx pins provide power additional ground reference for the power outputs, ROUT, LAMPOUT, and INJOUT. The VPWR supply is
referenced to the PGND pins.
5.1.6 Injector input (INJIN)
The INJIN pin is the parallel input controlling the Injector output, INJOUT. The INJIN pin is a logic level input with built-in pull-down to
ground to prevent accidental actuation of the injector if the connection to the pin is lost.
5.1.7 Injector and relay driver output (INJOUT/ROUT)
The INJOUT and ROUT output pins are the injector driver and relay driver outputs for the fuel Injector and the relay this IC supports. The
relay driver and injector drivers are identical in operation and features The injector driver output is controlled by the parallel input (INJIN)
and the relay driver output is controlled by the parallel input (RIN). The injector and relay outputs are turned off during VPWR overvoltage
and undervoltage events. Open circuit (during off state), short to battery (during on state), and overtemperature faults are detected and
annunciated as a logic high on the INJFLT and RELFLT lines. Overcurrent is limited by the current limiting circuitry, but is not annunciated
unless the overcurrent is due to a short to battery. For either driver, when a fault condition is detected, the driver turns off, and when the
fault condition clears, it tries to turn on again, if the input line goes low and then high.
5.1.8 Lamp driver output (LAMPOUT)
The LAMPOUT output pin is the lamp driver, a low-side driver capable of driving an incandescent lamp. The current limit blanking time is
set to allow the driver to handle the inrush current of a cold lamp filament. The LAMPOUT output is controlled by the parallel input pin
(LAMPIN). The LAMPOUT low-side driver is protected against overtemperature, and short to battery. Unlike the Injector driver, when a
fault condition is detected, the LAMPOUT driver turns off, but when the fault condition clears, it turns on again, while the input line, LAMPIN
is high.
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5.1.9 Pre-driver output, with feedback and supply voltage input (IGNSUP,
IGNOUTL, IGNOUTH, IGNFB)
The IGNOUTL and IGNOUTH output pins are the low-side and high-side output pins of the Ignition pre-driver. They are used to drive either
an IGBT or a Darlington BJT to control the ignition coil current to produce a spark. The choice of output device, IGBT or Darlington Bipolar
Junction Transistor, is indicated by the choice of supply voltage on the IGNSUP pin.
When driving a Darlington bipolar transistor, the IGNSUP line must be tied to the +5.0 V supply. When driving an IGBT, the IGNSUP may
be tied to a protected voltage source (e.g. VPWR) greater than +5.0 V to achieve the necessary gate drive voltage required by the IGBT.
The high-side output device current limits if the circuit is forced to supply currents greater than the maximum indicated.
The IGNOUTL and IGNOUTH lines are controlled by the parallel input (IGNIN).The IGNOUT(L,H) outputs and the associated feedback
pin, IGNFB, provide short to battery protection for the external driver transistor. A 10:1 voltage divider must be used on the feedback pin
to prevent >400 Volt Ignition Coil flyback voltage from damaging the IC.
Open circuit (off state), short to battery (on state), and temperature limit threshold exceeded on the pre-driver stage are detected on the
output, and all annunciated as a logic high on the IGNFLT line. There is no individual annunciation of these three fault conditions. The
IGNFLT line goes high when any of the three fault conditions are present. If an overcurrent /short to battery fault condition, as defined by
a VDS greater than the VIGNFB_OUT(FLT-TH) is detected, the IGNOUTH or IGNOUTL turns off and does not turn on again until the fault
condition has cleared and the IGNIN input line goes low and then high.
5.1.10 Outputs (INJFLT, RELFLT, IGNFLT)
The INJFLT, RELFLT and IGNFLT pins are the logic level outputs indicating when a fault condition has been detected on the INJOUT,
ROUT or IGNOUT pins. These pins are normally low and go high when a fault is detected. Toggling the respective input pin clears the
respective fault pin if the fault has been cleared.
