BF998 / BF998R / BF998RW
Document Number 85011
Rev. 1.5, 24-Nov-04
Vishay Semiconductors
www.vishay.com
1
19216
SOT-143
SOT-143R
SOT-343R
12
43
21
34
Electrostatic sensitive device.
Observe precautions for handling.
12
43
N-Channel Dual Gate MOS-Fieldeffect Tetrode, Depletion Mode
Features
• Integrated gate protection diodes
• Low noise figure
• Low feedback capacitance
• High cross modulation performance
• Low input capacitance
• High AGC-range
• High gain
Applications
Input and mixer stages in UHF tuners.
Mechanical Data
Typ: BF998
Case: SOT-143 Plastic case
Weight: approx. 8.0 mg
Marking: MO
Pinning:
1 = Source, 2 = Drain,
3 = Gate 2, 4 = Gate 1
Typ: BF998R
Case: SOT-143R Plastic case
Weight: approx. 8.0 mg
Marking: MOR
Pinning:
1 = Source, 2 = Drain,
3 = Gate 2, 4 = Gate 1
Typ: BF998RW
Case: SOT-343R Plastic case
Weight: approx. 6.0 mg
Marking: WMO
Pinning:
1 = Source, 2 = Drain,
3 = Gate 2, 4 = Gate 1
Parts Table
Part Ordering Code Marking Package
BF998 BF998A-GS08 or BF998B-GS08 MO SOT143
BF998A BF998A-GS08 MO SOT143
BF998B BF998B-GS08 MO SOT143
BF998R BF998RA-GS08 or BF998RB-GS08 MOR SOT143R
BF998RA BF998RA-GS08 MOR SOT143R
BF998RB BF998RB-GS08 MOR SOT143R
BF998RW BF998RAW-GS08 or BF998RBW-GS08 MOW SOT343R
BF998RAW BF998RAW-GS08 MOW SOT343R
BF998RBW BF998RBW-GS08 MOW SOT343R
www.vishay.com
2
Document Number 85011
Rev. 1.5, 24-Nov-04
VISHAY
BF998 / BF998R / BF998RW
Vishay Semiconductors
Absolute Maximum Ratings
Tamb = 25 °C, unless otherwise specified
Maximum Thermal Resistance
1) on glass fibre printed board (25 x 20 x 1.5) mm3 plated with 35 µm Cu
Electrical DC Characteristics
Tamb = 25 °C, unless otherwise specified
Electrical AC Characteristics
Tamb = 25 °C, unless otherwise specified
VDS = 8 V, ID = 10 mA, VG2S = 4 V, f = 1 MHz
Parameter Test condition Symbol Value Unit
Drain - source voltage VDS 12 V
Drain current ID30 mA
Gate 1/Gate 2 - source peak
current
± IG1/G2SM 10 mA
Gate 1/Gate 2 - source voltage ± VG1S/G2S 7V
Total power dissipation Tamb ≤ 60 °C Ptot 200 mW
Channel temperature TCh 150 °C
Storage temperature range Tstg - 65 to + 150 °C
Parameter Test condition Symbol Value Unit
Channel ambient 1) RthChA 450 K/W
Parameter Test condition Part Symbol Min Ty p. Max Unit
Drain - source breakdown
voltage
ID = 10 µA, - VG1S = - VG2S = 4 V V(BR)DS 12 V
Gate 1 - source breakdown
voltage
± IG1S = 10 mA, VG2S = VDS = 0 ± V(BR)G1SS 714V
Gate 2 - source breakdown
voltage
± IG2S = 10 mA, VG1S = VDS = 0 ± V(BR)G2SS 714V
Gate 1 - source leakage current ± VG1S = 5 V, VG2S = VDS = 0 ± IG1SS 50 nA
Gate 2 - source leakage current ± VG2S = 5 V, VG1S = VDS = 0 ± IG2SS 50 nA
Drain current VDS = 8 V, VG1S = 0, VG2S = 4 V BF998/
BF998R/
BF998RW
IDSS 418mA
BF998A/
BF998RA/
BF998RAW
IDSS 4 10.5 mA
BF998B/
BF998RB/
BF998RBW
IDSS 9.5 18 mA
Gate 1 - source cut-off voltage VDS = 8 V, VG2S = 4 V, ID = 20 µA- V
G1S(OFF) 1.0 2.0 V
Gate 2 - source cut-off voltage VDS = 8 V, VG1S = 0, ID = 20 µA- V
G2S(OFF) 0.6 1.0 V
Parameter Test condition Symbol Min Typ. Max Unit
Forward transadmittance |y21s|21 24 mS
Gate 1 input capacitance Cissg1 2.1 2.5 pF
Gate 2 input capacitance VG1S = 0, VG2S = 4 V Cissg2 1.1 pF
Feedback capacitance Crss 25 fF
Output capacitance Coss 1.05 pF
VISHAY
