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26184.29A
A3983
DMOS Microstepping Driver with Translator
The A3983 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 eighth-step modes, with an output
drive capacity of up to 35 V and ±2 A. The A3983 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 A3983.
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 A3983 interface is an ideal
fit for applications where a complex microprocessor is unavailable or is
overburdened.
The chopping control in the A3983 automatically selects the current
decay mode (Slow or Mixed). When a signal occurs at the STEP input
pin, the A3983 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 fixed off-time, then
to a slow decay for the remainder of the off-time). This current decay
control scheme results in 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.
Internal circuit protection includes: thermal shutdown with hysteresis,
undervoltage lockout (UVLO), and crossover-current protection.
Special power-on sequencing is not required.
The A3983 is supplied in a low-profile (1.2 mm maximum), 24-pin
TSSOP with exposed thermal pad (package LP). It is also available
in a lead (Pb) free version (suffix –T), with 100% matte tin plated
leadframes.
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
Use the following complete part number when ordering:
AB SO LUTE MAX I MUM RAT INGS
Part Number Pb-free Package Description
A3983SLP –
24-pin, TSSOP Exposed thermal pad
A3983SLP-T Yes
Load Supply Voltage,V
BB
...................................35 V
Output Current, I
OUT
......................................... ±2 A
*
Logic Input Voltage, V
IN
..................... –0.3 V to 7 V
Sense Voltage, V
SENSE
.......................................0.5 V
Reference Voltage, V
REF
………..........................4 V
Operating Temperature Range
Ambient, T
A
................................. –20°C to 85°C
Junction Temperature, T
J(MAX)
.....................150°C
Storage Temperature, T
S
.................... –55°C to 150°C
*
Output current rating may be limited by duty cycle,
ambient temperature, and heat sinking. Under any
set of conditions, do not exceed the specified current
rating or a junction temperature of 150°C.
Package LP
FEATURES
24
23
22
21
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
9
10
11
12
Translator
CP1
CP2
VCP
VREG
MS1
MS2
RESET
ROSC
SLEEP
VDD
STEP
REF
GND
ENABLE
OUT2B
VBB2
SENSE2
GND
OUT2A
OUT1A
SENSE1
VBB1
OUT1B
DIR
Charge
Pump
Reg
OSC
& Control Logic
Approximate Scale 1:1
