The LMD18245T is a 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 structure. It controls the motor current via a fixed off-time chopper technique. An all DMOS H-bridge power stage delivers continuous output currents up to 3A (6A peak) at supply voltages up to 55V. The DMOS power switches feature low RDS (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-analogue converter (DAC) provides a digital path for controlling the motor current and by extension.
DMOS power stage rated at 55V and 3A continuous
Low RDS (ON) of typically 0.3R per power switch
Internal clamp diodes
Low-loss current sensing method
Digital or analogue control of motor current
TTL and CMOS compatible inputs
Thermal shutdown (outputs off) at TJ = 155°C
Overcurrent protection
No shoot-through currents
For higher resolution applications, an external DAC can be used