ENOB of ADC if using 12bit single ended mode

[francisy]

Hi, I cannot find the ENOB of ADC 12bit mode for LPC5528. 

What is the ENOB if I use 12bit single ended mode?

[Omar_Anguiano]

Hello Francis Yeung 

Unfortunately, we don't have this value for 12bit ADC, only the 16bits value which can be found in table 36 of the datasheet.

The ENOB can be calculated with this formula:

Where SINAD is the Signal-to-Noise-and Distortion ratio.

For further information on the elements that make up the ENOB please refer to the following document: https://community.nxp.com/docs/DOC-103932

Let me know if this is helpful, if you have more questions do not hesitate to ask me.

Best regards,

Omar

[francisy]

Hi nxf54944 , thanks for your answer.

But I think it is impossible to me to do the measurement of ENOB using my simple equipment. ENOB should be provided by MCU manufacturer. 

LPC551x have 12bit mode ENOB in datasheet but LPC5528 doesn't have.

Is it possible for NXP to do the measurement for LPC5528?

best regards, 

Franics

[Omar_Anguiano]

Hello Francis Yeung

The ENOB for the LPC551x also applies to the LPC5528. So the ENOB of the LPC5528 in 12 bit SE is 11.5bits.

Let me know if this is helpful, if you have more questions do not hesitate to ask me.

Best regards,

Omar

[francisy]

Hi nxf54944 thanks for your answer.

Apart from the ENOB, may I know what is the different between LPC551x and LPC552x's ADC?

I know that LPC551x's adc can reach 2MSample/s with 48MHz clock.

I am using LPC5528. If I use high power setting(11), can I use clock above 24MHz?

In fact I want to achieve 1MSample/s, but seem not practical for me. I use STS=0, 24MHz ADC clock, it can only give me 900kSample/s. 

Does NXP have sample code that show achieve 1MSample/s?

Thanks. 

Best regards,

Francis

[Omar_Anguiano]

Hello Francis Yeung

The difference between the LPC552x and LPC551x ADC's are not very considerable, the most important feature between these two ADC's is the Sampling rate. For more detailed information I suggest you consult the datasheet from these parts.

In the LPC5528 the max clock value for the ADC is 24Mhz. The available sample codes are located at the SDK of the device.

Which average value you have in the ADC configuration? I suggest you configure the lowest possible.

Let me know if this is helpful, if you have more questions do not hesitate to ask me.

Best regards,

Omar