| Author |
Message |
Bob
Guest
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 Posted:
Fri Dec 16, 2005 5:05 pm Post subject:
Smallest Xtal |
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I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz. |
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PeteS
Guest
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| Posted:
Fri Dec 16, 2005 5:15 pm Post subject:
Re: Smallest Xtal |
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Bob wrote:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
|
See this page:
http://www.golledge.co.uk/docs/products/xtl_sm/xtl_sm.htm
for a typical selection.
The smallest I see is 2.6 x 2.1 x 0.6 (all mm)
Cheers
PeteS |
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Stef
Guest
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| Posted:
Fri Dec 16, 2005 5:15 pm Post subject:
Re: Smallest Xtal |
|
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In comp.arch.embedded,
Bob <bob3635x@yahoo.com> wrote:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
Does it have to be a crystal? You may have better luck finding smaller |
resonators and those also come with built-in caps. One example is the
Murata CSTCG_V series (20.00-33.86MHz), 2.0x1.3mm, built-in caps.
--
Stef (remove caps, dashes and .invalid from e-mail address to reply by mail)
Often statistics are used as a drunken man uses lampposts -- for support
rather than illumination. |
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Stef
Guest
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| Posted:
Fri Dec 16, 2005 5:15 pm Post subject:
Re: Smallest Xtal |
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In comp.arch.embedded,
Bob <bob3635x@yahoo.com> wrote:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
Another thought: Some small micro's have built-in oscs, but these |
are usually not very fast and not too accurate.
--
Stef (remove caps, dashes and .invalid from e-mail address to reply by mail)
You may have heard that a dean is to faculty as a hydrant is to a dog.
-- Alfred Kahn |
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MK
Guest
|
| Posted:
Fri Dec 16, 2005 5:15 pm Post subject:
Re: Smallest Xtal |
|
|
"Bob" <bob3635x@yahoo.com> wrote in message
news:1134731153.719531.309380@f14g2000cwb.googlegroups.com...
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
There are some very small crystals available but do your sums and test them |
carefully - I've found that AVRs can be very reluctant to start with small
crystals. It's much smaller (and cheaper) to use the built in RC oscillator
if you can. Silabs 8051 core parts and some AVRs these are pretty good.
MK
www.mkesc.co.uk |
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Spehro Pefhany
Guest
|
| Posted:
Fri Dec 16, 2005 5:15 pm Post subject:
Re: Smallest Xtal |
|
|
On Fri, 16 Dec 2005 16:23:12 -0000, the renowned "MK"
<nospam.please@here.ever> wrote:
| Quote: |
"Bob" <bob3635x@yahoo.com> wrote in message
news:1134731153.719531.309380@f14g2000cwb.googlegroups.com...
I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
There are some very small crystals available but do your sums and test them
carefully - I've found that AVRs can be very reluctant to start with small
crystals. It's much smaller (and cheaper) to use the built in RC oscillator
if you can. Silabs 8051 core parts and some AVRs these are pretty good.
MK
|
The smallest SMT crystals typically have rather low maximum power
dissipations, often <= 100uW, compared to the several mW that you can
safely pump into a HC49 can without damaging it. That means the
oscillator design is more fussy to get a circuit that will reliably
start over the temperature range without damaging it. Yeah, it's
usually just one extra resistor on the typical Pierce on-chip
oscillator, but...
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com |
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Jim Granville
Guest
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| Posted:
Sat Dec 17, 2005 12:19 am Post subject:
Re: Smallest Xtal |
|
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Bob wrote:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
|
Do you need the Xtal ? No crystal is the smallest :)
Quite a number of uC now have on chip OSC, that are calibrated,
and in the 10-30MHz region.
Actel's fusion specs 100MHz with 1% precision on chip osc.
(No curves published yet, but if true, and indication of the leading
edge....)
-jg |
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Mark Borgerson
Guest
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| Posted:
Sat Dec 17, 2005 1:07 am Post subject:
Re: Smallest Xtal |
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In article <2555d$43a2dee2$54f63171$9501@publishnet.news-service.com>,
stef33d@yahooI-N-V-A-L-I-D.com.invalid says...
| Quote: | In comp.arch.embedded,
Bob <bob3635x@yahoo.com> wrote:
I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
Does it have to be a crystal? You may have better luck finding smaller
resonators and those also come with built-in caps. One example is the
Murata CSTCG_V series (20.00-33.86MHz), 2.0x1.3mm, built-in caps.
