I want to inject a 100 ps test pulse into a 50 ohm transmission line, tee-wise, sometimes, from a 25 ohm source. So I need a series switch. I'd never paid much attention to PIN diodes... they are RF stuff. But this one is shocking: https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf 2 ohms on, 0.14 pF off. And that's packaged. Chip and beam-lead parts are even better. Of course, in the long-honored RF tradition, there are no DC specs. No hint of the forward conduction curve. A tiny note suggests that 10 mA, 1 volt might happen. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.
PIN diode
Started by ●October 19, 2021
Reply by ●October 20, 20212021-10-20
On 2021-10-20 04:20, jlarkin@highlandsniptechnology.com wrote:> I want to inject a 100 ps test pulse into a 50 ohm transmission line, > tee-wise, sometimes, from a 25 ohm source. So I need a series switch. > > I'd never paid much attention to PIN diodes... they are RF stuff. But > this one is shocking: > > https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf > > 2 ohms on, 0.14 pF off. > > And that's packaged. Chip and beam-lead parts are even better. > > Of course, in the long-honored RF tradition, there are no DC specs. No > hint of the forward conduction curve. A tiny note suggests that 10 mA, > 1 volt might happen.DC-wise, it's just a diode. Not too many surprises there. Jeroen Belleman
Reply by ●October 20, 20212021-10-20
On Tue, 19 Oct 2021 19:20:04 -0700, jlarkin@highlandsniptechnology.com wrote:>I want to inject a 100 ps test pulse into a 50 ohm transmission line, >tee-wise, sometimes, from a 25 ohm source. So I need a series switch. > >I'd never paid much attention to PIN diodes... they are RF stuff. But >this one is shocking: > >https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf > >2 ohms on, 0.14 pF off. > >And that's packaged. Chip and beam-lead parts are even better. > >Of course, in the long-honored RF tradition, there are no DC specs. No >hint of the forward conduction curve. A tiny note suggests that 10 mA, >1 volt might happen.Not much likelihood of recognizing one if you stumbled over it either, from lack of marking info. RL
Reply by ●October 20, 20212021-10-20
Buy Ivermectin, lyrica,valium, diazepam and variety of weed strains Hi Mates, we have in stock the following for you. We will deliver within UK,Ireland, Scotland ,Wales Only They are top quality and are sell at affordable street prices with 10% discount on bulk orders. In stock, we have the following: Valium Diazepam Ivermectin Temazepam Adderall Oxycodone Lyrica Cali weed strains(Contact for strains and videos) Hash Dab Coke Uk to Uk delivery Contact Wickr :Vendorvuggs1
Reply by ●October 20, 20212021-10-20
On 10/20/2021 5:20, jlarkin@highlandsniptechnology.com wrote:> I want to inject a 100 ps test pulse into a 50 ohm transmission line, > tee-wise, sometimes, from a 25 ohm source. So I need a series switch. > > I'd never paid much attention to PIN diodes... they are RF stuff. But > this one is shocking: > > https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf > > 2 ohms on, 0.14 pF off. > > And that's packaged. Chip and beam-lead parts are even better. > > Of course, in the long-honored RF tradition, there are no DC specs. No > hint of the forward conduction curve. A tiny note suggests that 10 mA, > 1 volt might happen. > > >Thanks for posting this John. I had been looking for something like that for a pulse generator I might want to build one day (after nearly 30 years this day may be coming closer...) and so far I had seen only parts with 1-2 V reverse voltage ability; this one seems to handle way more than I need.
Reply by ●October 20, 20212021-10-20
On Wed, 20 Oct 2021 08:29:17 +0200, Jeroen Belleman <jeroen@nospam.please> wrote:>On 2021-10-20 04:20, jlarkin@highlandsniptechnology.com wrote: >> I want to inject a 100 ps test pulse into a 50 ohm transmission line, >> tee-wise, sometimes, from a 25 ohm source. So I need a series switch. >> >> I'd never paid much attention to PIN diodes... they are RF stuff. But >> this one is shocking: >> >> https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf >> >> 2 ohms on, 0.14 pF off. >> >> And that's packaged. Chip and beam-lead parts are even better. >> >> Of course, in the long-honored RF tradition, there are no DC specs. No >> hint of the forward conduction curve. A tiny note suggests that 10 mA, >> 1 volt might happen. > >DC-wise, it's just a diode. Not too many surprises there. > >Jeroen BellemanI just found this in my spam folder: https://rfmwblog.com/2021/10/18/why-are-dc-specifications-included-on-rf-device-data-sheets/?utm_source=RFMWSource-Monthly&utm_campaign=20211017-Source&utm_medium=email&utm_term=blog-dc-specs&utm_content=blog This is hilarious, and attempt to answer their question "why take DC test measurements at all?" when all any RF guy needs is S-parameters. I can imagine dozens of diode types. This PIN is probably GaAs. I have +-5 volts available to turn it on and off, but I can imagine having 0/+2.5 from an FPGA, or +-0.8 differential PECL. Its DC curves and tolerances might matter. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.
