[time-nuts] Silicon Labs series of oscillators..
gonzo .
cadbloke at hotmail.com
Sat Jan 22 18:22:12 UTC 2011
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
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