Data Sheet

AD780

Rev. F | Page 9 of 12

AD780

4

2

6

1

µF

249

Ω

0V

Figure 16. Transient Resistive Load Test Circuit

0mA

10mA

10

µs/DIV

Figure 17. Settling under Transient Resistive Load

The dynamic load may be resistive and capacitive. For example,

the load may be connected via a long capacitive cable. Figure 18

and Figure 19 show the performance of the AD780 driving a

1000 pF, 0 mA to 10 mA load.

AD780

4

2

6

1

µF

249

Ω

0V

1000pF

Figure 18. Capacitive Load Transient Response Test Circuit

0mA

10mA

10

µs/DIV

Figure 19. Settling under Dynamic Capacitive Load

LINE REGULATION

Line regulation is a measure of change in output voltage due to

a specified change in input voltage. It is intended to simulate

worst-case unregulated supply conditions and is measured in

15.0 V.

200

100

0

–100

–200

4

15

10

INPUT VOLTAGE (V)

T = 25

°C

Figure 20. Output Voltage Change vs. Input Voltage

PRECISION REFERENCE FOR HIGH RESOLUTION

5 V DATA CONVERTERS

The AD780 is ideally suited to be the reference for most 5 V

high resolution ADCs. The AD780 is stable under any

capacitive load, has superior dynamic load performance, and its

3.0 V output provides the converter with the maximum

dynamic range without requiring an additional and expensive

buffer amplifier. One of the many ADCs that the AD780 is

suited for is the AD7884, a 16-bit, high speed sampling ADC

(see Figure 21). This part previously needed a precision 5 V

reference, resistor divider, and buffer amplifier to do this

function.