LMH0346SQ NSC [National Semiconductor], LMH0346SQ Datasheet - Page 10

• Manufacturer Part Number: LMH0346SQ
• Description: 3 Gbps HD/SD SDI Reclocker with Dual Differential Outputs
• Manufacturer: NSC [National Semiconductor]

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LOCK DETECT
SD/HD
The SD/HD output indicates whether the LMH0346 is pro-
cessing 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
X
0
1
0
1
OUTPUT MUTE
LOCK DETECT
LOCK DETECT
1
1
0
BYPASS/AUTO BYPASS
FIGURE 3. SDI, Lock Detect, and SD/HD Timing
TABLE 2. Control Functionality
X
X
X
0
0
10
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
is only valid when the PLL is locked and the Lock Detect out-
put 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 as-
sertion or deassertion due to a data rate change on SDI. See
Figure 3
tween SDI, Lock Detect, and SD/HD.
for a timing diagram showing the relationship be-
DEVICE STATUS
20215005