Reply by ●October 20, 20212021-10-20
On 2021-10-20 17:42, Dimiter_Popoff wrote:> On 10/20/2021 5:20, jlarkin@highlandsniptechnology.com wrote: >> I want to inject a 100 ps test pulse into a 50 ohm transmission line, >> tee-wise, sometimes, from a 25 ohm source. So I need a series switch. >> >> I'd never paid much attention to PIN diodes... they are RF stuff. But >> this one is shocking: >> >> https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf >> >> 2 ohms on, 0.14 pF off. >> >> And that's packaged. Chip and beam-lead parts are even better. >> >> Of course, in the long-honored RF tradition, there are no DC specs. No >> hint of the forward conduction curve. A tiny note suggests that 10 mA, >> 1 volt might happen. >> >> >> > > Thanks for posting this John. I had been looking for something like > that for a pulse generator I might want to build one day (after > nearly 30 years this day may be coming closer...) and so far I > had seen only parts with 1-2 V reverse voltage ability; this one > seems to handle way more than I need.You do realize that it's not the PIN diode that makes the pulse, right? A pin diode is merely a switch, and not even a very fast one at that. Jeroen Belleman
Reply by ●October 20, 20212021-10-20
On Wed, 20 Oct 2021 18:42:53 +0300, Dimiter_Popoff <dp@tgi-sci.com> wrote:>On 10/20/2021 5:20, jlarkin@highlandsniptechnology.com wrote: >> I want to inject a 100 ps test pulse into a 50 ohm transmission line, >> tee-wise, sometimes, from a 25 ohm source. So I need a series switch. >> >> I'd never paid much attention to PIN diodes... they are RF stuff. But >> this one is shocking: >> >> https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf >> >> 2 ohms on, 0.14 pF off. >> >> And that's packaged. Chip and beam-lead parts are even better. >> >> Of course, in the long-honored RF tradition, there are no DC specs. No >> hint of the forward conduction curve. A tiny note suggests that 10 mA, >> 1 volt might happen. >> >> >> > >Thanks for posting this John. I had been looking for something like >that for a pulse generator I might want to build one day (after >nearly 30 years this day may be coming closer...) and so far I >had seen only parts with 1-2 V reverse voltage ability; this one >seems to handle way more than I need.Yeah, the specs shocked me, after struggling to do this with a schottky. The carrier lifetime could be a problem with long pulses. I love pulse generators. Let me know if I can help. There are all sorts of cheap fungens and scopes and such, but pulse generators are generally still mediocre and expensive. I want to do one myself some day, a really fast version of our DDG. http://www.highlandtechnology.com/DSS/P500DS.shtml -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.
Reply by ●October 20, 20212021-10-20
On 2021-10-20 17:46, jlarkin@highlandsniptechnology.com wrote:> On Wed, 20 Oct 2021 08:29:17 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 2021-10-20 04:20, jlarkin@highlandsniptechnology.com wrote: >>> I want to inject a 100 ps test pulse into a 50 ohm transmission line, >>> tee-wise, sometimes, from a 25 ohm source. So I need a series switch. >>> >>> I'd never paid much attention to PIN diodes... they are RF stuff. But >>> this one is shocking: >>> >>> https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf >>> >>> 2 ohms on, 0.14 pF off. >>> >>> And that's packaged. Chip and beam-lead parts are even better. >>> >>> Of course, in the long-honored RF tradition, there are no DC specs. No >>> hint of the forward conduction curve. A tiny note suggests that 10 mA, >>> 1 volt might happen. >> >> DC-wise, it's just a diode. Not too many surprises there. >> >> Jeroen Belleman > > I just found this in my spam folder: > > https://rfmwblog.com/2021/10/18/why-are-dc-specifications-included-on-rf-device-data-sheets/?utm_source=RFMWSource-Monthly&utm_campaign=20211017-Source&utm_medium=email&utm_term=blog-dc-specs&utm_content=blog > > This is hilarious, and attempt to answer their question "why take DC > test measurements at all?" when all any RF guy needs is S-parameters. > > I can imagine dozens of diode types. This PIN is probably GaAs. I have > +-5 volts available to turn it on and off, but I can imagine having > 0/+2.5 from an FPGA, or +-0.8 differential PECL. Its DC curves and > tolerances might matter.Ah, OK! ;-) An RF guy would just apply ten volts through a kOhm and a choke or two, so he doesn't care! Jeroen Belleman
Reply by ●October 20, 20212021-10-20
Am 20.10.21 um 17:59 schrieb Jeroen Belleman:> On 2021-10-20 17:42, Dimiter_Popoff wrote: >> On 10/20/2021 5:20, jlarkin@highlandsniptechnology.com wrote: >>> I want to inject a 100 ps test pulse into a 50 ohm transmission line, >>> tee-wise, sometimes, from a 25 ohm source. So I need a series switch. >>> >>> I'd never paid much attention to PIN diodes... they are RF stuff. But >>> this one is shocking: >>> >>> https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf >>> >>> 2 ohms on, 0.14 pF off. >>> >>> And that's packaged. Chip and beam-lead parts are even better. >>> >>> Of course, in the long-honored RF tradition, there are no DC specs. No >>> hint of the forward conduction curve. A tiny note suggests that 10 mA, >>> 1 volt might happen.No. the S-parameter tables give the conditions used for the measurement.>> Thanks for posting this John. I had been looking for something like >> that for a pulse generator I might want to build one day (after >> nearly 30 years this day may be coming closer...) and so far I >> had seen only parts with 1-2 V reverse voltage ability; this one >> seems to handle way more than I need. > > You do realize that it's not the PIN diode that makes the pulse, > right? A pin diode is merely a switch, and not even a very fast > one at that.and, for the LTspice fans: spice cannot simulate it. Gerhard