REV. F

AD587

–5–

Output turn-on time is modified when an external noise reduc-

tion capacitor is used. When present, this capacitor acts as an

additional load to the internal Zener diode’s current source,

resulting in a somewhat longer turn-on time. In the case of a

1

µF capacitor, the initial turn-on time is approximately 400 ms

to 0.01% (see Figure 5c).

a. Electrical Turn-On

b. Extended Time Scale

c. Turn-On with 1

µF CN

Figure 5. Turn-On Characteristics

DYNAMIC PERFORMANCE

The output buffer amplifier is designed to provide the AD587

with static and dynamic load regulation superior to less complete

references.

Many ADCs and DACs present transient current loads to the

reference, and poor reference response can degrade the converter’s

performance.

Figures 6b and 6c display the characteristics of the AD587 output

amplifier driving a 0 mA to 10 mA load.

AD587

7.0V

1k

Ω

10V

0V

Figure 6a. Transient Load Test Circuit

Figure 6b. Large-Scale Transient Response

Figure 6c. Fine Scale Setting for Transient Load