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.