1997 Sep 05

8

Philips Semiconductors

Product specification

N-channel dual-gate MOS-FET

BF998WR

Fig.15 Gain control testcircuit at f = 200 MHz.

L1 = 45 nH; 4 turns 0.8 mm copper wire, internal diameter 4 mm.

L2 = 160 nH; 3 turns 0.8 mm copper wire, internal diameter 8 mm.

VAGC

1 nF

1 nF

50

Ω

input

50

Ω

input

1 nF

1 nF

L1

L2

20

µH

47

µF

1 nF

1 nF

1 nF

1 nF

47

k

Ω

1.8

k

Ω

360

Ω

140 k

Ω

1 nF

VDD

VDD

15 pF

10 pF

100

k

Ω

330

k

Ω

Vtun

D1

BB405

C1

5.5 pF

330

k

Ω

D2

BB405

input

Vtun

output

MGC481