BF998 / BF998R / BF998RW
Document Number 85011
Rev. 1.5, 24-Nov-04
Vishay Semiconductors
www.vishay.com
3
Typical Characteristics (Tamb = 25 °C unless otherwise specified)
Power gain GS = 2 mS, GL = 0.5 mS,
f = 200 MHz
Gps 28 dB
GS = 3,3 mS, GL = 1 mS,
f = 800 MHz
Gps 16.5 20 dB
AGC range VG2S = 4 to -2 V, f = 800 MHz ∆Gps 40 dB
Noise figure GS = 2 mS, GL = 0.5 mS,
f = 200 MHz
F1.0dB
GS = 3,3 mS, GL = 1 mS,
f = 800 MHz
F1.5dB
Parameter Test condition Symbol Min Ty p . Max Unit
Figure 1. Total Power Dissipation vs. Ambient Temperature
Figure 2. Drain Current vs. Drain Source Voltage
0
50
100
150
200
250
300
0 20 40 60 80 100 120 140 160
96 12159
P-Total Power Dissipation ( mW )
tot
T
amb
- Ambient Temperature ( °C)
0
5
10
15
20
25
30
0246810
V
DS
– Drain Source Voltage(V)
12812
I – Drain Current ( mA )
D
V
G1S
= 0.6 V
0.4 V
0
–0.4 V
0.2 V
V
G2S
=4V
–0.2 V
Figure 3. Drain Current vs. Gate 1 Source Voltage
Figure 4. Drain Current vs. Gate 2 Source Voltage
0
4
8
12
16
20
–0.8 –0.4 0.0 0.4 0.8 1.2
V
G1S
–Gate1Source Voltage(V)
12816
I – Drain Current ( mA)
D
6V
5V
4V
0
2V
1V
3V
V
DS
=8V
V
G2S
=–1V
0
4
8
12
16
20
–0.6 –0.2 0.2 0.6 1.0 1.4
V
G2S
– Gate 2 Source Voltage(V)
12817
I – Drain Current ( mA)
D
0
2V
1V
3V
V
DS
=8V 5V
V
G1S
=–1V
4V
www.vishay.com
4
Document Number 85011
Rev. 1.5, 24-Nov-04
VISHAY
BF998 / BF998R / BF998RW
Vishay Semiconductors
Figure 5. Gate 1 Input Capacitance vs. Gate 1 Source Voltage
Figure 6. Output Capacitance vs. Drain Source Voltage
Figure 7. Transducer Gain vs. Gate 1 Source Voltage
0.0
0.5
1.0
1.5
2.0
2.5
3.0
-2 -1.5 -1 -0.5 0 0.5 1.0 1.5
V
G1S
– Gate 1 Source Voltage(V)
12863
C – Gate 1 Input Capacitance ( pF )
issg1
V
DS
=8V
V
G2S
=4V
f=1MHz
0.0
0.5
1.0
1.5
2.0
2.5
3.0
24681012
V
DS
– Drain Source Voltage(V)
12864
C – Output Capacitance ( pF )
oss
V
G2S
=4V
f=1MHz
–50
–40
–30
–20
–10
0
10
–1.0 –0.5 0.0 0.5 1.0 1.5
V
G1S
– Gate 1 Source Voltage(V)
12818
S - Transducer Gain ( dB )
2
21
4V
0
2V
1V
3V
f = 800 MHz
–0.2 V
V
G2S
= –0.8 V
–0.4 V
Figure 8. Forward Transadmittance vs. Drain Current
Figure 9. Short Circuit Input Admittance
Figure 10. Short Circuit Forward Transfer Admittance
0
4
8
12
16
20
24
28
32
0 4 8 12 16 20 24 28
I
D
– Drain Current ( mA )
12819
V
DS
=8V
f=1MHz
V
G2S
=4V
2V
1V
0
3V
y – Forward Transadmittance ( mS )
21s
0
2
4
6
8
10
12
14
16
18
20
02468101214
Re (y
11
)(mS)
12820
Im(y)(mS)
11
V
DS
=8V
V
G2S
=4V
I
D
=10mA
f = 100...1300 MHz
f = 1300 MHz
700 MHz
400 MHz
1000 MHz
100 MHz
–40
–35
–30
–25
–20
–15
–10
–5
0
5
0 4 8 12 16 20 24 28 32
Re (y
21
)(mS)
12821
Im(y)(mS)
21
V
DS
=8V
V
G2S
=4V
f = 100...1300 MHz
f = 100 MHz
1300 MHz
1000 MHz
400 MHz
700 MHz
I
D
=5mA
10 mA
20 mA
VISHAY
BF998 / BF998R / BF998RW
Document Number 85011
Rev. 1.5, 24-Nov-04
Vishay Semiconductors
www.vishay.com
5
VDS = 8 V, ID = 10 mA, VG2S = 4 V, Z0 = 50 Ω
S11
S12
S21
S22
Figure 11. Short Circuit Output Admittance
0
1
2
3
4
5
6
7
8
9
0.00 0.25 0.50 0.75 1.00 1.25 1.50
Re (y
22
)(mS)
12822
Im(y)(mS)
22
V
DS
=15V
V
G2S
=4V
I
D
=10 mA
f = 100...1300 MHz
f = 1300 MHz
1000 MHz
400 MHz
100 MHz
700 MHz
Figure 12. Input Reflection Coefficient
Figure 13. Reverse Transmission Coefficient
12960
–j0.2
–j0.5
–j
–j2
–j5
0
j0.2
j0.5
j
j2
j5
0.2 0.5 1 2 5
1300 MHz