5.1.11 K-Line communication (MTX, MRX, ISO9141)
These three pins are used to provide an ISO914, K-line communication link for the MCU to provide diagnostic support for the system. MRX
is the +5.0 V logic level serial output line to the MCU. MTX is the +5.0 V logic level serial input to the IC from the MCU. The ISO9141 pin
is a bidirectional line, consistent with the ISO9141 specification for signalling to and from the MCU.
5.1.12 Reset (RESET)
The RESET pin is an open drain output. Without power on the circuit, RESET is held low by an internal pull-down resistor. When power
is applied to the circuit and the voltage on the VCCSENSE pin reaches the lower voltage threshold, (5.0 volts - 2% = 4.9 V) the RESET pin
remains at a low level (open drain FET turned on) for a period of time equal to the value WDRESET. After this time period, the RESET pin
then goes high and stays high until a watchdog RESET is generated, or an undervoltage event on VCC occurs. The watchdog time and
refresh features are controlled via the WDRFSH line.
5.1.13 Reload and Refresh time (WDRFSH)
The WDRFSH pin is an input supplied by an MCU output to set up the initial reload time, WDRELOAD, and to refresh the watchdog timer.
See the description of the watchdog timer for information on how to use this pin.
5.1.14 Watchdog Inhibit (WD_INH)
The WD_INH, watchdog inhibit pin, is normally tied to ground. If desired, during software development, it can be lifted from the ground pad
and pulled high through an external pull-up resistor. When high, WD_INH prevents the watchdog timer from causing a RESET because
of a watchdog timeout. The WD_INH should not be connected to an MCU I/O pin or left floating in normal operation.
5.1.15 Test pins (TEST1, TEST2, and TEST3)
These three pins are used only by NXP test engineering during the production testing of the 33812. They are not to be used for any
application purpose and must be handled as specified in the pinout section of this document.
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6 Functional device operation
6.1 Operational modes
The 33812 has two states of operation, Normal state and Reset state.
6.1.1 Reset state
Applying VPWR to the device generates a Power On RESET (POR) placing the device in the RESET state. The Power On RESET circuit
incorporates a timer to prevent high frequency transients from causing an erroneous POR. An undervoltage condition on VCC also places
the device in the RESET state causing a RESET pulse to be generated on the RESET line. All RESETs pre-loads the watchdog timer with
the maximum time value, WDMAX. The Watchdog begins counting on the rising edge of the pulse.
6.1.2 NORMAL state
The NORMAL State is entered after the RESET line goes high. Control register settings from RESET are as follows:
• All Outputs Off
• Watchdog timer loaded with the WDMAX time value
6.1.3 Power supply
The 33812 is designed to operate from 4.5 V to 36 V on the VPWR pin. The VPWR pin supplies power to all internal regulators, analog
and logic circuit blocks. The VCCREF output pin controls an external PNP bipolar transistor, such that the collector is driven to +5.0 V
2%. The VCCSENS input pin, connected to the collector of the PNP, is used to monitor the output voltage and provides the feedback to
regulate the PNP collector to +5.0 V.
6.2 Injector driver operation
The open drain low-side driver (LSD) INJOUT is designed to control a fuel injector. The injector driver is controlled through the logic level
parallel input pin, INJIN. When INJIN is high, the INJOUT pin is pulled to ground, turning on the fuel injector. When INJIN is low, the injector
pulls the INJOUT output to VBAT and the injector is turned off. The INJOUT driver includes off state open load detection and it’s output
device is protected against overcurrent, short to battery, overtemperature, inductive flyback overvoltage, and VPWR overvoltage.
6.2.1 INJOUT output protection features
6.2.1.1 Overcurrent (IOUT-LIM)
The Injector Driver protection scheme uses three separate protection schemes to prevent damage to the output device. The first protection
scheme is deployed when an overcurrent event occurs. In this case, the current limiting circuitry attempts to limit the maximum current
flow to the specified ILIM-INJ value.
