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

[gonzo .]

Hi    Mike,
I very much doubt you've killed both your chips
An awful lot of radio kits have been home built (using Si570) with very few reported failures.
http://www.wb5rvz.com/

Just checking, but you have tired OE high haven't you?

cheers,
ian



> Date: Sat, 22 Jan 2011 09:04:21 -0500
> From: Michael Baker <mpb45 at clanbaker.org>
> Subject: [time-nuts] Silicon Labs series of oscillators...
> To: time-nuts at febo.com
> Message-ID: <4D3AE3E5.4080709 at clanbaker.org>
> Content-Type: text/plain; charset="ISO-8859-1"
> 
>    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