# Understanding of the circuit

#### electronicsLearner77

Jul 2, 2015
252

I am analyzing the below circuit, i know the VRef will be the voltage at the +ve terminal. The voltage at point 12 is
V+ = (AVDD * R26)/(R26+R21) R26=R21 = 10K hence
V+ = AVDD/2; AVDD = 3.3V then
V+=VREF = 3.3/2 = 1.65V. Am i correct? But i am confused with the capacitor. Because the impedance of the capacitor is infinite for DC, hence no current flows through C59 that is the only purpose of C59?

#### bertus

Moderator
Nov 8, 2019
2,851
Hello

The capacitor is there for noise suppresion from AVDD

Bertus

#### electronicsLearner77

Jul 2, 2015
252
What is noise suppression. Any link to understand it? The explanation i provided is cirrect that it does not allow current or it works as RC filter, i am confused?

Last edited:

#### ratstar

Aug 20, 2018
485
Looks like to me the capacitor C59 is discharging through that resistor R26, I dont know if that helps, but it would be emptying itself as it fills.

Moderator
Nov 8, 2019
2,851

#### Audioguru

Sep 24, 2016
3,650
Many power supplies produce hum and hiss noises. The value of C59 is too low to reduce hum but it does reduce power supply hiss.

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