Maker Pro
Maker Pro

detect pulse of 140ns and 50mv.

[email protected]

Sep 4, 2012
3
Joined
Sep 4, 2012
Messages
3
Hi,

i want to detect a pulse with 140ns and 50mV amplitude. i want to design such a circuit when pulse comes pic microcontroller should get an interrupt. how can i do that?

thanks in advance...
 

Laplace

Apr 4, 2010
1,252
Joined
Apr 4, 2010
Messages
1,252
One approach would be to use a high speed comparator such as the LMV7239. It has low input offset, low cost, and 5V single supply operation. For 50mV detection I would pre-bias the input with 15mV offset and use capacitive coupling for the pulse signal. Since the input signal is fast switching, there should not be a need to incorporate hysteresis but you will still need to follow high speed layout rules on the PCB to minimize feedback. The PIC has edge-triggered interrupt input but I'm not sure what the minimum hold time may be. The 140nS pulse may be sufficient for connecting directly to the interrupt input.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,505
Joined
Jan 21, 2010
Messages
25,505
Check the datasheet first.
 

[email protected]

Sep 4, 2012
3
Joined
Sep 4, 2012
Messages
3
hi friends,

Finally i got the pulse using MC33274AP opamp and cd4098 pulse stretcher. thanks to all for being with me.
 
Top