[time-nuts] Silicon Labs series of oscillators..
cadbloke at hotmail.com
Sat Jan 22 18:22:12 UTC 2011
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.
Just checking, but you have tired OE high haven't you?
> 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
> 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
> 1. http://www.silabs.com/products/clocksoscillators/pages/default.aspx
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