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

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

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
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
--
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