MAX1062
Constraints on sequencing the power supplies and
inputs are as follows:
• Apply AGND before DGND.
• Apply AIN and REF after AV
DD
and AGND
are present.
•DV
DD
is independent of the supply sequencing.
Ensure that digital return currents do not pass through
the analog ground and that return-current paths are low
impedance. A 5mA current flowing through a PC board
ground trace impedance of only 0.05Ω creates an error
voltage of about 250µV, 1LSB error with a 4V full-scale
system.
The board layout should ensure that digital and analog
signal lines are kept separate. Do not run analog and
digital (especially the SCLK and DOUT) lines parallel to
one another. If one must cross another, do so at right
angles.
The ADCs high-speed comparator is sensitive to high-
frequency noise on the AV
DD
power supply. Bypass an
excessively noisy supply to the analog ground plane
with a 0.1µF capacitor in parallel with a 1µF to 10µF
low-ESR capacitor. Keep capacitor leads short for best
supply-noise rejection.
14-Bit, +5V, 200ksps ADC with 10µA Shutdown
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