Forums

Hot-carrier diode substitute

Started by garyr June 8, 2013
I want to make a simple rectifier for an RF signal, frequency less than 10
MHz. The schematic below (view with fixed font) is from an article
describing a circuit useable with much higher frequencies and used a
hot-carrier diode (1N5711). For relative low frequencies would a general
purpose diode such as a 1N4148 be adequate?

If a hot-carrier would be necessary I have a problem because I don't have
any but I do have a few high speed transistors: BSV52, BSF17, J310. Would
the base-emitter or base-collector junction of one of these transistors be a
suitable substitute for a hot-carrier diode?

      |
      \
      /R2 (20 uA bias current)
      \
   C1 |  R2     R3
  -||-+-/\/\-+-/\/\-
      |      |
      v D1   = C2
      -      |
      |     Gnd
     Gnd



On Sat, 8 Jun 2013 11:09:36 -0700, "garyr" <garyr@fidalgo.net> wrote:

>I want to make a simple rectifier for an RF signal, frequency less than 10 >MHz. The schematic below (view with fixed font) is from an article >describing a circuit useable with much higher frequencies and used a >hot-carrier diode (1N5711). For relative low frequencies would a general >purpose diode such as a 1N4148 be adequate? > >If a hot-carrier would be necessary I have a problem because I don't have >any but I do have a few high speed transistors: BSV52, BSF17, J310. Would >the base-emitter or base-collector junction of one of these transistors be a >suitable substitute for a hot-carrier diode? > > | > \ > /R2 (20 uA bias current) > \ > C1 | R2 R3 > -||-+-/\/\-+-/\/\- > | | > v D1 = C2 > - | > | Gnd > Gnd > >
Schottkies have lower voltage drops than PN diodes, which helps at any frequency. Low-barrier schottkies are best for rf detectors. Well, after germanium back diodes. Email me your address and I'll send you a few low-barrier schottkies. I don't know if DC bias helps, but you could try it. A transistor BE junction is a good diode, but it's still PN so has more voltage drop than a schottly. A jfet diode tends to have a lot of capacitance and it's in series with the channel resistance. An emitter follower is an interesting detector. A preamp, or a matching network, would of course improve low-level sensitivity. Or some fancy new detector chip. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
On Sat, 8 Jun 2013 11:09:36 -0700, "garyr" <garyr@fidalgo.net> wrote:

>I want to make a simple rectifier for an RF signal, frequency less than 10 >MHz. The schematic below (view with fixed font) is from an article >describing a circuit useable with much higher frequencies and used a >hot-carrier diode (1N5711). For relative low frequencies would a general >purpose diode such as a 1N4148 be adequate? > >If a hot-carrier would be necessary I have a problem because I don't have >any but I do have a few high speed transistors: BSV52, BSF17, J310. Would >the base-emitter or base-collector junction of one of these transistors be a >suitable substitute for a hot-carrier diode? > > | > \ > /R2 (20 uA bias current) > \ > C1 | R2 R3 > -||-+-/\/\-+-/\/\- > | | > v D1 = C2 > - | > | Gnd > Gnd > >
Less than 10MHz, a 1N4148 should work just fine. A diff-pair configured as a unity-gain follower, but with just a long-time-constant R/C as the load makes a quite accurate rectifier/detector. (Some PECL gates are easily configured into this arrangement.) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85140 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in 
message news:opv6r8hvktpml36sjh1d6ked2saa6f9clm@4ax.com...
> On Sat, 8 Jun 2013 11:09:36 -0700, "garyr" <garyr@fidalgo.net> wrote: > >>I want to make a simple rectifier for an RF signal, frequency less than 10 >>MHz. The schematic below (view with fixed font) is from an article >>describing a circuit useable with much higher frequencies and used a >>hot-carrier diode (1N5711). For relative low frequencies would a general >>purpose diode such as a 1N4148 be adequate? >> >>If a hot-carrier would be necessary I have a problem because I don't have >>any but I do have a few high speed transistors: BSV52, BSF17, J310. Would >>the base-emitter or base-collector junction of one of these transistors be >>a >>suitable substitute for a hot-carrier diode? >> >> | >> \ >> /R2 (20 uA bias current) >> \ >> C1 | R2 R3 >> -||-+-/\/\-+-/\/\- >> | | >> v D1 = C2 >> - | >> | Gnd >> Gnd >> >> > > Less than 10MHz, a 1N4148 should work just fine. > > A diff-pair configured as a unity-gain follower, but with just a > long-time-constant R/C as the load makes a quite accurate > rectifier/detector. (Some PECL gates are easily configured into this > arrangement.) > > ...Jim Thompson > -- > | James E.Thompson | mens | > | Analog Innovations | et | > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | > | San Tan Valley, AZ 85140 Skype: Contacts Only | | > | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | > | E-mail Icon at http://www.analog-innovations.com | 1962 | > > I love to cook with wine. Sometimes I even put it in the food.
I don't understand your diff-pair detector. Could you elaborate a bit?
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:qou6r89cdjt1q6rv6nseu73tpmd0p70knq@4ax.com...
> On Sat, 8 Jun 2013 11:09:36 -0700, "garyr" <garyr@fidalgo.net> wrote: > >>I want to make a simple rectifier for an RF signal, frequency less than 10 >>MHz. The schematic below (view with fixed font) is from an article >>describing a circuit useable with much higher frequencies and used a >>hot-carrier diode (1N5711). For relative low frequencies would a general >>purpose diode such as a 1N4148 be adequate? >> >>If a hot-carrier would be necessary I have a problem because I don't have >>any but I do have a few high speed transistors: BSV52, BSF17, J310. Would >>the base-emitter or base-collector junction of one of these transistors be >>a >>suitable substitute for a hot-carrier diode? >> >> | >> \ >> /R1 (20 uA bias current) >> \ >> C1 | R2 R3 >> -||-+-/\/\-+-/\/\- >> | | >> v D1 = C2 >> - | >> | Gnd >> Gnd >> >> > > Schottkies have lower voltage drops than PN diodes, which helps at any > frequency. Low-barrier schottkies are best for rf detectors. Well, after > germanium back diodes. > > Email me your address and I'll send you a few low-barrier schottkies. I > don't > know if DC bias helps, but you could try it. > > A transistor BE junction is a good diode, but it's still PN so has more > voltage > drop than a schottly. A jfet diode tends to have a lot of capacitance and > it's > in series with the channel resistance. > > An emitter follower is an interesting detector. > > A preamp, or a matching network, would of course improve low-level > sensitivity. > Or some fancy new detector chip. > > > > -- > > John Larkin Highland Technology Inc > www.highlandtechnology.com jlarkin at highlandtechnology dot com > > Precision electronic instrumentation > Picosecond-resolution Digital Delay and Pulse generators > Custom timing and laser controllers > Photonics and fiberoptic TTL data links > VME analog, thermocouple, LVDT, synchro, tachometer > Multichannel arbitrary waveform generators
I didn't realize that a hot-carrier was a type of schottky diode. I actually have a few SD101BW-TP schottky diodes which, according to the spec, have 2.1 pF capacitance at zero volts and a maximum forward voltage drop at 1 ma of 0.4 volts. They should be OK. My circuit will have about 30 dB gain ahead of the detector (two MMICs) and an opamp to buffer the output and provide some gain. Thanks for the info.
On Sat, 8 Jun 2013 18:27:52 -0700, "garyr" <garyr@fidalgo.net> wrote:

