SDI

143 MBPS DATA

NO DATA

270 MBPS DATA

1485 MBPS DATA

270 MBPS DATA

SDI

270 MBPS DATA

NO DATA

Lock

Detect

SD/HD

NO DATA

1485 MBPS DATA

NO DATA

Lock

Detect

SD/HD

LMH0056

www.ti.com

SNLS236C – AUGUST 2006 – REVISED APRIL 2013

Table 3. Control Functionality

LOCK DETECT

OUTPUT MUTE

BYPASS/AUTO BYPASS

DEVICE STATUS

0

1

0

PLL unlocked, reclocker bypassed

1

1

0

PLL locked to supported data rate, reclocker not bypassed

X

0

X

Outputs muted

0

LOCK DETECT

X

Outputs muted

1

LOCK DETECT

0

PLL locked to supported data rate, reclocker not bypassed

1

LOCK DETECT

1

PLL locked to supported data rate, reclocker bypassed

X

1

1

Outputs not muted, reclocker bypassed

SD/HD

The SD/HD output indicates whether the LMH0056 is processing SD or HD data rates. It may be used to control

another device such as the LMH0002 cable driver. When this output is high it indicates that the data rate is 270

Mbps (or 143 Mbps). When low, the indicated data rate is 1483 or 1485 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 de-assertion due to a data rate change on SDI. See Figure 4 for a timing

diagram showing the relationship between SDI, Lock Detect, and SD/HD.

Figure 4. SDI, Lock Detect, and SD/HD

Copyright © 2006–2013, Texas Instruments Incorporated

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