On Fri, 22 Oct 2021 08:16:21 +0200, Jeroen Belleman <jeroen@nospam.please> wrote:>On 2021-10-22 00:44, John Larkin wrote: >> On Thu, 21 Oct 2021 15:25:49 -0400, legg <legg@nospam.magma.ca> wrote: >> >>> On Wed, 20 Oct 2021 16:41:57 -0700, John Larkin >>> <jlarkin@highland_atwork_technology.com> wrote: >>> >>>> On Wed, 20 Oct 2021 18:30:45 -0400, legg <legg@nospam.magma.ca> wrote: >>>> >>>>> On Wed, 20 Oct 2021 13:09:01 -0700, John Larkin >>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>> >>>>>> On Wed, 20 Oct 2021 14:50:53 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>> >>>>>>> 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. >>>>>>> >>>>>>> What's so special? >>>>>>> >>>>>>> A simple re-sort of smd marking files by function, voltage and >>>>>>> current, pulls up quite a few similar or superior devices. >>>>>>> >>>>>>> http://ve3ute.ca/query/smd_PIN_V_A_210810E.zip >>>>>>> >>>>>>> RL >>>>>> >>>>>> The amps and volts numbers appear to be abs max, forward current and >>>>>> reverse voltage. That tells nothing about the conduction curve. >>>>>> >>>>>> RF! >>>>> >>>>> You mean the 'R' values . . . ? >>>> >>>> What is the hfe column? Some values seem to be ohms (RF resistance?) >>>> and some are volts and some are in RT's and one is RfT! >>>> >>>> RF! >>>> >>>>> >>>>> I'd assumed you were praising C and R specs. You can sort for >>>>> those. They're a start. For a nominal V/I plot, you'd have to >>>>> get the datasheet. >>>> >>>> That was my point. PIN diode data sheets don't seem to have V/I data. >>>> >>>>> >>>>> Nominal plots aren't much use in design, where every part used >>>>> has to work. >>>> >>>> No data at all is better? That's all over RF data sheets. >>> >>> I don't think a standard PIN data sheet (or diode, for that matter) >>> is going to help you much, if you intend to use <5V as bias. >>> >>> You must be anticipating mV signal levels . . . then why a PIN? >>> >>> RL >> >> I want to inject a fast pulse, 1 volt or so, into a transmission line. >> 25 ohm source, 25 ohm load. >> >> And I want to really disconnect when we're not injecting this pulse. >> >> A 0.25 pF schottky would have its diode drop and an extra 10 ohms of >> series resistance. The PIN is just 2 ohms. >> > >What? The PIN has its diode drop too. The 2 ohms is the dynamic >resistance. > >Jeroen BellemanPINs are ohmic for fast signals. That's the point. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
PIN diode
Started by ●October 19, 2021
Reply by ●October 22, 20212021-10-22
Reply by ●October 22, 20212021-10-22
On Fri, 22 Oct 2021 12:56:21 -0700, John Larkin <jlarkin@highland_atwork_technology.com> wrote:>On Fri, 22 Oct 2021 08:16:21 +0200, Jeroen Belleman ><jeroen@nospam.please> wrote: > >>On 2021-10-22 00:44, John Larkin wrote: >>> On Thu, 21 Oct 2021 15:25:49 -0400, legg <legg@nospam.magma.ca> wrote: >>> >>>> On Wed, 20 Oct 2021 16:41:57 -0700, John Larkin >>>> <jlarkin@highland_atwork_technology.com> wrote: >>>> >>>>> On Wed, 20 Oct 2021 18:30:45 -0400, legg <legg@nospam.magma.ca> wrote: >>>>> >>>>>> On Wed, 20 Oct 2021 13:09:01 -0700, John Larkin >>>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>>> >>>>>>> On Wed, 20 Oct 2021 14:50:53 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>> >>>>>>>> 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. >>>>>>>> >>>>>>>> What's so special? >>>>>>>> >>>>>>>> A simple re-sort of smd marking files by function, voltage and >>>>>>>> current, pulls up quite a few similar or superior devices. >>>>>>>> >>>>>>>> http://ve3ute.ca/query/smd_PIN_V_A_210810E.zip >>>>>>>> >>>>>>>> RL >>>>>>> >>>>>>> The amps and volts numbers appear to be abs max, forward current and >>>>>>> reverse voltage. That tells nothing about the conduction curve. >>>>>>> >>>>>>> RF! >>>>>> >>>>>> You mean the 'R' values . . . ? >>>>> >>>>> What is the hfe column? Some values seem to be ohms (RF