Drat. NTE is gone, and they took the last 5-GHz PNP with them.

Discussion:

(too old to reply)

Phil Hobbs

2024-09-04 21:54:19 UTC

The NTE2403, similar to the BFT92, but a bit better overall. Dunno who
actually made them. (I saw the news on s.e.repair today.)

Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.

I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(

Barstids.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

john larkin

2024-09-05 02:50:53 UTC

Permalink

On Wed, 4 Sep 2024 17:54:19 -0400, Phil Hobbs

Post by Phil Hobbs
The NTE2403, similar to the BFT92, but a bit better overall. Dunno who
actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(
Barstids.
Cheers
Phil Hobbs

There must be some property of this universe that prefers N-type
devices.

Phil Hobbs

2024-09-05 07:22:40 UTC

Permalink

Post by john larkin
On Wed, 4 Sep 2024 17:54:19 -0400, Phil Hobbs

There must be some property of this universe that prefers N-type
devices.

There seem to be a couple. The matter/antimatter asymmetry means that
getting p-type behavior in a practical device relies on holes, and holes
have much lower mobility than electrons.

The solid state physics notion of an electron is a bit confusing to lots of
people, because despite sounding like an isolated particle, it’s just as
much a collective phenomenon as a hole, with properties determined by the
band structure of the solid.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Jan Panteltje

2024-09-05 06:15:27 UTC

Permalink

On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Lots if RF snall signal low noise stoff in LNBs:
https://www.infineon.com/dgdl/Infineon-Design_guide_for_RF-transistors_and_diode_in_Low-Noise-Block-ApplicationNotes-v01_00-EN.pdf?fileId=8ac78c8c7e7124d1017f01f071aa5b8f
Does that help?

Complete LNBs inclusive transistors and peeseebees are 5 dollies on ebay.

Phil Hobbs

2024-09-05 07:30:50 UTC

Permalink

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

https://www.infineon.com/dgdl/Infineon-Design_guide_for_RF-transistors_and_diode_in_Low-Noise-Block-ApplicationNotes-v01_00-EN.pdf?fileId=8ac78c8c7e7124d1017f01f071aa5b8f
Does that help?
Complete LNBs inclusive transistors and peeseebees are 5 dollies on ebay.

Thanks. It’s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can’t put them in licensed designs, which
is what I’m moaning about.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

john larkin

2024-09-05 14:14:29 UTC

Permalink

On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. Its not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but cant put them in licensed designs, which
is what Im moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

Phil Hobbs

2024-09-05 14:49:42 UTC

Permalink

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. It’s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can’t put them in licensed designs, which
is what I’m moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,

VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)

the BJT needs to be a PNP.

It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.

Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(

The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)

The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.

Cheers

Phil Hobbs

john larkin

2024-09-05 22:06:26 UTC

Permalink

On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. Its not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but cant put them in licensed designs, which
is what Im moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

Phil Hobbs

2024-09-05 22:44:36 UTC

Permalink

Post by john larkin
On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. Its not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but cant put them in licensed designs, which
is what Im moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

I’ve used them a fair amount in front ends, generally with a SiGe NPN
cascode-slash-drain bootstrap. Their transconductance is a few times
higher than a CPH3910’s, but not as good as the local-feedback circuit’s.

pHEMTs have very low drain impedance—the late lamented ATF38143 had a
voltage gain of ~0.7 as a follower, even with a current sink in the tail.

Their amazing noise floor (~0.3 nV in 1 Hz) makes them well worth patching
up, but they do take some patching.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

john larkin

2024-09-05 22:55:04 UTC

Permalink

On Thu, 5 Sep 2024 22:44:36 -0000 (UTC), Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. It?s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can?t put them in licensed designs, which
is what I?m moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

Ive used them a fair amount in front ends, generally with a SiGe NPN
cascode-slash-drain bootstrap. Their transconductance is a few times
higher than a CPH3910s, but not as good as the local-feedback circuits.
pHEMTs have very low drain impedancethe late lamented ATF38143 had a
voltage gain of ~0.7 as a follower, even with a current sink in the tail.
Their amazing noise floor (~0.3 nV in 1 Hz) makes them well worth patching
up, but they do take some patching.
Cheers
Phil Hobbs

What is the Vdd in your circuit above?

