U479B

U479B Automotive Lamp Outage Monitor, VT = 8 mV Description The monolithic integrated bipolar circuit, U479B, is designed as a monitor for lamp failure in automobiles. The comparator threshold is matched to the PTC characteristic of incandescent lamps. The threshold is tied to V4,6 = VS – VT whereas VT = 8 mV. If the voltage drop across shunt resistor, Rsh, exceeds 8 mV, the output is turned off, otherwise the output is turned on. Without supply voltage or open input Pin 8, the output is turned off. A not used comparator input must be connected to Pin 7. Features D D D D 2 kV–ESD protection Two comparators with common reference Tight threshold tolerance Threshold matched to PTC characteristic of incandescent lamps D NPN output D Interference and damage–protection according to VDE 0839 D Temperature compensated D EMI protection D Reversal polarity protection D Load-dump protection Ordering Information Extended Type Number U479B U479B–FP Package DIP8 SO8 Remarks Block Diagram VS 2 Rsh Z2 – + 0.6 VS – + 8 – + 6 1 Lamps R1 150 W 95 10380 VBatt 7 5 & OUT1 4 Rsh 3 & OUT2 Figure 1. Schematic and application circuit TELEFUNKEN Semiconductors Rev. A2, 04-Feb-97 1 (5) U479B Pin Description Input switch VRef IN2 OUT1 Pin 1 2 3 4 5 6 7 8 Symbol GND VS OUT2 IN1 OUT1 IN2 VRef Input Function Reference point, ground Supply voltage Output 2 Input 1 Output 1 Input 2 Reference voltage Input switch GND VS OUT2 IN1 1 2 3 4 95 10634 8 7 6 5 Figure 2. Pinning Absolute Maximum Ra...