6.2.1.2 Short to battery
The second protection scheme is invoked when the overcurrent fault is due to a hard short to battery. In this case, the protection circuitry,
after the short detection filter time, turn off the output driver. The output does not try to turn on again until the INJIN input goes low and
then high again. A short to battery is reported as a high logic level on the INJFLT line.
NXP Semiconductors 15
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6.2.1.3 Temperature limit (TLIM)
The third protection scheme deals with the junction temperature of the output device. Any time the maximum temperature limit on the
output device is exceeded (TLIM), the device shuts down until the junction temperature falls below this maximum temperature minus the
hysteresis temperature value. The TLIM hysteresis value is TLIM(HYST).
The maximum temperature (TLIM) protection scheme controls the output device regardless of the state of the INJIN input. The device is
unable to be activated until the junction temperature falls below this maximum temperature minus the hysteresis temperature value. An
overtemperature fault is also reported as a high logic level on the INJFLT line.
6.2.1.4 Overvoltage (VCLAMP-INJ and VPWR(OV))
The injector driver is also protected against two types of overvoltage conditions:
• When the VPWR supply exceeds the VPWR(OV) threshold, the INJOUT output turns off and stays off until the overvoltage condition
abates and the INJIN input pin toggles low and then high again.
• The output device controls inductive flyback voltages by an active clamping network that limits the voltage across the output device to
VCLAMP-INJ volts.
6.2.2 INJOUT fault detection features
6.2.2.1 Off state, Open load detection
An open load on the injector driver is detected by the voltage level on the drain of the output device in the off state. Internal to the device
is a pull-down current source. In the event of an open injector the drain voltage is pulled low. When the voltage crosses the open load
detection threshold, an open load is detected. The open load fault detect threshold is set internally and is not programmable. The open
load fault is reported as a high logic level on the INJFLT line.
6.2.2.2 On state, Shorted load detection
The INJOUT driver is capable of detecting a shorted injector load (short to battery) in the on state. A shorted load fault is reported when
the drain pin voltage is greater than the preset short threshold voltage. The shorted load fault detect threshold is set internally and is not
programmable. The shorted load fault is reported as a high logic level on the INJFLT line.
6.2.2.3 Clearing the INJFLT line
When the INJFLT line goes high for any of the following reasons, while the INJIN line is high (on state):
• Short to battery
• Overtemperature
• Overvoltage
• Open load
The INJFLT line remains high until the INJIN line goes to a low logic level and the returns high (rising edge).
16 NXP Semiconductors
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6.3 Ignition pre-driver operation
The Ignition pre-driver output is controlled by the logic level input IGNIN. When IGNIN is high the IGNOUTH pin is pulled high to IGNSUP.
When the IGNIN pin is low, the IGNOUTL line is pulled to ground turning off the driver Darlington or IGBT. The IGNOUT pre-driver protects
the output device against overcurrent, short to battery, and VPWR overvoltage.
6.3.1 IGNOUT output protection features
6.3.1.1 Overcurrent and short to battery (ILIM)
The Ignition Pre-driver protection scheme senses overcurrent in the driver device by monitoring the voltage at the IGNFB pin. Since this
pin is protected by a 10:1 voltage divider, the overcurrent threshold voltage is set internally to 1/10 of the voltage expected on the drain
or collector of the output device in an overcurrent situation. Since the Ignition output device is external to the 33812, a short to battery is
the same as an overcurrent fault. An overcurrent fault or short to battery is reported as a high logic level on the IGNFLT line.
6.3.1.2 Temperature limit (TLIM)
Since the Ignition output device is external to the 33812, there is no overtemperature protection provided.
6.3.2 IGNOUT fault detection features
6.3.2.1 Off state, Open load detection
An open load on the ignition driver external device is detected by the voltage level on the drain or collector of the output device in the off
state (through a 10:1 voltage divider). In the event of an open ignition coil the drain/collector voltage is pulled low. When the voltage
crosses the open load detection threshold, an open load is detected. The open load fault detect threshold is set internally and is not
programmable. An open load fault is reported as a high logic level on the IGNFLT line.
