GX4002 Datasheet, PDF (21/74 Pages) Gennum Corporation – Dynamic on-chip power management control

Table 3-4: Typical Loop Bandwidths for Various Register Settings (Continued)
CH1PLLLBWMULT CH1PLLLBWCURVT CH1PLLLBWCURVBE
10
11111
10110
11
11000
11000
Loop
Bandwidth
13MHz
22.7MHz
3.3.4 Pre-Emphasis Driver with Auto-Mute
The channel 1 driver is a pre-emphasis driver that can be used to compensate for losses
in the connector and trace between the module and ASIC. The pre-emphasis can
compensate for up to 6dB of loss. The output swing can be set from 100mV to 800mV in
steps of 50mV through the CH1SDOSWING[3:0] register. The pre-emphasis amplitude
can be varied from 0dB to 6dB in eight non-linear steps through CH1SDOPECTRL[4:2].
Register Name
CH1SDO_REG1
CH1SDO_REG2
Register
Address^d
77
78
Parameter Name
CH1SDOSWING
CH1SDOPECTRL
Bit
Position
Access
3:0
RW
4:2
RW
Reset Value^b
1010
000
Valid
Range^d
Function
Driver swing.
0-15
0-15: 100-850mVppd, Default = 10: 600mV
Pre-emphasis amplitude.
0-7
0: 0dB, 7: 6dB for 200mVppd swing.
Ch1 signal after Pre-emphasis
0.6
V1
0.4
Pre-emphasis
0.2
V2
0.0
-V2
-0.2
-0.4
-0.6 ^{11110000 pattern}
-V1
268
269
270
271
272
273
274
275
UI
Figure 3-4: Pre-Emphasis Waveform Description
Figure 3-4 above shows the pre-emphasis waveform. Amplitudes V1, V2 and
pre-emphasis in dB are defined as follows:
GX4002 2x2 14.025Gb/s Crosspoint Switch with Trace
Equalization and Output De-Emphasis
Data Sheet
55972 - 0
March 2012
21 of 74
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