Data Sheet 29319.33

3972 CHARGE PUMP

DUAL DMOS FULL-BRIDGE MICROSTEPPING PWM MOTOR DRIVER OSC

23

SLEEP

3

22

VREG

OUT1B

4

21

OUT2B

LOAD SUPPLY1

5

20

LOAD SUPPLY2

GROUND

6

19

GROUND

GROUND

7

18

GROUND

SENSE1

8

17

SENSE2

OUT1A

99

16

OUT2A

STROBE

10

15

LOGIC SUPPLY

CLOCK

11

14

MUX

DATA

12

13

REF

2

CP2

VBB1

6-BIT DAC & LOGIC

CP1

SERIAL PORT

1

6-BIT DAC & LOGIC

24

VCP

VBB2

VDD

Dwg. PP-069-3

ABSOLUTE MAXIMUM RATINGS at TA = +25°C Load Supply Voltage, VBB ................ 50 V Output Current, IOUT ...................... ±1.5 A Logic Supply Voltage, VDD .............. 7.0 V Logic Input Voltage Range, VIN ................ -0.3 V to VDD + 0.3 V Reference Voltage, VREF ..................... 3 V Sense Voltage (dc), VS ................ 500 mV Package Power Dissipation, PD .......................................... 3.1 W Operating Temperature Range, TA .......................... -20°C to +85°C Junction Temperature, TJ ............. +150°C Storage Temperature Range, TS ......................... -55°C to +150°C 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.

Designed for pulse-width modulated (PWM) current control of bipolar microstepping stepper motors, the A3972SB 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-lead plastic DIP with a copper batwing power tab (suffix ‘B’). The power tab is at ground potential and needs no electrical isolation.

FEATURES ■ ±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 V or 5 V Control Signals ■ Sleep and Idle Modes Always order by complete part number: A3972SB .

3972 DUAL DMOS FULL-BRIDGE MICROSTEPPING PWM MOTOR DRIVER

FUNCTIONAL BLOCK DIAGRAM 0.22 µF

0.22 µF

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 µF

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

SENSE1 8

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 µF 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 µF 6

7

18 19

GROUND

Dwg. FP-050-1

2

115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 2000, Allegro MicroSystems, Inc.

3972 DUAL DMOS FULL-BRIDGE MICROSTEPPING PWM MOTOR DRIVER

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

—