resistance?) >>>>> and some are volts and some are in RT's and one is RfT! >>>>> >>>>> RF! >>>>> >>>>>> >>>>>> I'd assumed you were praising C and R specs. You can sort for >>>>>> those. They're a start. For a nominal V/I plot, you'd have to >>>>>> get the datasheet. >>>>> >>>>> That was my point. PIN diode data sheets don't seem to have V/I data. >>>>> >>>>>> >>>>>> Nominal plots aren't much use in design, where every part used >>>>>> has to work. >>>>> >>>>> No data at all is better? That's all over RF data sheets. >>>> >>>> I don't think a standard PIN data sheet (or diode, for that matter) >>>> is going to help you much, if you intend to use <5V as bias. >>>> >>>> You must be anticipating mV signal levels . . . then why a PIN? >>>> >>>> RL >>> >>> I want to inject a fast pulse, 1 volt or so, into a transmission line. >>> 25 ohm source, 25 ohm load. >>> >>> And I want to really disconnect when we're not injecting this pulse. >>> >>> A 0.25 pF schottky would have its diode drop and an extra 10 ohms of >>> series resistance. The PIN is just 2 ohms. >>> >> >>What? The PIN has its diode drop too. The 2 ohms is the dynamic >>resistance. >> >>Jeroen Belleman > >PINs are ohmic for fast signals. That's the point.Where are you able to find any MADP-008120-12790T parts in stock ?? boB
Reply by ●October 22, 20212021-10-22
On Tuesday, October 19, 2021 at 7:20:14 PM UTC-7, jla...@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. > > > > -- > > 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.Here is a paper that describes a pulse generator using step recovery diodes: https://arxiv.org/pdf/1610.07115.pdf
Reply by ●October 22, 20212021-10-22
On Fri, 22 Oct 2021 15:33:52 -0700, boB <boB@K7IQ.com> wrote:>On Fri, 22 Oct 2021 12:56:21 -0700, John Larkin ><jlarkin@highland_atwork_technology.com> wrote: > >>On Fri, 22 Oct 2021 08:16:21 +0200, Jeroen Belleman >><jeroen@nospam.please> wrote: >> >>>On 2021-10-22 00:44, John Larkin wrote: >>>> On Thu, 21 Oct 2021 15:25:49 -0400, legg <legg@nospam.magma.ca> wrote: >>>> >>>>> On Wed, 20 Oct 2021 16:41:57 -0700, John Larkin >>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>> >>>>>> On Wed, 20 Oct 2021 18:30:45 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>> >>>>>>> On Wed, 20 Oct 2021 13:09:01 -0700, John Larkin >>>>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>>>> >>>>>>>> On Wed, 20 Oct 2021 14:50:53 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>> >>>>>>>>> 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. >>>>>>>>> >>>>>>>>> What's so special? >>>>>>>>> >>>>>>>>> A simple re-sort of smd marking files by function, voltage and >>>>>>>>> current, pulls up quite a few similar or superior devices. >>>>>>>>> >>>>>>>>> http://ve3ute.ca/query/smd_PIN_V_A_210810E.zip >>>>>>>>> >>>>>>>>> RL >>>>>>>> >>>>>>>> The amps and volts numbers appear to be abs max, forward current and >>>>>>>> reverse voltage. That tells nothing about the conduction curve. >>>>>>>> >>>>>>>> RF! >>>>>>> >>>>>>> You mean the 'R' values . . . ? >>>>>> >>>>>> What is the hfe column? Some values seem to be ohms (RF resistance?) >>>>>> and some are volts and some are in RT's and one is RfT! >>>>>> >>>>>> RF! >>>>>> >>>>>>> >>>>>>> I'd assumed you were praising C and R specs. You can sort for >>>>>>> those. They're a start. For a nominal V/I plot, you'd have to >>>>>>> get the datasheet. >>>>>> >>>>>> That was my point. PIN diode data sheets don't seem to have V/I data. >>>>>> >>>>>>> >>>>>>> Nominal plots aren't much use in design, where every part used >>>>>>> has to work. >>>>>> >>>>>> No data at all is better? That's all over RF data sheets. >>>>> >>>>> I don't think a standard PIN data sheet (or diode, for that matter) >>>>> is going to help you much, if you intend to use <5V as bias. >>>>> >>>>> You must be anticipating mV signal levels . . . then why a PIN? >>>>> >>>>> RL >>>> >>>> I