Semiconductor Devices Numbering System

Semiconductor Devices Numbering System

From the semiconductor engineering came to existence, several numbering systems were adopted by different countries. However, the accepted numbering system is that announced by by Proelectron Standardisation Authority in Belgium. According to this system of numbering semiconductor devices:

Every semiconductor device is numbered by five alpha- numeric symbols, comprising either two letters and three numbers ( e.g.BF 194) or three letters and two numbers (e.g. BFX63). When two numbers are included in the symbol (e.g.BFX63) the device is intended for industrial and professional equipment. When the symbol contains three numbers ( e.g. BF194), the device is intended for entertainment or consumer equipment.

The first letter indicates the nature of semiconductor material. For example:

A= Germanium, B =silicon, C= gallium arsenide, R= compound material (e.g. Cadmium sulphide)Thus AC125 is a germanium transistor whereas BC149 is a silicon transistor.

The second letter indicates the device and circuit function.

Letter	Device and circuit function
A	Diode
B	Variable capacitance diode
C	A.F. Low powered transistor
D	A.F. Power transistor
E	Tunnel diode
F	H.F. Low power transistor
G	Multiple device
H	Magnetic sensitive diode
K	Hall effect device
L	H.F. Power transistor
M	Hall effect modulator
P	Radiation sensitive diode
Q	Radiation generating diode
R	Thyristor ( SCR or triac)
S	Low power switching transistor
T	Thyristor (power)
U	Power switching transistor
X	Diode, multiplier
Y	Power device
Z	Zener diode

Compiled by A.Devasena

Associate Professor/ ECE