Texas Instruments LMH6321TS

Overview

LMH6321TS from Texas Instruments is a high-speed unity-gain buffer IC with 1800 V/μs slew rate, 110 MHz small-signal bandwidth, and ±300 mA continuous output current drive capability. It features an externally adjustable current limit (10–300 mA, ±5 mA ±5% accuracy), thermal shutdown with error flag output, and stable operation into large capacitive loads-used in precision line drivers, sonar transducer excitation, and motor control current-boost stages.

For engineers reviewing the LMH6321TS datasheet, LMH6321TS pinout, LMH6321TS application, or LMH6321TS equivalent, key selection considerations include its open-loop complementary follower architecture, CL-pin programmable current limiting, EF-flag reporting of thermal shutdown, SO PowerPAD package thermal performance (θ_JA = 180°C/W), and ±5V to ±15V supply flexibility.

Technical Context

The LMH6321TS implements an open-loop complementary emitter-follower topology-not a closed-loop op-amp-enabling high bandwidth (110 MHz into 50 Ω) and low propagation delay. Its current-limit function uses a voltage-to-current converter (CL pin) that sets both sourcing and sinking limits via a single external resistor and reference voltage.

Thermal shutdown activates at 168°C junction temperature with 10°C hysteresis, asserting the EF pin low. The EF output is open-drain and requires external pull-up; it signals fault conditions without interrupting normal operation until thermal lockout occurs.

Key Specifications

Pinout & Package

LMH6321TS is packaged in an 8-pin SO PowerPAD (SOIC-8 with exposed thermal pad). The exposed pad is electrically connected to V− and must be soldered to a PCB copper pour for optimal thermal dissipation (θ_JA = 180°C/W with FR-4 board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-current buffer applications.

Compared with THS3091DR and OPA547FKTWT, the LMH6321TS uniquely balances 110 MHz bandwidth, programmable ±300 mA current limiting, and real-time thermal fault signaling in a compact SO PowerPAD package-making it optimal for adaptive, high-dynamic-range analog output stages.

Availability

LMH6321TS is available at Aetrix Electronics and suitable for line driver, sonar transducer excitation, motor gate drive, and precision ADC interface applications requiring stable component supply across extended temperature and voltage ranges.

Supply support for LMH6321TS 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 leader specializing in analog, embedded processing, and high-performance signal chain solutions.

The LMH6321TS belongs to TI's high-speed buffer product line, engineered for applications demanding wide bandwidth, high output current, and robust thermal management-particularly in test instrumentation, industrial automation, and ultrasonic sensing.

FAQ

What is the function of the CL pin on the LMH6321TS?

The CL pin on the LMH6321TS is a current-limit programming input that accepts an external reference current (25–750 μA) to set the output sourcing and sinking current limit between 10 mA and 300 mA. This current is converted internally to establish precise, matched limits for both directions without requiring separate components. The LMH6321TS achieves ±5 mA ±5% accuracy across temperature using this single-pin configuration.

Does the LMH6321TS require external compensation for stability?

No, the LMH6321TS does not require external compensation. It is designed as an open-loop complementary follower and remains stable into purely capacitive loads up to 1 nF when driven from a 50 Ω source. Its architecture inherently avoids phase-margin issues common in closed-loop op-amps, eliminating the need for feedback compensation networks-simplifying layout and improving high-frequency reliability in the LMH6321TS design.

How does the EF pin operate during thermal shutdown in the LMH6321TS?

The EF pin on the LMH6321TS is an open-drain output that pulls low when the junction temperature reaches 168°C, indicating thermal shutdown activation. It remains asserted low until temperature drops below 158°C (10°C hysteresis). The LMH6321TS requires an external 5 kΩ pull-up resistor to +5 V for proper logic-level signaling. This fault flag enables system-level thermal response without interrupting power or signal paths in the LMH6321TS application.

Can the LMH6321TS drive a 50 Ω load at ±15 V supply?

Yes, the LMH6321TS is fully specified to drive a 50 Ω load at ±15 V supply, delivering ±300 mA continuously with 11.2 V positive and −11.3 V negative output swing. Its 1800 V/μs slew rate and 110 MHz bandwidth ensure fidelity for high-speed signals, and its thermal design (SO PowerPAD package, θ_JA = 180°C/W) sustains this performance under sustained load-verified in the LMH6321TS electrical characteristics table.

What is the difference between LMH6321TS and LMH6321DDA?

The LMH6321TS uses an 8-pin SO PowerPAD package with an exposed thermal pad electrically connected to V−, while the LMH6321DDA uses a 7-pin DDPAK package with superior thermal resistance (θ_JC = 4°C/W). Both share identical electrical specifications and pin functions, but the LMH6321TS offers easier assembly and lower cost for moderate-power applications, whereas the LMH6321DDA targets higher ambient temperatures or continuous high-current operation. The LMH6321TS is not a drop-in replacement due to different pin count and pad layout.