Datasheet

AD9252 Data Sheet

Rev. E | Page 26 of 52

External Reference Operation

The use of an external reference may be necessary to enhance

the gain accuracy of the ADC or improve thermal drift charac-

teristics. Figure 54 shows the typical drift characteristics of the

internal reference in 1 V mode.

When the SENSE pin is tied to AVDD, the internal reference is

disabled, allowing the use of an external reference. The external

reference is loaded with an equivalent 6 kΩ load. An internal

reference buffer generates the positive and negative full-scale

references, REFT and REFB, for the ADC core. Therefore, the

external reference must be limited to a nominal voltage of 1.0 V.

0.02

–0.18

–0.14

–0.10

–0.06

–0.02

–0.16

–0.12

–0.08

–0.04

–40

VREF ERROR (%)

TEMPERATURE (°C)

06296-060

–20 0 20 40 60 80

Figure 54. Typical VREF Drift