Texas Instruments LMH0074SQX/NOPB

Overview

LMH0074SQX/NOPB from Texas Instruments is an SMPTE 259M/344M-compliant adaptive cable equalizer IC for serial digital video interfaces, supporting data rates from 125 Mbps to 540 Mbps, equalizing up to 400 meters of Belden 1694A coaxial cable at 270 Mbps, and operating from a single 3.3 V supply with 77 mA typical supply current.

For engineers reviewing the LMH0074SQX/NOPB datasheet, LMH0074SQX/NOPB pinout, LMH0074SQX/NOPB application, or LMH0074SQX/NOPB equivalent, this device serves as a critical signal integrity component in broadcast-grade SDI receivers where adaptive equalization, carrier detection, and programmable output muting are required under industrial temperature conditions (−40°C to +85°C).

Technical Context

The LMH0074SQX/NOPB implements a multi-stage adaptive filter controlled by an external 1 µF AEC capacitor across AEC+ and AEC− pins, enabling automatic gain and bandwidth adjustment based on cable loss. Its DC restoration block fully restores signal baseline for pathological SMPTE RP-178 test patterns without requiring transformer coupling.

It features dual differential inputs (SDI/SDI) and 50 Ω differential outputs (SDO/SDO), with independent carrier detect (CD) and manual mute (MUTE) control tied to a programmable MUTEREF threshold. Bypass mode disables both equalization and DC restoration, routing input directly to output.

Key Specifications

Pinout & Package

LMH0074SQX/NOPB uses a 16-pin WQFN package (RUM0016A) with 4 mm × 4 mm body, 0.65 mm pitch, and exposed thermal pad soldered to PCB ground for thermal and mechanical stability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adaptive SDI equalizer applications.

Compared with LMH0074SQX/NOPB, LMH0044SQ/NOPB offers lower cost but no adaptability to changing cable loss, while GS9074A provides equivalent pinout but demands additional external components and higher power - making LMH0074SQX/NOPB the optimal balance of integration, flexibility, and power efficiency for new SDI receiver designs.

Availability

LMH0074SQX/NOPB is available at Aetrix Electronics and suitable for broadcast infrastructure, professional video routing, and medical imaging systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for LMH0074SQX/NOPB 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, with leadership in high-speed interface solutions for professional video and communications markets.

The LMH0074SQX/NOPB belongs to TI's high-speed serial interface product line, designed specifically for SMPTE-compliant SDI signal conditioning in broadcast, medical, and industrial video systems where robustness, low jitter, and adaptive cable compensation are essential.

FAQ

What is the primary function of the LMH0074SQX/NOPB in an SDI system?

The LMH0074SQX/NOPB functions as an adaptive cable equalizer that compensates for high-frequency loss in coaxial cables used for SMPTE 259M and SMPTE 344M serial digital video transmission. It restores signal integrity across variable cable lengths up to 400 meters, supports data rates from 125 Mbps to 540 Mbps, and integrates DC restoration, carrier detection, and programmable muting - all within a single 16-pin WQFN package. This makes LMH0074SQX/NOPB ideal for broadcast receivers, video routers, and camera interface modules where signal fidelity must be maintained without manual tuning.

Does the LMH0074SQX/NOPB require external components to operate?

Yes, the LMH0074SQX/NOPB requires two key external components: a 1 µF capacitor between AEC+ and AEC− pins to set the adaptation loop dynamics, and AC-coupling capacitors (typically 1.0 µF) on the SDI inputs. The device also expects 50 Ω source and load terminations for optimal signal integrity. No external DC restoration circuitry is needed, as that function is fully integrated. All other functionality - including carrier detect, muting, and bypass - is controlled via dedicated pins without additional passive components. These requirements are explicitly defined in the LMH0074SQX/NOPB datasheet and validated on TI's SD074 evaluation board.

Can the LMH0074SQX/NOPB be used with single-ended input signals?

Yes, the LMH0074SQX/NOPB accepts both differential and single-ended input configurations, as confirmed in the official datasheet. Its SDI/SDI inputs are internally biased to support single-ended AC-coupled signals, though transformer coupling is not supported. When using single-ended input, one SDI pin is driven with the signal and the other is terminated to ground or left unterminated per layout guidance. The device's input return loss (15–20 dB) and common-mode voltage range (1.9 V) are specified for this mode. This flexibility allows LMH0074SQX/NOPB to interface directly with legacy video sources lacking differential drivers, while maintaining full SMPTE compliance in the receiver path.

How does the MUTEREF pin affect the operation of the LMH0074SQX/NOPB?

The MUTEREF pin on the LMH0074SQX/NOPB sets the threshold voltage for the carrier detect (CD) function, which in turn controls automatic output muting via the MUTE pin when CD is tied to it. Applying a higher voltage to MUTEREF reduces the allowable cable loss before CD de-asserts and mutes the outputs; leaving MUTEREF unconnected enables maximum equalization before muting. This allows system designers to precisely calibrate the mute point based on known cable characteristics - for example, 1.3 V corresponds to ~200 m of Belden 1694A at 270 Mbps. This behavior is documented in the LMH0074SQX/NOPB datasheet's "MUTE REFERENCE (MUTEREF)" section and verified in TI's application notes.

Is the LMH0074SQX/NOPB footprint compatible with other TI equalizers?

Yes, the LMH0074SQX/NOPB is footprint-compatible with the LMH0044 and GS9074A, as stated in its official datasheet features list. All three devices use the same 16-pin WQFN (RUM0016A) package with identical 4 mm × 4 mm outline, 0.65 mm pitch, and pin assignments for core functions including SDI/SDI, SDO/SDO, VCC, VEE, and MUTE. This allows direct replacement in existing layouts without PCB revision - though functional differences (e.g., absence of AEC loop in LMH0044) must be evaluated. TI confirms this compatibility in SNLS277D Rev D, making LMH0074SQX/NOPB a seamless upgrade path for designs seeking adaptive equalization capability.