A3955 Просмотр технического описания (PDF) - Allegro MicroSystems

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A3955

Full-Bridge PWM Microstepping Motor Driver

Allegro MicroSystems 

A3955

Full-Bridge PWM Microstepping Motor Driver

Description (continued)

Internal circuit protection includes thermal shutdown with hysteresis,

transient-suppression diodes, and crossover-current protection.

Special power-up sequencing is not required.

The A3955 is supplied in a choice of two power packages; a 16-pin

dual-in-line plastic package with copper heat-sink tabs (suffix ‘B’),

Selection Guide

Part Number

A3955SB-T

A3955SLB-T

A3955SLBTR-T

Packing

16-pin DIP with exposed thermal tabs

16-pin SOICW with internally fused pins

16-pin SOICW with internally fused pins

and a 16-lead plastic SOIC with internally fused pins (suffix ‘LB’).

For both package styles, the thermally enhanced pins are at ground

potential and need no electrical isolation. Both packages are lead

(Pb) free, with leadframe plating 100% matte tin.

Package

25 per tube

47 per tube

1000 per reel

Absolute Maximum Ratings

Characteristic

Load Supply Voltage

Logic Supply Voltage

Logic/Reference Input Voltage Range

Sense Voltage

Output Current, Continuous

Package Power Dissipation

Operating Ambient Temperature

Maximum Junction Temperature

Storage Temperature

Symbol

VBB

VCC

VIN

VS

IOUT

PD

TA

TJ(max)

Tstg

Notes

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 tempera-

ture of 150°C.

Range S

Fault conditions that produce excessive junction temperature

will activate the device’s thermal shutdown circuitry. These

conditions can be tolerated but should be avoided.

Rating

50

7.0

–0.3 to VCC + 0.3

1.0

±1.5

See graph

–20 to 85

150

–55 to 150

Units

V

V

V

V

mA

W

ºC

ºC

ºC

Thermal Characteristics

Characteristic

Symbol

Test Conditions*

Package Thermal Resistance, Junction

to Ambient

Package Thermal Resistance, Junction

to Tab

B Package, single-layer PCB, 1 in2. 2-oz. exposed copper

RθJA

LB Package, 2-layer PCB, 0.3 in2. 2-oz. exposed copper each

side

RθJT

*Additional thermal information available on Allegro website.

Value

43

67

6

4

R θJT = 6.0°C/W

3

SUFFIX 'B', RθJA = 43°C/W

2

Units

ºC/W

ºC/W

ºC/W

1

SUFFIX 'LB', R θJA = 67°C/W

0

25

50

75

100

125

150

TEMPERATURE IN °C

Allegro MicroSystems, Inc.

2

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

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