want to inject a fast pulse, 1 volt or so, into a transmission line. >>>> 25 ohm source, 25 ohm load. >>>> >>>> And I want to really disconnect when we're not injecting this pulse. >>>> >>>> A 0.25 pF schottky would have its diode drop and an extra 10 ohms of >>>> series resistance. The PIN is just 2 ohms. >>>> >>> >>>What? The PIN has its diode drop too. The 2 ohms is the dynamic >>>resistance. >>> >>>Jeroen Belleman >> >>PINs are ohmic for fast signals. That's the point. > > >Where are you able to find any MADP-008120-12790T parts in stock ?? > >boB > > >Digikey and Richardson show "factory stock." -- 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 23, 20212021-10-23
On Fri, 22 Oct 2021 18:47:56 -0700, jlarkin@highlandsniptechnology.com wrote:>On Fri, 22 Oct 2021 15:33:52 -0700, boB <boB@K7IQ.com> wrote: > >>On Fri, 22 Oct 2021 12:56:21 -0700, John Larkin >><jlarkin@highland_atwork_technology.com> wrote: >> >>>On Fri, 22 Oct 2021 08:16:21 +0200, Jeroen Belleman >>><jeroen@nospam.please> wrote: >>> >>>>On 2021-10-22 00:44, John Larkin wrote: >>>>> On Thu, 21 Oct 2021 15:25:49 -0400, legg <legg@nospam.magma.ca> wrote: >>>>> >>>>>> On Wed, 20 Oct 2021 16:41:57 -0700, John Larkin >>>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>>> >>>>>>> On Wed, 20 Oct 2021 18:30:45 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>> >>>>>>>> On Wed, 20 Oct 2021 13:09:01 -0700, John Larkin >>>>>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>>>>> >>>>>>>>> On Wed, 20 Oct 2021 14:50:53 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>>> >>>>>>>>>> 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. >>>>>>>>>> >>>>>>>>>> What's so special? >>>>>>>>>> >>>>>>>>>> A simple re-sort of smd marking files by function, voltage and >>>>>>>>>> current, pulls up quite a few similar or superior devices. >>>>>>>>>> >>>>>>>>>> http://ve3ute.ca/query/smd_PIN_V_A_210810E.zip >>>>>>>>>> >>>>>>>>>> RL >>>>>>>>> >>>>>>>>> The amps and volts numbers appear to be abs max, forward current and >>>>>>>>> reverse voltage. That tells nothing about the conduction curve. >>>>>>>>> >>>>>>>>> RF! >>>>>>>> >>>>>>>> You mean the 'R' values . . . ? >>>>>>> >>>>>>> What is the hfe column? Some values seem to be ohms (RF resistance?) >>>>>>> and some are volts and some are in RT's and one is RfT! >>>>>>> >>>>>>> RF! >>>>>>> >>>>>>>> >>>>>>>> I'd assumed you were praising C and R specs. You can sort for >>>>>>>> those. They're a start. For a nominal V/I plot, you'd have to >>>>>>>> get the datasheet. >>>>>>> >>>>>>> That was my point. PIN diode data sheets don't seem to have V/I data. >>>>>>> >>>>>>>> >>>>>>>> Nominal plots aren't much use in design, where every part used >>>>>>>> has to work. >>>>>>> >>>>>>> No data at all is better? That's all over RF data sheets. >>>>>> >>>>>> I don't think a standard PIN data sheet (or diode, for that matter) >>>>>> is going to help you much, if you intend to use <5V as bias. >>>>>> >>>>>> You must be anticipating mV signal levels . . . then why a PIN? >>>>>> >>>>>> RL >>>>> >>>>> I want to inject a fast pulse, 1 volt or so, into a transmission line. >>>>> 25 ohm source, 25 ohm load. >>>>> >>>>> And I want to really disconnect when we're not injecting this pulse. >>>>> >>>>> A 0.25 pF schottky would have its diode drop and an extra 10 ohms of >>>>> series resistance. The PIN is just 2 ohms. >>>>> >>>> >>>>What? The PIN has its diode drop too. The 2 ohms is the dynamic >>>>resistance. >>>> >>>>Jeroen Belleman >>> >>>PINs are ohmic for fast signals. That's the point. >> >> >>Where are you able to find any MADP-008120-12790T parts in stock ?? >> >>boB >> >> >> > >Digikey and Richardson show "factory stock."OK, it says they do ! I looked through OEMs Trade or Octopart and showed zero. But going to Digikey separately showed what you said. Wonder if there is any difference in "factory stock" and regular stock ?
