Data Sheet

AD1582/AD1583/AD1584/AD1585

Rev. J | Page 13 of 16

100

90

0

1

1M

10

100

1k

10k

100k

50

20

80

70

60

40

30

10

AD1582

AD1585

FREQUENCY (Hz)

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

Figure 19. 10 Hz to 10 kHz Wideband Noise

10

0%

100

90

10ms

100µV

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

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

10k

Ω

10k

Ω

DUT

5V OR 10V

0V OR 5V

Figure 21. Turn-On/Transient Response Test Circuit