ADS124S08: Programable delay

Shota Mago

Expert 8110 points

Part Number: ADS124S08

Hi all,

Let me double check about programable delay.

My customer uses ADS124S08 with following settings.

Continuous Conversion
Global Chop Enable
Sinc3 Filter
Data rate=2ksps

Is programable delay valid only 1st conversion even in case of above setting?

Datasheet states "(4) Subsequent readings in continuous conversion mode do not have the programmable delay time." in page42.

Best regards,

Shota Mago

over 4 years ago

0 Bob Benjamin over 4 years ago

TI__Guru** 113765 points

Hi Mago-san,

The primary purpose of the programmable delay is to allow for analog settling before starting the conversion. This allows the customer to not have to create a timer in firmware to delay start of conversion. The most typical application for the programmable delay would be when switching the mux. So the programmable delay would only apply to the first conversion unless global chop is enabled.

When global chop is enabled, the inputs are swapped and the conversions would be like two single-shot conversions. See page 49 of the datasheet and the notes and discussion following Table 19. So for each conversion cycle there would be the programmable delay and would effectively be twice the delay compared to when global chop is disabled in single-shot mode.

So the delay would apply not only to the first conversion cycle, but also to all subsequent conversion cycles when global chop is enabled.

Best regards,

Bob B

0 Shota Mago over 4 years ago in reply to Bob Benjamin

TI__Expert 8110 points

Hi Bob-san,

I overlooked Figure 74 in the datasheet.

Thanks for pointing out that programable delay applies every conversion cycle in case global chop is enabled.

Best regards,

Shota Mago

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ADS124S08: Programable delay