BF908; BF908R
Dual-gate MOS-FETs
Rev. 03 — 14 November 2007
Product data sheet
IMPORTANT NOTICE
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NXP Semiconductors
NXP
Semiconductors
Product specification
Dual-gate MOS-FETs
FEATURES
•
High forward transfer admittance
•
Short channel transistor with high forward transfer
admittance to input capacitance ratio
•
Low noise gain controlled amplifier up to 1 GHz.
APPLICATIONS
•
VHF and UHF applications with 12 V supply voltage,
such as television tuners and professional
communications equipment.
DESCRIPTION
Fig.1
Depletion type field-effect transistor in a plastic
microminiature SOT143 or SOT143R package. The
transistors are protected against excessive input voltage
surges by integrated back-to-back diodes between gates
and source.
CAUTION
The device is supplied in an antistatic package. The
gate-source input must be protected against static
discharge during transport or handling.
handbook, halfpage
handbook, halfpage
BF908; BF908R
4
3
g2
g
1
d
1
Top view
2
s,b
MAM039
BF908 marking code:
%M1.
Simplified outline (SOT143) and
symbol; BF908.
d
4
g2
g1
3
PINNING
PIN
1
2
3
4
SYMBOL
s, b
d
g
2
g
1
source
drain
gate 2
gate 1
DESCRIPTION
Top view
2
1
s,b
MAM040
BF908R marking code:
%M2.
Fig.2
Simplified outline (SOT143R) and
symbol; BF908R.
QUICK REFERENCE DATA
SYMBOL
V
DS
I
D
P
tot
T
j
y
fs
C
ig1-s
C
rs
F
drain current
total power dissipation
operating junction temperature
forward transfer admittance
input capacitance at gate 1
reverse transfer capacitance
noise figure
f = 1 MHz
f = 800 MHz
PARAMETER
drain-source voltage
CONDITIONS
−
−
−
−
36
2.4
20
−
MIN.
−
−
−
−
43
3.1
30
1.5
TYP.
MAX.
12
40
200
150
50
4
45
2.5
UNIT
V
mA
mW
°C
mS
pF
pF
dB
Rev. 03 - 14 November 2007
2 of 9
NXP
Semiconductors
Product specification
Dual-gate MOS-FETs
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL
V
DS
I
D
±I
G1
±I
G2
P
tot
PARAMETER
drain-source voltage
drain current
gate 1 current
gate 2 current
total power dissipation
BF908
BF908R
T
stg
T
j
Note
1. Device mounted on a printed-circuit board.
storage temperature
operating junction temperature
see Fig.3; note 1
up to T
amb
= 50
°C
up to T
amb
= 40
°C
−
−
−65
−
CONDITIONS
−
−
−
−
BF908; BF908R
MIN.
MAX.
12
40
10
10
200
200
+150
150
V
UNIT
mA
mA
mA
mW
mW
°C
°C
handbook, halfpage
250
MRC275
P
tot
(mW)
200
BF908
150
BF908R
100
50
0
0
50
100
150
200
o
Tamb ( C)
Fig.3 Power derating curves.
Rev. 03 - 14 November 2007
3 of 9
NXP
Semiconductors
Product specification
Dual-gate MOS-FETs
THERMAL CHARACTERISTICS
SYMBOL
R
th j-a
BF908
BF908R
Note
1. Device mounted on a printed-circuit board.
STATIC CHARACTERISTICS
T
j
= 25
°C;
unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
V
G2-S
= V
DS
= 0; I
G1-S
= 10 mA
V
G1-S
= V
DS
= 0; I
G2-S
= 10 mA
PARAMETER
thermal resistance from junction to ambient
CONDITIONS
note 1
BF908; BF908R
VALUE
500
550
UNIT
K/W
K/W
MIN.
8
8
TYP.
−
−
−
−
15
−
−
MAX.
20
20
2
1.5
27
50
50
UNIT
V
V
V
V
mA
nA
nA
±V
(BR)G1-SS
gate 1-source breakdown voltage
±V
(BR)G2-SS
gate 2-source breakdown voltage
−V
(P)G1-S
−V
(P)G2-S
I
DSS
±I
G1-SS
±I
G2-SS
gate 1-source cut-off voltage
gate 2-source cut-off voltage
drain-source current
gate 1 cut-off current
gate 2 cut-off current
V
G2-S
= 4 V; V
DS
= 8 V; I
D
= 20
µA −
V
G1-S
= 4 V; V
DS
= 8 V; I
D
= 20
µA −
V
G2-S
= 4 V; V
DS
= 8 V; V
G1-S
= 0
V
G2-S
= V
DS
= 0; V
G1-S
= 5 V
V
G1-S
= V
DS
= 0; V
G2-S
= 5 V
3
−
−
DYNAMIC CHARACTERISTICS
Common source; T
amb
= 25
°C;
V
DS
= 8 V; V
G2-S
= 4 V; I
D
= 15 mA; unless otherwise specified.
SYMBOL
y
fs
C
ig1-s
C
ig2-s
C
os
C
rs
F
PARAMETER
forward transfer admittance
input capacitance at gate 1
input capacitance at gate 2
output capacitance
reverse transfer capacitance
noise figure
f = 1 MHz
f = 1 MHz
f = 1 MHz
f = 1 MHz
f = 200 MHz; G
S
= 2 mS; B
S
= B
Sopt
f = 800 MHz; G
S
= G
Sopt
; B
S
= B
Sopt
CONDITIONS
pulsed; T
j
= 25
°C;
f = 1 MHz
MIN.
36
2.4
1.2
1.2
20
−
−
TYP.
43
3.1
1.8
1.7
30
0.6
1.5
MAX.
50
4
2.5
2.2
45
1.2
2.5
UNIT
mS
pF
pF
pF
fF
dB
dB
Rev. 03 - 14 November 2007
4 of 9
NXP
Semiconductors
Product specification
Dual-gate MOS-FETs
BF908; BF908R
handbook, halfpage
40
MRC281
MRC282
ID
(mA)
30
VG2-S = 4 V
3V
2V
handbook, halfpage
30
VG1-S = 0.3 V
ID
(mA)
0.2 V
20
20
1.5 V
1V
0.1 V
0V
0.5 V
10
10
−0.1
V
−0.2
V
0V
0
−0.6
−0.4
−0.2
0
−0.3
V
0
4
8
12
VDS (V)
16
0
0.2
0.4
VG1-S (V)
0.6
V
DS
= 8 V; T
j
= 25
°C.
V
G2-S
= 4 V; T
j
= 25
°C.
Fig.4 Transfer characteristics; typical values.
Fig.5 Output characteristics; typical values.
50
Yfs
(mS)
40
MRC280
4V
3V
2V
1.5 V
60
Yfs
(mS)
MRC276
40
30
1V
20
20
0.5 V
10
VG2-S = 0 V
0
0
0
5
10
15
20
25
I D (mA)
40
0
40
80
120
160
T (
o
C)
j
V
DS
= 8 V; T
j
= 25
°C.
V
DS
= 8 V; V
G2-S
= 4 V; I
D
= 15 mA.
Fig.6
Forward transfer admittance as a function
of drain current; typical values.
Fig.7
Forward transfer admittance as a function
of junction temperature; typical values.
Rev. 03 - 14 November 2007
5 of 9
