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

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:

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.

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

Welcome back. Cheers Phil Hobbs (Reposted)

What about a PFET/JEFT cascode buffer kinda like:

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

Cheers

Phil Hobbs

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

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

On 2024-09-04 17:54, Phil Hobbs wrote:

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 WIRE -192 480 -288 480 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 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 -560 624 -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

On 2024-09-09 21:59, Phil Hobbs wrote:

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 RECTANGLE Normal 48 528 -352 256 2