A3967
Microstepping Driver with Translator
Features and Benefits
▪
±750 mA, 30 V output rating
▪
Satlington® sink drivers
▪
Automatic current-decay mode detection/selection
▪
3.0 to 5.5 V logic supply voltage range
▪
Mixed, fast, and slow current-decay modes
▪
Internal UVLO and thermal shutdown circuitry
▪
Crossover-current protection
Description
The A3967 is a complete microstepping motor driver with built-
in translator. It is designed to operate bipolar stepper motors in
full-, half-, quarter-, and eighth-step modes, with output drive
capability of 30 V and ±750 mA. The A3967 includes a fixed
off-time current regulator that has the ability to operate in slow,
fast, or mixed current-decay modes. This current-decay control
scheme results in reduced audible motor noise, increased step
accuracy, and reduced power dissipation.
The translator is the key to the easy implementation of the
A3967. By simply inputting one pulse on the STEP input the
motor will take one step (full, half, quarter, or eighth depending
on two logic inputs). There are no phase-sequence tables, high-
frequency control lines, or complex interfaces to program. The
A3967 interface is an ideal fit for applications where a complex
μP
is unavailable or over-burdened.
Internal circuit protection includes thermal shutdown with
hysteresis, under-voltage lockout (UVLO) and crossover-
current protection. Special power-up sequencing is not
required.
The A3967 is supplied in a 24-pin SOIC, which is lead (Pb)
free with 100% matte tin leadframe plating. Four pins are
fused internally for enhanced thermal dissipation. The pins
are at ground potential and need no insulation.
Package: 24-pin SOIC with internally
fused pins (suffix LB)
Not to scale
Functional Block Diagram
LOGIC
SUPPLY
V
CC
REF.
SUPPLY
REF
1
14
LOAD
SUPPLY
UVLO
AND
FAULT
DETECT
V
BB1
20
÷8
DAC
+
-
SENSE
RC
1
23
PWM LATCH
BLANKING
MIXED DECAY
OUT
1A
16
OUT
1B
21
3
STEP
10
PWM TIMER
TRANSLATOR
DIR
11
RESET
22
MS
1 12
MS
2 13
SENSE
1
CONTROL LOGIC
17
5
V
BB2
SLEEP
3
ENABLE
15
V
PF
24
OUT
2A
PWM TIMER
3
PWM LATCH
BLANKING
MIXED DECAY
9
PFD
2
OUT
2B
4
RC
2
+
DAC
6
7
18 19
-
8
SENSE
2
Dwg. FP-050-3A
26184.24H
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
