1997 Sep 05

9

Philips Semiconductors

Product specification

N-channel dual-gate MOS-FET

BF998WR

L1 = L4 = 200 nH; 11 turns 0.5 mm copper wire, without spacing, internal diameter 3 mm.

L2 = 2 cm, silvered 0.8 mm copper wire, 4 mm above ground plane.

L3 = 2 cm, silvered 0.5 mm copper wire, 4 mm above ground plane.

Fig.16 Gain control test circuit at f = 800 MHz.

VAGC

1 nF

1 nF

1 nF

50

Ω

input

50

Ω

input

1 nF

270

k

Ω

360

Ω

1.8

k

Ω

140

k

Ω

100 k

Ω

VDD

VDD

1 nF

MGC480

VDD

1 nF

1 nF

L1

L2

C1

2-18 pF

C2

0.5-3.5 pF

C3

0.5-3.5 pF

,,

,,

L3

L4

C4

4-40 pF

,,

Fig.17 Automatic gain control characteristics

measured in circuit of Fig.15.

010

0

−50

−40

MGC479

−30

−20

−10

24

6

8

IDSS=

max

typ

min

∆G

tr

(dB)

VAGC(V)

Fig.18 Automatic gain control characteristics

measured in circuit of Fig.16.

010

0

−50

−40

MGC478

−30

−20

−10

24

6

8

IDSS=

max

typ

min

∆G

tr

(dB)

VAGC(V)