A3979SLP

A3979SLP Datasheet

A3979 Microstepping DMOS Driver with Translator

Part	Datasheet
A3979SLP	A3979SLP (pdf)

Related Parts	Information
A3979SLP-T	A3979SLP-T
A3979SLPTR	A3979SLPTR

PDF Datasheet Preview
A3979 Microstepping DMOS Driver with Translator A, 35 V output rating Low RDS On outputs Ω source, Ω sink, typical Automatic current decay mode detection/selection to V logic supply voltage range Slow, Fast or Mixed current decay modes Home output Synchronous rectification for low power dissipation Internal UVLO and thermal shutdown circuitry Crossover-current protection Package 28 lead TSSOP suffix LP with exposed thermal pad Not to scale 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 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 interfaces 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 undervoltage lockout , and crossover-current protection. Special power-on sequencing is not required. The A3979 is supplied in a low-profile height mm , 28-pin TSSOP with exposed thermal pad. The package is lead Pb free, with 100% matte tin leadframe plating. Pin-out Diagram SENSE1 1 HOME 2 DIR 3 OUT1A 4 PFD 5 RC1 6 AGND 7 REF 8 RC2 9 VDD 10 OUT2A 11 MS2 12 MS1 13 SENSE2 14 PWM Timer Translator and Control Logic Charge Pump 28 VBB1 27 SLEEP 26 ENABLE 25 OUT1B 24 CP2 23 CP1 22 VCP 21 PGND 20 VREG 19 STEP 18 OUT2B 17 RESET 16 SR 15 VBB2 AGND and PGND must be connected together externally 26184.23F A3979 DMOS Microstepping Driver with Translator Selection Guide Part Number A3979SLPTR-T Packing 4000 pieces per reel Absolute Maximum Ratings Load Supply Voltage Output Current Output current rating may be limited by duty cycle, IOUT ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current rating or a junction temperature of 150°C. Logic Supply Voltage Logic Input Voltage Range Sense Voltage Reference Voltage Operating Ambient Temperature Junction Temperature Storage Temperature VSENSE VREF TA TJ max Tstg tW > 30 ns tW < 30 ns Range S to VDD + to VDD + 1 to 85 to 150 Allegro MicroSystems, LLC 115 Northeast Cutoff, Box 15036

PDF Datasheet Preview

A3979 Microstepping DMOS Driver with Translator

A, 35 V output rating Low RDS On outputs Ω source, Ω sink, typical Automatic current decay mode detection/selection to V logic supply voltage range Slow, Fast or Mixed current decay modes Home output Synchronous rectification for low power dissipation Internal UVLO and thermal shutdown circuitry Crossover-current protection

Package 28 lead TSSOP suffix LP with exposed thermal pad

Not to scale

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 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 interfaces 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 undervoltage lockout , and crossover-current protection. Special power-on sequencing is not required.

The A3979 is supplied in a low-profile height mm , 28-pin TSSOP with exposed thermal pad. The package is lead Pb free, with 100% matte tin leadframe plating.

Pin-out Diagram

SENSE1 1 HOME 2 DIR 3 OUT1A 4 PFD 5 RC1 6 AGND 7 REF 8 RC2 9 VDD 10 OUT2A 11 MS2 12 MS1 13

SENSE2 14

PWM Timer

Translator and

Control Logic

Charge Pump
28 VBB1 27 SLEEP 26 ENABLE 25 OUT1B 24 CP2 23 CP1 22 VCP 21 PGND 20 VREG 19 STEP 18 OUT2B 17 RESET 16 SR 15 VBB2

AGND and PGND must be connected together externally
26184.23F

A3979

DMOS Microstepping Driver with Translator

Selection Guide Part Number A3979SLPTR-T

Packing 4000 pieces per reel

Absolute Maximum Ratings

Load Supply Voltage Output Current

Output current rating may be limited by duty cycle,

IOUT
ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current rating or a
junction temperature of 150°C.

Logic Supply Voltage

Logic Input Voltage Range

Sense Voltage Reference Voltage Operating Ambient Temperature Junction Temperature Storage Temperature

VSENSE VREF TA

TJ max Tstg
tW > 30 ns tW < 30 ns

Range S
to VDD +
to VDD + 1
to 85
to 150

Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036

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Datasheet ID: A3979SLP 516033