Datasheet

Typical Applications (Continued)

Functional Description

1.0 UNDERSTANDING A/D ERROR SPECS

A perfect A/D transfer characteristic (staircase waveform) is

shown in

Figure 1

. The horizontal scale is analog input

voltage and the particular points labeled are in steps of 1

LSB (19.53 mV with 2.5V tied to the V

REF

/2 pin). The digital

output codes that correspond to these inputs are shown as

D−1, D, and D+1. For the perfect A/D, not only will

center-value (A−1, A, A+1, ....)analog inputs produce

the correct output digital codes, but also each riser (the

transitions between adjacent output codes) will be located

⁄

LSB away from each center-value. As shown, the risers

are ideal and have no width. Correct digital output codes will

be provided for a range of analog input voltages that extend

Sampling an AC Input Signal

DS005671-78

Note 11: Oversample whenever possible [keep fs

2f(−60)] to eliminate input frequency folding (aliasing) and to allow for the skirt response of the filter.

Note 12: Consider the amplitude errors which are introduced within the passband of the filter.

70% Power Savings by Clock Gating

DS005671-79

(Complete shutdown takes ≈ 30 seconds.)

Power Savings by A/D and V

REF

Shutdown

DS005671-80

*Use ADC0801, 02, 03 or 05 for lowest power consumption.

Note: Logic inputs can be driven to V

with A/D supply at zero volts.

Buffer prevents data bus from overdriving output of A/D when in shutdown mode.

ADC0801/ADC0802/ADC0803/ADC0804/ADC0805