I learned about jfet impact ionization from AoE. Keep the drain
voltage low!

Phil Hobbs

2024-09-06 00:07:45 UTC

Permalink

Post by john larkin
On Thu, 5 Sep 2024 22:44:36 -0000 (UTC), Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. It?s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can?t put them in licensed designs, which
is what I?m moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

What is the Vdd in your circuit above?
I learned about jfet impact ionization from AoE. Keep the drain
voltage low!

Yup. I run them between 2.5 and 3 V_DS.

That gives full transconductance, low noise, low leakage, and low
dissipation.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Jan Panteltje

2024-09-06 06:44:17 UTC

Permalink

On a sunny day (Fri, 6 Sep 2024 00:07:45 -0000 (UTC)) it happened Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 22:44:36 -0000 (UTC), Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. It?s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can?t put them in licensed designs, which
is what I?m moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

IÂve used them a fair amount in front ends, generally with a SiGe NPN
cascode-slash-drain bootstrap. Their transconductance is a few times
higher than a CPH3910Âs, but not as good as the local-feedback circuitÂs.
pHEMTs have very low drain impedanceÂthe late lamented ATF38143 had a
voltage gain of ~0.7 as a follower, even with a current sink in the tail.
Their amazing noise floor (~0.3 nV in 1 Hz) makes them well worth patching
up, but they do take some patching.
Cheers
Phil Hobbs

What is the Vdd in your circuit above?
I learned about jfet impact ionization from AoE. Keep the drain
voltage low!

Yup. I run them between 2.5 and 3 V_DS.

I run some on a few mV:
Loading Image...

Loading Image...

bitrex

2024-09-07 23:40:38 UTC

Permalink

Post by john larkin
On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. It’s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can’t put them in licensed designs, which
is what I’m moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

What about a PFET/JEFT cascode buffer kinda like:

<https://imgur.com/a/5fBR8Gb>

Phil Hobbs

2024-09-08 00:02:34 UTC

Permalink

Post by bitrex

Post by john larkin
On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. It’s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can’t put them in licensed designs, which
is what I’m moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

<https://imgur.com/a/5fBR8Gb>

There aren’t any decent discrete pfets left, and there never was a 5 GHz
one.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Phil Hobbs

2024-09-08 00:16:59 UTC

Permalink

Post by Phil Hobbs

Post by bitrex

Post by john larkin
On Thu, 5 Sep 2024 10:49:42 -0400, Phil Hobbs

Post by Phil Hobbs

Post by john larkin
On Thu, 5 Sep 2024 07:30:50 -0000 (UTC), Phil Hobbs

Post by Phil Hobbs

Post by Jan Panteltje
On a sunny day (Wed, 4 Sep 2024 17:54:19 -0400) it happened Phil Hobbs

Thanks. It’s not a 50-ohm system, so using those would be hard. I have
thousands for personal use, but can’t put them in licensed designs, which
is what I’m moaning about.
Cheers
Phil Hobbs

Can you use mmics? There are some really cool, fast, cheap, low-noise
things around. Just because the RF boys test everything at 50 ohms
doesn't mean we have to use them at 50 ohms.

