ADS124S08: What is the total conversion time for using 2 channels(PT100)?

Shinichi Inoue

Guru 21566 points

Part Number: ADS124S08

Tool/software:

Dear Specialists,

My customer is considering ADS124S08 and has a question.

I would be grateful if you could advise?

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If I connect two PT100s (three-wire type) to the ADS124S08, what is the total conversion time for both channels?

I haven't decided whether to use the Low-Latency Filter or the Sinc3Filter.

Is it possible to think of this as a value that doubles the FIRST DATA CONVERSION in SINGLE-SHOT CONVERSION MODE, since I will be switching between channels?

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I appreciate your great help in advance.

Best regards,

Shinichi

2 months ago

+1 Bryan Lizon86 2 months ago

TI__Guru 51846 points

Hi Shinichi Inoue

Shinichi Inoue said:
Is it possible to think of this as a value that doubles the FIRST DATA CONVERSION in SINGLE-SHOT CONVERSION MODE, since I will be switching between channels?

This is basically correct. If the customer wants to measure one sample on the first RTD, then measure one sample on the second ADC, and then repeat, the latency per channel will be the first conversion latency. The total latency will then be 2 * First Conversion Latency

You can refer to this app note for more information: https://www.ti.com/lit/an/sbaa535a/sbaa535a.pdf?ts=1751041302570&ref_url=https%253A%252F%252Fwww.google.com%252F

Example 8-1 is similar to what you are talking about, but instead of taking 3x conversions per channel you would only take 1x. See the image below where you would just ignore conversions 2 and 3 on each channel

-Bryan

0 Shinichi Inoue 2 months ago in reply to Bryan Lizon86

Guru 21566 points

Hi Bryan,

Thank you for your reply.

I understand.

I'll share this information with the customer.

I appreciate your great help and cooperation.

Best regards,

Shinichi

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ADS124S08: What is the total conversion time for using 2 channels(PT100)?