5755	2011-01-20 06:39:29	wa9cgz	Pin Diode Help
Message	Date	From	Subject
I'm trying to locate a source for Pin diodes to use in a voltage controlled attenuator for HF (160 thru 10 meters). The following part numbers are known to work for this application Ba595,5082-3080,1n5957. I have been unable to locate a source for a small quanity does anyone have any of the these or know where to purchase them? (only need 4) I tried using 1n4007's and I could control the attenuation but the input Z when all over the place. the circuit I'm trying is a absorbtive attenuator with 4 diodes and was supposed to have a return loss of about 20db. If you know of other attenuator pin diodes that would work please let me know. Tnx Joe wa9cgz
5756	2011-01-20 06:47:02	John Levreault	Re: Pin Diode Help
Newark claims to have 36 pieces of the 5082-3080 in stock at $3.93 each. John NB1I
5757	2011-01-20 06:49:40	Weddig, Henning-C...	Re: Pin Diode Help
look at ebay.de e.g. http://shop.ebay.de/?_from=R40&_trksid=p5197.m570.l1313&_nkw=BA595&_sacat=See-All-Categories Tehy sell 50 for 6 Euros 50 cent + 5 euro shipping in Germany, may be a bit higher for tue US. Cheers Henning Weddig DK5LV Am 20.01.2011 15:39, schrieb wa9cgz: > I'm trying to locate a source for Pin diodes to use in > a voltage controlled attenuator for HF (160 thru 10 meters). > The following part numbers are known to work for this application > Ba595,5082-3080,1n5957. I have been unable to locate a source for a > small quanity does anyone have any of the these or know where to > purchase them? (only need 4) > I tried using 1n4007's and I could control the attenuation but the > input Z when all over the place. the circuit I'm trying is a absorbtive > attenuator with 4 diodes and was supposed to have a return loss > of about 20db. > If you know of other attenuator pin diodes that would work please > let me know. > > Tnx Joe wa9cgz > >
5758	2011-01-20 06:52:16	Chris Trask	Re: Pin Diode Help
> > I'm trying to locate a source for Pin diodes to use in > a voltage controlled attenuator for HF (160 thru 10 meters). > The following part numbers are known to work for this application > Ba595,5082-3080,1n5957. I have been unable to locate a source for a small > quanity does anyone have any of the these or know where to > purchase them? (only need 4) > I tried using 1n4007's and I could control the attenuation but the > input Z when all over the place. the circuit I'm trying is a absorbtive > attenuator with 4 diodes and was supposed to have a return loss > of about 20db. > If you know of other attenuator pin diodes that would work please > let me know. > There are a number of PIN diodes available on eBay, but not the types that you've asked about. Chris Trask N7ZWY / WDX3HLB Senior Member IEEE http://www.home.earthlink.net/~christrask/
5759	2011-01-20 07:30:22	bobtbobbo	Re: Pin Diode Help
Mouser has NTE555A pin diodes for $1.58 each. I forget their equivalant component but I believe they are good through VHF. Rs is .7 Ohms. Ct is 1.2 pf, Ir is 100nA, V(br)r is 35 Volts. Bob, K1AO
5760	2011-01-20 07:35:37	Weddig, Henning-C...	Re: Pin Diode Help
for lwo freqeuncy operati
5761	2011-01-20 10:23:09	popmedkoh	Re: Pin Diode Help
Hope this helps. It's an updated post from July, 2010: There is a fellow in Israel who parts out old Motorola commercial radios (Micoms, I recall) and sells the MA4P4006 which you can see in your data sheet is a 600 volt SMD part with a 6 microsecond carrier survival time instead of 3 us and capacitance of 2.2 pf instead of 0.7 pf. This is a hell-for-stout device that will easily tolerate tack soldering pigtail leads to the ends. He sells on eBay with the seller name 4z4rb which appears to be his callsign. His current listing for a lot of 10 for US $20 + $14.50 shipping is here: Expired Listing: http://cgi.ebay.com/10-HIGH-POWER-PIN-DIODES-MA4P7006-SMD-1072T-style-/150365460722?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item23027ad8f2 UPDATE!! Current price is USD 24.95 + 18.50 postage Current listing: http://shop.ebay.com/?_from=R40&_trksid=m570&_nkw=ma4p7006 Datasheet here: http://www.downeastmicrowave.com/PDF/ma4p.PDF This is a part designed to handle hundreds of watts of CW and at frequencies down to the 160 meter band (using the 10 x carrier survival time as mentioned) Having purchased some, I can vouch for his service and the quality of these parts which may have some flux
