Freescale MC33789FS Airbag system basis chip (sbc) with power supply and psi5 sensor interface Datasheet

Analog, Mixed-Signal and Power Management
MC33789
Airbag system basis chip (SBC) with power supply and PSI5 sensor interface
Applications
MC33789 Simplified Application Drawing
• Automotive Airbag Safety Systems
Basic Airbag Systems
Advanced Airbag Systems
MC33789
VBAT
• Motorcycle – ATV Safety Systems
Frame Mounted Single Loop Airbag System
The MC33789 is a mixed signal IC for airbag
safety applications. The MC33789 provides a cost
effective and flexible system IC solution across
the range of airbag partitions used in cars and
other vehicles.
The MC33789 connects to the 12 V vehicle
battery and supplies the multiple voltages of a
typical airbag system. The MC33789 can detect
switched input states, communicate with both
local and remote crash sensors. It offers an
industry standard interface (SPI) and four PSI5
master interfaces. The MC33789 has a dedicated
safing state machine that complements the
airbag’s MCU hardware/software safing
approach. Also included are a diagnostic - self
protection capability and a programmable analog
interface accessible by the system MCU.
The MC33789 is well suited for use in low to high
end airbag safety systems by allowing the
designer to scale a design for the number of firing
loops needed while providing enhanced safety
and system reliability.
IN1
IN2
9 Input
Monitors
IN8
IN9
LIN
PSI5_1
4 Satellite
Sensor
Interfaces
Wake Up
WAKE
BSTSW
33 V
VBST
VER
PSI5_2
PSI5_3
VBAT
VPWR
ERSW
PSI5_4
VPWR
OUT1_D
OUT1_S
5.0 V
X/Y Axis
Accel.
Sensor
Sensor SPI
5.0 V
VFIRE_x
SQB_H1
SQB_H1
BUCKSW
VBUCK
VCCDRI
SPI
5.0 V
Energy
Storage
9.0 V
5.0 V
Output
Squib
Driver 1
VCC
SQB_L1
5.0 V
SPI_A
VDD AIN
SQB_L1
AOUT
ARM
RESET
RESET
SPI_B
MCU
Squib
Driver 2
FEN_1
FEN_2
Squib Driver SPI
2 ARM_X and ARM_Y for Squib Driver 2 FENs
RESET
SPI
Cross-coupled
Squib
Connections
MC33789 Key Features
• Designed to operate 5.2 V ≤ VPWR ≤ 20 V,
up to 40 V transients
Performance
Performance
Typical Values
Operating Voltage
5.2 V ≤ VPWR ≤ 20 V
• Safing state machine with programmable
sensing thresholds
Energy Reserve and Squib Firing Supply
33 V
VCC Supply
5.0 V
• Two configurable high side/low side drivers
with PWM capability
Selectable Switch Input Detector Supplies
1.5 V, 2.5 V, 5.0 V, 6.5 V
Configurable Driver
Output Voltage
Output Current
PWM Frequency
0 V / VPWR
Min 70 mA
128 Hz
Analog Output Voltage
0 V ≤ VAOUT ≤ VCC
ESD (HBM)
±2000 V
Ambient Operating Temperature (TA)
-40 °C to+125 °C
Junction Temperature (TJ)
-40 °C to+150 °C
• Four PSI5 satellite sensor master
interfaces
• Self-protected and diagnostic capability
• System power mode control with watchdog
and system Power ON Reset (POR)
• Supports complete airbag system power
supply architecture, including supplies for
squib firing (33 V), satellite sensors (6.3 V),
and local ECU sensors and logic circuits
(5.0 V)
• Nine configurable switch input monitors for
simple switch and Hall-effect sensor
interfaces with internal power supply
• 16-bit SPI interface
Protection
Protection
Detect
Over-voltage
•
Over-current/SC
•
Over-temperature
•
Open load
•
Limiting
•
Shut Down
Auto Retry
Status
Reporting
•
•
•
•
•
•
•
•
Ordering Information
• LIN 2.1 physical layer interface
Part Number
Temperature Range
Package
Questions
MCZ33789AE/R2
-40 °C to 125 °C
64 LQFP-EP
Contact Sales
Evaluation board to demonstrate the key features of the MC33789
MC33789
Airbag System Basis Chip (SBC) with
Power Supply and PSI5 Sensor Interface - Data Sheet
SG1002
Analog and Power Management device comparison - Selector Guide
SG187
Automotive Selector Guide
• Question – Why are there no squib drivers
integrated?
Answer – The number of squib drivers
varies across vehicle platforms so a fixed
number could be too many or not enough
for an application.
• Question – What drove the MC33789 final
silicon partition?
Answer – The MC33789 was the result of
collaboration between Freescale and a
leading airbag system supplier who
addressed the need for low cost vs.
flexibility
• Question – Is the MC33789’s PSI5
Interface interoperable with other PSI5
products?
•
Benefits
• Master interface supports the PSI5
standard, V1.3.
.
• Provides an integrated solution for almost
all auxiliary functions in a typical airbag
control module
AE SUFFIX (PB-FREE)
EXPOSED PAD
98ASA10763D
64-PIN LQFP
• Automotive temperature range and
qualification
• Suitable for uses from low squib count to
high squib count airbag systems
Answer – Yes, Freescale is part of the PSI5
consortium and has an ecosystem of crash
sensor parts that communicate with the
MC33789. The MC33789’s PSI5 master
interface supports the P10P 500/3L
operation mode specified in the PSI5
standard V1.3.
Learn More: For current information about Freescale products,
please visit www.freescale.com.
Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc.
All other product or service names are the property of their respective owners.
© Freescale Semiconductor, Inc., 2010 - 2011 All rights reserved.
Document Number: MC33789FS, Rev. 2.0
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