6.3.2.2 Overvoltage (VPWR(OV))
The Ignition pre-driver is also protected against an overvoltage condition:
When the VPWR supply exceeds the VPWR(OV) threshold, the IGNOUTL and IGNOUTH outputs turn off and stays off until the overvoltage
condition clears and the next rising edge of the IGNIN input pin.
6.3.2.3 Clearing the IGNFLT line
When the IGNFLT line goes high for any of the following reasons, while the IGNIN line is high (on state):
• Short to battery
• Overvoltage
• Overtemperature of the IGNOUTL and IGNOUTH transistors
• Open load
The IGNFLT line remains high until the IGNIN line goes to the low logic level and then returns high.
6.4 Relay driver operation
The Relay Driver (ROUT) is a low-side driver controlled by the logic level RIN input pin. When RIN is high, the ROUT pin is pulled to
ground, turning on an external relay or other device. When RIN is low, the relay coil pulls the ROUT output to VBAT, and the relay is turned
off. The ROUT driver includes off state open load detection and it’s output device is protected against overcurrent, short to battery,
overtemperature, inductive flyback overvoltage, and VPWR overvoltage. The relay driver is functionally and electrically identical to the
Injector driver and can be used as a second Injector driver, for two cylinder applications, as long as maximum power dissipation
considerations are observed.
NXP Semiconductors 17
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6.4.1 ROUT protection features
6.4.1.1 Overcurrent (IOUT-LIM ROUT)
The ROUT Driver protection scheme uses three separate protection schemes to prevent damage to the output device. The first protection
scheme is deployed when an overcurrent event occurs. In this case, the current limiting circuitry attempts to limit the maximum current
flow to the specified IOUT LIM-RELvalue.
6.4.1.2 Short to battery
The second protection scheme is invoked when the overcurrent fault is due to a hard short to battery. In this case, the protection circuitry,
after the short detection filter time, turns off the output driver. The output does not try to turn on again until the RIN input goes low and then
high again. A short to battery is reported as a high logic level on the RELFLT line.
6.4.1.3 Temperature limit (TLIM)
The third protection scheme deals with the junction temperature of the output device. Any time the maximum temperature limit on the
output device is exceeded (TLIM), the device shuts down until the junction temperature falls below this maximum temperature minus the
hysteresis temperature value. The TLIM hysteresis value is TLIM(HYST).
The maximum temperature (TLIM) protection scheme controls the output device regardless of the state of the RIN input. The device is
unable to be activated until the junction temperature falls below this maximum temperature minus the hysteresis temperature value. An
overtemperature fault is also reported as a high logic level on the RELFLT line.
6.4.1.4 Overvoltage (VCLAMP-RELand VPWR(OV))
The relay driver is also protected against two types of overvoltage conditions:
• When the VPWR supply exceeds the VPWR(OV) threshold, the ROUT output turns off and stays off until the overvoltage condition abates
and the RN input pin toggles low and then high again.
• The output device is protected against inductive flyback voltages greater than VCLAMP-REL by an active clamping network that limits the
voltage across the output device to VCLAMP-REL volts.
6.4.2 ROUT fault detection features
6.4.2.1 Off state, open load detection
An open load on the relay driver is detected by the voltage level on the drain of the output device in the off state. Internal to the device is
a pull-down current source. In the event of an open injector, the drain voltage is pulled low. When the voltage crosses the open load
detection threshold, an open load is detected. The open load fault detect threshold is set internally and is not programmable. The open
load fault is reported as a high logic level on the RELFLT line.
6.4.2.2 On state, Shorted load detection
The ROUT driver is capable of detecting a shorted load (short to battery) in the on state. A shorted load fault is reported when the drain
pin voltage is greater than the preset short threshold voltage. The shorted load fault detect threshold is set internally and is not
programmable. The shorted load fault is reported as a high logic level on the RELFLT line.
