BC108 family

The BC107, BC108 and BC109 are general-purpose low power silicon NPN bipolar junction transistors found very often in equipment and electronics books/articles from Europe, Australia[1] and many other countries from the 1960s. They were created by Philips and Mullard in 1963 and introduced in April 1966. Initially in metal (TO-18) packages, the range expanded over time to include other package types, higher voltage ratings, and a better selection of gain (hFE and hfe) groupings, as well as complementary PNP types. Some manufacturers have specified their parts with a higher power dissipation rating (Ptot) than others.

The BC548 is an example of the modern low-cost member of this family, still in a through-hole package, while the BC848 is the surface-mount version.

Table of BC107 to BC860 variantsEdit

Case Ptot Polarity
≥ 70 VCBO
≥ 64 VCEO

50 VCBO

30 VCBO
Low-Noise (<4 dB)
30 VCBO
Low-Noise (<4 dB)
50 VCBO
Notes/Source
TO-18
(C-B-E)
 
Emitter is closest to tab
300 mW NPN BC190
64 VCEO
BC107
BC107A
BC107B

45 VCEO
BC108
BC108A
BC108B
BC108C
20 VCEO
BC109

BC109B
BC109C
20 VCEO
Philips Semiconductor Handbook Oct 1966
PNP BC177
45 VCEO
BC178
25 VCEO
BC179
25 VCEO
Philips Application Book: Audio Amplifier Systems, 1971
Lockfit
(C-B-E)
250 mW NPN BC147
45 VCEO
BC148
20 VCEO
BC149
20 VCEO
a discontinued plastic case with leads that lock into a PCB's holes.
PNP BC157
45 VCEO
BC158
25 VCEO
BC159
20 VCEO
TO92B
(E-C-B)
300 mW NPN BC167
45 VCEO
BC168
20 VCEO
BC169
20 VCEO
PNP BC257
45 VCEO
BC258
25 VCEO
BC259
20 VCEO
(Also: BC256 64 VCBO)
TO92F
(C-B-E)
rowspan="2"| 300 mW* NPN BC174
64 VCEO
BC171
BC237
45 VCEO
BC172
BC238
20 VCEO
BC173
BC239
20 VCEO
*Fairchild's power rating is 500 mW
Some devices have pre-formed leads with the base bent backwards like a TO-18 pinout (e.g. MEL).
PNP BC307
45 VCEO
BC308
25 VCEO
BC309
20 VCEO
TO92A
(E-B-C)
310 mW NPN BC317
45 VCEO
BC318
30 VCEO
BC319
20 VCEO
Note: 150 mA rating; BC318 VCBO 40 V to 45 V[2]
PNP BC320
45 VCEO
BC321
30 VCEO
BC322
20 VCEO
TO92F
(C-B-E)
500 mW* NPN BC546
65 VCEO
BC547
45 VCEO
BC548
30 VCEO
BC549
30 VCEO
BC550
45 VCEO
from Mullard 1977 and Fairchild 2001 specifications;
*Some manufacturers specify a 625 mW rating
PNP BC556
65 VCEO
BC557
45 VCEO
BC558
30 VCEO
BC559
30 VCEO
BC560
45 VCEO
SOT-23 150 mW NPN BC846
65 VCEO
BC847
45 VCEO
BC848
30 VCEO
BC849
30 VCEO
BC850
45 VCEO
Surface-mount
PNP BC856
65 VCEO
BC857
45 VCEO
BC858
30 VCEO
BC859
30 VCEO
BC860
45 VCEO

(See also: [1] for a neat summary of some of the family).

Noise figure (at 1 kHz, for a 2 kilohm source, BW = 200 Hz, IC=0.2 mA/VCE=5 V) is <10 dB for those not tabulated as "Low Noise".

Current ratingsEdit

All types have a maximum collector current of 100 mA, except that the original Philips tentative data dated 4.4.1966 specified a maximum collector current of 100 mA peak (ICM) for the BC107/8/9, and Telefunken originally specified a maximum collector current of 50 mA for the BC109, but since at least 1973 all have revised collector currents of 100 mA average or 200 mA peak, except that the BC317-BC322 range have a 150 mA (continuous) rating.

A,B and C gain groupingsEdit

The above devices' type numbers may be followed by a letter "A" to "C" to indicate low to high gain (hFE)[3] groups (see BC548 Gain groupings).

Other characteristicsEdit

Transistors in this family:

  • require a base-emitter voltage (VBE(on)) in the range of 0.55 to 0.7 Volts for a collector current of 2mA when the Collector voltage is 5 Volts.[4]
  • Will have a saturation voltage (VCE(sat)) of at most 0.2 Volts (typically 0.07 Volts) at a collector current of 10 mA and a base current of 0.5 mA (when the base voltage is typically 0.73 Volts; 0.83 Volts maximum).
  • Has greater than unity current gain up to a frequency (fT) of at least 150 MHz, typically 250 MHz, at a collector current of 10 mA (typically 85 MHz and a collector current of 0.5 mA)

See alsoEdit

ReferencesEdit

  1. ^ ""MiniWatt:" DIGEST" (PDF). Vol 7 Number 2. Philips Australia. February 1968. Retrieved 17 March 2014.
  2. ^ "Micro Electronics datasheet for BC107-9, BC167-9, BC237-9,BC317-9" (PDF). Archived from the original (PDF) on 13 January 2012. Retrieved 2 August 2015.
  3. ^ "BC546 through BC550".
  4. ^ "BC107/BC108 Series Low Power Bipolar Transistors - culticomp" (PDF).

Further readingEdit

Historical Databooks