Kinetis MicrocontrollersのトピックRe: KL25 ADC accuracy

KL25 ADC accuracy

kineya6 — Wed, 19 Nov 2014 08:14:05 GMT

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?

This is only a misstype of ADC0_DPx, ADC0_DMx.

Re: KL25 ADC accuracy

kerryzhou — Fri, 21 Nov 2014 03:29:24 GMT

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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Re: KL25 ADC accuracy

kineya6 — Fri, 21 Nov 2014 05:13:54 GMT

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

Re: KL25 ADC accuracy

kerryzhou — Fri, 21 Nov 2014 08:02:04 GMT

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

Re: KL25 ADC accuracy

kineya6 — Fri, 21 Nov 2014 10:40:28 GMT

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?