A3982 Datasheet, PDF (1/11 Pages) Allegro MicroSystems – DMOS Stepper Motor Driver with Translator

A3982
DMOS Stepper Motor Driver with Translator
Features and Benefits
▪ Low R_DS(on) outputs
▪ Automatic current decay mode detection/selection
▪ Mixed and Slow current decay modes
▪ Synchronous rectification for low power dissipation
▪ Internal UVLO and thermal shutdown circuitry
▪ Crossover-current protection
Package: 24 pin SOICW with internally
fused leads (suffix LB)
Description
The A3982 is a complete stepper motor driver with built-
in translator for easy operation. It is designed to operate
bipolar stepper motors in full- and half-step modes, with an
output drive capacity of up to 35 V and ±2 A. The A3982
includes a fixed off-time current regulator which has the
ability to operate in Slow or Mixed decay modes.
The translator is the key to the easy implementation of the
A3982. Simply inputting one pulse on the STEP input drives
the motor one step. There are no phase sequence tables, high
frequency control lines, or complex interfaces to program.
The A3982 interface is an ideal fit for applications where a
complex microprocessor is unavailable or is overburdened.
The chopping control in the A3982 automatically selects
the current decay mode (Slow or Mixed). When a signal
occurs at the STEP input pin, the A3982 determines if
that step results in a higher or lower current in each of the
motor phases. If the change is to a higher current, then the
decay mode is set to Slow decay. If the change is to a lower
current, then the current decay is set to Mixed (set initially
to a fast decay for a period amounting to 31.25% of the
Not to scale
Continued on the next page…
Pin-out Diagram
OUT2A 1
SENSE2 2
VBB2 3
OUT2B 4
ENABLE 5
PGND 6
PGND 7
CP1 8
CP2 9
VCP 10
VREG 11
MS1 12
24 ^OUT1A
23 ^SENSE1
22 ^VBB1
21 ^OUT1B
20 ^DIR
19 ^PGND
18 PGND
17 REF
16 STEP
15 VDD
14 ROSC
13 RESET
26184.28C