Maker Pro
Maker Pro

Re: Diff - 1N4148 & 1N4448

H

Herman

Jan 1, 1970
0
Paul said:
Hi,

Does anyone know the difference between the 1N4148 & 1N4448 made by
NXP -->

http://www.nxp.com/acrobat_download/datasheets/1N4148_1N4448_5.pdf

They have the same case, SOD-27, same I/V curves. If they're the same,
then why would NXP make two diode part #'s?

BTW, any recommendations for low leakage diodes? I prefer the the SOD
cases.

Regards,
Paul


The manufacturer spec sheet gives all of the pertinent information about a
device. The spec sheet is important to the designer so he/she can make the
wisest decision regarding a part. A part as simple as a two terminal diode
that needs 9 pages to describe it's characteristics should be a well
understood device. When a run of parts are made (grown) they are tested and
sorted according to min/max electrical characteristics. As a case in point,
a batch of 10,000 Ohm resistors. If one tests at 10,043 Ohms it would fall
into a 1% category. 10,922 Ohms goes into a 10% category. 11,012 Ohms goes
into the scrap bin.

The diode 1N4448 is the target part (1%) the 1N4148 is the grade out part.
As the spec sheet shows, the 1N4448 has a Ir (reverse leakage) of 3uA while
the 1N4148 has a Ir (reverse leakage) of 50uA.

Some devices use an A,B,C grade designator such as 1N753A or 1N753B to
designate the tighter tolerances.

By the way, the 1N4148 is 43 years old.
 
Top