GS9075B View Datasheet(PDF) - Semtech Corporation

Part Name

Description

Manufacturer

GS9075B

HD-LINX® II Multi-Rate SDI Automatic Reclocker

Semtech Corporation 

4.6 4:1 Input Mux

The 4:1 input mux allows the connection of four independent streams of video/data.

There are four differential inputs (DDI[3:0] and DDI[3:0]). The active channel can be

selected via the DDI_SEL[1:0] pins. Table 4-1 shows the input selected for a given state

at DDI_SEL[1:0].

Table 4-1: Bit Pattern for Input Select

DDI_SEL[1:0]

00

01

10

11

Selected Input

DDI0

DDI1

DDI2

DDI3

The DDI inputs are designed to be DC interfaced with the output of the GS1524A/9064A

Cable Equalizer. There are on chip 50Ω termination resistors which come to a common

point at the DDI_VT pins. Connect a 10nF capacitor to this pin and connect the other end

of the capacitor to ground. This terminates the transmission line at the inputs for

optimum performance.

If only one input pair is used, connect the unused positive inputs to +3.3V and leave the

unused negative inputs floating. This helps to eliminate crosstalk from potential noise

that would couple to the unused input pair.

4.7 Automatic and Manual Data Rate Selection

The GS1575B/9075B can be configured to manually lock to a specific data rate or

automatically search for and lock to the incoming data rate. The AUTO/MAN pin selects

automatic data rate detection mode (Auto mode) when HIGH and manual data rate

selection mode (Manual mode) when LOW.

In Auto mode, the SS[2:0] bi-directional pins become outputs and the bit pattern

indicates the data rate that the PLL is locked to (or previously locked to). The "search

algorithm" cycles through the data rates and starts over if that data rate is not found (see

Figure 4-3).

POWER-UP

143 Mb/s

177 Mb/s

270Mb/s

360 Mb/s

1.485Mb/s

(GS1575B only)

Figure 4-3: Data Rate Search Pattern

GS1575B / GS9075B HD-LINX® II Multi-Rate SDI

Automatic Reclocker

Data Sheet

40063 - 1

June 2009

540 Mb/s

19 of 28

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