AD7986

Rev. B | Page 8 of 28

Pin No.

Mnemonic

Type1

Description

16

AVDD

P

Input Analog Power. Nominally at 2.5 V.

17,18

AGND

P

Analog Power Ground.

19

BVDD

P

Reference buffer power. Nominally 5.0 V.

If an external reference buffer is used to achieve the maximum SNR performance with 5 V reference,

the reference buffer must be powered down by connecting the REFIN pin to ground. The external

reference buffer must be connected to the BVDD pin.

20

REFIN

AI/O

Internal Reference Output/Reference Buffer Input.

When PDREF = low, the internal band gap reference produces a 1.2 V (typical) voltage on this pin,

which needs external decoupling (0.1 µF typical).

When PDREF = high, use an external reference to provide a 1.2 V (typical) to this pin.

When PDREF = high, and REFIN = low, the on-chip reference buffer and band gap are powered down.

An external reference must be connected to REF and BVDD.

21 (EPAD)

Exposed Pad

EP

The exposed pad is not connected internally. For increased reliability of the solder joints, it is

recommended that the pad be soldered to the system ground plane.