Hello everyone,

I am designing an OBD tool. I want to add the Bluetooth CC2541, probably I will buy a module so I can solder it by hand.

My doubt is related to the power supply, on my designing, I am already converting

12 V battery -> 5 V ( TLE8366EV50 ) -> 3.3 V ( TLE8366EV33 ) .

The 3.3V volts powers the Microcontroller ATmega328p or ATmega4809, STN1170 (OBD interpreter), SD Card, IMU sensors and a couple of transceivers to communicate with the car. I am worried about the noise on the rails of 3.3V that may bias the CC2541, so I was thinking to use a voltage regulator just for the CC2541, the recommended one by Texas is the TPS62730.

What do you think? Should I add an extra voltage regulator or is it safe to use the one already implemented ( TLE8366EV33 )?

Thank you

 

You're going to wind up with digital noise on your rails- ground and positive. What matters is that the noise level is diminished below your thresholds (which is tough at 3.3V). Use filtering, and anything that is particularly sensitive, shield it and ground the shield. Use the necessary currents where you need it to make signal's 'stiff' and be careful with parallel traces, and radiating corners.

And put fuses in ahead of your regulators.

 

Ok thank you for the tips