Philips BLF278 - User manual

DATA SHEET
Product Specification
Supersedes data of 1996 Oct 21 2003 Sep 19
DISCRETE SEMICONDUCTORS
BLF278
VHF push-pull power MOS
transistor
M3D091

2003 Sep 19 2
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
FEATURES
•High power gain
•Easy power control
•Good thermal stability
•Gold metallization ensures excellent reliability.
APPLICATIONS
•Broadcast transmitters in the VHF frequency range.
DESCRIPTION
Dual push-pull silicon N-channel enhancement mode
vertical D-MOS transistor encapsulated in a 4-lead,
SOT262A1 balanced flange package with two ceramic
caps. The mounting flange provides the common source
connection for the transistors.
PINNING - SOT262A1
CAUTION
This product is supplied in anti-static packing to prevent
damage caused by electrostatic discharge during
transport and handling. For further information, refer to
Philips specs.: SNW-EQ-608, SNW-FQ-302A, and
SNW-FQ-302B.
PIN DESCRIPTION
1 drain 1
2 drain 2
3 gate 1
4 gate 2
5 source
Fig.1 Simplified outline and symbol.
12
34
MAM098
Top view
55
d
g
s
d
g
QUICK REFERENCE DATA
RF performance at Th=25°C in a push-pull common source test circuit.
MODE OF OPERATION f
(MHz) VDS
(V) PL (W) Gp (dB) ηD (%)
CW, class-B 108 50 300 >20 >60
CW, class-C 108 50 300 typ. 18 typ. 80
CW, class-AB 225 50 250 >14
typ. 16 >50 typ. 55
WARNING
Product and environmental safety - toxic materials
This product contains beryllium oxide. The product is entirely safe provided that the BeO discs are not damaged.
All persons who handle, use or dispose of this product should be aware of its nature and of the necessary safety
precautions. After use, dispose of as chemical or special waste according to the regulations applying at the location of
the user. It must never be thrown out with the general or domestic waste.

2003 Sep 19 3
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
LIMITING VALUES
In accordance with the Absolute Maximum System (IEC 60134).
THERMAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT
Per transistor section
VDS drain-source voltage −125 V
VGS gate-source voltage −±20 V
IDdrain current (DC) −18 A
Ptot total power dissipation Tmb ≤25 °C; total device; both
sections equally loaded −500 W
Tstg storage temperature −65 150 °C
Tjjunction temperature −200 °C
SYMBOL PARAMETER CONDITIONS VALUE UNIT
Rth j-mb thermal resistance from junction
to mounting base total device; both sections equally loaded. max. 0.35 K/W
Rth mb-h thermal resistance from
mounting base to heatsink total device; both sections equally loaded. max. 0.15 K/W
Fig.2 DC SOAR.
Total device; both sections equally loaded.
(1) Current is this area may be limited by RDSon.
(2) Tmb =25°C.
handbook, halfpage
1
10
100
1 10 100
(1)
500
ID
(A)
V (V)
DS
MRA988
(2)
Fig.3 Power derating curves.
Total device; both sections equally loaded.
(1) Continuous operation.
(2) Short-time operation during mismatch.
handbook, halfpage
0 40 80 160
500
0
400
MGE616
120
300
200
100
Ptot
(W)
Th (°C)
(2)
(1)

2003 Sep 19 4
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
CHARACTERISTICS
Tj=25°C unless otherwise specified.
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT
Per transistor section
V(BR)DSS drain-source breakdown voltage VGS = 0; ID= 100 mA 125 −−V
I
DSS drain-source leakage current VGS = 0; VDS =50V −−2.5 mA
IGSS gate-source leakage current VGS =±20 V; VDS =0 −−1µA
V
GSth gate-source threshold voltage VDS = 10 V; ID=50mA 2 −4.5 V
∆VGS gate-source voltage difference
of both sections VDS = 10 V; ID=50mA −−100 mV
gfs forward transconductance VDS = 10 V; ID= 5 A 4.5 6.2 −S
gfs1/gfs2 forward transconductance ratio
of both sections VDS = 10 V; ID=5A 0.9 −1.1
RDSon drain-source on-state resistance VGS = 10 V; ID=5A −0.2 0.3 Ω
IDSX drain cut-off current VGS = 10 V; VDS =10V −25 −A
Cis input capacitance VGS = 0; VDS = 50 V; f = 1 MHz −480 −pF
Cos output capacitance VGS = 0; VDS = 50 V; f = 1 MHz −190 −pF
Crs feedback capacitance VGS = 0; VDS = 50 V; f = 1 MHz −14 −pF
Cd-f drain-flange capacitance −5.4 −pF
VGS group indicator
GROUP LIMITS
(V) GROUP LIMITS (V)
MIN. MAX. MIN. MAX.
A 2.0 2.1 O 3.3 3.4
B 2.1 2.2 P 3.4 3.5
C 2.2 2.3 Q 3.5 3.6
D 2.3 2.4 R 3.6 3.7
E 2.4 2.5 S 3.7 3.8
F 2.5 2.6 T 3.8 3.9
G 2.6 2.7 U 3.9 4.0
H 2.7 2.8 V 4.0 4.1
J 2.8 2.9 W 4.1 4.2
K 2.9 3.0 X 4.2 4.3
L 3.0 3.1 Y 4.3 4.4
M 3.1 3.2 Z 4.4 4.5
N 3.2 3.3

