# U2043B Flasher IC

## Description

The U2043B is a relay-controlled automotive flasher IC designed for high EMC environments. It indicates lamp failure through frequency doubling in hazard and direction modes. The pilot lamp can be connected to either VBatt or GND.

## Features

️· Temperature and voltage compensated frequency
️· Lamp failure warning via frequency doubling
️· Minimum lamp load: 10W
️· High current carrying capacity relay output with low saturation voltage
️· Low susceptibility to EMI

## Pin Description

️· Pin 1: GND (IC Ground)
️· Pin 2 & 6: VS (Supply Voltage)
️· Pin 3: REL (Relay Driver)
️· Pin 4 & 5: OSC (Oscillator - C1 & R1 components determine frequency)
️· Pin 7: LD (Lamp Failure Detection)
️· Pin 8: SI (Start Input)

## Functional Description

️· GND (Pin 1): Protected against battery reversal with internal and external resistors.
️· Supply Voltage (Pin 2 & 6): Ensure lower resistance to Pin 6.
️· Relay Driver (Pin 3): High-side driver for automotive relays (min. coil resistance 60Ω).
️· Oscillator (Pins 4 & 5): Frequency determined by R1 & C1. Frequency doubles during lamp failure.
️· Lamp Failure Detection (Pin 7): Monitors lamp current via external shunt resistor (30mΩ recommended).
️· Start Input (Pin 8): Activated when voltage < VS - 5V.

## Electrical Characteristics

️· Supply Voltage Range: 9-15V
️· Supply Current: 4.5-11mA
️· Relay Output Saturation Voltage: 1.0V @ 150mA
️· Frequency Tolerance: ±5%
️· Lamp Load: 10W

## Absolute Maximum Ratings

️· Supply Voltage: 16.5V
️· Junction Temperature: 150°C
️· Ambient Temperature Range: -40 to +95°C

## Package Information

️· DIP8
️· SO8