4 pin vs. 2 pin crystal (3.57MHz)

F

Farce Milverk

Guest
Hi,

I have 2 crystals rated at 3.57 MHz (for driving video)

One is 2 pin, and the other is a 4 pin. I have the 4 pin working, but not
the 2 pin -

I am looking for info on how to substitute a 2 pin in place of a 4 pin.

thx,
Farce
 
On Sun, 26 Nov 2006 17:20:03 GMT, "Farce Milverk"
<farcmilverk@yahoo.com> wrote:

Hi,

I have 2 crystals rated at 3.57 MHz (for driving video)

One is 2 pin, and the other is a 4 pin. I have the 4 pin working, but not
the 2 pin -

I am looking for info on how to substitute a 2 pin in place of a 4 pin.
Click to expand...
---
For the 2 pin you must build an oscillator.

--
JF
 
"John Fields" <jfields@austininstruments.com> wrote in message
news:aadkm219nom7q0ifmo034o545m55bnbs8u@4ax.com...
On Sun, 26 Nov 2006 17:20:03 GMT, "Farce Milverk"
farcmilverk@yahoo.com> wrote:

Hi,

I have 2 crystals rated at 3.57 MHz (for driving video)

One is 2 pin, and the other is a 4 pin. I have the 4 pin working, but
not
the 2 pin -

I am looking for info on how to substitute a 2 pin in place of a 4 pin.

---
For the 2 pin you must build an oscillator.

--
JF
Click to expand...
Hi John,

Can you point me to info on why this is the case?

Thanks!

Farce
 
On Mon, 27 Nov 2006 02:32:43 GMT, "Farce Milverk"
<farcmilverk@yahoo.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:aadkm219nom7q0ifmo034o545m55bnbs8u@4ax.com...
On Sun, 26 Nov 2006 17:20:03 GMT, "Farce Milverk"
farcmilverk@yahoo.com> wrote:

Hi,

I have 2 crystals rated at 3.57 MHz (for driving video)

One is 2 pin, and the other is a 4 pin. I have the 4 pin working, but
not
the 2 pin -

I am looking for info on how to substitute a 2 pin in place of a 4 pin.

---
For the 2 pin you must build an oscillator.

--
JF

Hi John,

Can you point me to info on why this is the case?

Thanks!

Farce


What John means is that the 4 pin device you have is an active
Click to expand...
oscillator while the 2 pin device is simply a crystal which requires
other active components to get it to oscillate. The 4 pin oscillators
are commonly used to produce clock signals for IC devices. 2 of its
pins are simply to provide + and - power for the internal oscillator
which uses a crystal to set the frequency. The 2 pin crystal doesn't
have the oscillator part so you need to provide it.
 
On Mon, 27 Nov 2006 14:54:36 GMT, Ross Herbert
<rherber1@bigpond.net.au> wrote:


What John means is that the 4 pin device you have is an active
oscillator while the 2 pin device is simply a crystal which requires
other active components to get it to oscillate. The 4 pin oscillators
are commonly used to produce clock signals for IC devices. 2 of its
pins are simply to provide + and - power for the internal oscillator
which uses a crystal to set the frequency. The 2 pin crystal doesn't
have the oscillator part so you need to provide it.
Click to expand...
---
Right.

Thanks!


--
JF
 
"John Fields" <jfields@austininstruments.com> wrote in message
news:ir6mm2lmevdct0ckdn71p7j8s1lc9o1o4m@4ax.com...
On Mon, 27 Nov 2006 14:54:36 GMT, Ross Herbert
rherber1@bigpond.net.au> wrote:


What John means is that the 4 pin device you have is an active
oscillator while the 2 pin device is simply a crystal which requires
other active components to get it to oscillate. The 4 pin oscillators
are commonly used to produce clock signals for IC devices. 2 of its
pins are simply to provide + and - power for the internal oscillator
which uses a crystal to set the frequency. The 2 pin crystal doesn't
have the oscillator part so you need to provide it.

---
Right.

Thanks!


--
JF
Click to expand...
Great explanation thanks. I have one more question:

Does the 2 pin have a Pin 1 identifier?
Or is this a component that doesn't care?
I see XTAL and EXTAL in the schematic, but don't understand what this means?
 
On Mon, 27 Nov 2006 18:28:24 GMT, "Farce Milverk"
<farcmilverk@yahoo.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:ir6mm2lmevdct0ckdn71p7j8s1lc9o1o4m@4ax.com...
On Mon, 27 Nov 2006 14:54:36 GMT, Ross Herbert
rherber1@bigpond.net.au> wrote:


What John means is that the 4 pin device you have is an active
oscillator while the 2 pin device is simply a crystal which requires
other active components to get it to oscillate. The 4 pin oscillators
are commonly used to produce clock signals for IC devices. 2 of its
pins are simply to provide + and - power for the internal oscillator
which uses a crystal to set the frequency. The 2 pin crystal doesn't
have the oscillator part so you need to provide it.

---
Right.

Thanks!


--
JF

Great explanation thanks. I have one more question:

Does the 2 pin have a Pin 1 identifier?
Or is this a component that doesn't care?
Click to expand...
---
It's a don't care.
---

I see XTAL and EXTAL in the schematic, but don't understand what this means?
Click to expand...
If it's for a 4 pin oscillator, that will be a pin which is used to
Enable or disable the oscillator. It could be that either a low or
a high will enable the oscillator, so you can either try it and find
out or go to the manufacturer's website and get the data sheet for
the oscillator.


--
JF
 
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