The tolerance of voltage of DEC pins of 52840

[Hsu]

Hi Sir,

In the datasheet of 52840, we know the DEC1 is 1.1V, DEC2/4/5 are 1.3V, DECUSB is 3.3V.

When measuring these pins, we may not get a precision value, like we got the 1.08~1.101V for DEC1 / 1.262~1.268V for DEC2

Does it meet the spec. of IC when the system running?

What is the tolerance of these power pins?

If the voltage of these power pins are too high or low, how to adjust it to meet the tolerance?

Thank you.

BRs, Han

[Andreas]

Hi Han,

 

In the datasheet of 52840, we know the DEC1 is 1.1V, DEC2/4/5 are 1.3V, DECUSB is 3.3V.

This just refers to the 'name' of the rails to distinguish them from each other, it does not specify that e.g DEC2 is exactly 1.3 V. Voltages on all DEC pins will vary depending on the state of the regulator and the charge of the DEC capacitor. We do not specify tolerance or max/min on these rails, the voltages you are seeing are perfectly fine though.

 

Best regards,

Andreas

[Hsu]

HI Andreas,

We did some measurement for all DEC pin as below, could you help to check the tolerance?

And the ripple of DEC5 is large than other DEC pin, how do we fix this?

Thank you.

BRs, Han

[Andreas]

Hi Han,

 

This is normal behaviour.

 

Best regards,

Andreas