DocID025993 Rev 2

19/31

OA1NP, OA2NP, OA4NP

Application information

31

Equation 5

as a function of the maximum operating voltage and the absolute maximum rating (as

recommended by JEDEC rules).

different measurement conditions (see Equation 6).

Equation 6

calculated number of months (Equation 7).

Equation 7

duration.

4.5

Schematic optimization aiming for low power

To benefit from the full performance of the The OA1NP, OA2NP and OA4NP series, the

impedances must be maximized so that current consumption is not lost where it is not

required.

For example, an aluminum electrolytic capacitance can have significantly high leakage. This

leakage may be greater than the current consumption of the op amp. For this reason,

ceramic type capacitors are preferred.

For the same reason, big resistor values should be used in the feedback loop. However,

there are three main limitations to be considered when choosing a resistor.

1.

When the The OA1NP, OA2NP and OA4NP series is used with a sensor: the

resistance connected between the sensor and the input must remain much higher than

the impedance of the sensor itself.

2.

, a bigger resistor value generates

even more noise.

3.

Leakage on the PCB: leakage can be generated by moisture. This can be improved by

using a specific coating process on the PCB.

Months

A

F

1000 h



12 months

24 h

365.25 days









=

V

CC

maxV

V



==

V

io

V

months



------------------------------

=

nV

Hz

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