DMOS Driver. A3977 Datasheet


A3977 Driver. Datasheet pdf. Equivalent


Part Number

A3977

Description

Microstepping DMOS Driver

Manufacture

Allegro

Total Page 17 Pages
Datasheet
Download A3977 Datasheet


A3977
A3977
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
• Mixed, fast, and slow current decay modes
• Home output
• Synchronous rectification for low power dissipation
• Internal UVLO and thermal shutdown circuitry
• Crossover-current protection
Package: 28-pin TSSOP (suffix LP) with
Exposed Thermal Pad
Not to scale
DESCRIPTION
The A3977 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 35 V and ±2.5A. TheA3977 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
A3977. Simply inputting one pulse on the STEPinput drives the
motor one step (two logic inputs determine if it is a full-, half-,
quarter-, or eighth-step). There are no phase-sequence tables,
high-frequency control lines, or complex interfaces to program.
The A3977 interface is an ideal fit for applications where a
complex microprocessor is unavailable or overburdened.
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-up sequencing is not required.
The A3977 is supplied in a thin (<1.2 mm) 28-pin TSSOP with
an exposed thermal pad (suffix LP). The A3977 is lead (Pb)
free, with 100% matte tin leadframe plating.
A3977-DS, Rev. 14
MCO-0000420
Pinout Diagram
April 25, 2019

A3977
A3977
Microstepping DMOS Driver with Translator
SELECTION GUIDE
Part Number
A3977SLPTR-T
Packing
4000 per reel
SPECIFICATIONS
Package
28-pin TSSOP
Ambient Temperature, TA (°C)
–20 to 85
ABSOLUTE MAXIMUM RATINGS
Characteristic
Symbol
Load Supply Voltage
VBB
Logic Supply Voltage
VDD
Logic Input Voltage Range
VIN
Reference Voltage
Sense Voltage (DC)
VREF
VSENSE
Output Current
IOUT
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
TA
TJ(max)
Tstg
Notes
Pulsed, tw > 30 ns
Pulsed, tw < 30 ns
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.
Range K
Range S
Rating
35
7.0
–0.3 to VDD+ 0.3
–1.0 to VDD+ 1
VDD
0.5
Units
V
V
V
V
V
V
±2.5 A
–40 to 125
–20 to 85
150
–55 to 150
°C
°C
°C
°C
THERMAL CHARACTERISTICS
Characteristic
Symbol
Test Conditions*
Package Thermal Resistance
RθJA Package LP, on 4-layer PCB based on JEDEC standard
*Additional thermal information available on the Allegro website.
Value
28
Units
°C/W
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
2


Features A3977 Microstepping DMOS Driver with Tra nslator Features and Benefits ▪ ±2.5 A, 35 V output rating ▪ Low rDS(on) outputs, 0.45 Ω source, 0.36 Ω sink t ypical ▪ Automatic current decay mode detection/selection ▪ 3.0 to 5.5 V l ogic supply voltage range ▪ Mixed, fa st, and slow current decay modes ▪ Ho me output ▪ Synchronous rectification for low power dissipation ▪ Internal UVLO and thermal shutdown circuitry Crossover-current protection Descrip tion The A3977 is a complete microstepp ing motor driver, with builtin translat or. It is designed to operate bipolar s tepper motors in full-, half-, quarter- , and eighth-step modes, with output dr ive capability of 35 V and ±2.5 A. The A3977 includes a fixed off-time curren t regulator that has the ability to ope rate in slow-, fast-, or mixed-decay mo des. This current-decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced p ower dissipation. The translator is the key to the easy implementation of the A3977. .
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