AEC+

Equalizer

Filter

AEC-

MUTE

DC

Restoration/

Level Control

Automatic

Equalization

Control

SDI

SDI

SDO

SDO

BYPASS

Output

Driver

$

Energy

Detect

Energy

Detect

CD

AUTO SLEEP

Carrier

Detect

SPI_EN

SPI Control

De-Emphasis

Control

LMH0394

SNLS312M – AUGUST 2010 – REVISED JULY 2015

www.ti.com

7 Detailed Description

7.1 Overview

The LMH0394 is a 3 Gbps HD/SD SDI low power extended reach adaptive cable equalizer. It is designed to

equalize data transmitted over cable or any media with similar dispersive loss characteristics. The equalizer

operates over a wide range of data rates from 125 Mbps to 2.97 Gbps and supports ST 424, ST 292, ST 344, ST

259, and DVB-ASI standards. The LMH0394 features design enhancements including longer cable equalization,

lower output jitter, configurable pin mode and SPI modes, a power-saving sleep mode, and programmable output

common-mode voltage and swing. The LMH0394 implements DC restoration to correctly handle pathological

data conditions.

The LMH0394 provides extended cable reach with improved immunity to crosstalk and ultra-low power

consumption. The equalizer includes active sensing circuitry that ensures robust performance and enhanced

immunity to variations in the input signal launch amplitude. The output driver offers programmable de-emphasis

for up to 40” of FR4 trace losses. The LMH0394 includes power management to further reduce power

consumption when no input signal is present.

7.2 Functional Block Diagram

The LMH0394 supports two modes of operation. In pin mode, the LMH0394 operates with control pins to set its

operating state and is footprint compatible with the LMH0384, LMH0344, and legacy SDI equalizers. In SPI

mode, an optional SPI serial interface can be used to access and configure multiple LMH0394 devices in a

daisy-chain configuration.

This allows users to program the output common-mode voltage and swing, output de-emphasis level, input

launch amplitude, and power management settings. Users may also access a cable length indicator and all pin

mode features.

Figure 6. Functional Block Diagram (Pin Mode)

10

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