Texas Instruments LMD18200T

Overview

LMD18200T from Texas Instruments is a 3A, 55V monolithic H-bridge motor driver IC built using bipolar-CMOS-DMOS technology. It delivers up to 3A continuous output current, operates at supply voltages up to 55V, features low R_DS(ON) of 0.33Ω per switch at 3A, and integrates internal clamp diodes and thermal warning/thermal shutdown protection. It is used in DC motor drives requiring bidirectional control and current sensing.

For engineers reviewing the LMD18200T datasheet, LMD18200T pinout, LMD18200T application, or LMD18200T equivalent, key selection considerations include its 11-pin TO-220 package, TTL/CMOS-compatible logic inputs, integrated bootstrap charge pump for high-side drive, open-collector thermal flag output, and current sense output with 377 μA/A sensitivity.

Technical Context

The LMD18200T implements a full H-bridge topology with two independent half-bridges, each controlled via dedicated bootstrap pins (1 and 11) and outputs (2 and 10). Its internal charge pump operates at ~300 kHz and supports external 10 nF bootstrap capacitors for switching frequencies up to 500 kHz.

Logic control uses three inputs-DIRECTION (Pin 3), BRAKE (Pin 4), and PWM (Pin 5)-to configure sourcing/sinking output pairs or full-braking states. The current sense circuit monitors only upper sourcing outputs (not recirculating currents), delivering a linear 377 μA/A output on Pin 8, while Pin 9 provides an active-low thermal warning flag at 145°C junction temperature.

Key Specifications

Pinout & Package

Package: 11-lead TO-220 (NDJ), with mounting tab internally connected to Pin 7 (GROUND); requires mechanical heatsinking for >1.5A continuous operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar H-bridge motor driver applications.

Compared with LMD18200T, DRV8876PWPR offers digital configurability but sacrifices thermal flag visibility and high-voltage headroom, while VNH7040ASTR adds automotive robustness and diagnostics at the cost of increased BOM complexity and reduced design transparency.

Availability

LMD18200T is available at Aetrix Electronics and suitable for industrial motor control, factory automation robotics, and computer peripheral motion systems requiring stable component supply and long-term manufacturability.

Supply support for LMD18200T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and consumer applications.

The LMD18200T belongs to TI's legacy high-voltage motor driver product line, designed specifically for ruggedized, discrete-style H-bridge control in motion systems where reliability, thermal resilience, and analog current feedback are prioritized over digital integration.

FAQ

What is the maximum continuous output current rating for the LMD18200T?

The LMD18200T is rated for 3A continuous output current under specified thermal conditions (TA = 25°C, adequate heatsinking). This rating assumes proper PCB copper area for thermal dissipation and use within the −40°C to +125°C operating junction temperature range. Exceeding 3A continuously without enhanced cooling risks thermal shutdown activation at 170°C.

Does the LMD18200T require external bootstrap capacitors for normal operation?

Yes, the LMD18200T requires external 10 nF ceramic capacitors connected between Pins 1–2 and Pins 10–11 to enable reliable high-side (sourcing) switch operation. While the internal charge pump can function without them at low frequencies (<1 kHz), external bootstrap capacitors are mandatory for PWM operation above ~100 Hz and essential to achieve the specified 100 ns turn-on time for sourcing outputs.

How does the current sense output (Pin 8) of the LMD18200T function in practice?

The LMD18200T current sense output (Pin 8) delivers a sourcing current proportional to load current at 377 μA/A, but only for current flowing through the upper (sourcing) DMOS devices - it ignores freewheeling current paths. To convert to voltage, a resistor to ground is used; for 3A full-scale, a 1.33 kΩ resistor yields 5V output. The LMD18200T datasheet specifies ±6% linearity from 1A to 3A, enabling accurate analog current feedback loops.

What is the purpose of the thermal flag output (Pin 9) on the LMD18200T?

The thermal flag output (Pin 9) on the LMD18200T is an open-collector transistor that pulls low when junction temperature reaches 145°C, providing early thermal warning before shutdown at 170°C. It supports wired-OR connection with other LMD18200T units and interfaces directly with microcontroller interrupt inputs. The LMD18200T flag has 0.15V saturation voltage at 2 mA sink current, ensuring clean logic-level signaling under typical system conditions.

Can the LMD18200T drive stepper motors in bipolar configuration?

Yes, the LMD18200T can drive one winding of a bipolar stepper motor in each H-bridge channel, supporting full-step and half-step excitation when paired with external logic or a microcontroller. Its 55V supply rating and 6A peak current capability accommodate common 24–48V stepper systems. However, because the LMD18200T lacks integrated indexer or microstepping logic, external timing control (e.g., via FPGA or MCU) is required to sequence DIRECTION and PWM inputs for precise phase commutation.