prevalence of 4 pin crystal chips

[Kelvin Chu]

Hi Group,

I was ordering parts the other day (well today) and I noticed that there're
alot of 4-pin crystal chips out there now... indeed, there seem to be more
of these than the normal 2-pin ones for SMT

But 2 of the pins are unused anyway...

I was reading up on it, and it seems that these 4-pin crystals are easier to
mount using machines, is this the only reason for their prevalence?

(Searching on Farnell for 32khz crystals)

Thanks

Kelv

 

[Tam/WB2TT]

"Kelvin Chu" <kc@ih.unsw.edu.au> wrote in message
news:d6p31e$e05$1@tomahawk.unsw.edu.au...

Hi Group,

I was ordering parts the other day (well today) and I noticed that
there're
alot of 4-pin crystal chips out there now... indeed, there seem to be more
of these than the normal 2-pin ones for SMT

But 2 of the pins are unused anyway...

I was reading up on it, and it seems that these 4-pin crystals are easier
to
mount using machines, is this the only reason for their prevalence?

(Searching on Farnell for 32khz crystals)

Thanks

Kelv


Here are my guesses:

1. The 4 pin results in using a standard SO package.
2. They use 4 pins because of the weight.

Tam

 

[Rich Grise]

On Sun, 22 May 2005 16:17:16 -0400, Tam/WB2TT wrote:

"Kelvin Chu" <kc@ih.unsw.edu.au> wrote in message

I was ordering parts the other day (well today) and I noticed that
there're
alot of 4-pin crystal chips out there now... indeed, there seem to be more
of these than the normal 2-pin ones for SMT

But 2 of the pins are unused anyway...

I was reading up on it, and it seems that these 4-pin crystals are easier
to
mount using machines, is this the only reason for their prevalence?

(Searching on Farnell for 32khz crystals)

Here are my guesses:
1. The 4 pin results in using a standard SO package.

That's the one. Standard packaging, pick & place, that sort of thing.

2. They use 4 pins because of the weight.

Cheers!
Rich

 

[Kelvin Chu]

Learn something every day

Thanks to both of you!

Kelv

"Rich Grise" <richgrise@example.net> wrote in message
newsan.2005.05.22.21.54.32.844664@example.net...

On Sun, 22 May 2005 16:17:16 -0400, Tam/WB2TT wrote:
"Kelvin Chu" <kc@ih.unsw.edu.au> wrote in message

I was ordering parts the other day (well today) and I noticed that
there're
alot of 4-pin crystal chips out there now... indeed, there seem to be
more
of these than the normal 2-pin ones for SMT

But 2 of the pins are unused anyway...

I was reading up on it, and it seems that these 4-pin crystals are
easier
to
mount using machines, is this the only reason for their prevalence?

(Searching on Farnell for 32khz crystals)

Here are my guesses:
1. The 4 pin results in using a standard SO package.

That's the one. Standard packaging, pick & place, that sort of thing.

2. They use 4 pins because of the weight.


Cheers!
Rich