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, re-
sulting 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 com-
plete references.
Many A/D and D/A converters present transient current loads
to the reference, and poor reference response can degrade the
converter’s performance.
Figure 6 displays the characteristics of the AD587 output ampli-
fier 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 C
N
Figure 5. Turn-On Characteristics
Figure 6c. Fine Scale Settling for Transient Load
REV. D
–5–
AD [ ANALOG DEVICES ]
