CMOS Buffering Question

[John Speth]

You're listed options pretty much sums up all the ones I would consider - from simple (diodes) to overkill (opamps).  I'd use the 4050 buffers because, after all, that's what they were designed for.  Maybe you could doubly buffer the output with a 4050 driving a 7407 with a pull up resistor.  The 7407 is a TTL device with open collector outputs - using a pullup to whatever high level voltage you'd need.

John Speth
johns at oei.com

-----Original Message-----
From:	R.Fahl [SMTP:8brain at spiritone.com]
Sent:	Thursday, September 04, 1997 1:03 AM
To:	synth-diy at horus.sara.nl
Subject:	CMOS Buffering Question


Hello All,

I am in the process of designing a pulse programmer.  It's basically a CMOS
counter IC whose outputs go to individual jacks and are routed to trigger
events, such as advancing a sequencer, firing and ADSR, etc...

What I'd like your opinions on is what is the simplest way to buffer the
outputs, ie, protect them from the outside world?

I've seen several ways to do it - a diode, a transitor emitter follower, a
CMOS buffer (CD4050), and an opamp buffer.   I'd like to just use the
diodes, but I'm not sure this is the best way to go.

Romeo