6.4.2.3 Clearing the RELFLT line
When the RELFLT line goes high for any of the following reasons, while the RIN line is high (on state):
• Short to battery
• Overtemperature
• Overvoltage
• Open load
The RELFLT line remains high until the RIN line goes to a low logic level and the returns high (rising edge).
18 NXP Semiconductors
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6.5 Lamp driver operation
The Lamp Driver is a low side driver controlled by the logic level LAMPIN input pin. When LAMPIN is high, the LAMP pin is pulled to
ground, turning on an external bulb or LED. When LAMPIN is low, the bulb or LED pulls the LAMP output to VBAT, and the lamp is turned
off.
6.5.1 LAMPOUT protection features
6.5.1.1 Overcurrent (IOUT-LIM-LAMP)
The LAMPOUT Driver protection scheme uses three separate protection schemes to prevent damage to the output device. The first
protection scheme is deployed when an overcurrent event occurs. In this case, the current limiting circuitry attempts to limit the maximum
current flow to the specified IOUT LIM-LAMP value.
6.5.1.2 Short to battery
The second protection scheme is invoked when the overcurrent fault is due to a hard short to battery. In this case, the protection circuitry,
after the short detection filter time, turns off the output driver. There is an internal retry timer to try to turn on again if the fault clears. There
is no annunciation of any LAMPOUT faults.
6.5.1.3 Temperature limit (TLIM)
The third protection scheme deals with the junction temperature of the output device. Any time the maximum temperature limit on the
output device is exceeded (TLIM), the device shuts down until the junction temperature falls below this maximum temperature minus the
hysteresis temperature value. The TLIM hysteresis value is TLIM(HYST). The maximum temperature (TLIM) protection scheme controls the
output device regardless of the state of the LAMPIN input. The device is unable to be activated until the junction temperature falls below
this maximum temperature minus the hysteresis temperature value.
6.6 LAMPOUT fault detection features
6.6.1 Off state, Open load detection
Since there is no way to annunciate an open load fault for the lamp output driver, no open load fault detection is performed by the 33812.
6.6.2 On state, Shorted load detection
Even though there is no way to annunciate a shorted load fault for the lamp output driver, shorted fault detection is performed by the 33812
as part of the protection for the output FET. The LAMPOUT driver also has an overcurrent blanking time of tOC(BLANK) to allow for
incandescent lamp inrush current
NXP Semiconductors 19
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6.7 Over/undervoltage shutdown strategy
The behavior of the outputs after an overvoltage or undervoltage event on VPWR is listed in Table 6.
6.8 Watchdog timer operation
The purpose of the watchdog timer is to provide a RESET to the MCU whenever the MCU is locked up in a loop or otherwise hung up,
perhaps by executing erroneous code, such as a HALT instruction. The watchdog timer is initialized by a power on RESET or a RESET
occurring after a fault such as an undervoltage event on VCC.
Whenever the watchdog timer is refreshed, it is always reloaded with the value WDRELOAD, which initially has a value of WDMAX seconds.
Whenever a RESET occurs, the WDRELOAD value is set to WDMAX seconds and the watchdog timer is re-loaded with this value. When
the RESET pulse returns high, and, if the WDRFSH line is low, the watchdog timer starts counting. If the watchdog timer reaches the
WDMAX value before the next rising edge on the WDRFSH line, the watchdog circuit generates a RESET pulse to the MCU and reload
itself with the maximum time value of WDRELOAD, which has been set back to WDMAX seconds.
In normal operation, the MCU issues a WDRFSH pulse, periodically, which re-loads the watchdog timer with the WDRELOAD value and
starts the counting again, thus avoiding a watchdog timer generated RESET pulse. When the watchdog timer is refreshed by a WDRFSH
pulse, before the watchdog timer reaches the programmed value, the refresh prevents a RESET pulse from being issued to the MCU.
