AD1584C View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

AD1584C

2.5 V to 5.0 V Micropower, Precision Series Mode Voltage References

Analog Devices 

AD1582/AD1583/AD1584/AD1585

AC PERFORMANCE

To apply the AD1582/AD1583/AD1584/AD1585 family of

references, it is important to understand the effects of dynamic

output impedance and power supply rejection. In Figure 8a, a

voltage divider is formed by the AD1582’s output impedance and

by the external source impedance. Figure 8b shows the effect of

varying the load capacitor on the reference output. Power supply

rejection ratio (PSRR) should be determined when characterizing

the ac performance of a series voltage reference. Figure 9a shows a

test circuit used to measure PSRR, and Figure 9b demonstrates

the AD1582’s ability to attenuate line voltage ripple.

VLOAD DC 5V

10k⍀

2k⍀

2 ؋ VOUT

10k⍀

؋1

DUT

5␮F

؎2V 10k⍀

؎100␮A

1␮F

Figure 8a. Output Impedance Test Circuit

100

NOISE PERFORMANCE AND REDUCTION

The noise generated by the AD1582 is typically less than

70 µV p-p over the 0.1 Hz to 10 Hz frequency band. Figure 10

shows the 0.1 Hz to 10 Hz noise of a typical AD1582. 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 11

shows the broadband noise of a typical AD1582. If further noise

reduction is desired, a 1-pole low-pass filter may be added

between the output pin and the 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 µV rms. It should be noted,

however, that while additional filtering on the output may improve

the noise performance of the AD1582/AD1583/AD1584/AD1585

family, the added output impedance could degrade the ac

performance of the references.

10␮V

1s

100

90

1␮F CAP

10

AD1585

AD1582

1

0.1

10

100

1k

10k

100k

1M

FREQUENCY (Hz)

Figure 8b. Output Impedance vs. Frequency

10k⍀

10V

10k⍀

؎200mV

؋1

0.22␮F

5V ؎100mV

DUT

VOUT

0.22␮F

Figure 9a. Ripple Rejection Test Circuit

100

90

80

70

AD1582

60

50

AD1585

40

30

20

10

0

1

10

100

1k

10k

100k

1M

FREQUENCY (Hz)

Figure 9b. Ripple Rejection vs. Frequency

REV. D

10

0%

Figure 10. 0.1 Hz to 10 Hz Voltage Noise

100␮V

100

90

10ms

10

0%

Figure 11. 10 Hz to 10 kHz Wideband Noise

–11–

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