5762	2011-01-20 10:37:32	popmedkoh	Re: Pin Diode Help
Yikes, I double checked the links and I see that his current listing is for the 3 usec carrier lifetime device which may not work as well for 160 meters. You might contact him and see if he as any more of the MA4P4006 parts. David KE1LY
5763	2011-01-20 10:40:25	Brian Murrey	Re: Pin Diode Help
Diz has MPN3700's in stock if you can use them. http://www.kitsandparts.com
5764	2011-01-20 10:57:40	ehydra	Re: Pin Diode Help
I heard some of the 1N4007 variants have 100us plus. But this is inconsistent from part to part and not in the datasheet mentioned. I looked a long time around for diodes with extra long carrier lifetime and should be cheap. Nothing found. Any suggestions for 20KHz to 100KHz work? regards - Henry -- ehydra.dyndns.info Weddig, Henning-Christof schrieb: > for lwo freqeuncy operation to work, the PIUN diodes must have a long > carrier lifetime! > A rule of the thuimb: livetime 10 times larger than 1/fmin, i.e. for 1.8 > MHz the lifetime should be > 5.5 µs! > Rarely seen for PIN diodes, they most ahve lifetimes shorter than 1 µs. > > > Am 20.01.2011 16:30, schrieb bobtbobbo: >> Mouser has NTE555A pin diodes for $1.58 each. I forget their equivalant >> component but I believe they are good through VHF. Rs is .7 Ohms. Ct is >> 1.2 pf, Ir is 100nA, V(br)r is 35 Volts. >> >> Bob, K1AO >>
5765	2011-01-20 15:42:02	kb1gmx	Re: Pin Diode Help
Even if 1n4007 had a 10:1 variati
5766	2011-01-20 16:23:14	ehydra	Re: Pin Diode Help
Hi Allison - I think you misunderstood the two basic functions: 1. as a PIN storage device 2. as an (shunt/current) attenuator With the first it is possible to control with a power budget less than what you want to drive signal. The classical reflective antenna switch. With the second this is not possible, instead the control power is always more than the maximum to traverse thru the circuit: Look for schottky diode bridge. In older TTL datasheets there are in the output test circuits shown. Some of the LTC app notes use them. In WW2 there were severak 'ring-mixer attenuators' in the V2 rocket bomb. Please correct me, if I'm wrong. regards - Henry -- ehydra.dyndns.info kb1gmx schrieb: > Even if 1n4007 had a 10:1 variati
5767	2011-01-20 19:11:26	wa9cgz	Re: Pin Diode Help
all, My problem is not that the 1n4007 diodes won't work as a attenuator they do the issue is the attenuator return loss at minimum loss I see 1:15 but at say 8db loss the input SWR is 8:1 I can add a 3db fixed attenuator this improves the SWR to about 2.5:1. It would appear that diode rf resistance was wrong the the circuit values. This is why I'm trying to find the real diodes for the circuit in hope that I can obtain a better input SWR since the attenuator follows a filter that needs terminating. '-- In emrfd@yahoogroups.com, ehydra wrote: > > Hi Allison - > > I think you misunderstood the two basic functions: > 1. as a PIN storage device > 2. as an (shunt/current) attenuator > > With the first it is possible to control with a power budget less than > what you want to drive signal. The classical reflective antenna switch. > With the second this is not possible, instead the control power is > always more than the maximum to traverse thru the circuit: > Look for schottky diode bridge. In older TTL datasheets there are in the > output test circuits shown. > Some of the LTC app notes use them. > > In WW2 there were severak 'ring-mixer attenuators' in the V2 rocket bomb. > > Please correct me, if I'm wrong. > > > regards - > Henry > > > > -- > ehydra.dyndns.info > > > > kb1gmx schrieb: > > Even if 1n4007 had a 10:1 variati