1000
100
12973
0°
90 °
180 °
–90 °
0.08 0.16
–150 °
–120 ° –60 °
–30 °
120 °
150 °
60 °
30 °
1300 MHz
100
200
1200
Figure 14. Forward Transmission Coefficient
Figure 15. Output Reflection Coefficient
12962
0°
90 °
180 °
–90 °
1 2
–150°
–120 ° –60 °
–30°
120 °
150 °
60 °
30 °
1300 MHz
100
400
700 1000
12963
–j0.2
–j0.5
–j
–j2
–j5
0
j0.2
j0.5
j
j2
j5
0.2 0.5 1 2 5
1300 MHz
100
www.vishay.com
6
Document Number 85011
Rev. 1.5, 24-Nov-04
VISHAY
BF998 / BF998R / BF998RW
Vishay Semiconductors
Package Dimensions of SOT143 in mm
Package Dimensions of SOT143R in mm
Mounting Pad Layout
96 12240
0.50(0.020)
0.35 (0.014)
1.8 (0.070)
1.6 (0.062)
0.9 (0.035)
0.75 (0.029)
1.4 (0.055)
1.2 (0.047)
2.0 (0.078)
1.8 (0.070)
3.0 (0.117)
2.8 (0.109)
0.15 (0.006)
0.08 (0.003)
1.1 (0.043)
0.9 (0.035)
0...0.1 (0...0.004)
2.6 (0.101)
2.4 (0.094)
ISO Method E
0.65 (0.025) 1.17 (0.046)
96 12239
VISHAY
BF998 / BF998R / BF998RW
Document Number 85011
Rev. 1.5, 24-Nov-04
Vishay Semiconductors
www.vishay.com
7
Package Dimensions of SOT343R in mm
96 12238
www.vishay.com
8
Document Number 85011
Rev. 1.5, 24-Nov-04
VISHAY
BF998 / BF998R / BF998RW
Vishay Semiconductors
Ozone Depleting Substances Policy Statement
It is the policy of Vishay Semiconductor GmbH to
1. Meet all present and future national and international statutory requirements.
2. Regularly and continuously improve the performance of our products, processes, distribution and
operatingsystems with respect to their impact on the health and safety of our employees and the public, as
well as their impact on the environment.
It is particular concern to control or eliminate releases of those substances into the atmosphere which are
known as ozone depleting substances (ODSs).
The Montreal Protocol (1987) and its London Amendments (1990) intend to severely restrict the use of ODSs
and forbid their use within the next ten years. Various national and international initiatives are pressing for an
earlier ban on these substances.
Vishay Semiconductor GmbH has been able to use its policy of continuous improvements to eliminate the use
of ODSs listed in the following documents.
1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments
respectively
2. Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental
Protection Agency (EPA) in the USA
3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C (transitional substances) respectively.
Vishay Semiconductor GmbH can certify that our semiconductors are not manufactured with ozone depleting
substances and do not contain such substances.
We reserve the right to make changes to improve technical design
and may do so without further notice.
Parameters can vary in different applications. All operating parameters must be validated for each
customer application by the customer. Should the buyer use Vishay Semiconductors products for any
unintended or unauthorized application, the buyer shall indemnify Vishay Semiconductors against all
claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal
damage, injury or death associated with such unintended or unauthorized use.
Vishay Semiconductor GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany
Telephone: 49 (0)7131 67 2831, Fax number: 49 (0)7131 67 2423