2003 Sep 19 5
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.4 Temperature coefficient of gate-source
voltageasafunctionofdraincurrent;typical
values per section.
VDS =10V.
handbook, halfpage
0
−5
10−210−1
MGE623
110
−4
−3
−2
−1
T.C.
(mV/K)
ID (A)
Fig.5 Drain current as a function of gate-source
voltage; typical values per section.
VDS = 10 V; Tj=25°C.
handbook, halfpage
0
30
20
10
05
ID
(A)
10 VGS (V) 15
MGE622
Fig.6 Drain-source on-state resistance as a
function of junction temperature; typical
values per section.
VGS = 10 V; ID=5A.
handbook, halfpage
0 50 100 150
400
0
200
100
300
MGE621
RDSon
(mΩ)
Tj(°C)
Fig.7 Input and output capacitance as functions
of drain-source voltage; typical values per
section.
VGS = 0; f = 1 MHz.
handbook, halfpage
0
1200
800
400
020
C
(pF)
40 VDS (V) 60
MGE615
Cos
Cis

2003 Sep 19 6
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.8 Feedback capacitance as a function of
drain-source voltage; typical values per
section.
VGS = 0; f = 1 MHz.
handbook, halfpage
010 50
400
300
100
0
200
MGE620
20 30 40
Crs
(pF)
VDS (V)
APPLICATION INFORMATION
Class-B operation
RF performance in CW operation in a common source push-pull test circuit. Th=25°C; Rth mb-h = 0.15 K/W unless
otherwise specified. RGS =4Ωper section; optimum load impedance per section = 3.2 + j4.3 Ω(VDS = 50 V).
Ruggedness in class-B operation
The BLF278 is capable of withstanding a load mismatch corresponding to VSWR = 7:1 through all phases under the
following conditions: VDS = 50 V; f = 108 MHz at rated load power.
MODE OF OPERATION f
(MHz) VDS (V) IDQ (A) PL (W) Gp (dB) ηD (%)
CW, class-B 108 50 2 ×0.1 300 >20
typ. 22 >60 typ. 70
CW, class-C 108 50 VGS = 0 300 typ. 18 typ. 80

2003 Sep 19 7
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.9 Power gain as a function of load power;
typical values.
Class-B operation; VDS =50V;I
DQ =2×0.1 A; f = 108 MHz;
ZL= 3.2 + j4.3 Ω(per section); RGS =4Ω(per section).
(1) Th=25°C.
(2) Th=70°C.
handbook, halfpage
0
30
20
10
0200 400 600
MGE682
PL(W)
Gp
(dB) (1)
(2)
Fig.10 Efficiency as a function of load power;
typical values.
Class-B operation; VDS =50V;I
DQ =2×0.1 A; f = 108 MHz;
ZL= 3.2 + j4.3 Ω(per section); RGS =4Ω(per section).
(1) Th=25°C.
(2) Th=70°C.
handbook, halfpage
0 200 400 PL (W) 600
80
60
ηD
(%)
20
0
40
MGE683
(1)
(1)
(2)
(2)
Fig.11 Load power as a function of input power;
typical values.
Class-B operation; VDS =50V;I
DQ =2×0.1 A; f = 108 MHz;
ZL= 3.2 + j4.3 Ω(per section); RGS =4Ω(per section).
(1) Th=25°C.
(2) Th=70°C.
handbook, halfpage
0
600
400
200
051015
MGE684
Pi(W)
PL
(W)
(1)
(2)

