Philips Semiconductors
Product specification
Silicon N-channel dual-gate MOS-FETs
BF998; BF998R
handbook, full pagewidth
VDD
47
µF
Vagc
1 nF
1 nF
47 kΩ
1 nF
50
Ω
input
C1
5.5 pF
1 nF
15 pF
L1
140 kΩ
VDD
1 nF
D1
BB405
330 kΩ
D2
BB405
330 kΩ
360
Ω
10 pF
1.8 kΩ
L2
1 nF
20
µH
1 nF
50
Ω
output
100 kΩ
Vtun
input
1 nF
Vtun
output
1 nF
MGE802
V
DD
= 12 V; G
S
= 2 mS; G
L
= 0.5 mS.
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.
Tapped at approximately half a turn from the cold side, to adjust G
L
= 0.5 mS. C1 adjusted for G
S
= 2 mS.
Fig.17 Gain control test circuit at f = 200 MHz.
1996 Aug 01
8
PHILIPS [ NXP SEMICONDUCTORS ]
