18 Sep
2013
18 Sep
'13
10:51 a.m.
Hi Pete,
Anyone got practical experience of substituting for an
8881?
--- The SN7439 is commonly taken as a proper replacement for the DEC8881. I see a couple
7439's available on eBay at the moment. Also, questcomp.com is showing DEC8881 in
stock at $10 each at quantity-two. Some have mentioned substituting 7438 as a lower spec
version. I see from the datasheet that it does have the same schematic as the 7439.
However, it doesn't actually guarantee more than 16mA output sink current.
Steve Lafferty
http://www.tronola.com/
19 Sep
19 Sep
2:47 a.m.
Hi, Steve.
On 18/09/2013 18:51, Steve Lafferty wrote:
--- The SN7439 is commonly taken as a proper
replacement for the
DEC8881. I see a couple 7439's available on eBay at the moment.
Yes, I found those and also a few NOS 8881s. US suppliers aren't
helpful though as I'm in the UK.
Some have mentioned substituting 7438 as a lower spec
version. I see from the datasheet that it does have the same
schematic as the 7439. However, it doesn't actually guarantee more
than 16mA output sink current.
No, that's wrong. 7438 guarantees 48mA, still a little under spec, but
close, and the gates are the wrong way round.
--
Pete
Peter Turnbull
Network Manager
Information Directorate, University of York
DD: +44 1904 323804
5:53 a.m.
Am 18.09.2013 19:51, schrieb Steve Lafferty:
Hi Pete,
Unicornelectronics.com, 7439 at $1.49 (min order $25, though, but the
also have some other goodies as well)
--
Holger
Anyone got practical experience of substituting
for an 8881?
--- The SN7439 is commonly taken as a proper replacement for the
DEC8881. I see a couple 7439's available on eBay at the moment. Also, questcomp.com is
showing DEC8881 in stock at $10 each at quantity-two. Some have mentioned substituting
7438 as a lower spec version. I see from the datasheet that it does have the same
schematic as the 7439. However, it doesn't actually guarantee more than 16mA output
sink current. 
11:16 a.m.
Some have mentioned substituting 7438 as a lower spec
version. I see
from the datasheet that it does have the same schematic as the 7439.
However, it doesn't actually guarantee more than 16mA output sink current.
According to the 'TTL Databook for Design Engineers', 2nd Edition (Texas
Instrumnts), the 7438 (not LS or S or ...) is speciified to sink 48mA
-tony
4112
days inactive
4113
days old
3 comments
4 participants
participants (4)
-
ard＠p850ug1.demon.co.uk -
holger.veit＠iais.fraunhofer.de -
peter.turnbull＠york.ac.uk -
steve＠tronola.com