LPC55S16 - ADC

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631件の閲覧回数
Dhaya
Contributor III

Hi,

    I'm using LPC55S16 (100 pin package) and configured the ADC in 16-bit resolution. While reading the value, ADC value get oscillated more. How I can reduce the oscillation?. Even if i used average of 50, it gets oscillated. Kindy resolve it, if it is possible

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579件の閲覧回数
xiangjun_rong
NXP TechSupport
NXP TechSupport

Hi,

Pls refer to the spec of ADC of LPC5516,the ENOB is 12.1 bits in 16 bits resolution and single-ended mode, in other words, the low 4 bits is random, the random value is 16 LSB.

But you said that the Oscillating of value for current and previous value is about +/-80 LSB, it is too big, can you share the analog circuit and external analog source impedance?

BR

XiangJun Rong

 

xiangjun_rong_0-1697612855843.png

 

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617件の閲覧回数
xiangjun_rong
NXP TechSupport
NXP TechSupport

Hi,

Can you explain what the ADC sampling results oscillation is? If you sample a DC voltage, does the ADC sampling results oscillate? or just the low 3 bits oscillate for every ADC results.

BR

XiangJun Rong

607件の閲覧回数
Dhaya
Contributor III

Hi @xiangjun_rong ,

            Here we used DC voltage samplings (max. 3.3V) and taken average of 50. Oscillating of value for current and previous value is about +/-80. We used it to verify linear POT which datasheet is attached here

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580件の閲覧回数
xiangjun_rong
NXP TechSupport
NXP TechSupport

Hi,

Pls refer to the spec of ADC of LPC5516,the ENOB is 12.1 bits in 16 bits resolution and single-ended mode, in other words, the low 4 bits is random, the random value is 16 LSB.

But you said that the Oscillating of value for current and previous value is about +/-80 LSB, it is too big, can you share the analog circuit and external analog source impedance?

BR

XiangJun Rong

 

xiangjun_rong_0-1697612855843.png