LMH0056_07 Datasheet, PDF (11/16 Pages) National Semiconductor (TI) – HD/SD SDI Reclocker with 4:1 Input Multiplexer

SERIAL DATA INPUT SELECTOR
The Serial Data Input Selector (SEL [1:0]) allows the user to
select the active input channel. Table 2 shows the input se-
lected for a given state of SEL [1:0].
TABLE 2. Data Input Select Codes
SEL [1:0] Code
Selected Input
00
SDI0
01
SDI1
10
SDI2
11
SDI3
LOCK DETECT
The Lock Detect (LD) output, when high, indicates that data
is being received and the PLL is locked. LD may be connected
to the MUTE input to mute the data and clock outputs when
no data signal is being received. See Table 3.
MUTE
The MUTE input, when low, mutes the serial data and clock
outputs. It may be connected to Lock Detect or externally
driven to mute or un-mute the outputs. If MUTE is connected
to LD, then the data and clock outputs are muted when the
PLL is not locked. This function overrides the Bypass function:
see Table 3. MUTE has an internal pull-up device to enable
the output by default.
BYPASS/AUTO BYPASS
The Bypass/Auto Bypass input, when high, forces the device
to output the data without reclocking it. When this input is low,
the device automatically bypasses the reclocking function
when the device is in an unlocked condition or the detected
data rate is a rate which the device does not support. See
Table 3. BYPASS/AUTO BYPASS has an internal pull-down
device.
TABLE 3. Control Functionality
LOCK DETECT
0
1
X
0
1
1
X
OUTPUT MUTE
1
1
0
LOCK DETECT
LOCK DETECT
LOCK DETECT
1
BYPASS/AUTO BYPASS
0
0
X
X
0
1
1
DEVICE STATUS
PLL unlocked, reclocker bypassed
PLL locked to supported data rate, reclocker not bypassed
Outputs muted
Outputs muted
PLL locked to supported data rate, reclocker not bypassed
PLL locked to supported data rate, reclocker bypassed
Outputs not muted, reclocker bypassed
11
www.national.com