A3972SB-T

A3972 Dual DMOS Full-Bridge Microstepping PWM Motor Driver Features and Benefits Description ▪ ±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 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. Package: 24-pin DIP with 4 fused leads (suffix B) 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. Not to scale 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 Dual DMOS Full-Bridge Microstepping PWM Motor Driver A3972 Selection Guide Part Number A3972SB-T Packing 15 pieces/tube Absolute Maximum Ratings Rating Units Load Supply Voltage Characteristic VBB 50 V Output Current* IOUT ±1.5 A Logic Supply Voltage VDD 7.0 V Logic Input Voltage Range VIN –0.3 to VDD + 0.3 V Reference Voltage Symbol Notes VREF 3 V Sense Voltage (DC) VS 500 mV Package Power Dissipation PD Operating Ambient Temperature TA Range S 3.1 W –20 to 85 ºC Junction Temperature TJ 150 ºC Storage Temperature Tstg –55 to 150 ºC *Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current rating or a junction temperature of 150°C. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 Dual DMOS Full-Bridge Microstepping PWM Motor Driver A3972 FUNCTIONAL BLOCK DIAGRAM 0.22 MF 0.22 MF 22 LOGIC SUPPLY VREG CP2 3 CP1 2 2V UVLO AND FAULT DETECT 15 VDD LOAD SUPPLY VCP REGULATOR CHARGE PUMP 1 BANDGAP 0.22 MF VBB1 5 MUX 14 DMOS H-BRIDGE 6-BIT LINEAR DAC SENSE1 + VCP OUT1A 6 9 PROGRAMMABLE PWM TIMER OSCILATOR OSC 24 OUT1B 4 FIXED-OFF BLANK MIXED DECAY OSC SELECT/ DIVIDER 8 SENSE1 CLOCK 11 CONTROL LOGIC SERIAL PORT DATA 12 GATE DRIVE PHASE 1/2 SYNC. RECT. MODE SYNC. RECT. DISABLE MODE 1/2 STROBE 10 DMOS H-BRIDGE 0.1 MF 20 VBB2 SLEEP 23 OUT2A 16 PROGRAMMABLE PWM TIMER 2V 6 REF 13 OUT2B 21 FIXED-OFF BLANK MIXED DECAY BUFFER + SENSE2 6-BIT LINEAR DAC 17 0.1 MF 6 7 18 19 GROUND Dwg. FP-050-1 Copyright © 2000, Allegro MicroSystems, LLC Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 Dual DMOS Full-Bridge Microstepping PWM Motor Driver A3972 ELECTRICAL CHARACTERISTICS at TA = +25°C, VBB = 50 V, VDD = 5.0 V, VS = 0.5 V, fPWM < 50 kHz (unless otherwise noted). Limits Characteristic Load Supply Voltage Range Symbol VBB Test Conditions Min. Typ. Max. Units Operating 15 — 50 V During sleep mode 0 — 50 V Logic Supply Voltage Range VDD Operating 4.5 5.0 5.5 V Load Supply Current IBB fPWM < 50 kHz — — 8.0 mA Operating, outputs disabled — — 6.0 mA Sleep or idle mode — — 20 μA fPWM < 50 kHz — — 12 mA Outputs off — — 10 mA Idle mode (D0 = 1, D18 = 0) — — 1.5 mA Sleep mode — — 100 μA VOUT = VBB —