Allegro Announces New Automotive Grade Relay Driver with 5V Regulator

Allegro MicroSystems Inc. introduced a new automotive relay driver with 5V regulator to complement their existing family of relay drivers. Large numbers of relay-based applications require the use of a microprocessor that implements a complex system control. In these systems there is the need for microprocessor logic supply voltage, power-on reset circuitry, and watchdog capabilities. Allegro’s A2550 combines the functions of a voltage regulator, watchdog and reset, as well as three low-side DMOS relay driver outputs. Primarily targeted at automotive applications, this IC is designed to provide robust performance over extended voltage and temperature ranges.

Three low-side DMOS drivers are meant to drive relay coils of up to 250mA each. Each driver integrates rugged voltage clamps that survive automotive load dump pulses up to 48 V. The 40V rating on VBB also ensures adequate survival in harsh automotive environments.

A 5V linear regulator provides 40mA of output current with a tolerance of 2% over the operating temperature range. To enhance the IC's usefulness in automotive applications, the 5V regulator output as well as the three low-side driver outputs are protected against over-current conditions. The A2550 also includes power-on reset circuitry (NPOR) as well as an integrated watchdog circuit. Combined, they service the monitoring and reset requirements of a system microprocessor.