Path: csiph.com!weretis.net!feeder6.news.weretis.net!news.glorb.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!spln!extra.newsguy.com!newsp.newsguy.com!drn From: Winfield Hill Newsgroups: sci.electronics.design Subject: Re: PNP for soft switch and reverse battery protection Date: 10 Feb 2017 14:29:15 -0800 Organization: Rowland Institute Lines: 16 Message-ID: References: <20170209-191645.81.0@Peabody.ssl.astraweb.com> <20170209-224630.33.0@Peabody.ssl.astraweb.com> NNTP-Posting-Host: p98fa0828c65d22423f6722b22f8fef69eac4862fc77e4f31.newsdawg.com User-Agent: Direct Read News 5.60 X-Received-Bytes: 1090 X-Received-Body-CRC: 2996447591 Xref: csiph.com sci.electronics.design:447218 Peabody wrote... > > It's the pesky PNP base that I'n worried about. An interesting fact is that many (most?) PNP BJTs actually have quite high Veb breakdown voltages. They may not say so on the specs, but when you measure them, you discover this is true. Consider, as an example, the LM339 comparator's PNP input transistors, Q2 and Q3. They can handle 36 volts of reverse biasing. -- Thanks, - Win