cs5102a Cirrus Logic, Inc., cs5102a Datasheet - Page 16

• Manufacturer Part Number: cs5102a
• Description: 16-bit, 100/20 Khz A/d Converters
• Manufacturer: Cirrus Logic, Inc.

16
3.1
The ability of the CS5101A or the CS5102A to con-
vert accurately to 16-bits clearly depends on the
accuracy of its comparator and DAC. Each device
utilizes an “auto-zeroing” scheme to null errors in-
troduced by the comparator. All offsets are stored
on the capacitor array while in the track mode and
are effectively subtracted from the input signal
when a conversion is initiated. Auto-zeroing en-
hances power supply rejection at frequencies well
below the conversion rate.
To achieve 16-bit accuracy from the DAC, the
CS5101A and CS5102A use a novel self-calibra-
Calibration
tion scheme. Each bit capacitor shown in Figure 3
actually consists of several capacitors in parallel
which can be manipulated to adjust the overall bit
weight. An on-chip microcontroller precisely ad-
justs each capacitor with a resolution of 18 bits.
The CS5101A and CS5102A should be reset upon
power-up, thus initiating a calibration cycle. The
device then stores its calibration coefficients in on-
chip SRAM. When the CS5101A and CS5102A are
in power-down mode (SLEEP low), they retain the
calibration coefficients in memory, and need not be
recalibrated when normal operation is resumed.
CS5101A CS5102A
DS45F6