4-pin Crystal

I usually see crystals with 2-pins. Can anybody tell me what are the other
legs for in 4-pin crystal oscillator packages? Thanks in advance.

-- Hoi

 

These are oscillators, ie crystals + the required circuitry to make them
oscillate. The pins are vcc, gnd, clock out and the last is not connected.

They orivide a good accuracy and can be used as a clock line for several
chips.

vic

 

A crystal oscillator has power/gnd/out and possibly adjust or a no-connect.
There are 4-connector surface mount crystals. Two opposite corners are
the crystal and the other two seem to connect to the case (so you could
ground it).

 

Three of them are: VCC, GND and OUTPUT.

Sometimes they have an ENABLE.

 

Thanks a lot folks! I couldn't find the datasheet for the 4-pin oscillators
I have. Is there a general way to test which pin is which? I knew only one
of them is connected to the case, and I don't want to blow it up by putting
the power pin in the wrongest place.

 

Should be on Mouser.com










....

 

Most of these oscillators would fit in a 14 pin IC socket. Pin 1 is
marked (sharp corner while others are rounded) and may be a control or
enable input. Pin 7 is ground, 8 is output, and 14 is +5 volts.

Have a look at Digikey for oscillators - the package and pinout is
common to most manufacturers.

 

cool..... thank you all