ADR1581

Rev. 0 | Page 10 of 12

USING THE ADR1581 WITH 3 V DATA

CONVERTERS

The ADR1581 is ideal for creating the reference level to use

with 12-bit multiplying DACs, such as the AD7943, AD7945,

and AD7948. In the single-supply bias mode (see Figure 25), the

than 0.2 LSBs of additional linearity error results. The buffer amp

eliminates linearity degradation resulting from variations in the

reference level.

The ADR1581 low output drift (50 ppm/°C) and compact

subminiature SOT-23 package make it ideally suited for today’s

high performance converters in space-critical applications.

One family of ADCs for which the ADR1581 is well suited is the

AD7714-3 and AD7715-3. The AD7714/AD7715 are charge-

balancing (∑-Δ) ADCs with on-chip digital filtering intended for

the measurement of wide dynamic range, low frequency signals,

such as those representing chemical, physical, or biological

processes.

DAC

AGND

DGND

A1

C1

3.3V

29.4kΩ

3.3V

ADR1581

SIGNAL GROUND

A1: OP295

AD822

OP2283

A1

AD7943

Figure 24 shows the ADR1581 connected to the

AD7714/AD7715 for 3 V operation.

AD7714-3/AD7715-3

ADR1581

3V

28.7kΩ

REF IN(+)

REF IN(–)

HIGH

IMPEDANCE

>1GΩ

5kΩ (TYP)

(3pF TO 8pF)

SWITCHING

FREQUENCY DEPENDS

ON

Figure 24. Reference Circuit for the AD7714-3/AD7715-3

Figure 25. Single-Supply System