A3984_13 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – DMOS Microstepping Driver with Translator

A3984
DMOS Microstepping Driver with Translator
Features and Benefits
▪ Low RDS(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 TSSOP with exposed
thermal pad (suffix LP)
Description
The A3984 is a complete microstepping motor driver with
built-in translator for easy operation. 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 ±2 A. The A3984 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
A3984. 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 A3984 interface is an ideal fit for applications
where a complex microprocessor is unavailable or is
overburdened.
The chopping control in the A3984 automatically selects
the current decay mode (Slow or Mixed). When a signal
occurs at the STEP input pin, the A3984 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
Not to scale
Continued on the next page…
Pin-out Diagram
CP1 1
CP2 2
VCP 3
VREG 4
MS1 5
MS2 6
RESET 7
ROSC 8
SLEEP 9
VDD 10
STEP 11
REF 12
24 ^GND
23 ^ENABLE
22 ^OUT2B
21 ^VBB2
20 ^SENSE2
19 ^OUT2A
18 OUT1A
17 SENSE1
16 VBB1
15 OUT1B
14 DIR
13 GND
26184.30E