GS1675 datasheet(11/37 Pages) SEMTECH

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GS1675 SD/HD SDI Reclocker

Data Sheet

54174 - 1

June 2011

11 of 37

3. Functional Description

The GS1675 is a multi-standard reclocker for serial digital SDTV signals operating at

270Mb/s, and HDTV signals operating at 1.485Gb/s, 1.485/1.001Gb/s.

3.1 Serial Data Input

The GS1675 features two differential input buffers.

The serial data input signal is connected to the DDI0/DDI0 and DDI1/DDI1 input pins of

the device.

Input signals can be single-ended or differential, DC or AC-coupled.

The input circuit is self-biasing, to allow for simple AC or DC-coupling of input signals to

the device.

The serial digital data inputs are also compatible when DC-coupled with LVPECL or

CML differential outputs from crosspoint switches which operate from 3.3V or 2.5V

supplies. This includes but is not limited to the GS1674 Equalizer.

3.2 Modes of Operation

The GS1675 has two modes of operation: Legacy Mode (HIF = HIGH) and SPI Mode (HIF

= LOW).

In Legacy Mode, chip functions are controlled via pins only, and offers limited control of

input equalization.

In SPI mode, access is gained to extended digital controls like: Bypass, Autobypass,

Auto/Manual selection, Control status inputs or outputs, changes to KBB settings, as well

as access to additional features such as LOS adjustment, polarity invert, auto-mute, etc.

3.3 2:1 Input Mux

The GS1675 incorporates a 2:1 input mux, which allows the connection of two

independent streams of video/data. There are two differential inputs (DDI[1:0] /

DDI[1:0]). The active channel can be selected via the DDI_SEL[1:0] registers as shown in

Table 3-1.

Table 3-1: Input Selection Table

DDI_SEL[1:0]

Selected Input

DDI0*

NOT VALID

DDI1

* Power-up default

GS1675 Datasheet(PDF) 11 Page - Semtech Corporation