6.8.1 Loading the Watchdog timer and WDRELOAD
Aside from the RESET case, which always loads the WDRELOAD value and the watchdog timer with the maximum time value, WDMAX,
there is an additional way that the watchdog timer and the value WDRELOAD can be re-loaded. During initialization, if the WDRFSH pulse
width is greater than WDLOAD, both the watchdog timer and the value WDRELOAD loads with a timer count value, corresponding to the
width of the pulse present on the WDRFSH input. Once this value is set, no further setting of the WDLOAD value is possible until a RESET
is performed.
Once the WDRFSH input goes low, the watchdog timer begins incrementing again, counting up to the new value loaded into the reload
register. The watchdog must be refreshed by another pulse on the WDRFSH line, before the watchdog timer counts up to the reload value,
or else a RESET pulse is generated and sent to the MCU.
If the WDRFSH line is ever kept high for longer than WDRELOAD seconds, the watchdog issues an immediate RESET to the MCU. Upon
receiving a RESET input from the 33812, the MCU should always be programmed to bring the WDRFSH line low to avoid being locked in
a “deadly embrace” condition where the MCU and 33812 alternate back and forth between the RESET and Normal states.
6.8.2 Disabling the Watchdog timer
If the WD_INH line is pulled high through a pull-up resistor of 10 K or less, (i.e. not tied to ground), the watchdog timer is inhibited from
issuing a RESET to the MCU, while the line is held in this state. This “watchdog Inhibited” state should only be used during software testing
and development to avoid being concerned about an inadvertent watchdog RESET.
Table 6. Overvoltage/undervoltage truth table
Output State Before OV or UV State When Returning From Overvoltage
State When Returning
From Undervoltage
INJOUT X OFF OFF
IGNOUT X OFF OFF
ROUT OFF OFF OFF
ROUT ON ON OFF
LAMPOUT OFF OFF OFF
LAMPOUT ON ON OFF
20 NXP Semiconductors
33812
6.8.2.1 Watchdog timing diagrams
Figure 5. Watchdog loaded with WDMAX
Time
5
3 WDRFSH
2
0
5
4
3
2
1
0
Voltage
Time
5
4
3
2
1
0
Voltage
Time
RESET
Watchdog timer
WDRFSH
PWA
RESET loads the watchdog timer and WDRELOAD with WDMAX
Refresh pulses, PWA, on WDRFSH load the Watchdog timer with the WDRELOAD
5
4
3
2
1
0
Voltage
Time
WDRFSH
PWB >WDLOAD
During initialization, for the first WDRFSH pulse only, PWB, that is greater than
WDLOAD but less than WDMAX, the Watchdog timer and WDRELOAD value will be
loaded with a time value corresponding to the width of that pulse, PWB. All pulses
on the WDRFSH line width less than WDRELOAD, will result in the Watchdog timer
being reloaded with the time value corresponding to PWB. This programmability is
only allowed once per RESET.
1
4
Holding WDRFSH high triggers RESET every WDMAX time
& WDRELOAD= WDMAX
NXP Semiconductors 21
33812
6.9 ISO-9141 transceiver operation
6.9.1 Bus I/O pin (ISO9141)
This I/O pin represents the single-wire bus transmitter and receiver.
6.9.2 Transmitter characteristics
The ISO-9141 bus transmitter is a low-side MOSFET with internal overcurrent thermal shutdown. An internal pull-up resistor with a serial
diode structure is integrated so no external pull-up components are required for the application in a slave node. Voltage can go from -18 V
to 40 V without current supplied from any other source than the pull-up resistance. The ISO9141 pin exhibits no reverse current from the
ISO9141 bus line to VPWR, even in the event of GND shift or VPWR disconnection. The transmitter has one slew rate (normal slew rate)
6.9.3 Receiver characteristics
The receiver thresholds are ratiometric with the VPWR supply pin. 
