Texas Instruments LMH0318RTWR

Overview

LMH0318RTWR from Texas Instruments is a 3 Gbps HD/SD SDI reclocker with integrated 75 Ω and 100 Ω cable drivers, supporting SMPTE-424 (2.97 Gbps), SMPTE-292 (1.485 Gbps), SMPTE-259M (270 Mbps), and DVB-ASI standards. It features reference-free CDR with <5 ms lock time, dual differential inputs (IN0±/IN1±) with 100 Ω termination and 4.7 µF AC coupling, and dual outputs: 75 Ω CML OUT0± and 100 Ω differential OUT1± - used in broadcast video routers and digital video processing equipment.

For engineers reviewing the LMH0318RTWR datasheet, LMH0318RTWR pinout, LMH0318RTWR application, or LMH0318RTWR equivalent, key selection criteria include its multi-rate CDR lock capability across 270 Mbps–2.97 Gbps, programmable CTLE for FR4 trace loss compensation, eye monitor for real-time signal integrity validation, and SPI/SMBus configurability without external loop filter components.

Technical Context

The LMH0318RTWR implements a reference-free clock-and-data recovery architecture using a phase-frequency detector (PFD), charge pump (CP), and voltage-controlled oscillator (VCO) to achieve automatic rate detection and sub-5-ms lock across SMPTE-compliant data rates. Its dual-input 2:1 multiplexer selects between IN0± or IN1±, each with dedicated 100 Ω on-chip termination and configurable continuous-time linear equalizer (CTLE) offering 256 boost settings per channel.

Output path flexibility includes independent control of 75 Ω CML OUT0± (SMPTE-compliant launch amplitude: 720–880 mV_P-P) and 100 Ω differential OUT1± (600 mV_P-P, de-emphasis up to −9 dB), both supporting simultaneous 1:2 fanout. Real-time non-disruptive eye monitoring and loss-of-signal (LOS) interrupt generation via LOS_INT_N enable field-tunable system diagnostics.

Key Specifications

Pinout & Package

LMH0318RTWR is housed in a 4 mm × 4 mm, 24-pin WQFN package (RTWA0024A) with exposed thermal pad (DAP) requiring ≥5 vias to ground. Pin functions are mode-dependent (SPI vs SMBus); MODE_SEL pin configures interface protocol.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMH0318RTWR, LMH1218RTWR offers higher bandwidth and drop-in upgrade path, while GS2971-IBE3 provides lower power and simpler integration at the expense of diagnostic features and output versatility.

Availability

LMH0318RTWR is available at Aetrix Electronics and suitable for broadcast video routers, digital video processing equipment, and DVB-ASI distribution amplifiers requiring stable component supply across extended product lifecycles.

Supply support for LMH0318RTWR 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 and embedded processing technologies, with leadership in high-speed interface and video infrastructure solutions.

The LMH0318RTWR belongs to TI's high-speed serial video interface product line, designed specifically for SMPTE-compliant broadcast equipment requiring jitter-cleaning, media-flexible output drive, and field-serviceable diagnostics.

FAQ

What data rates does the LMH0318RTWR support?

The LMH0318RTWR supports SMPTE-259M (270 Mbps), SMPTE-292 (1.485 Gbps), SMPTE-424 (2.97 Gbps), and DVB-ASI rates. It automatically detects and locks to any of these without external reference clocks, with tolerance within ±1000 ppm. The CDR achieves lock in under 5 ms across all supported rates, making LMH0318RTWR suitable for dynamic broadcast routing where rapid source switching is required.

How does the LMH0318RTWR handle input signal loss?

The LMH0318RTWR integrates dual independent loss-of-signal (LOS) detectors - one per input (IN0 and IN1). Each has programmable assert/de-assert thresholds (e.g., 22 mV_P-P assert, 16 mV_P-P de-assert at 2.97 Gbps). When signal drops below threshold, LOS_INT_N asserts low, triggering an interrupt. ENABLE pin can be configured to auto-power-down LMH0318RTWR until valid signal returns, reducing power in idle states.

Can the LMH0318RTWR drive both coaxial and differential PCB traces simultaneously?

Yes. LMH0318RTWR provides two independent outputs: OUT0± is a 75 Ω CML driver compliant with SMPTE ST 424/292/259M for coaxial cable, while OUT1± is a 100 Ω differential output optimized for FR4 PCB traces. Both can operate simultaneously in 1:2 fanout mode, enabling hybrid media routing - e.g., sending cleaned video to a monitor via coax (OUT0) and to an FPGA processor via differential pair (OUT1) - without external splitters or level shifters.

What is the purpose of the eye monitor in the LMH0318RTWR?

The LMH0318RTWR includes a non-disruptive eye monitor that samples the reclocked serial data stream in real time to generate a visual representation of the eye diagram. This allows system designers and field technicians to validate signal integrity during startup or troubleshooting without interrupting video flow. Threshold violations trigger LOS_INT_N, and the monitor supports adjustable thresholds - a feature unique to LMH0318RTWR among pin-compatible reclockers.

How is the LMH0318RTWR configured - SPI or SMBus?

Configuration interface is selected via the MODE_SEL pin: tie to VDD (1 kΩ) for SPI mode (using SS_N, SCK, MOSI, MISO), or to GND (1 kΩ) for SMBus mode (using SCL, SDA, ADDR0/1). Both modes support full register access for CTLE programming, input selection, output enable, and interrupt control. SPI supports up to 20 MHz clocking; SMBus operates at 100–400 kHz and allows up to 16 device addresses on shared bus - choice depends on host controller capability and system bus architecture.