CS5101A CS5102A
cies. The proprietary architecture of the CS5101A
and CS5102A avoids applying the input voltage
across a sampling switch, thus avoiding any “aper-
ture window” effects. The second type of aperture
jitter, due to component noise, assumes a random
nature. With only 100 ps peak-to-peak aperture jit-
ter, the CS5101A and CS5102A can process full-
scale signals up to 1/2 the throughput frequency
without significant errors due to aperture jitter.
90
80
70
60
50
40
30
20
1 kHz
10 kHz 100 kHz
1 MHz
Power Supply Ripple Frequency
Figure 25. Power Supply Rejection
7.6 Power Supply Rejection
The power supply rejection performance of the
CS5101A and CS5102A is enhanced by the on-
chip self-calibration and an “auto-zero” process.
Drifts in power supply voltages at frequencies less
than the calibration rate have negligible effect on
the device's accuracy. This is because the
CS5101A and CS5102A adjust their offset to within
a small fraction of an LSB during calibration. Above
the calibration frequency the excellent power sup-
ply rejection of the internal amplifiers is augmented
by an auto-zero process. Any offsets are stored on
the capacitor array and are effectively subtracted
once conversion is initiated. Figure 25 shows pow-
er supply rejection of the CS5101A and CS5102A
in the bipolar mode with the analog input grounded
and a 300 mV p-p ripple applied to each supply.
Power supply rejection improves by 6 dB in the un-
ipolar mode.
32
DS45F6