A3979 Driver Datasheet

A3979 Datasheet, PDF, Equivalent


Part Number

A3979

Description

Microstepping DMOS Driver

Manufacture

Allegro MicroSystems

Total Page 15 Pages
Datasheet
Download A3979 Datasheet


A3979
A3979
Microstepping DMOS Driver with Translator
Features and Benefits
±2.5 A, 35 V output rating
Low RDS(On) outputs: 0.28 Ω source, 0.22 Ω sink, typical
Automatic current decay mode detection/selection
3.0 to 5.5 V logic supply voltage range
Slow, Fast or Mixed current decay modes
Home output
Synchronous rectification for low power dissipation
Internal UVLO and thermal shutdown circuitry
Crossover-current protection
Package: 28 lead TSSOP (suffix LP) with
exposed thermal pad
Not to scale
Description
The A3979 is a complete microstepping motor driver with
built-in translator, designed as a pin-compatible replacement for
the successful A3977, with enhanced microstepping (1/16 step)
precision. 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 ±2.5 A. The A3979 includes a
fixed off-time current regulator that has the ability to operate in
Slow, Fast, or Mixed 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
A3979. It allows the simple input of one pulse on the STEP
pin to drive the motor one microstep, which can be either a full
step, half, quarter, or sixteenth, depending on the setting of the
MS1 and MS2 logic inputs.There are no phase-sequence tables,
high-frequency control lines, or complex interfaces to program.
The A3979 interface is an ideal fit for applications where a
complex microprocessor is unavailable or is overburdened.
Internal synchronous-rectification control circuitry is provided
to improve power dissipation during PWM operation. Internal
circuit protection includes: thermal shutdown with hysteresis,
UVLO (undervoltage lockout), and crossover-current
protection. Special power-on sequencing is not required.
The A3979 is supplied in a low-profile (height 1.20 mm),
28-pin TSSOP with exposed thermal pad. The package is lead
(Pb) free, with 100% matte tin leadframe plating.
Pin-out Diagram
SENSE1 1
HOME 2
DIR 3
OUT1A 4
PFD 5
RC1 6
AGND 7
REF 8
RC2 9
VDD 10
OUT2A 11
MS2 12
MS1 13
SENSE2 14
PWM
Timer
÷8
Translator
and
Control
Logic
Charge
Pump
Reg
28 VBB1
27 SLEEP
26 ENABLE
25 OUT1B
24 CP2
23 CP1
22 VCP
21 PGND
20 VREG
19 STEP
18 OUT2B
17 RESET
16 SR
15 VBB2
AGND and PGND must be
connected together externally
26184.23F

A3979
A3979
DMOS Microstepping Driver with Translator
Selection Guide
Part Number
A3979SLPTR-T
Packing
4000 pieces per reel
Absolute Maximum Ratings
Load Supply Voltage
Output Current
Logic Supply Voltage
Logic Input Voltage Range
Sense Voltage
Reference Voltage
Operating Ambient Temperature
Junction Temperature
Storage Temperature
VBB
IOUT
VDD
VIN
VSENSE
VREF
TA
TJ(max)
Tstg
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.
tW > 30 ns
tW < 30 ns
Range S
35
±2.5
7.0
–0.3 to VDD + 0.3
–1 to VDD + 1
0.5
VDD
–20 to 85
150
–55 to 150
V
A
V
V
V
V
V
°C
°C
°C
Allegro MicroSystems, LLC
2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com


Features www.DataSheet4U.com A3979 Microstepping DMOS Driver with Translator Features a nd Benefits ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ±2.5 A, 35 V output rating Lo w RDS(On) outputs: 0.28 Ω source, 0.22 Ω sink, typical Automatic current dec ay mode detection/selection 3.0 to 5.5 V logic supply voltage range Slow, Fast or Mixed current decay modes Home outp ut Synchronous rectification for low po wer dissipation Internal UVLO and therm al shutdown circuitry Crossover-current protection Description The A3979 is a complete microstepping motor driver wi th built-in translator, designed as a p in-compatible replacement for the succe ssful A3977, with enhanced microsteppin g (1/16 step) precision. It is designed to operate bipolar stepper motors in f ull-, half-, quarter-, and sixteenth-st ep modes, with an output drive capacity of up to 35 V and ±2.5 A. The A3979 i ncludes a fixed off-time current regula tor that has the ability to operate in Slow, Fast, or Mixed decay modes. This current-decay control scheme results in reduce.
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