GS2985 datasheet(24/45 Pages) SEMTECH

24 / 45 page

GS2985 Multi-Rate SDI Reclocker with Equalization &

De-emphasis

Data Sheet

36663 - 5

July 2012

24 of 45

Proprietary & Confidential

When DEn_EN is set LOW or left unconnected, the de-emphasis for output n is OFF. When HIF

is HIGH, these DE_EN controls select between OFF and a setting that compensates for roughly

five inches of trace.

All other settings are available only via the host interface.

When a DEn_EN pin is tied HIGH, the output de-emphasis for output n is ON.

The default de-emphasis setting upon power-up is 0dB (OFF).

NOTE: Changing the de-emphasis setting will vary both V1 & V2 (see Figure 4-2).

Figure 4-2: De-emphasis Waveform

4.10 Automatic and Manual Data Rate Selection

The GS2985 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[1:0] bi-directional pins become outputs and the bit pattern indicates the

data rate at which the PLL is currently locked to (or previously locked to). The search algorithm

Table 4-7: Output De-emphasis

DEn_EN pin

Status of Output n

HIGH

Output De-emphasis

LOW

Output De-emphasis

OFF

-V1

-V2

Tx signal after de-emphasis

11110000 pattern

268

269

270

271

272

273

274

275

-0.6

-0.4

-0.2

0.2

0.4

0.6

De-emphasis (dB)

=20 log (V1/V2)

GS2985 Datasheet(PDF) 24 Page - Semtech Corporation

GS2985 Datasheet(HTML) 24 Page - Semtech Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

Datasheet Download

Link URL