Datasheet

Data Sheet AD780
APPLYING THE AD780
analog.com Rev. J | 9 of 12
Figure 16. Transient Resistive Load Test Circuit
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.
Figure 18. Capacitive Load Transient Response Test Circuit
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 µV/V.
Figure 20 shows typical performance with 4.0 V < V
IN
< 15.0 V.
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.