Features and Benefits
▪ Low R
DS(ON)
outputs
▪ Internal mixed current decay mode
▪ Synchronous rectification for low power dissipation
▪ Internal UVLO
▪ Crossover-current protection
▪ 3.3 and 5 V compatible logic supply
▪ Thin profile QFN and TSSOP packages
▪ Thermal shutdown circuitry
▪ Short-to-ground protection
▪ Shorted load protection
▪ Low current Sleep mode, < 10 μA
Description
The A4986 is a dual DMOS full-bridge stepper motor driver
with parallel input communication and overcurrent protection.
Each full-bridge output is rated up to 35 V and ±2 A.
The A4986 includes fixed off-time pulse width modulation
(PWM) current regulators, along with 2- bit nonlinear DACs
(digital-to-analog converters) that allow stepper motors to be
controlled in full, half, and quarter steps. The PWM current
regulator uses the Allegro
®
patented mixed decay mode for
reduced audible motor noise, increased step accuracy, and
reduced power dissipation.
Internal synchronous rectification control circuitry is provided
to improve power dissipation during PWM operation.
The outputs are protected from shorted load and short-to-
ground events, which protect the driver and associated circuitry
from thermal damage or flare-ups. Other protection features
include thermal shutdown with hysteresis, undervoltage lockout
(UVLO) and crossover current protection. Special power-up
sequencing is not required.
The A4986 is supplied in a 24-contact QFN package (ES), and
a 24-pin TSSOP package (LP) with an overall package height
of ≤1.2 mm. Both packages have exposed pads for enhanced
thermal dissipation, and are lead (Pb) free (suffix –T), with
100% matte tin plated leadframes.
4986-DS, Rev. 4
DMOS Dual Full-Bridge PWM Motor Driver
With Overcurrent Protection
A4986
24-contact QFN
4 mm × 4 mm × 0.75 mm
(ES package)
Microcontroller or
Controller Logic
V
DD
VREF
GND GND
PH2
IN12
SLEEP
IN11
PH1
IN02
IN01
VBB1
CP1 VCPVREG
VDD
ROSC
0.22 F
0.22 F
0.1 F0.1 F
100 F
CP2
VBB2
OUT1A
OUT1B
SENSE1
OUT2A
OUT2B
SENSE2
A4986
Typical Application Diagram
Packages:
24-pin TSSOP
with exposed thermal pad
(LP Package)
Approximate size
