16 Jun
2010
16 Jun
'10
11:13 a.m.
From: cclist at sydex.com
To: cctalk at classiccmp.org
Date: Wed, 16 Jun 2010 10:34:42 -0700
Subject: OC/OD 48 ma transceivers
I'm working on a controller to drive some long >1m bidirectional
lines that require 220/330 termination and 48 ma. drive current
capability. For sake of argument, call them SCSI-1 SE (but they're
not SCSI (or HPIB)).
I'm finding that my choices are pretty limited. I could use a
74F621, 74FCT621 (CMOS) or a good old 75160. All appear to be within
the same approximate price range.
Can anyone make any recommendations?
Thanks,
Chuck
Hi Chuck
You can always parallel outputs of something like a '244 or
similar. I've done this in the past when I needed more drive.
The CMOS versions share well but the TTL versions don't.
I found that if using TTL, I had to over spec by 100% to get
good sharing while the CMOS I found about +25% worked quite well.
Dwight
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