3951

3951 A3951SB 1 2 3 4 LOGIC GROUND LOGIC SUPPLY PHASE ENABLE 5 6 7 8 VBB VCC 12 11 10 9 GROUND SENSE OUTA LOAD SUPPLY 16 15 14 13 LOAD SUPPLY OUTB GROUND GROUND FULL-BRIDGE PWM MOTOR DRIVER Designed for bidirectional pulse-width modulated current control of inductive loads, the A3951SB and A3951SW are capable of continuous output currents to ±2 A and operating voltages to 50 V. Internal fixed off-time PWM current-control circuitry can be used to regulate the maximum load current to a desired value. The peak load current limit is set by the user’s selection of an input reference voltage and external sensing resistor. The fixed off-time pulse duration is set by a userselected external RC timing network. Internal circuit protection includes thermal shutdown with hysteresis, transient suppression diodes, and crossover-current protection. Special power-up sequencing is not required. The A3951SB and A3951SW are improved replacements for the UDN2953B and UDN2954W, respectively. For new system designs, the A3952SB/SEB/SLB/SW are recommended. With the ENABLE input held low, the PHASE input controls load current polarity by selecting the appropriate source and sink driver pair. A user-selectable blanking window prevents false triggering of the PWM current control circuitry. With the ENABLE input held high, all output drivers are disabled. When a logic low is applied to the BRAKE input, the braking function is enabled. This overrides ENABLE and PHASE to turn off both source drivers and ...