For the wraparound topology, which is the second-best follower I know of,
VDD 0------*---------*
| |
R |
R |
R /
| |V
*-------| BFT92
| |\
|--* \
In 0-->| CPH3910 |
|--* |
| |
| |
*---------*----0 Follower output
|
V (tail current source)
the BJT needs to be a PNP.
It's a nice circuit, because the PNP reduces the output impedance a lot
without adding much noise at all--way better than an NPN follower after
the FET.
Because of the local feedback, the transistors need to be fairly
different in speed to maintain stability. The FET is about a 750-MHz
device, so a 5-GHz PNP is great. The alternative would be a 100-MHz
PNP, which would be too depressing to contemplate. :(
The very best follower topology I know about is a fancy bootstrapped
version of the White cathode follower, where the feedback is applied via
the tail source. That's much harder to stabilize, because there are
three transistors in the local feedback loop, but on the other hand its
gain is 0.9997 at baseband and above 0.995 at 10 MHz. (You can't
readily measure those sorts of numbers directly, so I inferred them from
its performance as a bootstrap.)
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.
Cheers
Phil Hobbs

The CPH3910 is a jfet. Might an un-assisted PHEMT be better?

<https://imgur.com/a/5fBR8Gb>

There aren’t any decent discrete pfets left, and there never was a 5 GHz
one.

I should add that a partially integrated solution could probably do a good
job at this.

The NFET has many performance constraints that might be hard to reproduce
on-chip, but the following stages are more flexible.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Gerhard Hoffmann

2024-09-05 23:43:20 UTC

Permalink

It seems, my 1st try did not work

Post by Phil Hobbs
The reason I care about getting such accurate bootstraps is a bit
subtle--probably I'd have enough bandwidth improvement with a gain of
0.9, but that extra 10% shows up as a gnarly settling transient at late
times, which screws up measurements. 0.9997 is dramatically better.

I've played with Bob Widlar's FET follower replacement:

<
https://www.flickr.com/photos/***@N07/53830817262/in/dateposted-public/
Gain seems to be 1.000 and noise is quite OK.
I wonder how this would work with today's transistors such as
BFP840 & friends. And no PNPs.
I have not yet built it.

E1 makes a noisy Vcc to see how many nV/rtHz I need there,
Q4, Q5 are just parking lots. V3 prevents Spice from crashing.

---
Vceo is no problem ( slightly older post)
Nobody forces us to leave the base open.

Post by Phil Hobbs
Cheers

Gerhard

john larkin

2024-09-05 23:58:35 UTC

Permalink

Post by Gerhard Hoffmann
It seems, my 1st try did not work

<
Gain seems to be 1.000 and noise is quite OK.
I wonder how this would work with today's transistors such as
BFP840 & friends. And no PNPs.
I have not yet built it.
E1 makes a noisy Vcc to see how many nV/rtHz I need there,
Q4, Q5 are just parking lots. V3 prevents Spice from crashing.
---
Vceo is no problem ( slightly older post)
Nobody forces us to leave the base open.

Post by Phil Hobbs
Cheers

Gerhard

BUF602 is a fabulous part, but it's crazy noisy by Phil's standards.

Phil Hobbs

2024-09-06 00:13:00 UTC

Permalink

Post by Gerhard Hoffmann
It seems, my 1st try did not work

Post by Phil Hobbs
Cheers

Gerhard

Fun.
That’s half of the LM11 input stage?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Bill Sloman

2024-09-05 11:15:16 UTC

Permalink

The NTE2403, similar to the BFT92, but a bit better overall. Dunno who
actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(

But you could use the Renesa HFA3096, which includes two 5.5GHz PNP parts.

https://www.renesas.com/us/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet

Not cheap, but still in production.

--
Bill Sloman, Sydney

bitrex

2024-09-05 14:24:56 UTC

Permalink

Post by Bill Sloman

The NTE2403, similar to the BFT92, but a bit better overall. Dunno
who actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(

But you could use the Renesa HFA3096, which includes two 5.5GHz PNP parts.
https://www.renesas.com/us/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet
Not cheap, but still in production.

They even provide the S parameters, isn't that nice. 8 volts CEO is a
bit limiting, though.

Someone must make the NTE2403 as far as I know they're just a re-seller,
yeah? Who would have thought repackaging 2N3055s and selling them for $3
a pop wasn't a growth industry..

Phil Hobbs

2024-09-05 18:17:50 UTC

Permalink

Post by bitrex

Post by Bill Sloman

The NTE2403, similar to the BFT92, but a bit better overall. Dunno
who actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(

But you could use the Renesa HFA3096, which includes two 5.5GHz PNP parts.
https://www.renesas.com/us/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet
Not cheap, but still in production.

