ON Semiconductort
JFET VHF/UHF Amplifiers
N–Channel — Depletion
BF245A
BF245B
MAXIMUM RATINGS
Rating
Drain–Source Voltage
Drain–Gate Voltage
Gate–Source Voltage
Drain Current
Forward Gate Current
Total Device Dissipation @ TA = 25°C
Derate above 25°C
Storage Channel Temperature Range
3 DRAIN
Symbol
VDS
VDG
VGS
ID
IG(f)
PD
Tstg
Value
±30
30
30
100
10
350
2.8
–65 to +150
3 DRAIN
Unit
Vdc
Vdc
Vdc
mAdc
mAdc
mW
mW/°C
°C
1
2
3
BF244A, BF244B
CASE 29–11, STYLE 22
TO–92 (TO–226AA)
1
2
3
2
GATE
STYLE 22
1
GATE
STYLE 23
BF245, BF245A,
BF245B, BF245C
CASE 29–11, STYLE 23
TO–92 (TO–226AA)
2 SOURCE
1 SOURCE
ELECTRICAL CHARACTERISTICS
(TA = 25°C unless otherwise noted)
Characteristic
Symbol
Min
Typ
Max
Unit
OFF CHARACTERISTICS
Gate–Source Breakdown Voltage
(IG = 1.0
µAdc,
VDS = 0)
Gate–Source
(VDS = 15 Vdc, ID = 200
µAdc)
BF245(1)
BF245A, BF244A(2)
BF245B, BF244B
BF245C
V(BR)GSS
VGS
0.4
0.4
1.6
3.2
VGS(off)
IGSS
–0.5
—
—
—
—
—
—
—
7.5
2.2
3.8
7.5
–8.0
5.0
Vdc
nAdc
30
—
—
Vdc
Vdc
Gate–Source Cutoff Voltage
(VDS = 15 Vdc, ID = 10 nAdc)
Gate Reverse Current
(VGS = 20 Vdc, VDS = 0)
ON CHARACTERISTICS
Zero–Gate–Voltage Drain Current
(VDS = 15 Vdc, VGS = 0)
BF245(1)
BF245A, BF244A(2)
BF245B, BF244B
BF245C
IDSS
2.0
2.0
6.0
12
—
—
—
—
25
6.5
15
25
mAdc
1. On orders against the BF245, any or all subgroups might be shipped.
2. On orders against the BF244A, any or all subgroups might be shipped.
©
Semiconductor Components Industries, LLC, 2001
1
June, 2001 – Rev. 0
Publication Order Number:
BF245A/D
BF245A BF245B
ELECTRICAL CHARACTERISTICS
(TA = 25°C unless otherwise noted) (Continued)
Characteristic
Symbol
Min
Typ
Max
Unit
SMALL–SIGNAL CHARACTERISTICS
Forward Transfer Admittance
Output Admittance
Forward Transfer Admittance
Reverse Transfer Admittance
Input Capacitance
Reverse Transfer Capacitance
Output Capacitance
Cut–off Frequency(3)
