Texas Instruments LMH1218RTWR

Overview

LMH1218RTWR from Texas Instruments is a dual-input, dual-output SMPTE/10GbE reclocker IC with integrated CDR, CTLE equalization, and eye monitoring. It supports data rates from 270 Mbps to 11.88 Gbps (SMPTE) or 10.3125 Gbps (10GbE), features programmable input/output routing, and delivers real-time horizontal/vertical eye opening measurements. It is used in broadcast video infrastructure for signal regeneration across coaxial or backplane links.

For engineers reviewing the LMH1218RTWR datasheet, LMH1218RTWR pinout, LMH1218RTWR application, or LMH1218RTWR equivalent, this page provides verified technical context, confirmed register-level configuration logic, validated pin functions, exact SMPTE/10GbE rate-locking behavior, and engineering-grade alternatives for broadcast timing and serial digital interface reclocking.

Technical Context

The LMH1218RTWR implements a fully configurable Clock Data Recovery (CDR) engine with independent receiver channel control, supporting automatic or selective lock to SMPTE ST-259/292/424/2082-1 and IEEE 802.3ae 10GbE standards. Its CTLE compensates up to 27 dB loss at 6 GHz, with boost settings programmable via register 0x03 for FR4 trace lengths up to 30 inches.

It integrates an on-chip Eye Opening Monitor (EOM) that captures 64×64 voltage-phase histograms of the post-equalized waveform, enabling direct HEO (in UI) and VEO (in mV) calculation. Configuration is performed via SMBus (400 kHz max) or SPI (20 MHz max), with MODE_SEL pin selecting interface mode and ADDR0/ADDR1 strapping SMBus address.

Key Specifications

Pinout & Package

LMH1218RTWR is housed in a 32-pin QFN package (5 mm × 5 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are validated per TI SNLS474 datasheet and SNLU174B programming guide.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMH1218RTWR, LMH1228RTWR removes input selection and dual-output routing but retains identical jitter performance and diagnostic capability, while MAX3798ETJ+ offers lower cost for fixed-rate use cases at the expense of SMPTE/10GbE adaptability and real-time eye analytics.

Availability

LMH1218RTWR is available at Aetrix Electronics and suitable for broadcast video infrastructure, IP media gateways, SMPTE-compliant switchers, and 10GbE optical transport interfaces requiring stable component supply and long-term design-in support.

Supply support for LMH1218RTWR 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 for industrial, automotive, and communications markets.

The LMH1218RTWR belongs to TI's high-speed serial interface product line, engineered specifically for broadcast video and professional media applications demanding SMPTE multi-rate reclocking, deterministic jitter suppression, and real-time link diagnostics.

FAQ

What data rates does the LMH1218RTWR support in SMPTE mode?

The LMH1218RTWR supports SMPTE ST-259 (270 Mbps), ST-292 (1.485 Gbps), ST-424 (2.97 Gbps), ST-2081 (5.94 Gbps), and ST-2082-1 (11.88 Gbps) in automatic or selectively enabled configurations. Rate selection is controlled via bits [4:0] of register 0xA0, allowing lock restriction to optimize acquisition time. The LMH1218RTWR achieves sub-100 ns lock time when configured for a single target rate.

How is CTLE boost configured for different PCB trace lengths on the LMH1218RTWR?

CTLE boost on the LMH1218RTWR is set via register 0x03, with values ranging from 0x00 (4.9 dB @ 3 GHz) to 0x94 (16.2 dB @ 3 GHz). For example, 15-inch FR4 traces require 0x50 (10.9 dB @ 3 GHz), while 30-inch traces need 0x94. The LMH1218RTWR includes a CTLE test mode (enabled via registers 0x2D/0x2C/0x3E) that automatically determines the optimal setting at the highest operating data rate and writes it to register 0x03 for deployment.

Can the LMH1218RTWR output both reclocked data and a recovered clock simultaneously?

Yes-the LMH1218RTWR supports independent output configuration: OUT0 (75 Ω) and OUT1 (50 Ω) can be set to different modes via register 0x1C. For instance, OUT0 can deliver reclocked SMPTE data while OUT1 outputs a recovered 297 MHz clock (for ≤3 Gbps locked rates) or full-rate clock (for >3 Gbps). This is implemented using the 2-bit field in bits [3:2] of register 0x1C, with mode 0b01 explicitly assigning OUT0 to reclocked data and OUT1 to clock.

What is the function of the Eye Opening Monitor (EOM) in the LMH1218RTWR?

The EOM in the LMH1218RTWR captures a 64×64 histogram of the post-equalized waveform's voltage and phase distribution across one unit interval. It directly measures Horizontal Eye Opening (HEO) and Vertical Eye Opening (VEO): HEO = reg0x27 decimal ÷ 64 (yielding UI), and VEO = reg0x28 decimal × 3.125 mV. This provides quantitative, real-time signal integrity feedback without external sampling oscilloscopes-critical for automated diagnostics in broadcast equipment.

How does the LMH1218RTWR handle loss-of-signal (LOS) conditions?

The LMH1218RTWR monitors LOS independently on IN0 and IN1 using dedicated signal detectors. When LOS is asserted on the selected input, the CDR, equalizer, and output drivers enter low-power state automatically. Software can force LOS de-assertion via registers 0x14 (IN0) or 0x15 (IN1) to simulate signal presence and maintain powered-up operation-even with no physical input-enabling controlled diagnostics and test mode activation without hardware stimulus.