LMD18245_06 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – 3A, 55V DMOS Full-Bridge Motor Driver

March 2006
LMD18245
3A, 55V DMOS Full-Bridge Motor Driver
General Description
The LMD18245 full-bridge power amplifier incorporates all
the circuit blocks required to drive and control current in a
brushed type DC motor or one phase of a bipolar stepper
motor. The multi-technology process used to build the device
combines bipolar and CMOS control and protection circuitry
with DMOS power switches on the same monolithic struc-
ture. The LMD18245 controls the motor current via a fixed
off-time chopper technique.
An all DMOS H-bridge power stage delivers continuous out-
put currents up to 3A (6A peak) at supply voltages up to 55V.
The DMOS power switches feature low R_DS(ON) for high
efficiency, and a diode intrinsic to the DMOS body structure
eliminates the discrete diodes typically required to clamp
bipolar power stages.
An innovative current sensing method eliminates the power
loss associated with a sense resistor in series with the motor.
A four-bit digital-to-analog converter (DAC) provides a digital
path for controlling the motor current, and, by extension,
simplifies implementation of full, half and microstep stepper
motor drives. For higher resolution applications, an external
DAC can be used.
Features
n DMOS power stage rated at 55V and 3A continuous
n Low R_DS(ON) of typically 0.3Ω per power switch
n Internal clamp diodes
n Low-loss current sensing method
n Digital or analog control of motor current
n TTL and CMOS compatible inputs
n Thermal shutdown (outputs off) at T_J = 155˚C
n Overcurrent protection
n No shoot-through currents
n 15-lead TO-220 molded power package
Applications
n Full, half and microstep stepper motor drives
n Stepper motor and brushed DC motor servo drives
n Automated factory, medical and office equipment
Functional Block and Connection Diagram
(15-Lead TO-220 Molded Power Package (T) )
Order Number LMD18245T
See NS Package Number TA15A
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