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A3973: Dual DMOS Full-Bridge Microstepping PWM Motor Driver (PDF)
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A3973
Dual DMOS Full-Bridge Microstepping PWM Motor Driver
This part is in production but has been determined to be LAST TIME BUY. This classification indicates that the product is obsolete and notice has been given. Sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because of obsolescence in the near future. Samples are no longer available.
Date of status change: May 3, 2010.
Deadline for receipt of LAST TIME BUY orders: October 29, 2010.
Recommended substitution: For existing customer transition, and for new customers or new applications, refer to the A3992.
Features
- ±1 A, 35 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
Description
Designed for pulse-width modulated (PWM) current control of bipolar microstepping stepper motors, the A3973SB and A3973SLB are capable of continuous output currents to ±1 A and operating voltages to 35 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 A3973SB (DIP) and the A3973SLB (SOIC) are electrically identical and differ only in package style.
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.
A3973SB-T variant is in production but has been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of the variant is currently restricted to existing customer applications. The variant should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Status change: May 4, 2009. Recommended alternative: A3992.
Functional Block Diagram
| Part Number | Package Type | RoHS Compliant |
Part Composition/ RoHS Data |
Temperature | Comments | Samples | Distributor Stock |
|---|---|---|---|---|---|---|---|
| A3973SB-T | 24-pin DIP | Yes | view data | -20 °C to 85 °C | last-time buy |
Contact Local Sales Representative or check distributor stock |
|
| A3973SLBTR-T | 24-lead SOIC | Yes | view data | -20 °C to 85 °C | last-time buy |
Contact Local Sales Representative or check distributor stock |
Allegro's products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system.