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Hi, is there a formula I can use for Delay calculation with PT2399 : Delay-time Vs resistance-value ?
I have a table from datasheet showing some delay time and resistance values but I can't get the formula...

I'd like to build the echo-base having a multi-switch option for specific delay time.
THANKS

Regression of the table gives a nice linear formula:
delay = 1.14657e-5*R + 0.02974,
with delay in seconds, R in ohms.

This formula reproduces the table*, but I make no guarantees that the table is accurate or consistent between devices.

*The maximum error between the formula and the table is 4.2 ms, the average error is 1 ms.

accurate method to get delay time is only to measure frequency at pin5 of PT2399, than regulate resistor value. Like PLL.
With analog delays is the same thing.