Transistor Switching Noise???
Transistor Switching Noise???
(OP)
Hello everyone,
I have a prototype board that has a microcontroller that sends out a status heatbeat signal. The signal is generated by 2 transistors switching from high to low. One transistor for each line. The transmission lines appear to be equal and opposite of each other which is the recommended waveforms.
My problem is that the heartbeat can be heard in the AM band on an AM Radio. I think I've tried almost every possibilty to fix this problem. Any suggestions will be greatly appreciated.
Thanks,
eetrit
I have a prototype board that has a microcontroller that sends out a status heatbeat signal. The signal is generated by 2 transistors switching from high to low. One transistor for each line. The transmission lines appear to be equal and opposite of each other which is the recommended waveforms.
My problem is that the heartbeat can be heard in the AM band on an AM Radio. I think I've tried almost every possibilty to fix this problem. Any suggestions will be greatly appreciated.
Thanks,
eetrit





RE: Transistor Switching Noise???
so slow it down. The radiated noise is proportional with the speed.
<nbucska@pcperipherals.com>
RE: Transistor Switching Noise???
Try using a differential driver IC instead.
RE: Transistor Switching Noise???
RE: Transistor Switching Noise???
bandwidth should be more than enough.
<nbucska@pcperipherals.com>
RE: Transistor Switching Noise???
Good luck and keep us posted!
RE: Transistor Switching Noise???
RE: Transistor Switching Noise???
RE: Transistor Switching Noise???
2. Put the transistors as close as possible to the microcontroller and the transistor outputs as close as possible to the loads.
3. Keep the two lines as close to each other as possible.
(i.e. keep the entire circuit small so it doesn't act like a big loop antenna)
4. Use surface mounts instead of through holes, and try not to break the ground plane.
5. Bypass close to the microcontroller.