MPL(3)115A2 capacitors

[andrey_g]

I've notices that there are differences in required capacitors between MPL115A2 and MPL3115A2. Pic is from datasheets.

My question is, what function does the capacitor connected to CAP pin have and what effect on performance would using MPL115A2 capacitor setup with MPL3115A2 have (i.e. single 1uF cap on Vcc pin, 1uF cap on CAP pin)?

[TomasVaverka]

Hello Andrey,

The capacitor connected to the CAP pin is used to bypass the internal LDO regulator. As this regulator is different on both the MPL115A2 and MPL3115A2 pressure sensors, different bypass as well as decoupling capacitors are required. As shown above, the MPL115A2 requires a 1uF bypass capacitor while the MPL3115A2 internal LDO regulator was designed for a capacitive load of 100nF. We do not guarantee operation at a different capacitor value.

Let me know if you have any other questions.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.

[andrey_g]

So what effect exactly would a larger capacitor at CAP pin have? And what about capacitors connected to pin Vdd?

[TomasVaverka]

Andrey,

There may occur oscillations when using a larger bypass capacitor at the CAP pin. The decoupling capacitors were chosen to minimize the average current consumption while still maintaining an acceptable level of power supply high-frequency filtering.

Regards,

Tomas