Document
U6268B
Side-Airbag Sensor Dual Interface
Description
The U6268B is an interface IC for remote automotive sensors. It links the crash sensors in the driver- and passenger door with the main airbag unit in the dashboard. Two identical channels supply the external sensors and receive digital information from them via one active wire each. The interface supplies the external sensors with a pre-regulated smoothed voltage, the external units transmit the digital information back to the interface by current modulation. As the device is for safety critical applications, highest data transmission security is mandatory. With high immunity against cross-coupling between the two channels, the U6228B is tailored for the harsh automotive environment.
Features
D Two identical interface channels D Provides a pre-regulated smoothed voltage and a
supply current up to 50 mA for the sensors
D TTL-compatible input activate the sensor D Data output can be directly connected to a microcontroller input
D Receives data from the sensors by current modulation
with a transmission rate of 60 kBaud (transmission bandwidth 500 kHz)
D Operation supply voltage range 5.7 V
method 3015.7
v V v 40 V
S
D ESD protection according to MIL-STD-883C test D High-level EMI protection
D Current modulation provides high noise immunity for
data transfer
Benefits
D Voltage supply and data transmission with one active
wire over long distances
Ordering Information
Extended Type Number U6268B Package SO16 Remarks
Block Diagram
Data Channel 1 Enable Voltage comparator I/U converter Smoothed voltage regulator Channel 1 power supply Data trans– mission Crash sensor
µC
Enable Channel 2 Data
Channel 1 Channel 2
Temperature monitor
Short circuit detection Channel 2 power supply Data trans– mission
Smoothed voltage regulator Voltage comparator I/U converter
Crash sensor
13839
Figure 1. Block diagram
TELEFUNKEN Semiconductors Rev. A1, 21-May-97
1 (12)
Preliminary Information
U6268B
Pin Description
Pin 1 2 Symbol Function GND Ground and reference pin RETURN1 Return line of the external unit, internally connected to GND via a line-protection transistor OUT1 Voltage-stabilized supply output and current-modulation input VS Supply voltage of the IC OUT2 Voltage stabilized supply output and current modulation input SC Smooth time constant for slow voltage change at both OUT pins RETURN2 Return line of the external unit, internally connected to GND via a line-protection transistor GND Ground and reference pin ENABLE1 Controls OUT1 voltage, ENABLE1 High means OUT1 active, ENABLE1 Low or open means OUT1 switched off CLL2 Current logic level output, low at high OUT2 current, monitoring via OCM2 OCM2 Analog current output, representing 1/10 current of OUT2 OCM1 Analog current output, representing 1/10 current of OUT1 CLL1 Current logic level output, low at high OUT1 current, monitoring via OCM1 ENABLE2 Controls OUT2 voltage, ENABLE2 High means OUT2 active, ENABLE1 Low or open means OUT2 switche.