Hello all,

I am currently working on 74HC4046 vco. I am not really good in looking at the datasheet as I am a student. I am searching for the information about what is the input square wave for 74HC4046 vco. Anybody that know please help me in finding it because I need to work out the input by using voltage adder circuit before I feed the input to the vco, therefore, i need to confirm with the square wave input of 74HC4046. thanks!

 

Can you describe your application where you are using the 74HC4046 PLL?

hgmjr

 

I am building a circuit adder and I want to feed the output of it to the VCO in of 74HC4046 vco, because based on the datasheet, this type of VCO can output up to 12MHz. for my circuit, I want to get the output of 13.5MHz.

 

Hello,

I have an other datasheet from philips where is stated the maximum VCO center frequency is 17 MHz.
The absolute maximum is 19 MHz.

Bertus

 

thanks Bertus. do u know how to find the square wave input voltage for it? because i couldn't find it in the datasheet.

 

Hello,

The VCO has an analog input.
This is a control voltage on pin 9.

See also this thread:
4046 resistor capacitor frequency ranges?

Bertus

 

ok got it! tq Bertus!