KL25 ADC accuracy

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KL25 ADC accuracy

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kineya6
Contributor I

In KL25P80M48SF0.pdf there is,

3.6.1 ADC electrical specifications

The 16-bit accuracy specifications listed in Table 25 and Table 26 are achievable on the

differential pins ADCx_DP0, ADCx_DM0.

Does anyone knows  KL25Z supports only single pair of pins for 16bit ADC?

or

This is only a misstype of ADC0_DPx, ADC0_DMx.

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kerryzhou
NXP TechSupport
NXP TechSupport

Hi Yasuhiko Inoue,

      According to the datasheet, actually, the 16bit accuracy specifications listed in Table 25 and Table 26 are only achievable on differential pins ADCx_DP0,ADCx_DM0, pin ADCx_DP0 and ADCx_DM0 are the special pins.

All other pins just meet the 13-bit differential/12-bit single-ended accuracy specifications, including ADC0_DP1, ADC0_DM1, DP2,DP3, SE8,SEx ADC channels. Not all pin pair for defferential mode had same performance, just pin ADCx_DP0 and ADCx_DM0 meet the 16bit accuracy specifications.

Wish it helps you!

If you still have question, please contact me!

Jingjing

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kerryzhou
NXP TechSupport
NXP TechSupport

Hi Yasuhiko Inoue,

Thank you for your interest in Freescale's kinetis product.

KL25Z does not only support the differential channel, but also the single-ended ADC channel for 16 bit ADC.

I already test the single ended channel ADC0_SE8 before, it can works ok with 16 bit mode.

I think the description of "The 16-bit accuracy specifications listed in Table 25 and Table 26 are achievable on the

differential pins ADCx_DP0, ADCx_DM0." means 16bit accuracy specifications in table 25 and 26 is tested based on

differential pins ADCx_DP0, ADCx_DM0. This is the test condition, not a misstype.

Have a great day,
Jingjing

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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kineya6
Contributor I

Thank you Jingjing,

I understand.

> I think the description

>16bit accuracy specifications in table 25 and 26 is tested based on differential pins ADCx_DP0, ADCx_DM0.

>This is the test condition, not a misstype.

But the manual makes little confuse.

If it is talking about test condition. It should "ADC0_DP0, ADC0_DM0", There is no ADC1,2,3_DP0/DM0 on KL25Z.

Also there is ENOB in Table 26

In same page "All other ADC channels meet the 13-bit differential/12-bit single-ended accuracy specifications."

can read

"ADC0_DP1, ADC0_DM1, DP2,DP3, SE8,SEx ADC channels meet the 13-bit differential/12-bit single-ended accuracy specifications."

=> For better effective number, only appear on using ADC0_DP0/DM0 pair, no other includes DP1/DM1,2,3.

Some of guy I working with, were understood like this.

But all pin pair for differential mode had same performance / same ENOB spec.

Thank you for your answer.

Yasu-I

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kerryzhou
NXP TechSupport
NXP TechSupport

Hi Yasuhiko Inoue,

      According to the datasheet, actually, the 16bit accuracy specifications listed in Table 25 and Table 26 are only achievable on differential pins ADCx_DP0,ADCx_DM0, pin ADCx_DP0 and ADCx_DM0 are the special pins.

All other pins just meet the 13-bit differential/12-bit single-ended accuracy specifications, including ADC0_DP1, ADC0_DM1, DP2,DP3, SE8,SEx ADC channels. Not all pin pair for defferential mode had same performance, just pin ADCx_DP0 and ADCx_DM0 meet the 16bit accuracy specifications.

Wish it helps you!

If you still have question, please contact me!

Jingjing

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

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kineya6
Contributor I

Hi Jingjing,


Thanks it meant KL25Z has only one 16bit ADC.


KL25P80M48SF0.pdf is only the document wrote like those. But not clear.

Could I hear your original source document that wrote more clearly?


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