Allegro Manuals

The A3979 is a complete microstepping motor driver with built-in translator, designed as a pin-compatible replacement for the successful A3977, with enhanced microstepping (1/16 step) precision.

The A3979 is a complete microstepping motor driver with built-in translator, designed as a pin-compatible replacement for the successful A3977, with enhanced microstepping (1/16 step) precision. It is designed to operate bipolar stepper motors in full-, half-, quarter-, and sixteenth- step modes, with an output drive capacity of up to 35 V and ±2.5 A. The A3979 includes a fixed off-time current regulator that has the ability to operate in Slow, Fast, or Mixed decay modes. This current-decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. The translator is the key to the easy implementation of the A3979. It allows the simple input of one pulse on the STEP pin to drive the motor one microstep, which can be either a full step, half, quarter, or sixteenth, depending on the setting of the MS1 and MS2 logic inputs. There are no phase-sequence tables, high-frequency control lines, or complex inter- faces to program. The A3979 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened. Internal synchronous-rectification control circuitry is provided to improve power dissipation during PWM operation. Internal circuit protection includes: thermal shutdown with hysteresis, UVLO (under- voltage lockout), and crossover-current protection. Special power-on sequencing is not required. The A3979 is supplied in a low-profile

A3977xED and A3977xLP are complete microstepping motor drivers with built-in translator. They are designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes, with output drive capability of 35 V and ±2.5 A.

The A3974SED is a dual full-bridge PWM motor driver designed for pulse-width modulated (PWM) current control of two dc motors. It can output ±1.5 A current and operate at up to 50 V. The 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. Independent ENABLE input terminals are provided for use in controlling the speed and torque of each dc motor with externally applied PWM control signals. 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, undervoltage monitoring of VDD and the charge pump, and crossover-current protection. Special power-up sequencing is not required. The A3974SED is supplied in a 44-lead plastic PLCC with four copper batwing tabs for maximum heat dissipation. The power tabs are at ground potential and need no electrical isola- tion.

The A3973SB and A3973SLB are dual DMOS full-bridge micro-stepping PWM motor drivers designed for bipolar microstepping stepper motor pulse-width modulated (PWM) current control.

A3976 is a high performance dual H-bridge motor driver that can be used to drive bipolar stepper motors or to bidirectionally control 2 DC Motors. A3976 uses full digital control and has high drive capacity and high reliability. The device has multiple protections such as output current, voltage, temperature, etc., which are suitable for use in harsh automotive application environments.

The A3972SB is a dual DMOS full-bridge micro-stepping PWM motor driver designed for pulse-width modulated (PWM) current control of bipolar microstepping stepper motors. It is capable of continuous output currents to ±1.5 A and operating voltages to 50 V. The driver features internal fixed off-time PWM current-control timing circuitry that 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. The driver also includes synchronous rectification circuitry, which allows the load current to flow through the low rDS(on) of the DMOS output driver during the current decay. This eliminates the need for external clamp diodes in most applications, saving cost and minimizing power dissipation. The driver features internal circuit protection, including 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. The lead (Pb) free version has 100% matte tin leadframe plating.

The A3972SB is a dual DMOS full-bridge micro-stepping PWM motor driver designed for pulse-width modulated (PWM) current control of bipolar microstepping stepper motors. It is capable of continuous output currents to ±1.5 A and operating voltages to 50 V.

The A3968SA and A3968SLB are designed to bidirectionally control two dc motors. Each device includes two H-bridges capable of continuous output currents of ±650 mA and operating voltages to 30 V. Motor winding current can be controlled by the internal fixed-frequency, pulse-width modulated (PWM), current-control circuitry. The peak load current limit is set by the user’s selection of a reference voltage and current-sensing resistors. Except for package style and pinout, the two devices are identical. The fixed-frequency pulse duration is set by a user-selected external RC timing network. The capacitor in the RC timing network also determines a user-selectable blanking window that prevents false triggering of the PWM current-control circuitry during switching transitions. To reduce on-chip power dissipation, the H-bridge power outputs have been optimized for low saturation voltages. The sink drivers feature the Allegro® patented Satlington® output structure. The Satlington outputs combine the low voltage drop of a saturated transistor and the high peak current capability of a Darlington. For each bridge, the INPUTA and INPUTB terminals determine the load current polarity by enabling the appropriate source and sink driver pair. When a logic low is applied to both INPUTs of a bridge, the braking function is enabled. In brake mode, both source drivers are turned OFF and both sink drivers are turned ON, thereby dynamically braking.

The A3968 is a dual full-bridge PWM motor driver with brake from Allegro. It can bidirectionally control two dc motors with output currents of ±650 mA and operating voltages to 30 V.

The A3966SA and A3966SLB are designed to drive both windings of a two-phase bipolar stepper motor. Each device includes two H-bridges capable of continuous output currents of ±650 mA and operating voltages to 30 V. Motor winding current can be controlled by the internal fixed-frequency, pulse-width modulated (PWM), current-control circuitry. The peak load current limit is set by the user’s selection of a reference voltage and current-sensing resistors. Except for package style and pinout, the two devices are identical. The fixed-frequency pulse duration is set by a user-selected external RC timing network. The capacitor in the RC timing network also determines a user-selectable blanking window that prevents false triggering of the PWM current-control circuitry during switching transitions. To reduce on-chip power dissipation, the H-bridge power outputs have been optimized for low saturation voltages. The sink drivers feature the Allegro patented Satlington output structure. The Satlington outputs combine the low voltage drop of a saturated transistor and the high peak current capability of a Darlington. For each bridge, a PHASE input controls load-current polarity by selecting the appropriate source and sink driver pair. For each bridge, an ENABLE input, when held high, disables the output drivers. Special power-up sequencing is not required. Internal circuit protection includes thermal shutdown with hysteresis.

The A3967SLB is a complete microstepping motor driver with built-in translator. It is designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes, with output drive capability of 30 V and ±750 mA. The A3967SLB includes a fixed off-time current regulator that has the ability to operate in slow, fast, or mixed current-decay modes. This current-decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. The translator is the key to the easy implementation of the A3967SLB. By simply inputting one pulse on the STEP input the motor will take one step (full, half, quarter, or eighth depending on two logic inputs). There are no phase-sequence tables, high-fre

The A3965 is a unique device within Allegro’s portfolio, typically fitting niche low-voltage, battery-driven stepper motor applications.