They even provide the S parameters, isn't that nice. 8 volts CEO is a
bit limiting, though.
Someone must make the NTE2403 as far as I know they're just a re-seller,
yeah? Who would have thought repackaging 2N3055s and selling them for $3
a pop wasn't a growth industry..

The Renesas parts are very disappointing in actual use, on account of their
huge Ree’, Rbb’, and package inductance, as I found out to my cost long
ago.

Otherwise I’d be all over them.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Gerhard Hoffmann

2024-09-05 18:57:44 UTC

Permalink

Post by Phil Hobbs
The Renesas parts are very disappointing in actual use, on account of their
huge Ree’, Rbb’, and package inductance, as I found out to my cost long
ago.

They helped me make a nice 20-30 ns 1:1000 time stretcher, even in these
funny space-proof flatpacks with even more L.

Gerhard

Phil Hobbs

2024-09-05 19:58:28 UTC

Permalink

Post by Gerhard Hoffmann

Post by Phil Hobbs
The Renesas parts are very disappointing in actual use, on account of their
huge Ree’, Rbb’, and package inductance, as I found out to my cost long
ago.

They helped me make a nice 20-30 ns 1:1000 time stretcher, even in these
funny space-proof flatpacks with even more L.
Gerhard

Really terrible noise and log conformity though, which are what I cared
about most.

I was making a 100-MHz laser noise canceller.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Chris Jones

2024-09-06 12:47:10 UTC

Permalink

The NTE2403, similar to the BFT92, but a bit better overall. Dunno who
actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(
Barstids.
Cheers
Phil Hobbs

If most your designs are similar enough, perhaps you can consilidate it
into a single version and persuade Analog Devices to make it on their
XFCB3 process, either if you pay NRE and the design belongs to you, sold
as a custom part that they can only sell via you, or that they sell
themself and somehow give you a royalty. If you had a patent it might
help with that negotiation.

The other option I can imagine is that there might be a fab in China
capable of makine fast PNPs and who might find some pride in selling a
faster PNP than any western company does.

Gerhard Hoffmann

2024-09-06 15:31:55 UTC

Permalink

Post by Chris Jones
If most your designs are similar enough, perhaps you can consilidate it
into a single version and persuade Analog Devices to make it on their
XFCB3 process, either if you pay NRE and the design belongs to you, sold
as a custom part that they can only sell via you, or that they sell
themself and somehow give you a royalty. If you had a patent it might
help with that negotiation.

Some years ago I asked Scott Wurcer, RIP (Designer of AD797) in a
different context if AD could't make sth. like PNP or mixed MAT-02, 03,
04 on steroids. He said no way, even if hell freezes over or sth. to
that effect.

cheers, Gerhard.

Phil Hobbs

2024-09-06 17:33:06 UTC

Permalink

Post by Chris Jones

The NTE2403, similar to the BFT92, but a bit better overall. Dunno
who actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(
Barstids.
Cheers
Phil Hobbs

If most your designs are similar enough, perhaps you can consilidate it
into a single version and persuade Analog Devices to make it on their
XFCB3 process, either if you pay NRE and the design belongs to you, sold
as a custom part that they can only sell via you, or that they sell
themself and somehow give you a royalty. If you had a patent it might
help with that negotiation.
The other option I can imagine is that there might be a fab in China
capable of makine fast PNPs and who might find some pride in selling a
faster PNP than any western company does.

I've considered doing that sort of thing. We've done a couple of IC
designs in the past couple of years, in collaboration with a design
house in Tucson, but that was fancier than we'd really need.

I'd very much like to do a dual laser noise canceller chip on a decent
junction-isolated complementary bipolar process with superbeta NPNs.
There are all sorts of tricks you can play with that.

Cheers

Phil Hobbs

Joerg

2024-09-06 22:59:28 UTC

Permalink

The NTE2403, similar to the BFT92, but a bit better overall. Dunno who
actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(
Barstids.

