Hi everyone!
I am looking to connect a Meter CTD to the Particle Boron. The data wire from the CTD has a Voutput of 3.6V, however, the max for the Boron pins are 3.3V according to Particle Docs.
Has anyone attempted to send more than 3.3V to the Boron or will it fry at any voltage above 3.3V?
Thanks for the help!
Is this an analog or digital output sensor?
The recommended maximum GPIO or ADC voltage is 3.3V.
The absolute maximum GPIO voltage is VDD+0.3V, so 3.6V. However, that is the absolute maximum, and you should not regularly use the device at absolute maximum. It would be best to use a level shifter for a 3.6V digital signal.
The absolute maximum ADC voltage is 3.6V as well, but because of the way to voltage is scaled, anything over 3.3V reads as 4095. It would be best to use a voltage divider for 3.6V analog signal, and probably also add a rail-to-rail TVS+Zener diode as well.
If this is a digital sensor with pulse shift or similar timing-related design it may be difficult to use the Boron because of variable interrupt latency. This can be worked around, but is a fairly large amount of effort. One example is JSN-SR04_Gen3_RK which uses the SPI peripiheral to achieve precise measurement of a TDR distance sensor, but the process works with any timing-sensitive signal.
Thank you for your response!
We are using digital with a steady 3.6V supply, so we will use a level shifter. We have order this level shifter from Sparkfun.