Datasheet

BC847BS_3 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 03 — 18 February 2009 4 of 12
NXP Semiconductors
BC847BS
45 V, 100 mA NPN/NPN general-purpose transistor
6. Thermal characteristics
[1] Device mounted on an FR4 PCB, single-sided copper, tin-plated and standard footprint.
[2] Device mounted on an FR4 PCB, single-sided copper, tin-plated, mounting pad for collector 1 cm
2
.
Table 6. Thermal characteristics
Symbol Parameter Conditions Min Typ Max Unit
Per transistor
R
th(j-a)
thermal resistance from
junction to ambient
in free air
[1]
- - 568 K/W
[2]
- - 500 K/W
R
th(j-sp)
thermal resistance from
junction to solder point
- - 230 K/W
Per device
R
th(j-a)
thermal resistance from
junction to ambient
in free air
[1]
- - 416 K/W
[2]
- - 313 K/W
FR4 PCB, standard footprint
Fig 2. Per transistor: Transient thermal impedance from junction to ambient as a function of pulse duration;
typical values
006aab420
10
−5
1010
−2
10
−4
10
2
10
−1
t
p
(s)
10
−3
10
3
1
10
2
10
10
3
Z
th(j-a)
(K/W)
1
δ = 1
0.75
0.50
0.33
0.10
0.05
0.02
0.01
0
0.20