A5985 Datasheet, PDF (1/26 Pages) Allegro MicroSystems – DMOS Microstepping Driver with Translator

A5985
DMOS Microstepping Driver with Translator
and Overcurrent Protection
FEATURES AND BENEFITS
• Drop-in replacement for A4988
• Proprietary Adaptive Percent Fast Decay option
• Low R_DS(on) outputs
• Single supply
• Microstepping up to 32 microsteps per full step
• Full torque step modes
• Short-to-ground protection
• Shorted load protection
• Short-to-battery protection
• Fault output
• Low current Sleep mode, < 10 µA
• Thin profile QFN
• Thermal shutdown circuitry
• Synchronous rectification for low power dissipation
• Internal UVLO
• Crossover-current protection
APPLICATIONS
• Video Security Cameras
• Printers
• Scanners
• Robotics
• ATM
• POS
DESCRIPTION
The A5985 is a complete microstepping motor driver with
built-in translator for easy operation. It is designed to operate
bipolar stepper motors from full-step up to 1/32 step modes.
Step modes are selectable by MSx logic inputs. It has an output
drive capacity of up to 40 V and ±2 A.
A5985 introduces a proprietary Adaptive Percent Fast Decay
(APFD) algorithm to optimize the current waveform over a
wide range of stepper speeds and stepper motor characteristics.
APFD adjusts on-the-fly the amount of fast decay during a
PWM cycle to keep current ripple at a low level over the
various operating conditions. This adaptive feature improves
performance of the system resulting in reduced audible motor
noise, reduced vibration, and increased step accuracy.
The translator is the key to the easy implementation of the
A5985. Simply inputting one pulse on the STEP input drives
the motor one microstep. There are no phase sequence tables,
high frequency control lines, or complex interfaces to program.
The A5985 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,
undervoltage lockout (UVLO), and crossover-current
protection. Special power-on sequencing is not required.
Continued on the next page…
Microcontroller or
Controller Logic
5985-DS
5V
5 kΩ
5V
5 kΩ
0.1 µF
0.1 µF
SLEEP ^{ROSC CP1 CP2 VCP VBB1}
STEP
MS1
MS2
MS3
DIR
ENABLE
RESET
VREF
nFAULT
A5985
VBB2
OUT1A
OUT1B
SENSE1
GND
OUT2A
PAD
OUT2B
SENSE2
Typical Application Diagram
100 µF