A3972 Ver la hoja de datos (PDF) - Allegro MicroSystems

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A3972

Dual DMOS Full-Bridge Microstepping PWM Motor Driver

Allegro MicroSystems 

A3972

Dual DMOS Full-Bridge Microstepping PWM Motor Driver

Features and Benefits

▪ ±1.5 A, 50 V Continuous Output Rating

▪ Low RDS(on) DMOS Output Drivers

▪ Optimized Microstepping via 6-Bit Linear DACs

▪ Programmable Mixed, Fast, and Slow Current-Decay

Modes

▪ 4 MHz Internal Oscillator for Digital Timing

▪ Serial-Interface Controls Chip Functions

▪ Synchronous Rectification for Low Power Dissipation

▪ Internal UVLO and Thermal Shutdown Circuitry

▪ Crossover-Current Protection

▪ Precision 2 V Reference

▪ Inputs Compatible with 3.3 or 5 V Control Signals

▪ Sleep and Idle Modes

Package: 24-pin DIP with 4 fused leads

(suffix B)

Not to scale

Description

Designed for pulse-width modulated (PWM) current control

of bipolar microstepping stepper motors, the A3972 is capable

of continuous output currents to ±1.5 A and operating voltages

to 50 V. Internal fixed off-time PWM current-control timing

circuitry can be programmed via a serial interface to operate

in slow, fast, and mixed current-decay modes.

The desired load-current level is set via the serial port with

two 6-bit linear DACs in conjunction with a reference voltage.

The six bits of control allow maximum flexibility in torque

control for a variety of step methods, from microstepping to

full-step drive. Load current is set in 1.56% increments of the

maximum value.

Synchronous rectification circuitry allows the load current

to flow through the low RDS(on) of the DMOS output driver

during the current decay. This feature will eliminate the

need for external clamp diodes in most applications, saving

cost and external component count, while minimizing power

dissipation.

Internal circuit protection includes thermal shutdown with

hysteresis, transient-suppression diodes, and crossover-current

protection. Special power-up sequencing is not required.

The A3972SB is supplied in a 24-pin plastic DIP with two

batwing power tabs (suffix ‘B’). The power tabs are at ground

potential and need no electrical isolation. The device is lead

(Pb) free with 100% matte tin leadframe plating.

Pin-out Diagram

29319.33, Rev. D

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