3948

DMOS FULL-BRIDGE PWM

MOTOR DRIVER

Always order by complete part number:

Part Number

Package

A3948SB

24-pin batwing DIP

40

°C/W

6

°C/W

A3948SLB

24-lead batwing SOIC

77

°C/W

6

°C/W

Designed for pulse-width modulated (PWM) current control of dc

motors, the A3948SB and A3948SLB are capable of continuous output

currents to

±1.5 A and operating voltages to 50 V. Internal fixed off-

time PWM current-control timing circuitry can be programmed via a

serial interface to operate in slow, fast, and mixed current-decay

modes. Similar devices with outputs rated to

±2 A are available as the

A3958SB/SLB.

PHASE and ENABLE input terminals are provided for use in

controlling the speed and direction of a dc motor with externally

applied PWM-control signals. The ENABLE input can be

programmed via the serial port to PWM the bridge in fast or slow

current decay. Internal synchronous rectification control circuitry is

provided to reduce power dissipation during PWM operation.

Internal circuit protection includes thermal shutdown with

hysteresis, and crossover-current protection. Special power-up

sequencing is not required.

The A3948SB/SLB is supplied in a choice of two power

packages, a 24-pin plastic DIP with a copper batwing tab (package

suffix ‘B’), and a 24-lead plastic SOIC with a copper batwing tab

(package suffix ‘LB’). In both cases, the power tab is at ground

potential and needs no electrical isolation.

FEATURES

s

±1.5 A, 50 V Continuous Output Rating

s Programmable Mixed, Fast, and Slow Current-Decay Modes

s Serial Interface Controls Chip Functions

s Synchronous Rectification for Low Power Dissipation

s Internal UVLO and Thermal-Shutdown Circuitry

s Crossover-Current Protection

24

23

22

21

20

19

18

17

16

15

14

13

GROUND

GROUND

RANGE

NO

CONNECTION

LOAD SUPPLY

SENSE

NO

CONNECTION

MODE

REF

Dwg. PP-069A

1

2

3

4

5

6

7

8

9

12

11

10

9

GROUND

GROUND

CP

PHASE

ENABLE

DATA

CLOCK

STROBE

LOGIC SUPPLY

θ

OSC

NC

NC

÷

ABSOLUTE MAXIMUM RATINGS

A3948SB ................................. 3.1 W*

A3948SLB ............................... 1.6 W*

Operating Temperature Range,

Junction Temperature,

Storage Temperature Range,

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.

* Per SEMI G42-88 Specification.

Note that the A3948SLB(SOIC) and A3948SB

(DIP) do not share a common terminal

assignment.