Freescale Semiconductor
Advance Information
Document Number: MC33797
Rev 5.0, 11/2011
Four Channel Squib Driver IC
The Four Channel Squib Driver IC is a complete squib diagnostic
and deployment interface for use in automotive air bag modules.
Extensive diagnostics and system control features are incorporated
to provide fail-safe operation. The device contains a serial peripheral
interface (SPI) compatible 8-bit interface to allow microprocessor
control.
The device has the capability to be used in a standard four channel
squib driver IC or in a cross-coupled state with the high and low side
squib drivers located on separate squib driver ICs. Both the high and
low side output drivers are protected against temporary shorts to
battery or ground. The current limit threshold is set by an external
resistor.
Features
• Four channel high side and low side 2.0 A FET switches
• Externally adjustable FET current limiting
• Adjustable current limit range: 0.8 to 2.0 A
• Individual channel current limit detection with timing duration
measurement, communicated via the SPI
• 8-Bit SPI for diagnostics and FET switch activation
• Diagnostics for high side safing sensor status
• Resistance and voltage diagnostics for squibs
• Squib driver IC capability to be used for cross-coupled driver firing
application (allows high and low side FET switches to be located
on separate squib driver ICs)
33797
SQUIB DRIVER
EW SUFFIX (PB-FREE)
98ARH99137A
32-PIN SOICW
ORDERING INFORMATION
Device
MC33797BPEW/R2
Temperature
Range (T
A
)
-40 to 85 °C
Package
32 SOICW
33797
V
PWR
VIN
VBOS1
FIRING
CAP
VDIA_
VFIRE_1
VFIRE_1B
VDIAG_2
VFIRE_2A
5.0 V
FIRING
CAP
VFIRE_2B
R_LIMIT_1
VDD
CS
CLK
MISO
MOSI
RST
FEN1
FEN_2
R_LIMIT_2
SENSE
SQB_LO
VFIRE_RTN
SQB_HI
Typical
Air Bag
Power Supply
VBOOST2
Squib
(1A, B 2A, 2B)
R_DIAG
Microprocessor
ENABLE
ENABLE
GND
Figure 1. 33797 Simplified Application Diagram
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
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