August 1986

12

Philips Semiconductors

Product specification

HF/VHF power transistor

BLW77

List of components:

Component layout and printed-circuit board for 87,5 MHz test circuit are shown in Fig.17.

f (MHz)

η (%)

87,5

28

130

typ. 23,2

typ. 7,5

typ. 6,2

typ. 75

0,62

+ j0,73

273

− j42

C1

=

4 to 40 pF film dielectric trimmer (cat. no. 2222 809 07008)

C2

=

C9 = C10 = 7 to 100 pF film dielectric trimmer (cat. no. 2222 809 07015)

C3

=

C8 = 22 pF ceramic capacitor (500 V)

C4

=

4

× 82 pF ceramic capacitors in parallel (500 V)

C5

=

390 pF polystyrene capacitor

C6

=

220 nF polyester capacitor

C7a

=

2

× 10 pF ceramic capacitors in parallel (500 V)

C7b

=

2

× 8,2 pF ceramic capacitors in parallel (500 V)

L1

=

25 nH; 2 turns Cu wire (1,6 mm); int. dia. 5,0 mm; length 4,6 mm; leads 2

× 5 mm

L2

=

L5 = 2,4 nH; strip (12 mm

× 6 mm); tap for L4 and L6 at 5 mm from transistor

L3

=

L7 = Ferroxcube wide-band h.f. choke, grade 3B (cat. no. 4312 020 36640)

L4

=

100 nH; 7 turns closely wound enamelled Cu wire (0,5 mm); int. dia. 3 mm; leads 2

× 5 mm

L6

=

46 nH; 2 turns Cu wire (2,0 mm); int. dia. 9,0 mm; length 6,0 mm; leads 2

× 5 mm

L8

=

44 nH; 2 turns Cu wire (2,0 mm); int. dia. 9,0 mm; length 6,7 mm; leads 2

× 5 mm

L2 and L5 are strips on a double Cu-clad printed-circuit board with epoxy fibre-glass dielectric.

R1

=

10

Ω (± 10%) carbon resistor

R2

=

10

Ω (± 10%) carbon resistor

Fig.16 Test circuit; c.w. class-B.

handbook, full pagewidth

C9

50

Ω

50

Ω

MGP535

,,

,,

,,

C1

C2

C3

C4

C5

C6

R2

R1

C8

C7ab

C10

L1

L2

L4

L3

L5

L8

T.U.T.

L6

L7

+VCC