I did wonder if the DEC 3639 part might have an integral Schotky diode, a question for DEC ..., a bit unobtanium these days but bipolar transistor + Schotky diode do / did exist - as integrated components.
Martin -----Original Message----- From: Jon Elson via cctalk <[email protected]> Sent: 28 October 2025 19:59 To: [email protected] Cc: Jon Elson <[email protected]> Subject: [cctalk] Re: Replacements for DEC 3639 On 10/28/25 14:03, Martin Bishop via cctalk wrote: > Schotky diode the keep the base out of saturation ? > As used in 74S 74LS, appreciate it's an extra component to bodge in > see eg > https://electronics.stackexchange.com/questions/242715/using-a-schottk > y-diode-to-improve-pnp-transistor-turn-off-time That's called a Baker clamp, was commonly used back in the mid '60s. Jon
