AD1582/AD1583/AD1584/AD1585

Data Sheet

Rev. M | Page 14 of 17

100

AD1585

AD1582

10

1

0.1

10

100

1k

10k

100k

1M

FREQUENCY (Hz)

1µF CAP

Figure 17. Output Impedance vs. Frequency

5V ± 100mV

0.22µF

0.22µF

10V

10kΩ

10kΩ

±200mV

×1

DUT

VOUT

Figure 18. Ripple Rejection Test Circuit

100

90

0

11M

10

100

1k

10k

100k

50

20

80

70

60

40

30

10

AD1582

AD1585

FREQUENCY (Hz)

Figure 19. 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 20 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 21 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 20. 10 Hz to 10 kHz Wideband Noise

10

0%

100

90

10ms

100µV

Figure 21. 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 22 shows the turn-on settling and transient response test

circuit. Figure 23 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 24 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 VSUPPLY 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.