Help identifying a crystal oscillator

[rob.manderson]

Well, it's pretty well identified on the can - the problem is I can't find anything on line about it (like pinouts, working voltage etc).

I acquired 5 100 Mhz crystal oscillators - 14 pin dip form factor but only pins in the 1, 7, 8 and 14 positions.  The printing on the can is Cardinal LM 1400E 100 MHz.  Tried the obvious (pin 1 as o/c or en/dis able, pin 7 as ground, pin 8 as output and pin 14 as VCC - 3.3 volts initial guess).  Can't see any output but draws about 400 mA which seems very high.  Since the current drain seemed high I haven't tried 5 volts or higher.

I found the Cardinal website but could find nothing about LM 1400E on there.  Any ideas?

Rob

[dadler]

Maybe this is similar?

http://www.gedlm.com/DataSheets/LM1400.pdf

[uncle_bob]

Hi

The data sheet cited above is a pretty good guess. The fact that you get 400 ma strongly suggests you have the supply hooked up backwards.

One comment on the data sheet:

The supply is either -5.2 to a supply pin, case to ground *or* +5.2 to supply pin, case to ground. The sheet sort of suggests that you hook it up with -5.2 to one pin and +5.2 to the other .... not a good idea.

If it is PECL (per the data sheet), you may not see anything on the outputs until you terminate them with a load resistor.

Bob

[PA0PBZ]

The data sheet cited above is a pretty good guess. The fact that you get 400 ma strongly suggests you have the supply hooked up backwards.

But... the E suggests that VCC is pin 14 and max current is 140mA @ 5V. I guess you can try to reverse the supply but I don't have a lot of hope it will work.

[uncle_bob]

The data sheet cited above is a pretty good guess. The fact that you get 400 ma strongly suggests you have the supply hooked up backwards.

But... the E suggests that VCC is pin 14 and max current is 140mA @ 5V. I guess you can try to reverse the supply but I don't have a lot of hope it will work.

Hi

The E on the part may not correspond to the E pinout on the data sheet. The ECL pinouts listed are the next set to run through if the normal CMOS pinouts have not got the part working.

Bob

[rob.manderson]

Thanks.  It turns out that it does indeed follow the E pinouts in that data sheet - buggered if I know why it was drawing 400 mA yesterday when it's drawng about 130 mA today.  But it was necessary to load the output as commented upon - for test purposes I've run two 510 ohm resistors in series from Vcc to ground and connected the output to the junction.  And there it is, a nice 100 MHz sine wave on the 'scope - which goes to show how deceptive the 'scope can be - lots of nice odd harmonics on the Spectrum Analyser - out to 1.1GHz.  I think my simple comb generator will be easy to finish now! 

[PA0PBZ]

Weird stuff happens  Good that you have it running now!