Resonator Suppliers for 40 MHz?

[mcphill]

I am trying to find a place where I can order a few resonators at 40 MHz. I would prefer a 3-pin throughole style. I can find manufactures and datasheets, but I can't find the parts at any source that will supply in low quanitities (Mouser, Newark, Digikey, etc.).

A couple questions...

I have a 20 MHz resonator already, is there a way to "divide" that signal to provide my 40 MHz clock?

How would I use a crystal in place of my resonator - is there more hardware involved? They only have two pins, so what happens to the third?

Anyone have a source for 3-pin 40 MHz ceramic resonators?

TIA!

[rmteo]

Since you mentioned 40MHz, I assume that you are intending to use the resonator with a PIC18. With PIC18s, you can use 40MHz only in EC mode (external oscillator - not crystal or resonator). However, by using a 10MHz resonator (or crystal) in HS mode you can achieve a 40MHz clock by using the 4x PLL. In which case, one these will work:
http://search.digikey.com/scripts/Dk...me=490-1213-ND

Note: the "K" series will support up to 64MHz clock (and the PIC18s with USB, 48Mhz).

[Byte_Butcher]

The SMT resonators aren't THAT small. You could always solder wires on to one and *pretend* it's through hole...

Digikey has 40mhz in stock in SMT package...

[mcphill]

Thanks for that input, it is indeed for a PIC18. Is the 4x PLL a setting in the chip itself?

[rmteo]

It is a config word setting. Here is an example:

2.1 Oscillator Types

PIC18F2525/2620/4525/4620 devices can be operated
in ten different oscillator modes. The user can program
the Configuration bits, FOSC3:FOSC0, in Configuration
Register 1H to select one of these ten modes:
1. LP Low-Power Crystal
2. XT Crystal/Resonator
3. HS High-Speed Crystal/Resonator
4. HSPLL High-Speed Crystal/Resonator
with PLL Enabled
5. RC External Resistor/Capacitor with
FOSC/4 Output on RA6
6. RCIO External Resistor/Capacitor with I/O
on RA6
7. INTIO1 Internal Oscillator with FOSC/4 Output
on RA6 and I/O on RA7
8. INTIO2 Internal Oscillator with I/O on RA6
and RA7
9. EC External Clock with FOSC/4 Output
10. ECIO External Clock with I/O on RA6

[mcphill]

Thanks!

Looking up the 18F4420...

Yup, good to go! Thanks again.