Datasheet

Data Sheet AD1582/AD1583/AD1584/AD1585
Rev. J | Page 13 of 16
100
90
0
1 1M10 100 1k 10k 100k
50
20
80
70
60
40
30
10
AD1582
AD1585
PSRR (dB)
FREQUENCY (Hz)
00701-018
Figure 18. Ripple Rejection vs. Frequency
NOISE PERFORMANCE AND REDUCTION
The noise generated by the AD1582/AD1583/AD1584/AD1585 is
typically less than 70 µV p-p over the 0.1 Hz to 10 Hz frequency
band. Figure 19 shows the 0.1 Hz to 10 Hz noise of a typical
AD1582/AD1583/AD1584/AD1585. The noise measurement
is made with a high gain band-pass filter. Noise in a 10 Hz to
10 kHz region is approximately 50 µV rms. Figure 20 shows the
broadband noise of a typical AD1582/AD1583/AD1584/AD1585.
If further noise reduction is desired, add a 1-pole, low-pass
filter between the output pin and ground. A time constant of
0.2 ms has a −3 dB point at roughly 800 Hz and reduces the
high frequency noise to about 16 V rms. It should be noted,
however, that while additional filtering on the output can
improve the noise performance of the AD1582/AD1583/
AD1584/AD1585, the added output impedance can degrade
the ac performance of the references.
100
90
10
0%
10µV 1s
00701-019
Figure 19. 10 Hz to 10 kHz Wideband Noise
1
0
0%
10
0
9
0
10m
s
100µV
00701-020
Figure 20. 1 Hz to 10 Hz Voltage Noise
TURN-ON TIME
Many low power instrument manufacturers are concerned
with the turn-on characteristics of the components used in their
systems. Fast turn-on components often enable the end user to
save power by keeping power off when not needed. Turn-on
settling time is defined as the time required, after the application of
power (cold start), for the output voltage to reach its final value
within a specified error. The two major factors affecting this are
the active circuit settling time and the time required for the
thermal gradients on the chip to stabilize. Figure 21 shows the
turn-on settling and transient response test circuit. Figure 22
shows the turn-on characteristics of the AD1582/AD1583/
AD1584/AD1585. These characteristics are generated from cold-
start operation and represent the true turn-on waveform after
power-up. Figure 23 shows the fine settling characteristics of
the AD1582/AD1583/AD1584/AD1585. Typically, the reference
settles to within 0.1% of its final value in about 100 µs.
The device can momentarily draw excessive supply current
when V
SUPPLY
is slightly below the minimum specified level.
Power supply resistance must be low enough to ensure reliable
turn-on. Fast power supply edges minimize this effect.
0.22µF
0.22µF
0V OR 10V
0V
TO 10V
10kΩ
10kΩ
DUT
V
O
UT
5
V OR 10
V
0V O
R 5V
00701-021
Figure 21. Turn-On/Transient Response Test Circuit