March 1993

6

Philips Semiconductors

Product specification

HF/VHF power transistor

BLW85

APPLICATION INFORMATION

List of components:

f (MHz)

η (%)

175

12,5

45

< 16

> 4,5

< 4,8

> 75

1,4

+ j1,5

2,7

− j1,3

175

13,5

45

−

typ. 6,0

−

typ. 75

−−

C1

=

2,5 to 20 pF film dielectric trimmer (cat. no. 2222 809 07004)

C2

=

C8 = 4 to 40 pF film dielectric trimmer (cat. no. 2222 809 07008)

C3a =

C3b = 47 pF ceramic capacitor (500 V)

C4

=

120 pF ceramic capacitor (500 V)

C5

=

100 nF polyester capacitor

C6a =

C6b = 8,2 pF ceramic capacitor (500 V)

C7

=

5 to 60 pF film dielectric trimmer (cat. no. 2222 809 07011)

L1

=

1 turn Cu wire (1,6 mm); int. dia. 9,0 mm; leads 2

× 5 mm

L2

=

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

× 5 mm

L3

=

L8 = Ferroxcube wide-band h.f. choke, grade 3B (cat. no. 4312 020 36640)

L4

=

L5 = strip (12 mm

× 6 mm); taps for C3a and C3b at 5 mm from transistor

L6

=

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

× 5 mm

L7

=

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

× 5 mm

L4 and L5 are strips on a double Cu-clad printed-circuit board with epoxy fibre-glass dielectric, thickness 1/16".

R1

=

10

Ω (±10%) carbon resistor (0,25 W)

R2

=

4,7

Ω (±5%) carbon resistor (0,25 W)

Component layout and printed-circuit board for 175 MHz test circuit are shown in Fig.8.

Fig.7 Test circuit; c.w. class-B.

handbook, full pagewidth

C7

50

Ω

50

Ω

MGP604

,,

,,

,,

C1

C2

C3b

C3a

C6a

C4

C5

R2

L3

C6b

C8

L1

L2

L4

R1

L5

L7

T.U.T.

L6

L8

+VCC