AD580

Rev. B | Page 7 of 8

THE AD580 AS A LOW POWER, LOW VOLTAGE,

PRECISION REFERENCE FOR DATA CONVERTERS

The AD580 has a number of features that make it ideally suited

for use with A/D and D/A data converters used in complex

microprocessor-based systems. The calibrated 2.500 V output

minimizes user trim requirements and allows operation from a

single, low voltage supply. Low power consumption (1 mA

quiescent current) is commensurate with that of CMOS-type

devices, while the low cost and small package complements the

decreasing cost and size of the latest converters.

Figure 12 shows the AD580 used as a reference for the AD7542

12-bit CMOS DAC with complete microprocessor interface.

The AD580 and the AD7542 are specified to operate from a

single 5 V supply, thus eliminating the need to provide a 15 V

power supply for the sole purpose of operating a reference. The

AD7542 includes three 4-bit data registers, a 12-bit DAC

register, and address decoding logic. It may thus be interfaced

directly to a 4-, 8- or 16-bit data bus. Only 8 mA of quiescent

current from the single 5 volt supply is required to operate the

AD7542 which is packaged in a small, 16-pin DIP. The AD544

output amplifier is also low power, requiring only 2.5 mA

quiescent current. Its laser-trimmed offset voltage preserves the

±1/2 LSB linearity of the AD7542KN without user trims, and it

typically settles to ±1/2 LSB in less than 3 µs. It will provide the

0 V to –2.5 V output swing from ±5 V supplies.

7

D0

6

D1

5

D2

4

D3

AD7542

CLR

13

FROM SYSTEM RESET

FROM ADDRESS BUS

A0

10

A0

A1

11

A1

WR

9

FROM WR

CS

812

3

15

14

16

1

2

FROM ADDRESS DECODER

AD7

AD0

SYSTEM

8-BIT DATA BUS

AD544L

DGND

–5V

ANALOG

INPUT

AGND

RFB

22pF

200

Ω

500

Ω

GAIN

ADJUST

+E

+5V

–E

AD580

Figure 12. Low Power, Low Voltage Reference for the AD7542

Microprocessor-Compatible, 12-Bit DAC