If your micro will accept a clock input, you might try a LTC1799 |
resistor-set oscillator. It would require only the space of
an SOT23-5 and an 0603 resistor.
Mark Borgerson |
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Scott Moore
Guest
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| Posted:
Sat Dec 17, 2005 1:15 am Post subject:
Re: Smallest Xtal |
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Bob wrote On 12/16/05 03:05,:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
|
Surface mount. It does not get any smaller. |
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Mike Harrison
Guest
|
| Posted:
Sat Dec 17, 2005 5:15 pm Post subject:
Re: Smallest Xtal |
|
|
On Fri, 16 Dec 2005 11:07:40 -0800, Mark Borgerson <mborgerson.at.comcast.net> wrote:
| Quote: | In article <2555d$43a2dee2$54f63171$9501@publishnet.news-service.com>,
stef33d@yahooI-N-V-A-L-I-D.com.invalid says...
In comp.arch.embedded,
Bob <bob3635x@yahoo.com> wrote:
I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
Does it have to be a crystal? You may have better luck finding smaller
resonators and those also come with built-in caps. One example is the
Murata CSTCG_V series (20.00-33.86MHz), 2.0x1.3mm, built-in caps.
If your micro will accept a clock input, you might try a LTC1799
resistor-set oscillator. It would require only the space of
an SOT23-5 and an 0603 resistor.
Mark Borgerson
|
Could you use a MCU with an on-chip RC oscillator. e.g. the newer PICs can be as good as 1% - if you
need better could you calibrate agains some external signal ?
I think Dallas/Maxim do some programmable oscillator chips that may be worth a look if cost is not
too critical.
Another possibility is to use an LC oscillator - I think many MCU on-chip oscillators can be used
with an LC combination instead of a crystal. |
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Arie de Muynck
Guest
|
| Posted:
Sun Dec 18, 2005 4:13 pm Post subject:
Re: Smallest Xtal |
|
|
"Bob" <bob3635x@yahoo.com> wrote
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
|
If exact frequency is not needed, either use a MCU with internal
RC-oscillator (as suggested) or use an SMD inductor instead of the XTAL,
most chips work fine with that.
Frequency is 1 / (2 * pi * squareroot(L * C)) with C being the series
replacement of the external caps (half the C's value if both are equal).
---
Arie de Muijnck |
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Mike Harrison
Guest
|
| Posted:
Sun Dec 18, 2005 5:15 pm Post subject:
Re: Smallest Xtal |
|
|
On 16 Dec 2005 03:05:53 -0800, "Bob" <bob3635x@yahoo.com> wrote:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
|
Depending on the shape of the available space, maybe you could use aw atch crystal type package
sitting on top of other parts. |
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Anton Erasmus
Guest
|
| Posted:
Mon Dec 19, 2005 9:15 am Post subject:
Re: Smallest Xtal |
|
|
On 16 Dec 2005 03:05:53 -0800, "Bob" <bob3635x@yahoo.com> wrote:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
|
Use one of the new generation silicon clock generators. They are
available in very small packages. Some can be programmed over a
1 wire bus to the frequency you need. Others use one external resistor
to set the frequency. Maxim, Linear Technology and others manufacture
these devices.
Regards
Anton Erasmus |
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Mat Nieuwenhoven
Guest
|
| Posted:
Tue Dec 20, 2005 12:21 pm Post subject:
Re: Smallest Xtal |
|
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On 16 Dec 2005 03:05:53 -0800, Bob wrote:
| Quote: | I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
|
If you get hold of a old/bad computer motherboard, there is likely a very
small 14.something MHz crsytal on there.
Mat Nieuwenhoven |
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Jim Stewart
Guest
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| Posted:
Wed Dec 21, 2005 12:18 am Post subject:
Re: Smallest Xtal |
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Mat Nieuwenhoven wrote:
| Quote: | On 16 Dec 2005 03:05:53 -0800, Bob wrote:
I am working on a design that needs to be as small as possible. I
am using 0201 caps and resistors, and the smallest microcontroller
I can find. So now the biggest component is the crystal. What is
the smallest crystal package available?
I am not too picky about the freq, something in the range of 10 to
20 MHz.
If you get hold of a old/bad computer motherboard, there is likely a very
small 14.something MHz crsytal on there.
|
Likewise, old NTSC video gear. |
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