Texas Instruments LMH1226RTWR

Overview

LMH1226RTWR from Texas Instruments is a low-power, dual-output 12-Gbps UHD reclocker supporting SMPTE ST-2082-1 (12G), ST-2081-1 (6G), ST-424 (3G), ST-292 (HD), ST-259 (SD), SFF-8431 (SFP+), DVB-ASI, and AES10 (MADI). It features adaptive board trace equalization at IN1±, integrated loop filter, eye opening monitor, and 1:2 fanout with programmable de-emphasis - deployed in broadcast video routers, 4K/8K media gateways, and SDI signal conditioning paths.

For engineers reviewing the LMH1226RTWR datasheet, LMH1226RTWR pinout, LMH1226RTWR application, or LMH1226RTWR equivalent, key selection criteria include reference-less lock capability across 270 Mbps–11.88 Gbps, 100-Ω differential I/O termination, dual supply operation (2.5 V + 1.8 V), 214 mW typical power, and QFN-24 package compatibility with LMH1219.

Technical Context

The LMH1226RTWR implements a fully integrated CDR with adaptive equalizer on IN1±, eliminating need for external reference clock while achieving sub-5 ms lock time across all supported rates. Its PLL bandwidth is data-rate dependent (1–13 MHz), and jitter attenuation is validated to reduce total jitter to ≤0.15 UI at 11.88 Gbps with 20-inch FR4 trace input.

It supports three operational modes: reclocked output (with integrated loop filter), bypassed reclocker (equalized-only path), and bypassed equalizer+reclocker (raw pass-through). Control is configurable via 4-level logic pins (IN_OUT_SEL, OUT_CTRL, VOD_DE, MODE_SEL) or SPI/SMBus interface, enabling flexible system integration without firmware dependency.

Key Specifications

Pinout & Package

LMH1226RTWR is housed in a 4.00 mm × 4.00 mm, 24-pin QFN package (RTW) with exposed thermal pad (EP = VSS). The package supports standard reflow profiles and requires via-stitched ground connection to EP for thermal and EMI performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar reclocker applications.

Compared with LMH1219RTWR and CDCLVP1208RHBT, the LMH1226RTWR uniquely combines reference-less reclocking, adaptive equalization, dual fanout, and real-time eye monitoring - making it the only option among the three capable of end-to-end 12G-SDI signal regeneration without external components.

Availability

LMH1226RTWR is available at Aetrix Electronics and suitable for broadcast video routers, UHDTV media gateways, and digital video editing systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LMH1226RTWR 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 and signal conditioning solutions.

The LMH1226RTWR belongs to TI's high-speed reclocker product line, designed specifically for SMPTE-compliant video infrastructure demanding jitter attenuation, multi-rate flexibility, and minimal power in compact form factors.

FAQ

What data rates does the LMH1226RTWR support?

The LMH1226RTWR supports SMPTE SD (270 Mbps), HD (1.485 Gbps), 3G (2.97 Gbps), 6G (5.94 Gbps), 12G (11.88 Gbps), 10GbE (10.3125 Gbps), MADI (125 Mbps), and 1GbE (1.25 Gbps). It locks referencelessly to all these rates with ≤5 ms acquisition time and maintains ≤0.15 UI total jitter at 11.88 Gbps - verified per SFF-8431 and SMPTE ST-2082-1 requirements. The LMH1226RTWR also supports divide-by-1.001 sub-rates for broadcast compatibility.

How is power managed on the LMH1226RTWR?

The LMH1226RTWR offers dual-supply (2.5 V + 1.8 V) and single-supply (2.5 V only) configurations. In dual mode, VIN and VDD_LDO accept 1.8 V while VDDIO and VDD_CDR run at 2.5 V - reducing total power to 214 mW typical. Power-save mode drops consumption to 16 mW when no input signal is present. The MODE_SEL pin can force power-save, and the device automatically enters low-power state during loss-of-signal events - all without firmware intervention. This behavior is intrinsic to the LMH1226RTWR's analog control architecture.

Does the LMH1226RTWR require an external reference clock?

No, the LMH1226RTWR operates referencelessly - it acquires and locks to incoming serial data rates from 270 Mbps to 11.88 Gbps without any external clock source. Its integrated PLL and on-chip loop filter eliminate the need for precision crystal oscillators or clock synthesizers. This capability is confirmed across all supported standards including SMPTE ST-2082-1, ST-2081-1, and SFF-8431. The LMH1226RTWR achieves this using adaptive frequency acquisition and jitter-tolerant CDR architecture, delivering ≤0.15 UI output jitter even with high-input-jitter waveforms.

What is the function of the LOCK_N pin on the LMH1226RTWR?

The LOCK_N pin on the LMH1226RTWR is an open-drain, 3.3 V–tolerant LVCMOS output that asserts low when the reclocker achieves lock to the input data stream. It is pulled up externally with a 2–5 kΩ resistor to the host logic supply. Crucially, LOCK_N can be reconfigured via register write to serve as an interrupt (INT_N) output - enabling dynamic status reporting in systems using SPI or SMBus control. This dual-role functionality is unique to the LMH1226RTWR and supports both simple hardware monitoring and advanced firmware-driven fault detection.

Can the LMH1226RTWR drive two independent SDI outputs simultaneously?

Yes, the LMH1226RTWR provides true dual-output fanout: OUT0± and OUT1± are independently controllable, each with full 100-Ω differential termination, programmable VOD (410–810 mV_p-p), and de-emphasis. Both outputs can be enabled simultaneously and driven with identical or different configurations - for example, OUT0± set to SMPTE 12G with maximum de-emphasis for long traces, and OUT1± configured for 3G-SDI with lower amplitude for short-board routing. This capability is implemented in hardware and does not require external splitters or buffers - a core design feature of the LMH1226RTWR.