OA1NP Datasheet, PDF (20/31 Pages) STMicroelectronics – Rail-to-rail input and output

Application information
OA1NP, OA2NP, OA4NP
4.6
PCB layout considerations
For correct operation, it is advised to add 10 nF decoupling capacitors as close as possible
to the power supply pins.
Minimizing the leakage from sensitive high impedance nodes on the inputs of the OA1NP,
OA2NP, OA4NP series can be performed with a guarding technique. The technique consists
of surrounding high impedance tracks by a low impedance track (the ring). The ring is at the
same electrical potential as the high impedance node.
Therefore, even if some parasitic impedance exists between the tracks, no leakage current
can flow through them as they are at the same potential (see Figure 38).
Figure 38. Guarding on the PCB
OAxNP
20/31
DocID025993 Rev 2