> >"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message >news:qou6r89cdjt1q6rv6nseu73tpmd0p70knq@4ax.com... >> On Sat, 8 Jun 2013 11:09:36 -0700, "garyr" <garyr@fidalgo.net> wrote: >> >>>I want to make a simple rectifier for an RF signal, frequency less than 10 >>>MHz. The schematic below (view with fixed font) is from an article >>>describing a circuit useable with much higher frequencies and used a >>>hot-carrier diode (1N5711). For relative low frequencies would a general >>>purpose diode such as a 1N4148 be adequate? >>> >>>If a hot-carrier would be necessary I have a problem because I don't have >>>any but I do have a few high speed transistors: BSV52, BSF17, J310. Would >>>the base-emitter or base-collector junction of one of these transistors be >>>a >>>suitable substitute for a hot-carrier diode? >>> >>> | >>> \ >>> /R1 (20 uA bias current) >>> \ >>> C1 | R2 R3 >>> -||-+-/\/\-+-/\/\- >>> | | >>> v D1 = C2 >>> - | >>> | Gnd >>> Gnd >>> >>> >> >> Schottkies have lower voltage drops than PN diodes, which helps at any >> frequency. Low-barrier schottkies are best for rf detectors. Well, after >> germanium back diodes. >> >> Email me your address and I'll send you a few low-barrier schottkies. I >> don't >> know if DC bias helps, but you could try it. >> >> A transistor BE junction is a good diode, but it's still PN so has more >> voltage >> drop than a schottly. A jfet diode tends to have a lot of capacitance and >> it's >> in series with the channel resistance. >> >> An emitter follower is an interesting detector. >> >> A preamp, or a matching network, would of course improve low-level >> sensitivity. >> Or some fancy new detector chip. >> >> >> >> -- >> >> John Larkin Highland Technology Inc >> www.highlandtechnology.com jlarkin at highlandtechnology dot com >> >> Precision electronic instrumentation >> Picosecond-resolution Digital Delay and Pulse generators >> Custom timing and laser controllers >> Photonics and fiberoptic TTL data links >> VME analog, thermocouple, LVDT, synchro, tachometer >> Multichannel arbitrary waveform generators > >I didn't realize that a hot-carrier was a type of schottky diode.
They are the same thing. I
>actually have a few SD101BW-TP schottky diodes which, according to the spec, >have 2.1 pF capacitance at zero volts and a maximum forward voltage drop at >1 ma of 0.4 volts. They should be OK.
Sounds fine at 10 MHz. For higher frequencies, you can get schottkies down to about 0.2 pF.
> >My circuit will have about 30 dB gain ahead of the detector (two MMICs) and >an opamp to buffer the output and provide some gain.
OK, lots of signal. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
On Sat, 8 Jun 2013 18:11:53 -0700, "garyr" <garyr@fidalgo.net> wrote:

