Hi everybody!
I'm making a RC relaxation oscillator with the 74**14 Trigger Schmitt inverter. I have found out that the frequency of the circuit depends on the technology of the logic family (LS, HC, HCT...),that is, it depends not only on the values of R and C but also on the parameters of the chip; Ioh,Iol,Iih,Iil,Voh...
I need to find out the formula and all i've got is this information from the Philips 74HC14 datasheet that says:
HC--> f= 1/0.8RC
HCT--> f= 1/0.67RC
(Datasheet: http://www.farnell.com/datasheets/5029.pdf)
Can any of you help me and tell me how they get to these values??? What do 0.8 and 0.67 stand for?
Thanks in advance for your time!
I'm making a RC relaxation oscillator with the 74**14 Trigger Schmitt inverter. I have found out that the frequency of the circuit depends on the technology of the logic family (LS, HC, HCT...),that is, it depends not only on the values of R and C but also on the parameters of the chip; Ioh,Iol,Iih,Iil,Voh...
I need to find out the formula and all i've got is this information from the Philips 74HC14 datasheet that says:
HC--> f= 1/0.8RC
HCT--> f= 1/0.67RC
(Datasheet: http://www.farnell.com/datasheets/5029.pdf)
Can any of you help me and tell me how they get to these values??? What do 0.8 and 0.67 stand for?
Thanks in advance for your time!