Feb-13-2004
1
BF998...
Silicon N_Channel MOSFET Tetrode
Short-channel transistor
with high S / C quality factor
For low-noise, gain-controlled
input stage up to 1 GHz
ESD
: Electrostatic discharge sensitive device, observe handling precaution!
Type
Package
Pin Configuration
Marking
BF998
BF998R
BF998W
SOT143
SOT143R
SOT343
1=S
1=D
1=D
2=D
2=S
2=S
3=G2
3=G1
3=G1
4=G1
4=G2
4=G2
-
-
-
-
-
-
MOs
MRs
MR
Maximum Ratings
Parameter
Symbol
Value
Unit
Drain-source voltage
V
DS
12
V
Continuous drain current
I
D
30
mA
Gate 1/ gate 2-source current
I
G1/2SM
10
Total power dissipation
T
S
76 C, BF998, BF998R
T
S
94 C, BF998W
P
tot
200
200
Storage temperature
T
stg
-55 ... 150
C
Channel temperature
T
ch
150
Thermal Resistance
Parameter
Symbol
Value
Unit
Channel - soldering point
1)
BF998, BF998R
BF998W
R
thchs
370
280
K/W
1For calculation of R
thJA
please refer to Application Note Thermal Resistance
Feb-13-2004
2
BF998...
Electrical Characteristics
Parameter
Symbol
Values
Unit
min.
typ.
max.
DC Characteristics
Drain-source breakdown voltage
I
D
= 10 A, V
G1S
= -4 V, V
G2S
= -4 V
V
(BR)DS
12
-
-
V
Gate 1 source breakdown voltage
I
G2S
= 10 mA, V
G2S
= V
DS
= 0
V
(BR)G1SS
8
-
12
Gate2 source breakdown voltage
I
G2S
= 10 mA, V
G2S
= V
DS
= 0
V
(BR)G2SS
8
-
12
Gate 1 source leakage current
V
G1S
= 5 V, V
G2S
= V
DS
= 0
I
G1SS
-
-
50
nA
Gate 2 source leakage current
V
G2S
= 5 V, V
G2S
= V
DS
= 0
I
G2SS
-
-
50
nA
Drain current
V
DS
= 8 V, V
G1S
= 0 , V
G2S
= 4 V
I
DSS
5
9
15
mA
Gate 1 source pinch-off voltage
V
DS
= 8 V, V
G2S
= 4 V, I
D
= 20 A
-V
G1S(p)
-
0.8
2.5
V
Gate 2 source pinch-off voltage
V
DS
= 8 V, V
G1S
= 0 , I
D
= 20 A
-V
G2S(p)
-
0.8
2
Feb-13-2004
3
BF998...
Electrical Characteristics
Parameter
Symbol
Values
Unit
min.
typ.
max.
AC Characteristics
Forward transconductance
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V
g
fs
20
24
-
-
Gate1 input capacitance
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 1 MHz
C
g1ss
-
2.1
2.5
pF
Gate 2 input capacitance
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 1 MHz
C
g2ss
-
1.2
-
pF
Feedback capacitance
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 1 MHz
C
dg1
-
25
-
fF
Output capacitance
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 1 MHz
C
dss
-
1.1
-
pF
Power gain
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 45 MHz
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 800 MHz
G
p
-
-
28
20
-
-
dB
Noise figure
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 45 MHz
V
DS
= 8 V, I
D
= 10 mA, V
G2S
= 4 V,
f
= 800 MHz
F
-
-
2.8
1.8
-
-
dB
Gain control range
V
DS
= 8 V, V
G2S
= 4 ...-2 V, f = 800 MHz
G
p
40
50
-
Feb-13-2004
4
BF998...
Total power dissipation P
tot
=
(T
S
)
BF998, BF998R
0
15
30
45
60
75
90 105 120 C
150
T
S
0
20
40
60
80
100
120
140
160
180
mA
220
P
tot
Total power dissipation P
tot
=
(T
S
)
BF998W
0
15
30
45
60
75
90 105 120 C
150
T
S
0
20
40
60
80
100
120
140
160
180
mA
220
P
tot
Output characteristics I
D
=
(V
DS
)
V
G2S
= 4 V
V
G1S
= Parameter
0
2
4
6
8
10
V
14
V
DS
0
2
4
6
8
10
12
14
16
18
20
22
mA
26
I
D
0.4V
0.2V
0V
-0.2V
-0.4V
Gate 1 forward transconductance
g
fs
=
(I
D
)
V
DS
= 5V, V
G2S
= Parameter
0
4
8
12
16
mA
24
I
D
0
2
4
6
8
10
12
14
16
18
20
22
mS
26
g
fs
4V
2V
1V
0V
Feb-13-2004
5
BF998...
Gate 1 forward transconductance
g
fs1
=
(V
G1S
)
-1
-0.75
-0.5
-0.25
0
0.25
V
0.75
V
G1S
0
2
4
6
8
10
12
14
16
18
20
22
mS
26
G
fs
4V
2V
1V
0V
Drain current I
D
=
(V
G1S
)
V
DS
= 5V
V
G2S
= Parameter
-1
-0.75 -0.5 -0.25
0
0.25
0.5
V
1
V
G1S
0
5
10
15
20
mA
30
I
D
4V
2V
1V
0V
Power gain G
ps
=
(V
G2S
)
f
= 45 MHz
0
1
2
V
4
V
G2S
0
5
10
15
20
dB
30
G
ps
Noise figure F =
(V
G2S
)
f
= 45 MHz
0
1
2
V
4
V
G2S
0
1
2
3
4
5
6
7
8
dB
10
F
Feb-13-2004
6
BF998...
Power gain G
ps
=
(V
G2S
)
f
= 800 MHz
0
1
2
V
4
V
G2S
-10
-5
0
5
10
dB
20
G
ps
Power gain G
ps
=
(V
G2S
)
f
= 800 MHz
0
1
2
V
4
V
G2S
-10
-5
0
5
10
dB
20
G
ps
Gate 1 input capacitance C
g1ss
=
(V
G1S
)
-3
-2.6
-2.2
-1.8
-1.4
-1
-0.6
V
0.2
V
G1S
1
1.2
1.4
1.6
1.8
2
2.2
pF
2.6
C
g1ss
Output capacitance C
dss
=
(V
DS
)
0
2
4
6
8
V
12
V
DS
0
0.5
1
1.5
2
2.5
3
pF
4
C
dss
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