2003 Sep 19 8 Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
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Fig.12 Class-B test circuit at f = 108 MHz.
handbook, full pagewidth
MGE688
R11 IC1
C36 C37 C11
C35
L14 L18 L20
R5
C14
C15
C10
R6
R7
R2
R3
R4
L1
T1
C5
C4
C3
R1
C1
C2 C6 C7 C27 C28
C26 C29 C30
C33
C31 L21
L22
L23
L19L17L13
D.U.T.
C32
C34
R10
L3 L5 L7
L2
50 Ω
input
50 Ω
output
L4 L6 L8
C9
C8 C12
C13
C20
C16 C21
C22
L11R8
L9
L12
C17
+VDD1
,,,,
,,,,
,,,,
,,,,
,,
,,
A
A
+VDD1
L10
C18
C19
R9 L16
C24
C25
C23
L15
+VDD2

2003 Sep 19 9
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
List of components (see Figs 12 and 13).
COMPONENT DESCRIPTION VALUE DIMENSIONS CATALOGUE NO.
C1, C2, C33, C34 multilayer ceramic chip capacitor;
note 1 22 pF, 500 V
C3, C4 multilayer ceramic chip capacitor;
note 1 100pF+68pF in parallel, 500 V
C5, C6, C28 film dielectric trimmer 5 to 60 pF 2222 809 08003
C7 multilayer ceramic chip capacitor;
note 1 2×100 pF + 1×120 pF in
parallel, 500 V
C8, C11, C12,
C15, C16, C19,
C36
multilayer ceramic chip capacitor 100 nF, 500 V 2222 852 47104
C9, C10, C13,
C14, C20, C25 multilayer ceramic chip capacitor; note 1 1 nF, 500 V
C17, C18, C22,
C23 multilayer ceramic chip capacitor; note 1 470 pF, 500 V
C21, C24, C35 electrolytic capacitor 10 µF, 63 V
C26 multilayer ceramic chip capacitor;
note 1 2×15 pF + 1×18 pF in
parallel, 500 V
C27 multilayer ceramic chip capacitor;
note 1 3×15 pF in parallel, 500 V
C29 multilayer ceramic chip capacitor;
note 1 2×18 pF + 1×15 pF in
parallel, 500 V
C30 film dielectric trimmer 2 to 18 pF 2222 809 09006
C31, C32 multilayer ceramic chip capacitor;
note 1 3×43 pF in parallel, 500 V
L1, L2 stripline; note 2 43 Ωlength 57.5 mm
width 6 mm
L3, L4 stripline; note 2 43 Ωlength 29.5 mm
width 6 mm
L5, L6 stripline; note 2 43 Ωlength 14 mm
width 6 mm
L7, L8 stripline; note 2 43 Ωlength 6 mm
width 6 mm
L9, L10 stripline; note 2 43 Ωlength 17.5 mm
width 6 mm
L11, L16 2 ×grade 3B Ferroxcube wideband
HF chokes in parallel 4312 020 36642
L12, L15 4 turns enamelled 2 mm copper wire 85 nH length 13.5 mm
int. dia. 10 mm
leads 2 ×7mm
L13, L14 stripline; note 2 43 Ωlength 19.5 mm
width 6 mm

2003 Sep 19 10
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Notes
1. American Technical Ceramics capacitor, type 100B or capacitor of same quality.
2. L1 to L10, L13, L14, L17 to L21 and L23 are striplines on a double copper-clad printed-circuit board, with fibre-glass
PTFE dielectric (εr= 2.2), thickness 1⁄16 inch; thickness of copper sheet 2 ×35 µm.
3. L22 is soldered on to stripline L21.
L17, L18 stripline; note 2 43 Ωlength 24.5 mm
width 6 mm
L19, L20 stripline; note 2 43 Ωlength 66 mm
width 6 mm
L21, L23 stripline; note 2 50 Ωlength 160 mm
width 4.8 mm
L22 semi-rigid cable; note 3 50 Ωext. dia. 3.6 mm
outer conductor
length 160 mm
R1 metal film resistor 10 Ω, 0.4 W
R2, R7 10 turn potentiometer 50 kΩ
R3, R6 metal film resistor 3 ×12.1 Ωin
parallel, 0.4 W
R4, R5 metal film resistor 10 Ω; 0.4 W
R8, R9 metal film resistor 10 Ω±5%, 1 W
R10 metal film resistor 4 ×10 Ωin
parallel, 1 W
R11 metal film resistor 5.11 kΩ, 1W
IC1 voltage regulator 78L05
T1 1:1 Balun; 7 turns type 4C6 50 Ω
coaxial cable wound around toroid 14 ×9×5 mm 4322 020 90770
COMPONENT DESCRIPTION VALUE DIMENSIONS CATALOGUE NO.

