SDI

270 MBPS DATA

NO DATA

T2

1485 MBPS DATA

2970 MBPS DATA

270 MBPS DATA

T1

TACQ

T2

T2

SDI

270 MBPS DATA

NO DATA

Lock

Detect

SD/HD

T2

NO DATA

1485 MBPS DATA

NO DATA

T2

Lock

Detect

SD/HD

TACQ = Acquisition Time, defined in the AC Electrical Characteristics Table

T1 = Time from Lock Detect assertion or deassertion until SD/HD output is valid, typically 37 ns (one 27 MHz clock period)

T2 = Time from SDI input change until Lock Detect de-assertion, 1 ms maximum. SD/HD output is not valid during this time.

T1

TACQ

T1

TACQ

TACQ

T1

TACQ

T1

T1

TACQ

T1

T1

LMH0346

SNLS248J – APRIL 2007 – REVISED APRIL 2013

www.ti.com

SD/HD

The SD/HD output indicates whether the LMH0346 is processing SD or HD / 3 Gbps data rates. It may be used

to control another device such as the LMH0302 cable driver. When this output is high it indicates that the data

rate is 270 Mbps. When low, the indicated data rate is 1483, 1485, 2967, or 2970 Mbps. The SD/HD output is a

registered function and is only valid when the PLL is locked and the Lock Detect output is high. When the PLL is

not locked (the Lock Detect output is low), the SD/HD output defaults to HD (low). The SD/HD output is

undefined for a short time after lock detect assertion or deassertion due to a data rate change on SDI. See

Figure 5 for a timing diagram showing the relationship between SDI, Lock Detect, and SD/HD.

Figure 5. SDI, Lock Detect, and SD/HD Timing

SCO_EN

Input SCO_EN enables the SCO/SDO2 differential output to function either as a serial clock or second serial

data output. SCO/SDO2 functions as a serial clock when SCO_EN is high. This pin has an internal pull-down

device. The default state (low) enables the SCO/SDO2 output as a second serial data output.

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