22 NXP Semiconductors
33812
7 Typical applications
7.1 Low-voltage operation
During a low voltage condition (4.5 V < VPWR < 9.0 V) the device operates as described in the functional description, however, certain
parameters listed in the tables may be out of specification. Fault condition annunciation is not guaranteed below the minimum parametric
operating voltage.
7.2 Low-side injector driver voltage clamp
The Injector output of the 33812 incorporates an internal voltage clamp to provide fast turn OFF and transient protection. Each clamp
independently limits the drain-to-source voltage to VCLAMP_INJ. The total energy clamped (EJ) can be calculated by multiplying the peak
current (IPEAK) times the clamp voltage (VCL) times the Time (all divided by 2 (see Figure 6). Characterization of the output clamp, using
a repetitive pulse method at 1.0 A, indicates the maximum energy to be 100 mJ at 125 C junction temperature per output
.
Figure 6. Output Voltage Clamping
7.2.1 Reverse battery and transient protection
The 33812 device requires external reverse battery protection on the VPWR pin. All outputs consist of a power MOSFET with an integral
substrate diode. During a reverse battery condition, current flows through the load via the substrate diode. Under this condition, load
devices turn on. If reverse battery protection for the loads is required, a diode must be placed in series with the load. Good automotive
engineering practices recommend the use of transient voltage suppression on the VPWR line. A TVS device and adequate capacitive
decoupling are necessary for a robust design.
Drain-to-Source Clamp
Voltage (VCL = 50 V)
Drain-to-Source ON
Voltage (VDS(ON))
Drain Voltage
Clamp Energy
EJ=(x IPEAK xVCL)/2
GND Time
Drain Current
(IPEAK = 0.3 A)


NXP Semiconductors 23
33812
8 Packaging
8.1 Package dimensions
Package dimensions are provided in package drawings. To find the most current package outline drawing, go to www.nxp.com and perform
a keyword search for the drawing's document number.
Table 7. Package drawing information
Package Suffix Package outline drawing number
32 SOICW-EP EK 98ASA10556D
24 NXP Semiconductors
33812

NXP Semiconductors 25
33812

26 NXP Semiconductors
33812
9 Revision history
Revision Date Description of changes
4.0 7/2009 • Initial release
5.0
7/2010 • Changed Part Number from PCZ33812AEK/R2 to MCZ33812AEK/R2
4/2013
• No technical changes. Revised back page. Updated document properties
• Added SMARTMOS sentence to first paragraph
6.0 4/2016
• PN consolidation: MCZ33812EK & MCZ33812AEK are consolidated in one device MC33812EK as per DM 17148
• Updated data sheet document form and style
NXP Semiconductors 27
33812
Information in this document is provided solely to enable system and software implementers to use NXP products. There
are no expressed or implied copyright licenses granted hereunder to design or fabricate any integrated circuits based on
the information in this document. NXP reserves the right to make changes without further notice to any products herein.
NXP makes no warranty, representation, or guarantee regarding the suitability of its products for any particular purpose,
nor does NXP assume any liability arising out of the application or use of any product or circuit, and specifically disclaims
any and all liability, including without limitation, consequential or incidental damages. "Typical" parameters that may be
provided in NXP data sheets and/or specifications can and do vary in different applications, and actual performance may
vary over time. All operating parameters, including "typicals," must be validated for each customer application by the
customer's technical experts. NXP does not convey any license under its patent rights nor the rights of others. NXP sells
products pursuant to standard terms and conditions of sale, which can be found at the following address:
http://www.nxp.com/terms-of-use.html.
NXP, the NXP logo, Freescale, the Freescale logo and SMARTMOS are trademarks of NXP B.V. All other product or
service names are the property of their respective owners. All rights reserved.
© 2016 NXP B.V.
How to Reach Us:
Home Page:
NXP.com
Web Support:
http://www.nxp.com/support
Document Number: MC33812
Rev. 6.0
4/2016

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