Texas Instruments LMH6574MA

Overview

LMH6574 from Texas Instruments is a 4:1 high-speed video multiplexer IC with current-feedback output buffer, optimized for professional video routing and multi-channel analog signal switching. It delivers 400 MHz −3 dB bandwidth at 2 V_PP, 8 ns channel switching time, 70 dB channel-to-channel isolation at 10 MHz, and supports ±3.3 V to ±6 V dual supply operation - enabling use in HDTV receivers, video routers, and multi-input instrumentation systems.

For engineers reviewing the LMH6574 datasheet, LMH6574 pinout, LMH6574 application, or LMH6574 equivalent, key selection criteria include its 0.02% differential gain / 0.05° differential phase accuracy for NTSC/PAL, 2200 V/μs slew rate, external gain-setting flexibility (AV = 1–10), and dual functional modes (EN disable vs SD shutdown) with distinct glitch and power trade-offs.

Technical Context

The LMH6574 implements a current-feedback architecture with externally set gain via RF/RG resistors - where closed-loop bandwidth depends directly on RF value (e.g., 575 Ω for AV = 2). Its four buffered input channels are selected by A0/A1 address bits, with independent EN (output disable) and SD (full-chip shutdown) control pins enabling precise timing management of switching transients and power states.

It operates without internal ground reference, supporting both single-ended and differential signaling across ±3.3 V to ±6 V supplies. Channel isolation is maintained via high-impedance input buffers and low-output-impedance current-feedback output stage (ROUT = 0.04 Ω active), while back-termination compatibility ensures stable 75-Ω video load driving with <0.1 dB gain flatness to 150 MHz.

Key Specifications

Pinout & Package

The LMH6574 is housed in a 14-pin SOIC package (8.65 mm × 3.91 mm body size), with exposed pad not present. Pin functions are validated per TI SNCS103E datasheet Rev E (August 2018).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4:1 high-speed video multiplexer applications.

Compared with LMH6574, LMH6570MA reduces channel count and control flexibility but simplifies design for 2-input cases, while THS4521DR offers superior bandwidth and noise performance at the cost of requiring discrete switching and layout overhead - making LMH6574 the optimal balance of integration, video fidelity, and ease of use for 4-input video routing.

Availability

LMH6574 is available at Aetrix Electronics and suitable for video routers, multi-input instrumentation, and receiver IF diversity systems requiring stable component supply, long-term manufacturability, and guaranteed TI production continuity.

Supply support for LMH6574 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 and embedded processing technologies, with decades of expertise in high-speed amplifiers and precision signal chain solutions.

The LMH6574 belongs to TI's high-speed video amplifier product line, designed specifically for broadcast, medical imaging, and test equipment applications demanding low distortion, fast switching, and robust 75-Ω drive capability.

FAQ

What is the maximum output voltage swing for LMH6574 at ±5 V supply?

The LMH6574 delivers ±3.54 V output voltage range under no-load conditions and ±3.18 V into a 100-Ω load at ±5 V supply. This corresponds to 7.1 V_PP open-circuit and 6.36 V_PP loaded - sufficient to drive standard 75-Ω video lines with back-termination while maintaining linearity and low distortion. The LMH6574 output remains linear up to ±80 mA, supporting multiple parallel loads without clipping.

How does LMH6574 handle capacitive loads, and what series resistor is recommended?

The LMH6574 requires an external series output resistor (ROUT) to stabilize operation with capacitive loads. For a 10 pF load, TI recommends ROUT = 45 Ω; for 18 pF, 48 Ω; for 56 pF, 24 Ω; and for 100 pF, 19 Ω - values derived from Figure 4 of the SNCS103E datasheet. These values limit peaking to ≤0.5 dB while preserving settling time and bandwidth, preventing ringing or oscillation in PCB traces or connector interfaces.

What is the difference between EN and SD pins on LMH6574, and when should each be used?

The EN pin disables only the output buffer (10 ns transition, 50 mV glitch, 4.7 mA supply current), preserving input buffer activity for fast re-enable. The SD pin shuts down the entire device (1.8 mA, 400 mV output spike, full isolation). Use EN for minimal-glitch channel blanking during live switching; use SD for deep power savings or maximum channel-to-channel isolation in standby mode. TI recommends asserting EN ≥10 ns before SD to suppress the shutdown spike.

Can LMH6574 drive a 75-Ω back-terminated video load directly, and what gain configuration is typical?

Yes - the LMH6574 is explicitly characterized for 75-Ω back-terminated loads, delivering 0.02% differential gain and 0.05° differential phase error for NTSC/PAL signals. With AV = 2 (RF = 575 Ω), the net system gain is 1 V/V due to 50% voltage division across the 75-Ω source and load. This configuration ensures optimal video fidelity, flat frequency response to 150 MHz, and minimal group delay variation - meeting broadcast infrastructure requirements.

What are the absolute maximum supply ratings and thermal limits for LMH6574?

The LMH6574 has an absolute maximum supply voltage of ±6.6 V (13.2 V total), junction temperature limit of +150°C, and storage temperature range of −65°C to +150°C. Its SOIC-14 package exhibits R_θJA = 130°C/W and R_θJC(top) = 40°C/W. At ±5 V and 16 mA supply current, power dissipation is ~160 mW - keeping junction temperature rise below 21°C above ambient in typical layouts, well within safe operating margins for continuous video routing applications.