cancel
Showing results for 
Search instead for 
Did you mean: 

PSoC 4 MCU

New Contributor II

Does anyone know what the input current drain on the VDDA input is in normal operation?

I'm having some issues with voltage spikes/droop on my VDDD rail, which is directly connected to my VDDA input.  This is causing spurious triggers on my ADC.  To get around this, I want to put an RC filter on the voltage to the VDDA input, but need to know how much current it sinks so that I know what the maximum series resistance I can use is without causing excessive voltage drop.

I've trawled through the PSOC 4100 datasheet voltage/current specs, but can't seem to find the info I need.

Cheers,

Mike

0 Likes
Reply
1 Solution
Moderator
Moderator

Hi Mike,

I thought you were interested in the worst case/absolute maximum values. The device current consumption depends on your application and the blocks are that are active. As you are using BLE device, Designing for Low Power and Estimating Battery Life for BLE Applications application note will be useful. A power calculator based on an Excel worksheet is provided with this application note. Note that the calculator provides only an estimation of the current consumption. The actual current measured in your system may be different depending on your system design and how you use the various low-power modes.

Best Regards,
Vasanth

View solution in original post

0 Likes
Reply
3 Replies
Moderator
Moderator

Hello Mike,

In PSoC 4100 datasheet check for the maximum current the chip can sink and source is,

pastedImage_0.png

This is the maximum possible current the chip can sink or source. Regarding the spikes, please check you have connected the recommended capacitors described under power section in PSoC 4 Hardware Design Guide.

Best Regards,
Vasanth

0 Likes
Reply
New Contributor II

Hi Vasanth,

That’s an absolute max rating. And it’s for the GPIO.

I’m trying to establish what current, when the chip is operating normally (i.e. not in a low power mode) would be flowing into the VDDA input - the analog reference voltage input.

This input is not used to power the chip, or drive any I/O, so I suspect the current will be low (uA probably) but I can’t find anywhere in the data sheet that explicitly mentions what this current is.

And yes, I have all the appropriate capacitors at all the relevant inputs. I’ve even taken to significantly increasing the capacitance on my 3.3V rail from 10uF to 30uF. This has helped, but not completely resolved the issue. Hence why I want to filter the analog reference input.

Cheers,

Mike

0 Likes
Reply
Moderator
Moderator

Hi Mike,

I thought you were interested in the worst case/absolute maximum values. The device current consumption depends on your application and the blocks are that are active. As you are using BLE device, Designing for Low Power and Estimating Battery Life for BLE Applications application note will be useful. A power calculator based on an Excel worksheet is provided with this application note. Note that the calculator provides only an estimation of the current consumption. The actual current measured in your system may be different depending on your system design and how you use the various low-power modes.

Best Regards,
Vasanth

View solution in original post

0 Likes
Reply