Philips BLF278 - Page 17

2003 Sep 19 17
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Notes
1. American Technical Ceramics capacitor, type 100B or other capacitor of the same quality.
2. L1, L3 to L13, L18 to L22 and L24 are microstriplines on a double copper-clad printed-circuit board, with fibre-glass
reinforced PTFE dielectric (ε
r
= 2.2), thickness
1
⁄
16
inch; thickness of copper sheet 2 × 35 µm.
3. L2 and L23 are soldered on to striplines L1 and L24 respectively.
L14, L17 2 × grade 3B Ferroxcube
wideband HF chokes in parallel
4312 020 36642
L15, L16 1
3
⁄
4
turns enamelled 2 mm copper
wire
40 nH int. dia. 10 mm
leads 2 × 7mm
space 1 mm
L18, L19 stripline; note 2 43 Ω length 13 mm
width 6 mm
L20, L21 stripline; note 2 43 Ω length 29.5 mm
width 6 mm
R1 metal film resistor 10 Ω, 0.4 W
R2, R7 10 turns potentiometer 50 kΩ
R3, R6 metal film resistor 1 kΩ, 0.4 W
R4, R5 metal film resistor 2 × 5.62 Ω, in
parallel, 0.4 W
R8, R9 metal film resistor 10 Ω±5%, 1 W
R10 metal film resistor 4 × 42.2 Ω in
parallel, 1 W
R11 metal film resistor 5.11 kΩ, 1W
IC1 voltage regulator 78L05
COMPONENT DESCRIPTION VALUE DIMENSIONS CATALOGUE NO.