Some of the good stuff is going away because there aren't many people
left who know how to use it and then trigger substantial sales.

How about the HFA3135 pair? Less noisy than the HFA3096 but not sure if
good enough for your projects:

https://www.renesas.com/us/en/document/dst/hfa3134-hfa3135-datasheet?r=532781

They are long leadtime and pricey though, often around 10 bucks.
Currently 18 weeks which often is code for "could be half a year", or so ...

The BFQ149 is probably to big and noisy for you.

--
Regards, Joerg

http://www.analogconsultants.com/

Phil Hobbs

2024-09-07 21:46:06 UTC

Permalink

Post by Joerg

The NTE2403, similar to the BFT92, but a bit better overall.� Dunno who
actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(
Barstids.

Some of the good stuff is going away because there aren't many people
left who know how to use it and then trigger substantial sales.
How about the HFA3135 pair? Less noisy than the HFA3096 but not sure if
https://www.renesas.com/us/en/document/dst/hfa3134-hfa3135-datasheet?r=532781
They are long leadtime and pricey though, often around 10 bucks.
Currently 18 weeks which often is code for "could be half a year", or so ...

Suggesting a $10 boutique part? Who are you, and what have you done with
Joerg S-C?
;)

Welcome back.
Cheers
Phil Hobbs
(Reposted)

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

Joerg

2024-09-09 21:02:21 UTC

Permalink

Post by Phil Hobbs

Post by Joerg

Some of the good stuff is going away because there aren't many people
left who know how to use it and then trigger substantial sales.
How about the HFA3135 pair? Less noisy than the HFA3096 but not sure if
https://www.renesas.com/us/en/document/dst/hfa3134-hfa3135-datasheet?r=532781
They are long leadtime and pricey though, often around 10 bucks.
Currently 18 weeks which often is code for "could be half a year", or so ...

Suggesting a $10 boutique part? Who are you, and what have you done with
Joerg S-C?
;)

Only when it's for a module that then sells for $10k :-)

--
Regards, Joerg

http://www.analogconsultants.com/

Phil Hobbs

2024-09-10 01:59:59 UTC

Permalink

The NTE2403, similar to the BFT92, but a bit better overall. Dunno who
actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(
Barstids.
Cheers
Phil Hobbs

Something like this. This is what I call a Type 2 bootstrap, in which
the bootstrap device is inside the TIA feedback loop. You have to worry
about drift and 1/f noise in the FET, but that's usually the least of
your worries.

