ADC12281 datasheet(4/16 Pages) NSC

4 / 16 page

Pin Descriptions and Equivalent Circuits (Continued)

Symbol

Equivalent Circuit

Description

IN COM

Analog input common. Connect to a quiet point in

analog ground near the driving device. See Section

1.2.

Positive analog supply pin. Connect to a clean,

quiet voltage source of +5V. V

A and VD should

have a common supply and be separately

bypassed witha5µFto10µF capacitor and a

0.1 µF chip capacitor.

4, 6

AGND

The ground return for the analog supply, AGND and

DGND should be connected together close to the

ADC12281 package. See Section 5.0.

Positive digital supply pin. Connect to a clean, quiet

voltage source of +5V. V

A and VD should have a

common supply and be separately bypassed with a

5 µF to 10 µF capacitor and a 0.1 µF chip

capacitor.

9, 12

DGND

The ground return for the digital supply. AGND and

DGND should be connected together close to the

ADC12281 package. See Section 5.0.

D I/O

The digital output driver supply pins. This pin can

be operated from a supply voltage of 3V to 5V, but

the voltage on this pin should never exceed the V

supply pin voltage. See Section 3.4.

DGND I/O

The ground return for the digital output drivers. This

pin should be returned to a point in the digital

ground that is removed from the other ground pins

of the ADC12281.

ADC12281 Datasheet(PDF) 4 Page - National Semiconductor (TI)