[time-nuts] Silicon Labs series of oscillators...

Bob Bownes bownes at gmail.com
Sat Jan 22 14:27:22 UTC 2011


depending on the complexity, I use one of 3 approaches:

1) Premade adapter (aka surfboard) which adapts the package to
something with pins on 0.1" spacing. These can be bought various
places or made with traditional methods at home.

2) Quick home made version of above. Usually double sided pcb cut up
with an x-acto knife, pins coming out the top, the other side as
ground plane.

3) straight to pcb design. With it being very inexpensive to get pcb's
made, you can often skip the old hand made prototype stage and either
get your whole design made or get it built in stages, then integrate
it all in a final pcb.


Bob, KI2L

On Sat, Jan 22, 2011 at 9:13 AM, J. L. Trantham <jltran at att.net> wrote:
> Surfboards?  From Alltronics?
>
> Joe
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Michael Baker
> Sent: Saturday, January 22, 2011 8:04 AM
> To: time-nuts at febo.com
> Subject: [time-nuts] Silicon Labs series of oscillators...
>
>
>   Hello, TimeNutters-
>   Silicon Labs
>   [1]http://www.silabs.com/products/clocksoscillators/pages/default.aspx
>   offers a large assortment of various types of oscillator
>   chips: XO, VCXO, programmable XO, clock generators,
>   clock distribution chips, Jitter Attenuators, Clock cleaners,
>   etc, etc....
>   I have a need for a 110 MHz VCXO in a 1.8GHz to 7.5GHz
>   tracking generator I am building for my Tek 494 spectrum
>   analyzer.  I bought a pair of Silicon Labs 110 MHz VCXO
>   chips for less than $25 for the pair from Cramer
>   Distributors. The Si595 VCXO chips are in an
>   "industry standard" 5mm X 7mm surface-mount package.
>   Yikes!  I knew I was going to have trouble (for lack
>   of thru-hole leads) breadboarding this chip.  However,
>   I managed (using a magnifier-loupe and a v-e-r-r-r-y
>   tiny soldering iron tip) to get some "legs" soldered
>   onto the surface-mount pads. Great...  I inserted the
>   critter into the socket-strips of my breadboard, hooked
>   up the required 3.3vdc Vdd and ground and checked to
>   see what it's output looks like.
>   No joy.  Drat.  It has a set of complementary output
>   pins. One sits at around 50% of Vdd and the other is low.
>   When I pull the Output Enable pin high, the 50% output
>   pin goes low.  The other (complementary) pin just stays
>   low.  If I pull the Output Enable pin low, neither
>   output pin changes.
>   Drat.  I must have destroyed the little critter during
>   the leg soldering process.  These chips are supposed
>   to be pretty static from normal handling and-- here in
>   humid Flori-DUH, handling problems from static build-up
>   is almost a non-existent problem.  Even so, I do all my
>   breadboarding on a 3-foot X 2-foot static-drain pad.
>   Sooooo.... I used the utmost care in soldering legs to
>   the second chip.  The surface-mount pads are gold-plated
>   and it is super easy to just momentarily tap them with the
>   soldering iron tip and leave a very teensy blob of
>   solder on each one.  Using pre-tinned gold-plated
>   legs stripped from some surplus 1/8 Watt resistors, I
>   fastened the legs on the chip with only the briefest
>   time of soldering-iron tip contact; less than one second,
>   I am guessing.
>   Same result with the second chip; the outputs appear to
>   be dead.
>   I guess this sad saga boils down to my question for the
>   Time-Nutters List: How do you deal with breadboarding
>   when it comes to parts that are ONLY available in
>   surface-mount configuration (and are just at the size
>   limit for hand soldering?
>   Thanks for any input on this!
>   Mike Baker
>   Micanopy, FL
>   ------------------------
>
> References
>
>   1. http://www.silabs.com/products/clocksoscillators/pages/default.aspx
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