GS6042 Datasheet, PDF (12/21 Pages) Semtech Corporation – 6G UHD-SDI/3G/HD/SD Adaptive Cable Equalizer

Table 4-1: Typical Common Mode Output Voltage Levels (V_CMOUT)
Supply
Voltage
(VCC_O)
Termination Type 1 (See Figure 4-1) (See 1)
425mV_ppd Swing
850mV_ppd Swing
3.3V
3.19V
2.5V
2.39V
1.8V
1.69V
3.09V
2.29V
1.59V
1.2V
1.09V
0.99V
Note:
1. The values shown for termination type 1 only apply when V_TERM = VCC_O
Termination Type 2 (See Figure 4-2)
425mV_ppd Swing
3.09V
2.29V
1.59V
0.99V
850mV_ppd Swing
2.88V
2.08V
1.38V
0.78V
GS6042 VCC_O
VV
TERM TERM
50Ω
50Ω
50Ω 50Ω
DDO
50Ω
DDO
50Ω
GS6042 VCC_O
50Ω
50Ω
DDO
50Ω
DDO
50Ω
100Ω
Figure 4-1: 50Ω Termination to V_TERM
Figure 4-2: 100Ω Parallel Output Termination
4.4 Programmable Squelch Adjust (SQ_ADJ)
The GS6042 features a programmable Squelch Adjust (SQ_ADJ) threshold.
This feature can be useful in applications where there are multiple input channels using
the GS6042 and the maximum gain of each device must be limited to avoid crosstalk.
The SQ_ADJ pin acts to change the threshold of the Carrier Detect (CD) pin. When the
input signal level drops below the threshold set by SQ_ADJ, the CD pin will be driven
HIGH, indicating that there is not a valid input signal.
This feature has been designed for use in applications such as routers, where signal
crosstalk and circuit noise cause the equalizer to output erroneous data when no input
signal is present. The use of a Carrier Detect function with a fixed internal reference does
not solve this problem since the signal-to-noise ratio on the circuit board could be
significantly less than the default signal detection level set by the on-chip reference.
In applications where programmable squelch adjust is not required, the SQ_ADJ pin can
be left unconnected.
Note: When using SQ_ADJ to limit the maximum gain of the GS6042, CD should not be
connected to SLEEP.
GS6042
Final Data Sheet
PDS-060055
Rev. 3
May 2014
www.semtech.com
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