Cheers

Phil Hobbs

===========
Version 4
SHEET 1 2276 1088
WIRE -496 112 -656 112
WIRE -464 112 -496 112
WIRE -224 112 -240 112
WIRE -112 112 -128 112
WIRE -224 128 -224 112
WIRE -128 128 -128 112
WIRE -496 144 -496 112
WIRE -656 192 -656 112
WIRE -224 224 -224 208
WIRE -128 224 -128 208
WIRE -496 240 -496 224
WIRE -496 240 -592 240
WIRE -496 256 -496 240
WIRE 160 288 112 288
WIRE 288 288 224 288
WIRE -656 320 -656 288
WIRE -288 320 -448 320
WIRE -192 320 -288 320
WIRE 112 320 112 288
WIRE 112 320 -192 320
WIRE -288 336 -288 320
WIRE -192 368 -192 320
WIRE 112 368 112 320
WIRE 160 368 112 368
WIRE 288 368 288 288
WIRE 288 368 240 368
WIRE 288 432 288 368
WIRE -656 480 -656 400
WIRE -496 480 -496 352
WIRE -496 480 -656 480
WIRE -368 480 -496 480
WIRE -288 480 -288 416
WIRE -288 480 -368 480
WIRE -192 480 -192 432
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WIRE 64 480 -192 480
WIRE 160 480 144 480
WIRE 288 496 288 432
WIRE 288 496 224 496
WIRE 160 512 128 512
WIRE -368 528 -368 480
WIRE 128 560 128 512
WIRE -672 576 -704 576
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WIRE -496 576 -560 576
WIRE -432 576 -496 576
WIRE -704 592 -704 576
WIRE -496 592 -496 576
WIRE -560 624 -560 576
WIRE -368 640 -368 624
WIRE -560 736 -560 688
WIRE -560 736 -576 736
WIRE -496 736 -496 672
WIRE -496 736 -560 736
WIRE -368 736 -368 720
WIRE -368 736 -496 736
FLAG -128 224 0
FLAG -224 224 0
FLAG -240 112 VCC
FLAG -112 112 VEE
FLAG -576 736 VEE
FLAG -464 112 VCC
FLAG 192 464 VCC
FLAG 192 528 VEE
FLAG 128 560 0
FLAG 288 432 out
FLAG -704 592 0
SYMBOL voltage -128 112 R0
WINDOW 0 41 50 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value -5
SYMBOL voltage -224 112 R0
WINDOW 0 -69 56 Left 2
SYMATTR InstName V2
SYMATTR Value +5
SYMBOL njf -448 256 M0
WINDOW 3 -112 -9 Left 2
SYMATTR Value BF862_1pA
SYMATTR InstName J1
SYMBOL res -512 128 R0
SYMATTR InstName R5
SYMATTR Value 100
SYMBOL pnp -592 288 R180
SYMATTR InstName Q2
SYMATTR Value BFT92
SYMBOL current -288 336 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
WINDOW 3 -58 -60 Left 2
SYMATTR InstName I1
SYMATTR Value PULSE(1u 1n 10n 10n 10n 0.5u)
SYMBOL res 144 384 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R4
SYMATTR Value 1Meg
SYMBOL cap 160 304 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName C3
SYMATTR Value 0.09p
SYMBOL cap -208 368 R0
SYMATTR InstName C4
SYMATTR Value 100p
SYMBOL res 160 464 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1m
SYMBOL res -640 304 M0
SYMATTR InstName R3
SYMATTR Value 1m
SYMBOL npn -432 528 R0
SYMATTR InstName Q1
SYMATTR Value BFU520D
SYMBOL res -384 624 R0
SYMATTR InstName R2
SYMATTR Value 160
SYMBOL res -512 576 R0
SYMATTR InstName R7
SYMATTR Value 1k
SYMBOL res -576 560 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R8
SYMATTR Value 1k
SYMBOL cap -576 624 R0
SYMATTR InstName C1
SYMATTR Value 1u
SYMBOL OpAmps\\UniversalOpAmp2 192 496 R0
WINDOW 123 -32 90 Left 2
WINDOW 39 -32 141 Left 2
WINDOW 40 -35 115 Left 2
SYMATTR InstName U1
SYMATTR Value2 Avol=50k GBW=100Meg Slew=3G
SYMATTR SpiceLine Ilimit=50m Rail=0 Vos=0
SYMATTR SpiceLine2 En=12n Enk=0 In=0 Ink=0 Rin=500Meg
TEXT 408 512 Left 2 !.lib \\electronics\\SpiceModels\\PHParts.lib
TEXT -824 736 Left 2 !.tran 1.5u
TEXT -104 344 Left 2 ;Photodiode
TEXT 248 520 Left 2 ;Similar to \nLM6171
TEXT -152 680 Left 2 !.model BF862_1pA NJF(Beta=47.800E-3 Betatce=-.5
Rd=.8 Rs=7.5000 Lambda=37.300E-3 Vto=-.57093\n+ Vtotc=-2.0000E-3
Is=6e-15 Isr=6e-15 N=1 Nr=2 Xti=3 Alpha=-1.0000E-3\n+ Vk=59.97
Cgd=7.4002E-12 M=.6015 Pb=.5 Fc=.5 Cgs=8.2890E-12 Kf=87.5E-18\n+ Af=1)
RECTANGLE Normal 48 496 -352 256 2

Phil Hobbs

2024-09-10 02:12:52 UTC

Permalink

Post by Phil Hobbs

The NTE2403, similar to the BFT92, but a bit better overall. Dunno
who actually made them. (I saw the news on s.e.repair today.)
Rochester claims to have 1,500,000 of the 2SA1462 (1.8 GHz) for 20
cents, but that's all she wrote.
I have a couple of reels of BFT92s and one of BFG31s, so I'm good for
protos and small production, but I can't use PNP wraparound bootstraps
for customer designs anymore. :(
Barstids.

