Add a delay between A/D sample and conversion

[brianzenowich]

Kinetis K64: I have a short window of opportunity (like 300 ns) to sample a signal before process noise corrupts it. Unfortunately, the process noise also corrupts the conversion process, so I need to sample & hold the signal at one moment, then convert it during the next quiet moment. The reference manual says the conversion always immediately follows the sample, but I need to put a delay between these two actions. I don't think I can turn off the A/D peripheral after the sample while still preserving the sample, can I? How about reducing the A/D clock to zero Hertz right after the sample but before the conversion? If I then wait for a quiet moment to re-enable the A/D clock, would it still perform the conversion correctly? Are there any other techniques I could use to delay the conversion process after taking a sample? Or is there an app note which can help the conversion process become more immune to noise spikes on 3.3V/GND? I'm not using the 1.2V external voltage reference, would that help? Thanks!

[Hui_Ma]

Hi

K64 ADC module conversion clock frequency in range of 1MHz to 18MHz, there could not be halted during ADC sample and conversion.

Customer could consider to replace K64 product with LPC546xx product, which provides up to 5Msamples/s 12-bit ADC module.

More detailed info, please check here.

Wish it helps.

Have a great day,
Ma Hui
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