3974
DMOS DUAL FULL-BRIDGE
PWM MOTOR DRIVER
Designed for pulse-width modulated (PWM) current control
of two dc motors, the A3974SED is capable of 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.
V
BB1
NC
STROBE
CLOCK
NC
7
8
9
39
38
37
36
35
34
33
32
31
30
29
CP2
CP1
CP
PROGRAM
PWM TIMER
LOGIC
Independant ENABLE input terminals are provided for use in
controlling the speed and torque of each dc motor with externally
applied PWM control signals.
DATA 10
GND
GND
GND
GND
GND
GND
OSC
SLEEP
11
12
13
14
15
16
17
Synchronous rectification circuitry allows the load current to
flow through the low rDS(on) of the DMOS output driver during
the current decay. This feature will eliminate the need for
external clamp diodes in most applications, saving cost and
external component count, while minimizing power dissipation.
REF
1
2
÷
÷
REF
PROGRAM
PWM TIMER
LOGIC
LOGIC
SUPPLY
VREG
VDD
NC
NC
V
BB2
Internal circuit protection includes thermal shutdown with
hysteresis, undervoltage monitoring of VDD and the charge
pump, and crossover-current protection. Special power-up
sequencing is not required.
Dwg. PP-073
ABSOLUTE MAXIMUM RATINGS
The A3974SED is supplied in a 44-lead plastic PLCC with
four copper batwing tabs for maximum heat dissipation. The
power tabs are at ground potential and need no electrical isola-
tion.
at TA = +25°C
Load Supply Voltage, VBB ............................ 50 V
Output Current, IOUT .................................. ±1.5 A
Logic Supply Voltage, VDD .......................... 7.0 V
Logic Input Voltage Range, VIN
FEATURES
■ ±1.5 A, 50 V Continuous Output Rating
■ Low rDS(on) DMOS Output Drivers
Continous ................... -0.3 V to VDD + 0.3 V
tW < 30 ns ................... -1.0 V to VDD + 1.0 V
Reference Voltage, VREF ................................. 3 V
Sense Voltage (dc), VS
■
Programmable Slow, Fast, and Mixed Current-Decay Modes
■ Serial-Interface Controls Chip Functions
■ Synchronous Rectification for Low Power Dissipation
■ Internal UVLO and Thermal Shutdown Circuitry
■ Crossover-Current Protection
Continous .............................................. 0.5 V
tW < 1 µs ................................................ 2.5 V
Package Power Dissipation, PD .................. 3.9 W
Operating Temperature Range,
TA ......................................... -20°C to +85°C
Junction Temperature, TJ ......................... +150°C
Storage Temperature Range,
■ Sleep and Idle Modes
TS ....................................... -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.
Always order by complete part number: A3974SED .