GX4002 Datasheet, PDF (41/74 Pages) Gennum Corporation – Dynamic on-chip power management control

Table 3-5: ADC Clock Rate (Continued)
ADCCLKRATE[2:0]
010
011
100
101
110
111
ADC Sampling Clock Rate
(MHz)
2.1
2.7
3.3
3.9
4.4
5
ADC Conversion Time
(μs) Res = 10 bits
477
377
311
265 (default)
231
205
The following registers are used to control the conversion, and read-out the converted
data:
Register Name
ADC_REG3
ADC_REG4
ADC_REG5
ADC_REG6
Register
Address^d
145
146
147
148
PWRDN_REG2
161
Parameter Name
ADCSTARTCONV
ADCDONECONV
ADCOUTLO
ADCOUTHI
PDTEMPSENSOR
PDSUPPLYSENSOR
PDADC
Bit Position
0:0
0:0
7:0
7:0
3:3
4:4
5:5
Access
RW
RO
RO
RO
RW
RW
RW
Reset Value^b
0
0
00000000
00000000
1
1
1
Valid Range^d
Function
0-1
0-1
0-255
0-255
0-1
0-1
0-1
ADC starts conversion.
ADC conversion done flag.
ADC output LOW MSB.
ADC output HIGH MSB.
When HIGH, power-down the
temperature sensor.
When HIGH, power-down the supply
sensor.
When HIGH, power-down the ADC.
3.7.1.3 ADC Offset Calibration
The ADC supports conversion of several different sources. Each source can have a
different offset associated with it. To allow accurate conversion for each source, it is
recommended that the offset be calibrated for each source, so that the appropriate
correction can be applied when converting a given source.
There are two steps involved in the calibration of offsets:
1. Offset measurement.
2. Offset correction.
3.7.1.3.1 OFFSET MEASUREMENT
Offset measurement of any source requires zeroing-out the source, such that its output
constitutes the offset only. With the source zeroed-out, the output of the ADC is then the
cumulative offset. This offset is subtracted from subsequent measurements of the same
source to get an accurate offset corrected conversion.
GX4002 2x2 14.025Gb/s Crosspoint Switch with Trace
Equalization and Output De-Emphasis
Data Sheet
55972 - 0
March 2012
41 of 74
Proprietary & Confidential