Three 1N4148 diodes in glass
DO-35 axial package. The black band on the right is the
cathode side.Diode
schematic symbol vs cathode marking on the package.
The 1N4148 is a standard
silicon switching signal
diode. It is one of the most popular and long-lived switching diodes because of its dependable specifications and low cost. Its name follows the
JEDEC nomenclature. The 1N4148 is useful in switching applications up to about 100 MHz with a
reverse-recovery time of no more than 4 ns.
History
Texas Instruments announced the 1N914 diode in 1960.[1] It was registered at
JEDEC by
Texas Instruments no later than 1961, and was
second-sourced by 11 manufacturers that same year.[2]
The 1N4148 was registered at
JEDEC in 1968 as a silicon switching signal diode for military and industrial applications.[3] It was second-sourced by many manufacturers;
Texas Instruments listed their version of the device in an October 1966 data sheet.[4]
These 1N914 and 1N4148 have an enduring popularity in low-current applications.[5]
Overview
Cross section of a 1N914 in glass axial package
As the most common mass-produced switching diode, the 1N4148 replaced the older 1N914. They can be used interchangeably, and are cross-reference replacements for each other. They differed mainly in their
leakage current specification, however, today most manufacturers list common specifications. For example,
Vishay lists the same leakage current for both parts:[6][7]
25 nA at -20 V, 25°C
5 μA at -75 V, 25°C
50 μA at -20 V, 150°C
Packages
The JEDEC registered part numbers 1N914 and 1N4148 were originally only available in an axial package, but over time similar parts became available in
surface-mount packages too.