AD587
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).
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.
V
OUT
7.0V
1kΩ
AD587
V
L
10V
0V
a. Electrical Turn-On
Figure 6a. Transient Load Test Circuit
b. Extended Time Scale
Figure 6b. Large-Scale Transient Response
c. Turn-On with 1
µ
F CN
Figure 5. Turn-On Characteristics
Figure 6c. Fine Scale Setting for Transient Load
REV. F
–5–
AD [ ANALOG DEVICES ]
