EN5322QI without AVIN connection

[Galant]

Hi,

in 2012 we used the EN5322QI device on one of our boards still in production, the apparatuses equipped with our board passed the qualifications and have been operating since then without showing any problems.
The operating conditions of the EN5322QI device are as follows:
Input voltage 4.5V
Output voltage with VID Codes 2.5V
Load current 1A
During the qualifications the measured parameters, VOUT Accuracy, Ripple Voltage, etc. resulted to specification.
Today for updates we have revised the project and we realized that, probably due to an oversight, the pin of AVIN 16 is connected only to its 1 μF bypass capacitor.
Although not connected to the input voltage on pin 16 there is a voltage of 3.6V and everything has been working regularly for many years!
Can you give us an explanation that will reassure us?

Thanks in advance
Antonio

[Mostafa_Intel_AE]

Hello @Galant ,

It looks there is a leakage voltage from Enable, VS0, VS1 or VS2 that enough to drive the control circuit.

The controller circuit doesn't need high power to work and it looks that leakage was enough.

But in general this is not the recommended connection and we advice to connect AVIN through RC filter to PVIN such that 10R between PVIN and AVIN and 4.7uF between AVIN and PGND.

Thanks,

Mostafa

[Galant · Accepted solution]

Dear Mostafa,

thanks for your support, we will integrate the connection you recommended.

Best regards

Antonio