charlie@oakhill.UUCP (Charlie Thompson) (07/12/89)
I need an opto isolator capable of passing a 3 MHz clock with reasonable symmetry. Such an opto would have to have a t-rise and t-fall of around 50-100 nanoseconds or better. Any suggestions out there?? Charlie Thompson Austin, TX
mjr@hpcvca.CV.HP.COM (Mark Reed) (07/18/89)
Checking my HP "Optoelectronic Designer's Catalog" 1988-1989 The fastest I see with a cursory examination is the HCPL-2400 "20 M Baud High CMR Logic Gate Optocoupler" It has a tri-state gate logic output, 4-8 mA input current, tr (typical) 20ns tf (typical) 10ns tPHL max 60ns tPLH max 60ns These specifications are from specific test circuits shown in the book. The HCPL-2300 is slower, but still meets your tr, tf specs. with propagation delays in the 100ns range. It has an NPN output, so needs a pullup. The book contains lots more data which can be supplemented with the "Optoelectronics Applications Manual" (hardback, $$) Disclaimer: I do work for HP, but not in the optoelectronics division. (just happened to have the data book handy) Mark Reed