A3959

Designed for pulse-width modulated (PWM) current control of dc motors, the A3959SB, A3959SLB, and A3959SLP are capable of output currents to ±3 A and operating voltages to 50 V. Internal fixed off-time PWM current-control timing circuitry can be adjusted via control inputs to operate in slow, fast, and mixed current-decay modes.

PHASE and ENABLE input terminals are provided for use in controlling the speed and direction of a dc motor with externally applied PWM-control signals. Internal synchronous rectification control circuitry is provided to reduce power dissipation during PWM operation.

Internal circuit protection includes thermal shutdown with hysteresis, undervoltage monitoring of supply and charge pump, and crossover-current protection. Special power-up sequencing is not required.

The A3959SB/SLB/SLP is a choice of three power packages, a 24-pin plastic DIP with a copper batwing tab (package suffix 'B'), a 24-lead plastic SOIC with a copper batwing tab (package suffix 'LB'), and a thin (<1.2 mm) 28-lead plastic TSSOP with an exposed thermal pad (suffix 'LP'). In all cases, the power tab is at ground potential and needs no electrical isolation. Each package is available in a leadfree version (100% matte tin leadframe).