5768	2011-01-21 04:44:14	joop_l	Re: Pin Diode Help
Your experience in high loss using 1N4007 seems to be mentioned here as well: http://qrp.kd4ab.org/1997/970319/0038.html That post also refers to: "Exploring IMD in RF switching & tuning diodes, QST 12/94" Perhaps you can find the QST article and get some more part numbers that are hopefully easier to obtain? Joop - pe1cqp
5769	2011-01-21 07:11:38	kb1gmx	Re: Pin Diode Help

5770	2011-01-21 07:42:10	popmedkoh	Re: Pin Diode Help
There was an article in QST about a year ago on PIN diodes and the sidebar mentioned that standard PN diodes do work as RF switches but the amount of power needed to switch the signal had to be equal or greater than the signal being switched and therefore usable gain did not result. PIN diodes are a different kettle of fish and because of the long minority carrier survival times, a small control signal could switch hundreds of watts of RF. Here's a discussion about rectifier diodes that sometimes work as PIN diodes. The interesting point is that there was no standardized internal structure for the 1N4007 as manufactured by 50 or more companies and some devices worked as varactors and PINs (and probably had terrible recovery times for switchmode power supply use). The discussi
5771	2011-01-21 08:19:49	Brooke Clarke	Re: Pin Diode Help
Hi Joe: Diodes can be put into two categories: 1) those that do not store charge like the 1N40xx, schottky, tunnel, and most diodes, 2) those that do store charge like PIN & varactor diodes. If a diode does not store charge then when RF (and or DC) is applied the operating point moves along the I-V curve of the diode. If the diode stores charge and the lifetime is much greater than the period of an RF signal then the operating point of the diode can be very different from the I-V curve. That's to say the diode impedance is not related to the slope of the I-V curve. So if you want to attenuate or switch signals over say 0.5 Vp-p then you need a PIN diode. But if you're working with small signals you can use almost any diode. Can you describe your application? http://www.prc68.com/I/Diodes.html -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com
5772	2011-01-21 09:55:21	kb1gmx	Re: Pin Diode Help
WB2wik said it nicely.. "Understanding its limitations the 1N4007 a reasonable, if not perfect, substitute in some applications for a PIN diode. I used it to reduce the power of my homebrew transcievers to about 2 watts to drive a small 50W amplifier. The diode works well in this application and tests well, too." The diode is not quite as random as Steve pointed out. Its a standard device and has to be at least close to the datasheets. For it's intended use the tolerances are adequate. So whats to do for our use? TEST it in the circuit and measure the results. If the results are off the mark try a different source and retest. At a $1 for 10 (gross overcharge) to $1/100 there are not so expensive to try a few different vendors. My experience is for $0.01 each it works ok and and any lack of performance has to be balanced against that. On the other hand at $4.00 each the critter better work, and work well! For "production" circuits or high performance where repeatability is a criteria use the real thing and pay accordingly. I always keep a hundred or so in the parts draw as they are handy for so many things with the significant quality is they are on hand and not a week away when I need one now at 11:30PM Saturday. Note: I only use the epoxy types for non rectifier use as the glass types are photo sensitive (can you cay optical FM hum as varicaps). For some applications that can make an unacceptable difference unrelated to how the silicon was made or works! Allison