ADC采样基于3.6V参考电压,芯片内部是否内置了300K欧姆的电阻?能否去掉?

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MintCandy5
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ADC采样基于3.6V参考电压,芯片内部是否内置了300K欧姆的电阻?能否去掉?

我们采用ADC采样一个精密电阻的电压,基于3.6V参考电压,设置了GP_ADC_ATTN3X。但是测出来的电压值和我们的理论值差别比较大。我们查手册发现Figure 55里,芯片内部是内置并联两个电阻,加起来300K欧姆。请问我们的理解是否正确?另外,这两个电阻可否取消?

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PM_Dialog
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MintCandy5,

MintCandy5,

Thanks for your question but this is our English forum and customers post their questions in English. So, please translate it to English, or kindly post it in our Chinese forums. Link is provided below:

https://support.dialog-semiconductor.com/forums/dialog-smartbond-bluetooth-low-energy-%E2%80%93-software-dialog-%E2%80%9Csmartbond%E2%80%9D%E7%B3%BB%E5%88%97%E4%BD%8E%E5%8A%9F%E8%80%97%E8%93%9D%E7%89%99%E2%80%94%E8%BD%AF%E4%BB%B6

Thanks, PM_Dialog

MintCandy5
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Hi, PM_Dialog,

Hi, PM_Dialog,

Thank you for your response. We're trying to read the voltage from a resistor divider (NTC thermistor and a fixed R). We use P01(single end) and the reference voltage is 3.6V. We set GP_ADC_ATTN3X, we find the result is different from what we suppose. We find Figure 55 of the datasheet, but we have some problems. When we set GP_ADC_ATTN3X to 1, how does the above switch connect? If we set it to 1, can we think P01 always parallel 300KOhm resistance ( 200K + 100K )? If we set it to 0, dose P01 connect to the ADC module directly (no any parallel resistance)?

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Hi MintCandy5,

Hi MintCandy5,

I’ve replied you in this forum thread:

https://support.dialog-semiconductor.com/forums/post/dialog-smartbond-bluetooth-low-energy-%E2%80%93-hardware-device-reference-designs/adc-sample

Thanks for translating it to English!

Thanks, PM_Dialog