11 Feb
2014
11 Feb
'14
11:43 p.m.
On 02/11/2014 09:49 AM, Vincent Slyngstad wrote:
From: allison: Tuesday, February 11, 2014 6:05 AM
Most 1n914/4148s I've used don't see .75V till you near the max
current. Usually then are more
like .6-.62. If you need real low forward drop the Schottky 1n5711 are
around .25-.30 depending
on current.
On 02/11/2014 07:49 AM, Michael Thompson wrote:
My understanding of the difference between a D662 and a D664 is that
the D664 is supposed to be a fast switching diode with a low forward
voltage drop. The D662 is a similar diode, but requires a known,
fairly high forward voltage drop. (I'd recommend select 1N914 or
1N4148 for the D662, but only some manufacturers have forward voltage
drops
of 0.75V.) Unfortunately, forward voltage drop doesn't seem to be a
thing that part numbers of modern switching diodes routinely control.
The RICM needs to repair a S603 triple pulse
amplifier flip-chip. The
failed diode is listed as a DEC D-664. The DEC enthusiast
cross-reference
lists show it as a 1N3606. These diodes are nearly impossible to
find. Can
someone recommend a substitution for the 1N3606 diode?
A quick lookup suggests that 1n914 or 1n4148 are suitable choices.
These are
very common fast switching doides. The D664, however, wants the forward drop as low as
possible. Some
1N914 and 1N4148 will fit the bill, but others won't. If you are
looking for a general purpose substitution (rather than a specific
application), the 1N4154 should work well. (When I studied the issue,
I didn't find any manufacturers of 1N4154 which had high forward
voltage drops.)
Generally the voltage drop MAY affect the noise margin at the inter
flip-chip level. However there
is already margin there to addow for temperature and other things.
I suspect a working diode (not open or shorted) will make it go. Keep
in mind fast by then standard is
slower then 1n914.
Allison