LMD18200T

The Texas Instruments LMD18200T is a 3A H-bridge designed for motion control applications, built using a multi-technology process combining bipolar and CMOS control circuitry with DMOS power devices on the same monolithic structure. It is ideal for driving DC and stepper motors, accommodating peak output currents up to 6A. An innovative circuit facilitates low-loss sensing of the output current at 377uA/A typical. The device includes internal clamp diodes for driving inductive loads, a charge pump with external bootstrap capability, and comprehensive thermal management with a warning flag at 145C and shutdown at 170C. The TTL/CMOS compatible direction, brake, and PWM inputs simplify microcontroller interfacing.

The LMD18200T operates as a full H-bridge motor driver with four key subsystems: 1) H-Bridge Power Stage: Four DMOS switches (two sourcing, two sinking) form the H-bridge. The low RDS(ON) of 0.33Ohm per switch minimizes conduction losses. Anti-shoot-through circuitry prevents both switches on the same half-bridge from conducting simultaneously. 2) Control Logic: Three logic inputs (Direction, Brake, PWM) control the bridge state. Direction sets current flow, Brake shorts the motor terminals for rapid deceleration, and PWM controls speed through duty-cycle modulation. 3) Current Sense: A dedicated output provides a current proportional to the motor current (377uA/A), enabling external current monitoring and closed-loop control without a sense resistor in the motor path. 4) Protection: Thermal warning flag at 145C alerts the system, thermal shutdown at 170C disables outputs, and internal clamp diodes protect against inductive kickback.

• DC motor bidirectional speed and position control
• Stepper motor drive in CNC and 3D printers
• Industrial actuator control with current monitoring