Wrong file--this should be the right one
===========Version 4
SHEET 1 2276 1012
WIRE -496 112 -656 112
WIRE -464 112 -496 112
WIRE -224 112 -240 112
WIRE -112 112 -128 112
WIRE -224 128 -224 112
WIRE -128 128 -128 112
WIRE -496 144 -496 112
WIRE -656 192 -656 112
WIRE -224 224 -224 208
WIRE -128 224 -128 208
WIRE -496 240 -496 224
WIRE -496 240 -592 240
WIRE 160 240 112 240
WIRE 288 240 224 240
WIRE -496 256 -496 240
WIRE -656 320 -656 288
WIRE -288 320 -448 320
WIRE -192 320 -288 320
WIRE 112 320 112 240
WIRE 112 320 -192 320
WIRE 160 320 112 320
WIRE 288 320 288 240
WIRE 288 320 240 320
WIRE -288 336 -288 320
WIRE -192 368 -192 320
WIRE 288 432 288 320
WIRE -656 480 -656 400
WIRE -496 480 -496 352
WIRE -496 480 -656 480
WIRE -368 480 -496 480
WIRE -288 480 -288 416
WIRE -288 480 -368 480
WIRE -192 480 -192 432
WIRE -192 480 -288 480
WIRE -48 480 -192 480
WIRE 160 480 32 480
WIRE 288 496 288 432
WIRE 288 496 224 496
WIRE 160 512 128 512
WIRE -368 528 -368 480
WIRE 128 544 128 512
WIRE -672 576 -704 576
WIRE -560 576 -592 576
WIRE -496 576 -560 576
WIRE -432 576 -496 576
WIRE -704 592 -704 576
WIRE -496 592 -496 576
WIRE -560 608 -560 576
WIRE -368 640 -368 624
WIRE -560 736 -560 672
WIRE -560 736 -576 736
WIRE -496 736 -496 672
WIRE -496 736 -560 736
WIRE -368 736 -368 720
WIRE -368 736 -496 736
FLAG -128 224 0
FLAG -224 224 0
FLAG -240 112 VCC
FLAG -112 112 VEE
FLAG -576 736 VEE
FLAG -464 112 VCC
FLAG 192 464 VCC
FLAG 192 528 VEE
FLAG 128 544 0
FLAG 288 432 out
FLAG -704 592 0
SYMBOL voltage -128 112 R0
WINDOW 0 41 50 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value -5
SYMBOL voltage -224 112 R0
WINDOW 0 -69 56 Left 2
SYMATTR InstName V2
SYMATTR Value +5
SYMBOL njf -448 256 M0
WINDOW 3 -112 -9 Left 2
SYMATTR Value BF862_1pA
SYMATTR InstName J1
SYMBOL res -512 128 R0
SYMATTR InstName R5
SYMATTR Value 100
SYMBOL pnp -592 288 R180
SYMATTR InstName Q2
SYMATTR Value BFT92
SYMBOL current -288 336 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
WINDOW 3 -58 -60 Left 2
SYMATTR InstName I1
SYMATTR Value PULSE(1u 1n 10n 10n 10n 0.5u)
SYMBOL res 144 336 R270
WINDOW 0 32 64 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R4
SYMATTR Value 1Meg
SYMBOL cap 160 256 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName C3
SYMATTR Value 0.1p
SYMBOL cap -208 368 R0
SYMATTR InstName C4
SYMATTR Value 100p
