GS2964 Adaptive Cable Equalizer

Data Sheet

51913 - 3

March 2010

12 of 17

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.

4.6 Output Rise/Fall Times

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.

Table 4-1: Mute Input Table

Mute

Function

0

SDO and SDO operate normally

1

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

40

60

80

100

120

140

160

180

0

10 20 30 40 50 60 70 80 90 100 110

130

150

170

Cable Length (m)