ADR391/ADR392/ADR395

Rev. H | Page 17 of 20

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CAPACITORS

Input Capacitor

Input capacitors are not required on the ADR39x. There is no

limit for the value of the capacitor used on the input, but a 1 μF

to 10 μF capacitor on the input improves transient response in

applications where the supply suddenly changes. An additional

0.1 μF in parallel also helps reduce noise from the supply.

Output Capacitor

The ADR39x does not require output capacitors for stability under

any load condition. An output capacitor, typically 0.1 μF, filters

out any low level noise voltage and does not affect the operation

of the part. On the other hand, the load transient response can

improve with the addition of a 1 μF to 10 μF output capacitor in

parallel. A capacitor here acts as a source of stored energy for a

sudden increase in load current. The only parameter that degrades

by adding an output capacitor is the turn-on time, and it depends

on the size of the capacitor chosen.

Figure 40. ADR391 Typical Long-Term Drift over 1000 Hours