A4979 Datasheet, PDF (1/44 Pages) Allegro MicroSystems – The A4979 is a flexible microstepping motor driver with built-in translator for easy operation.

A4979
Microstepping Programmable Stepper Motor Driver
With Stall Detect and Short Circuit Protection
Features and Benefits
• Typical application up to 1.5 A, 50 V
• Stall detect features
• Low R_DS(on) outputs, 0.5 Ω source and sink, typical
• Automatic current decay mode detection/selection
• Mixed, Fast, and Slow current decay modes
• Synchronous rectification for low power dissipation
• Internal UVLO and Thermal Shutdown circuitry
• Crossover-current protection
• Short circuit and open load diagnostics
• Hot and cold thermal warning
• SPI-compatible or simple Step and Direction motion control
• Highly configurable via SPI-compatible serial interface
Applications
• Industrial stepper motor drives
• Printers
• Textile machines
Package: 28-pin TSSOP with exposed
thermal pad (suffix LP)
Not to scale
Description
The A4979 is a flexible microstepping motor driver with
built-in translator for easy operation. It is a single-chip solution,
designed to operate bipolar stepper motors in full-, half-,
quarter- and sixteenth-step modes, at up to 50 V and 1.5 A. The
A4979 can be controlled by simple Step and Direction inputs,
or through the SPI-compatible serial interface that also can be
used to program many of the integrated features and to read
diagnostic information.
The current regulator can be programmed to operate in fixed
off-time or fixed frequency PWM, with several decay modes
to reduce audible motor noise and increase step accuracy.
In addition the phase current tables can be programmed via
the serial interface to create unique microstep current
profiles to further improve motor performance for
specific applications.
The current in each phase of the motor is controlled through a
DMOS full bridge, using synchronous rectification to improve
power dissipation. Internal circuits and timers prevent cross-
conduction and shoot-through, when switching between high-
side and low-side drives.
The outputs are protected from short circuits, and features
for low load current and stalled rotor detection are included.
Chip-level protection includes: hot and cold thermal warnings,
overtemperature shutdown, and undervoltage lockout.
The A4979 is supplied in a 28-pin TSSOP power package with
an exposed thermal pad (package type LP). This package is
lead (Pb) free with 100% matte-tin leadframe plating.
Logic
Supply
Micro-
controller
or
ECU
CP1 CP2 VCP VBB
VDD
STEP
DIR
MS0
MS1
ENABLE
RESETn
OAP
OAM
DIAG _A4979
REF
SDI
SDO
SCK
STRn
VREG
OSC
OBP
OBM
SENSA
SENSB
AGND PGND
Typical Applications
VBB
Logic
Supply
Stepper
Motor
Micro-
controller
or
ECU
CP1 CP2 VCPVBB
VDD
STEP
DIR
MS0
MS1
ENABLE
RESETn
OAP
OAM
DIAG _A4979
REF
SDI
SDO
SCK
STRn
VREG
OSC
OBP
OBM
SENSA
SENSB
AGND PGND
A4979-DS, Rev. 1
Serial Interface Control
Parallel Control
VBB
Stepper
Motor