3. The frequency at which gfs is 0.7 of its value at 1 kHz.
(VDS = 15 Vdc, VGS = 0, f = 1.0 kHz)
(VDS = 15 Vdc, VGS = 0, f = 1.0 kHz)
(VDS = 15 Vdc, VGS = 0, f = 200 MHz)
(VDS = 15 Vdc, VGS = 0, f = 200 MHz)
(VDS = 20 Vdc, –VGS = 1.0 Vdc)
(VDS = 20 Vdc, –VGS = 1.0 Vdc, f = 1.0 MHz)
(VDS = 20 Vdc, –VGS = 1.0 Vdc, f = 1.0 MHz)
(VDS = 15 Vdc, VGS = 0)
Y
fs
Y
os
Y
fs
Y
rs
Ciss
Crss
Coss
F(Yfs)
3.0
—
—
—
—
—
—
—
—
40
5.6
1.0
3.0
0.7
0.9
700
6.5
—
—
—
—
—
—
—
mmhos
mmhos
mmhos
mmhos
pF
pF
pF
MHz
COMMON SOURCE CHARACTERISTICS
ADMITTANCE PARAMETERS
(VDS = 15 Vdc, Tchannel = 25°C)
grs , REVERSE TRANSADMITTANCE (mmhos)
brs , REVERSE SUSCEPTANCE (mmhos)
30
20
10
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
10
20
30
bis @ IDSS
5.0
3.0
2.0
1.0
0.7
0.5
0.3
0.2
grs @ IDSS, 0.25 IDSS
10
20
30
50 70 100
200 300
f, FREQUENCY (MHz)
500 700 1000
brs @ IDSS
0.25 IDSS
gis, INPUT CONDUCTANCE (mmhos)
bis, INPUT SUSCEPTANCE (mmhos)
gis @ IDSS
gis @ 0.25 IDSS
bis @ 0.25 IDSS
50 70 100
200 300
f, FREQUENCY (MHz)
500 700 1000
0.1
0.07
0.05
Figure 1. Input Admittance (yis)
Figure 2. Reverse Transfer Admittance (yrs)
gfs, FORWARD TRANSCONDUCTANCE (mmhos)
|b fs|, FORWARD SUSCEPTANCE (mmhos)
20
10
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
0.2
10
|bfs| @ IDSS
|bfs| @ 0.25 IDSS
20
30
50 70 100
200 300
f, FREQUENCY (MHz)
gos, OUTPUT ADMITTANCE (mhos)
bos, OUTPUT SUSCEPTANCE (mhos)
10
5.0
2.0
1.0
0.5
0.2
0.1
gos @ IDSS
bos @ IDSS and 0.25 IDSS
gfs @ IDSS
gfs @ 0.25 IDSS
0.05
0.02
0.01
10
20
30
gos @ 0.25 IDSS
50 70 100
200 300
f, FREQUENCY (MHz)
500 700 1000
500 700 1000
Figure 3. Forward Transadmittance (yfs)
Figure 4. Output Admittance (yos)
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2
BF245A BF245B
COMMON GATE CHARACTERISTICS
ADMITTANCE PARAMETERS
(VDG = 15 Vdc, Tchannel = 25°C)
grg , REVERSE TRANSADMITTANCE (mmhos)
brg , REVERSE SUSCEPTANCE (mmhos)
20
gig, INPUT CONDUCTANCE (mmhos)
big, INPUT SUSCEPTANCE (mmhos)
10
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
0.2
10
20
30
0.5
0.3
0.2
0.1
0.07
0.05
0.03
0.02
0.01
10
20
30
gig @ IDSS, 0.25 IDSS
50 70 100
200 300
f, FREQUENCY (MHz)
500 700 1000
0.25 IDSS
brg @ IDSS
gig @ IDSS
grg @ 0.25 IDSS
big @ IDSS
big @ 0.25 IDSS
50 70 100
200 300
f, FREQUENCY (MHz)
500 700 1000
0.007
0.005
Figure 9. Input Admittance (yig)
Figure 10. Reverse Transfer Admittance (yrg)
gfg , FORWARD TRANSCONDUCTANCE (mmhos)
bfg , FORWARD SUSCEPTANCE (mmhos)
3.0
2.0
1.0
0.7
0.5
0.3
0.2
0.1
10
20
30
bfg @ IDSS
gfg @ 0.25 IDSS
gog, OUTPUT ADMITTANCE (mmhos)
bog, OUTPUT SUSCEPTANCE (mmhos)
10
7.0
5.0
gfg @ IDSS
1.0
0.7
0.5
0.3
0.2
0.1
0.07
0.05
0.03
0.02
0.01
10
bog @ IDSS, 0.25 IDSS
gog @ IDSS
brg @ 0.25 IDSS
50 70 100
200 300
f, FREQUENCY (MHz)
gog @ 0.25 IDSS
20
30
50 70 100
200 300
f, FREQUENCY (MHz)
500 700 1000
500 700 1000
Figure 11. Forward Transfer Admittance (yfg)
Figure 12. Output Admittance (yog)
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4
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