Reply by ●October 23, 20212021-10-23
On a sunny day (Fri, 22 Oct 2021 17:06:58 -0700 (PDT)) it happened Flyguy <soar2morrow@yahoo.com> wrote in <6ce38fc3-741f-4ea8-aa2c-3aaf75bcd425n@googlegroups.com>:>Here is a paper that describes a pulse generator using step recovery diodes: >https://arxiv.org/pdf/1610.07115.pdfNice, thanks.
Reply by ●October 27, 20212021-10-27
On Wednesday, October 20, 2021 at 6:38:37 PM UTC-7, Gerhard Hoffmann wrote:> Am 21.10.21 um 03:12 schrieb Gerhard Hoffmann: > > Am 21.10.21 um 01:15 schrieb John Larkin: > >> On Thu, 21 Oct 2021 00:22:10 +0200, Gerhard Hoffmann <dk...@arcor.de> > >> wrote: > > > >>> Am 20.10.21 um 23:34 schrieb Clifford Heath: > >>>> On 21/10/21 6:18 am, John Larkin wrote: > >>>>> On Wed, 20 Oct 2021 20:24:22 +0200, Gerhard Hoffmann <dk...@arcor.de> > > > >>>>>> Getting 20 mA forward current through a xyzzy diode is for beginners. > > > >>>>> Beginners with big power supplies. > > > >>>> RF switches typically need to stay turned on for the whole cycle. If > >>>> you > >>>> want to pass 10mA of RF current, you need 20mA of DC, or more, > >>>> depending > >>>> on linearity requirements. > > > >>> There is no way around the 20mA. It is needed that the serial resistance > >>> goes below 2 Ohms. > > > > > >> A pin diode doesn't quit conducting when the current reverses. That's > >> the point of the thick I region with a long charge recombination > >> lifetime. A little DC current can switch a lot of RF current. > > > >> The Macom part that I cited is under 2 ohms RF resistance at 100 MHz > >> and 10 mA DC. The RF current is limited by power dissipation. Which, > >> of sourse, they don't specify. > > > >> Without useful data and without Spice models, I suppose people design > >> around these parts by fiddling. > > > > > > you won't get a spice model because spice does not understand > > carrier lifetime which is crucial for PIN diode operation. > > You can easily get a Keysight ADS or a MWO model. > > > > But getting ADS or MWO will set you back > $100K unless you know the > > net and have enough criminal energy. ;-) > > > > Gerhard > To make the Ingrid: > I would not call it fiddling, applying the S-parameters and assume 20 mA > DC through the diode, or -10V across.Yeah, I don't really understand why John can't bias a diode--he seems so competent otherwise. lol PIN switch diode bias networks can create spikes on the signal lines at transition because of the energy stored in the bias chokes. In many apps that does not matter because the signal is not "looked at" during transition. In spook monitors/equipment, that spike is not allowed to go out to antennas. https://cdn.macom.com/applicationnotes/AG312.pdf I have not used PINs lately. I used the MASW-004103-1365 and family siblings on some stuff maybe 10 years ago. Nice parts. (carrier lt 300 ns and I thickness 8 um). The tiny thing can switch 4 watts 4 ways. I used HP HSMP-3802 in an IF variable attenuator 20+ years ago. Those too were nice. Approaching a "linear" dB/V attenuation in the control circuit was an interesting exercise. I almost had a need for a switch with something like a 105 dBm SHI rating a while back. I was looking at Metelics PINs (Macom has Metelics now). GaN did not cut it at all. We got off to other things--it never came to fruition. Robert H. Caverly is "the guy" for PIN diodes. He wrote a lot of papers. Caverly and Quinn: A SPICE MODEL FOR SIMULATING THE IMPEDANCE-FREQUENCY CHARACTERISTICS OF HIGH FREQUENCY PIN SWITCHING DIODES ^ disclaimer: I have not personally used this or looked into it at all. Microsemi used to have THE PIN DIODE CIRCUIT DESIGNERS’ HANDBOOK. I did not look for it.
