LMH0394_15 Datasheet, PDF (10/35 Pages) Texas Instruments – 3G HD/SD SDI Low Power Extended Reach Adaptive Cable Equalizer

LMH0394
SNLS312M – AUGUST 2010 – REVISED JULY 2015
7 Detailed Description
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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.
SDI
SDI
Equalizer
Filter
DC
Restoration/
Level Control
Output
Driver
BYPASS
SDO
SDO
CD
Carrier
Detect
Energy
Detect
Energy
Detect
MUTE_REF
$
MUTE_REF
Automatic
Equalization
Control
De-Emphasis
Control
SPI Control
AEC+ AEC-
AUTO SLEEP
Figure 6. Functional Block Diagram (Pin Mode)
MUTE
SPI_EN
10
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