Allegro’s A2550 automotive relay driver incorporates a 5-V regulator. 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 watch-dog capabilities. The A2550 combines the functions of a voltage regulator, watch-dog and reset, as well as three low-side DMOS relay driver outputs.
Three low-side DMOS drivers drive relay coils of up to 250 mA each. Each driver integrates rugged voltage clamps that survive automotive load dump pulses up to 48 V. The 40-V rating on VBB also ensures adequate survival in harsh automotive environments. The 5-V linear regulator provides 40 mA of output current with a tolerance of 2% over the operating temperature range.
The A2550 also includes power-on reset circuitry (NPOR) as well as an integrated watch-dog circuit. Combined, they service the monitoring and reset requirements of a system microprocessor. The A2550 is priced at $1.00 in quantities of 1000.