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PSoc3 ADC Maximum Voltage. | Cypress Semiconductor

PSoc3 ADC Maximum Voltage.

Summary: 2 Replies, Latest post by rahulram on 08 Aug 2012 12:22 AM PDT
Verified Answers: 0
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SalmanJavaid's picture
3 posts

I am using Single Mode ADC on PSoc3 Development kit. Now even when I select Input Range upto a maximum of 6.048 volts, I am only being able to retrieve 4.023 volts on LCD as the maximum voltage. The voltages on the lower ranges like 2.87, 3 volts are correctly identified. Any help will be deeply appreciated.

user_14586677's picture
7646 posts

This note in datasheet on input Common Mode Range -


VSSA to 6 × VBG range is used for direct measurement of VDDA power supply. Actual scale is limited to VDDA.


This makes sense, that input range, in a CMOS device designed for R-R performance, is limited to

supply rails +, if we are lucky, a diode drop.


Regards, dana.


rahulram's picture
Cypress Employee
115 posts

I agree with Daana, the Vdda limit is around 5.3V.

Hence we cannot have have inputs beyond this to  the adc.

The reason why we have an option of choosing up to 6 V Range is to improve the linearity of the ADC while operating in the 0 to VDDA range. Higher the range,improved is the linearity.! 

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