tony_lth
Advanced Member level 5
Hi, All,
For switch on/off RS232 signals, I used CD4066, and because my control signal is TTL level, I have to use CD4054 to convert 0V/5V TTL signal to +5V/-5V signal to control CD4066 On or OFF.
But unfortunately, the circuit doesn't work, and the total current is about 0.8A and CD4054 is fired.
I wonder what's the reason for the burn CD4054?
1. Is it because that CD4054 GND is nor directly linked to main GND, in fact, through a think wire about 10mm length? I think RS232 is very low freq, maybe this is not the root cause.
2. Is it because that STR4/STR1 directly linked to +5V? Should it be by a 10K?
3. Other comment?
many thanks.
Best,
Tony Liu
For switch on/off RS232 signals, I used CD4066, and because my control signal is TTL level, I have to use CD4054 to convert 0V/5V TTL signal to +5V/-5V signal to control CD4066 On or OFF.
But unfortunately, the circuit doesn't work, and the total current is about 0.8A and CD4054 is fired.
I wonder what's the reason for the burn CD4054?
1. Is it because that CD4054 GND is nor directly linked to main GND, in fact, through a think wire about 10mm length? I think RS232 is very low freq, maybe this is not the root cause.
2. Is it because that STR4/STR1 directly linked to +5V? Should it be by a 10K?
3. Other comment?
many thanks.
Best,
Tony Liu