GS2964 Datasheet, PDF (12/17 Pages) Gennum Corporation – SMPTE 424M, SMPTE 292M and SMPTE 259M compliant

NOTE 2: If the maximum cable length is exceeded (set by the SQ_ADJ pin) and the
device is not in Bypass mode, the CD pin will not be driven low, even if a carrier is
present.
Table 4-1: Mute Input Table
Mute
0
1
Function
SDO and SDO operate normally
SDO and SDO are forced to a steady
state (either high or low)
Table 4-2: CD Output Table
CD
Input Status
0
Valid Input on SDI, SDI pins
1
Input is not valid
4.6 Output Rise/Fall Times
180
160
140
120
100
80
60
40
0 10 20 30 40 50 60 70 80 90 100 110 130 150 170
Cable Length (m)
Figure 4-2: Typical Rise/Fall time for 270Mb/s data rate (VCC=3.3V, room
temperature, 800mV launch swing)
The GS2964 was designed to limit bandwidth as cable length is increased. During 3G
(2.97Gb/s) and HD (1.485Gb/s) operation, the impact of this is minimal on rise and fall
time over the operating range. For SD (270Mb/s), the bandwidth limitation becomes
more significant, particularly at longer cable lengths where a reduction in rise and fall
time is observed. This means that for SD (270Mb/s) operation, rise and fall times slow as
shown in Figure 4-2 above. This is beneficial because at 270Mb/s, one unit interval is
equal to 3.7ns, therefore rise and fall times less than 100ps are not required, and slower
rise and fall times actually help to reduce EMI.
GS2964 Adaptive Cable Equalizer
Data Sheet
51913 - 3
March 2010
12 of 17