> >"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in >message news:opv6r8hvktpml36sjh1d6ked2saa6f9clm@4ax.com... >> On Sat, 8 Jun 2013 11:09:36 -0700, "garyr" <garyr@fidalgo.net> wrote: >> >>>I want to make a simple rectifier for an RF signal, frequency less than 10 >>>MHz. The schematic below (view with fixed font) is from an article >>>describing a circuit useable with much higher frequencies and used a >>>hot-carrier diode (1N5711). For relative low frequencies would a general >>>purpose diode such as a 1N4148 be adequate? >>> >>>If a hot-carrier would be necessary I have a problem because I don't have >>>any but I do have a few high speed transistors: BSV52, BSF17, J310. Would >>>the base-emitter or base-collector junction of one of these transistors be >>>a >>>suitable substitute for a hot-carrier diode? >>> >>> | >>> \ >>> /R2 (20 uA bias current) >>> \ >>> C1 | R2 R3 >>> -||-+-/\/\-+-/\/\- >>> | | >>> v D1 = C2 >>> - | >>> | Gnd >>> Gnd >>> >>> >> >> Less than 10MHz, a 1N4148 should work just fine. >> >> A diff-pair configured as a unity-gain follower, but with just a >> long-time-constant R/C as the load makes a quite accurate >> rectifier/detector. (Some PECL gates are easily configured into this >> arrangement.) >> >> ...Jim Thompson >> -- >> | James E.Thompson | mens | >> | Analog Innovations | et | >> | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | >> | San Tan Valley, AZ 85140 Skype: Contacts Only | | >> | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | >> | E-mail Icon at http://www.analog-innovations.com | 1962 | >> >> I love to cook with wine. Sometimes I even put it in the food. > >I don't understand your diff-pair detector. Could you elaborate a bit? >
Tomorrow. I'm watching a movie on TV right now ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85140 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
On Sat, 8 Jun 2013 18:27:52 -0700, "garyr" <garyr@fidalgo.net> wrote:

>I didn't realize that a hot-carrier was a type of schottky diode.
<http://en.wikipedia.org/wiki/Schottky_diode> "The Schottky diode (named after German physicist Walter H. Schottky); also known as hot carrier diode is a semiconductor diode with a low forward voltage drop and a very fast switching action." This might be of interest: <http://www.elecraft.com/Apps/RF_Det_application_note.htm> I have a roll of 1N270 (germanium) diodes if you want some. Send me a mailing address and I put some in an envelope. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Jun 8, 9:09=A0pm, "garyr" <ga...@fidalgo.net> wrote:
> I want to make a simple rectifier for an RF signal, frequency less than 1=
0
> MHz. The schematic below (view with fixed font) is from an article > describing a circuit useable with much higher frequencies and used a > hot-carrier diode (1N5711). For relative low frequencies would a general > purpose diode such as a 1N4148 be adequate? > > If a hot-carrier would be necessary I have a problem because I don't have > any but I do have a few high speed transistors: BSV52, BSF17, J310. Would > the base-emitter or base-collector junction of one of these transistors b=
e a
> suitable substitute for a hot-carrier diode? > > =A0 =A0 =A0 | > =A0 =A0 =A0 \ > =A0 =A0 =A0 /R2 (20 uA bias current) > =A0 =A0 =A0 \ > =A0 =A0C1 | =A0R2 =A0 =A0 R3 > =A0 -||-+-/\/\-+-/\/\- > =A0 =A0 =A0 | =A0 =A0 =A0| > =A0 =A0 =A0 v D1 =A0 =3D C2 > =A0 =A0 =A0 - =A0 =A0 =A0| > =A0 =A0 =A0 | =A0 =A0 Gnd > =A0 =A0 =A0Gnd
I have used a 1N4148 at VHF frequencies. I am sure something like 1N5711 is better or atleast better with low level signals but you get DC out with 1N4148 too.
On Sat, 08 Jun 2013 20:22:46 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>This might be of interest: ><http://www.elecraft.com/Apps/RF_Det_application_note.htm> >I have a roll of 1N270 (germanium) diodes if you want some. >Send me a mailing address and I put some in an envelope.
Some followup on the above article comparing 1N4148, 1N270, and 1N5771: <http://www.diystompboxes.com/smfforum/index.php?topic=90503.0;prev_next=next> <http://www.cliftonlaboratories.com/diodes_for_rf_probes.htm> For sensitivity and linearity, 1N270. For high frequency sensitivity or broadband performance, 1N5771. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558