SYMBOL res 48 464 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName Rsense2
SYMATTR Value 1m
SYMBOL res -640 304 M0
SYMATTR InstName Rsense1
SYMATTR Value 1m
SYMBOL npn -432 528 R0
SYMATTR InstName Q1
SYMATTR Value BFU520D
SYMBOL res -384 624 R0
SYMATTR InstName R2
SYMATTR Value 160
SYMBOL res -512 576 R0
SYMATTR InstName R7
SYMATTR Value 1k
SYMBOL res -576 560 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R8
SYMATTR Value 1k
SYMBOL cap -576 608 R0
SYMATTR InstName C1
SYMATTR Value 1u
SYMBOL OpAmps\\UniversalOpAmp2 192 496 R0
WINDOW 123 -101 86 Left 2
WINDOW 39 -97 152 Left 2
WINDOW 40 -106 117 Left 2
SYMATTR InstName U1
SYMATTR Value2 Avol=50k GBW=120Meg Slew=3G
SYMATTR SpiceLine Ilimit=50m Rail=0 Vos=0
SYMATTR SpiceLine2 En=12n Enk=0 In=0 Ink=0 Rin=500Meg
TEXT -808 688 Left 2 !.tran 1.5u
TEXT -104 344 Left 3 ;Photodiode
TEXT 248 520 Left 2 ;Similar to \nLM6171
TEXT 408 432 Left 2 !.model BF862_1pA NJF(Beta=47.800E-3 Betatce=-.5
Rd=.8 Rs=7.5000 Lambda=37.300E-3 Vto=-.57093\n+ Vtotc=-2.0000E-3
Is=6e-15 Isr=6e-15 N=1 Nr=2 Xti=3 Alpha=-1.0000E-3\n+ Vk=59.97
Cgd=7.4002E-12 M=.6015 Pb=.5 Fc=.5 Cgs=8.2890E-12 Kf=87.5E-18\n+ Af=1)
TEXT 400 288 Left 2 !.MODEL BFU520D NPN( IS = 71.49E-18 BF = 133.81 NF =
1.00 VAF = 183.69 IKF = 252.72E-3 ISE = 89.40E-15\n+NE = 2.50 BR =
512.49E-3 NR = 1.00 VAR = 2.40 IKR = 31.59E-3 ISC = 71.49E-18 NC =
1.10\n+RB = 1.17 IRB = 26.78E-3 RBM = 0.67 RE = 0.59 RC = 0.89 CJE =
506.04E-15 VJE = 950.00E-3\n+MJE = 335.33E-3 CJC = 74.16E-15 VJC =
720.00E-3 MJC = 318.44E-3 XCJC = 0.50 FC = 850.00E-3 TF =
10.04E-12\n+XTF = 10.00 VTF = 1.00 ITF = 42.55E-3 PTF = 0.00 TR = 0.00
KF = 109.67e-12 AF = 2.00)
TEXT 616 528 Left 2 !.MODEL BFT92 PNP( IS = 4.3756E-016 BF = 33.5815
NF = 1.0097 VAF = 23.3946\n+ IKF = 9.9538E-002 ISE = 8.7054E-014 NE =
1.94395 BR = 4.9472\n+ NR = 1.00254 VAR = 3.90385 IKR = 5.2816E-003
ISC = 3.5886E-014\n+ NC = 1.3933 RB = 5 IRB = 1E-006 RBM = 5 RE = 1
RC = 10 EG = 1.11\n+ XTI = 3 CJE = 7.4666E-013 VJE = .6 MJE = .35683
TF = 1.7492E-011\n+ XTF = 1.3546 VTF = .155654 ITF = 1E-003 PTF = 45
CJC = 9.371E-013\n+ VJC = .396455 MJC = .19995 XCJC = .106 TR =
8.422E-009\n+ VJS = .75 FC = .767856)
TEXT 352 96 Left 3 ;PNP WRAPAROUND BOOTSTRAP\nType 2: Bootstrap inside
TIA loop, A_V = 0.993, 154 ns t_R\n \nPhil Hobbs\nElectroOptical
Innovations LLC
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