GS2962 Datasheet, PDF (58/82 Pages) Gennum Corporation – Integrated Narrow-Bandwidth PLL

DUT
GS2962
ORL
Matching
Network
Measuring Device
1m Belden 1694A 75Ω
BNC
Coaxial Cable
BNC
75Ω
Resistive
Load
Figure 4-20: ORL Matching Network, BNC and Coaxial Cable Connection
4.9.1 Output Signal Interface Levels
The Serial Digital Output signals (SDO and SDO pins), of the device meet the amplitude
requirements as defined in SMPTE 424M for an unbalanced generator (single-ended).
The signal amplitude is controlled to better than +/-7% of the nominal level defined in
SMPTE 424M, when an external 750Ω 1% resistor is connected between the RSET pin of
the device and VCC.
The output signal amplitude can be reduced to less than 1/10th of the nominal
amplitude, defined above, by increasing the value of the resistor connected between the
RSET pin of the device and VCC.
These requirements are met across all ambient temperature and power supply
operating conditions described in the Electrical Characteristics on page 15.
The output amplitude of the GS2962 can be adjusted by changing the value of the RSET
resistor as shown in Table 4-8. For a 800mVp-p output a value of 750Ω is required. A
±1% SMT resistor should be used.
The RSET resistor is part of the high speed output circuit of the GS2962. The resistor
should be placed as close as possible to the RSET pin. In addition, an anti-pad should be
used underneath the resistor.
Table 4-8: R_SET Resistor Value vs. Output Swing
R_SET Resistor Values (Ω)
995
824
750
680
Output Swing (mV_p-p)
608
734
800
884
4.9.2 Overshoot/Undershoot
The serial digital output signal overshoot and undershoot is controlled to be less that 7%
of the output signal amplitude, when operating as an unbalanced generator
(single-ended).
This requirement is met for nominal signal amplitudes as defined by SMPTE 292.
GS2962 3G/HD/SD-SDI Serializer with Complete
SMPTE Video Support
Data Sheet
48005 - 7
October 2010
58 of 82