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Tek tunnel diode pulser
Hi, Gang
I picked up a Tek 067-0554-00 tunnel diode pulser. (There's one for sale on eBay now, it you'd like to see a photo). It is a little box that goes between a 100 volt square wave generator and the scope's vertical input, to test the risetime. The effect of the tunnel diode is to "sharpen" the edge of the square wave. Does anyone have the specs for this unit? I'd like to know the specified risetime of the tunnel diode pulser output and the type of tunnel diode used. There are only a few parts in the box, and should be easy to home-brew. I think a Tek TU-5 tunnel diode pulser is the same thing, except it uses UHF type connectors instead of BNC. The manual for the 1A1 (Nuvistor input) plug-in, page 6-9 shows a TU-5 in use to check risetime. Thanks, Ed Knobloch |
Craig Sawyers
I picked up a Tek 067-0554-00 tunnel diode pulser.Well, I'd like to say that I had the answer to that, having compiled lists cross referencing TD's to Instruments to Specifications - but I draw a blank on that one. I *think* that a later version was made for the PG506 calibration generator - that is called an 067-0681-01 and is specified at <=125ps. The tunnel diode for this is a 152-0177-02 or -03. The -02 is 10mA, 3pF germanium. The switching time for a Ge TD is about C/(2I) ps so in this case 3/0.02 = about 150ps, consistent enough with Tek's specification. The -03 version of the TD might have lower capacitance, but I don't have figures for this. The fastest TD's that Tek used were the 152-0383-00, at 50mA, 1.5pF used in the S51 and S52 TDR pulse heads - which should be capable of 15ps, but actually do a bit slower than that, because circuit capacitance adds a pF or two. Another fast one was the 067-0513-00 pulser, which used a 152-0254-01 diode with 100mA, 6pF characteristics. Theory says it should do 30ps, which is what the pulser is capable of (I've measured mine with an S4 head, and even that involves care and calculation to unravel what you see from the S4's 25ps rise). As for making a roll-your-own, problem 1 is finding a TD with the right capability. You could cannibalise an old 7B92 to harvest the right TD. Next is making sure that the layout doesn't compromise the switching time - stay capacitance and inductance is a killer. Cheers Craig |
--- In TekScopes@..., "Edward Knobloch" <k4pf@j...> wrote:
Hi, Gangbrew. --------- Ed, the specs for your little box is: Output: Ampl: 200 mV +/-10% into 50 ohm Risetime: 1 ns or less into 50 ohm Abberations: +2%,-2% total 4% pp Input: + or - 100 V squarewave capable of 10 mA at 1kHz It uses 153-0038-00 tunneldiode which is a selected 152-0154-00 which is also the reason Craig didn't have it his list. The info on the selection I have says that it is selected with a 100 to 250 ohm resistor to produce 200 mV pp waveform. Mail me off list if you want a scan of the schematics and parts list. /Zenith, Sweden |
Craig Sawyers
Risetime: 1 ns or less into 50 ohm It uses 153-0038-00 tunneldiode which is a selected 152-0154-00 whichThat's interesting - thanks! I'll put that one on the list. The 152-0154-00 is used in a number of things, including the TU-5. The diode is 10mA/9pF, giving a switching speed of about 450ps, which is consistent with the specification. Assuming wiring stray capacitance of 3pF, a composite switching speed of 600ps comes out of the calculation. Others interested in a roll-your-own might be interested that this diode is also in the RM546, RM547, R544, R556, 1S1, 1S2, 21A, 22A, 544, 546, 547, 556, 7B70 and 7B71. Craig |
--- In TekScopes@..., "Craig Sawyers" <c.sawyers@t...> wrote:
Didn't realize this stuff was so valuable.Risetime: 1 ns or less into 50 ohmIt uses 153-0038-00 tunneldiode which is a selected 152-0154-00 whichThat's interesting - thanks! I'll put that one on the list. The I have a few items I could probably be bribed out of. Self contained 30ps pulser works transmission line from same, need to check the diode. also have a 284 line somewhere in the attic. its diode is definitely bad. mike |
Hello Ed,
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Here is what I have on TU-5, a data sheet that I got on this list. I have a hulk of a TU-5 and it does have BNC connectors; perhaps in earlier version this unit had UHF connectors. Be careful when connecting the unit to the signal source. What looked intuitive connector polarity to me, is actually wrong and I connected 10 V pulses directly to tunnel diode, so now I have a hulk of a TU-5. Regards Miroslav Pokorni ----- Original Message -----
From: "Edward Knobloch" <k4pf@...> To: <TekScopes@...> Sent: Thursday, March 18, 2004 9:43 AM Subject: [TekScopes] Tek tunnel diode pulser Hi, Gang |
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