GS2960 Datasheet, PDF (29/97 Pages) Semtech Corporation – 3Gb/s, HD, SD SDI Receiver Complete with SMPTE Video Processing

Table 4-2: PLL Loop Bandwidth
Input Data Rate
LB_CONT Pin Connection
SD
3.3V
Floating
0V
HD
3.3V
Floating
0V
3G
3.3V
Floating
0V
1_{Measured with 0.2UI input jitter applied}
Loop Bandwidth (MHz)¹
0.135
0.27
0.54
0.75
1.5
3.0
1.5
3.0
6.0
4.6 External Crystal/Reference Clock
The GS2960 requires an external 27MHz reference clock for correct operation. This
reference clock is generated by connecting a crystal to the XTAL1 and XTAL2 pins of the
device. See Application Reference Design on page 92. Table 4-3 shows XTAL
characteristics.
Alternately, a 27MHz external clock source can be connected to the XTAL1 pin of the
device, as shown in Figure 4-3.
The frequency variation of the crystal including aging, supply and temperature
variation should be less than +/-100ppm.
The equivalent series resistance (or motional resistance) should be a maximum of 50Ω.
The external crystal is used in the frequency acquisition process. It has no impact on the
output jitter performance of the part when the part is locked to incoming data. Because
of this, the only key parameter is the frequency variation of the crystal that is stated
above.
GS2960 3Gb/s, HD, SD SDI Receiver Complete with
SMPTE Video Processing
Data Sheet
48003 - 6
September 2012
29 of 97