Path: ...!feeds.phibee-telecom.net!weretis.net!feeder8.news.weretis.net!reader5.news.weretis.net!news.solani.org!.POSTED!not-for-mail
From: Gerhard Hoffmann <dk4xp@arcor.de>
Newsgroups: sci.electronics.design
Subject: Re: Drat. NTE is gone, and they took the last 5-GHz PNP with them.
Date: Fri, 6 Sep 2024 01:43:20 +0200
Message-ID: <vbdfmo$26l8a$1@solani.org>
References: <6b1217f0-f55b-95b4-6516-6914d18d0e91@electrooptical.net>
 <vbbia5$25sla$1@solani.org> <vbbmn9$8mib$1@dont-email.me>
 <j2fjdjhn1e4uht19jlundnl45mtanlsghq@4ax.com>
 <60cd9dfe-42b7-8d6c-d101-8e771bc762e8@electrooptical.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Thu, 5 Sep 2024 23:43:20 -0000 (UTC)
Injection-Info: solani.org;
	logging-data="2315530"; mail-complaints-to="abuse@news.solani.org"
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:C2j7tnGlxX/9/5LNu2OeLfY335E=
In-Reply-To: <60cd9dfe-42b7-8d6c-d101-8e771bc762e8@electrooptical.net>
X-User-ID: eJwFwYEBwCAIA7CXhrRFzkGG/59gQpepA6LAy+v4I2KMrfWtXp5NU27LkyXYgWazB/sUauoBAO8QqQ==
Content-Language: en-US
Bytes: 2124
Lines: 31


It seems, my 1st try did not work

Am 05.09.24 um 16:49 schrieb 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/137684711@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.


 > Cheers
Gerhard