2003 Sep 19 11
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.13 Printed-circuit board and component layout for 108 MHz class-B test circuit.
The circuit and components are situated on one side of the PTFE fibre-glass board, the other side being fully metallized to serve as an earth.
Earth connections are made by means of copper straps for a direct contact between upper and lower sheets.
Dimensions in mm.
handbook, full pagewidth
130 150
100
strap
strap
strap
strap
strap
strap
strap
strap
MBC438
R1 C3
C2
C1
C4
L1
L2 C6
R11 C36
L3
L4
IC1
VDD1
R2 and R7
C8C11
C7 L5
L6
L7
L8
C9 C13
R3
C12
slider R2
R4
slider R7
C15 R6
R5
C10C14
C23 C24
C25
C19
C18
VDD2
L11
R8
L11
C22 C21
C20
C16
C17
VDD1
L9
L10
L13
L14
L17
L18
C26 C27
C28
L19
L20 C29C30
C31
C32
C33
C34
R10
50 Ω
input 50 Ω
output
L23
L21
L22
L12
L15
C35
C5
T1
L16
R9
L16

2003 Sep 19 12
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.14 Input impedance as a function of frequency
(series components); typical values per
section.
Class-B operation; VDS = 50 V; IDQ =2×0.1 A;
RGS =4Ω(per section); PL= 300 W.
handbook, halfpage
25 75 125 f (MHz) 175
2
1
Zi
(Ω)ri
xi
−1
−2
0
MGE685
Fig.15 Load impedance as a function of frequency
(series components); typical values per
section.
Class-B operation; VDS = 50 V; IDQ =2×0.1 A;
RGS =4Ω(per section); PL= 300 W.
handbook, halfpage
25 75 125 f (MHz) 175
8
6
ZL
(Ω)
XL
RL
2
0
4
MGE686
Fig.16 Definition of MOS impedance.
handbook, halfpage
MBA379
ZiZL
Fig.17 Power gain as a function of frequency;
typical values per section.
Class-B operation; VDS = 50 V; IDQ =2×0.1 A;
RGS =4Ω(per section); PL= 300 W.
handbook, halfpage
25
30
20
10
075 125 175
MGE687
f (MHz)
Gp
(dB)

2003 Sep 19 13
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Class-AB operation
RF performance in CW operation in a common source push-pull test circuit. Th=25°C; Rth mb-h = 0.15 K/W unless
otherwise specified. RGS = 2.8 Ωper section; optimum load impedance per section = 0.74 + j2 Ω; (VDS = 50 V).
Ruggedness in class-AB operation
The BLF278 is capable of withstanding a load mismatch corresponding to VSWR = 7:1 through all phases under the
following conditions: VDS = 50 V; f = 225 MHz at rated output power.
MODE OF OPERATION f
(MHz) VDS
(V) IDQ (A) PL (W) Gp (dB) ηD (%)
CW, class-AB 225 50 2 ×0.5 250 >14
typ. 16 >50 typ. 55

2003 Sep 19 14
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.18 Power gain as a function of load power;
typical values.
Class-AB operation; VDS = 50 V; IDQ =2×0.5 A; f = 225 MHz;
ZL= 0.74 + j2 Ω(per section); RGS = 2.8 Ω(per section).
(1) Th=25°C.
(2) Th=70°C.
handbook, halfpage
0 100 200 300
20
0
10
MGE614
Gp
(dB)
PL(W)
(2)
(1)
Fig.19 Efficiency as a function of load power;
typical values.
Class-AB operation; VDS = 50 V; IDQ =2×0.5 A; f = 225 MHz;
ZL= 0.74 + j2 Ω(per section); RGS = 2.8 Ω(per section).
(1) Th=25°C.
(2) Th=70°C.
handbook, halfpage
0
60
40
ηD
(%)
20
0100 200 PL(W) 300
MGE612
(2)
(1)
Fig.20 Load power as a function of input power;
typical values.
Class-AB operation; VDS = 50 V; IDQ =2×0.5 A; f = 225 MHz;
ZL= 0.74 + j2 Ω(per section); RGS = 2.8 Ω(per section).
(1) Th=25°C.
(2) Th=70°C.
handbook, halfpage
0 5 10 15
400
300
100
0
200
MGE613
PL
(W)
Pi(W)
(1)
(2)

2003 Sep 19 15 Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
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Fig.21 Class-AB test circuit at f = 225 MHz.
handbook, full pagewidth
MGE617
L13
C17
C18
C19
R9
R11 IC1
C38 C37 C36
C35 L17
C26
C27
C25
L19 L21
R5
C12
C13
C9
R6
R7
L16
C22
C14 C23
C24
L14R8
R2
R3
R4
L4
L1
C5
C4
C3
R1
C1
C2 C6 C7 C20 C21 C28 C29 C30
C33
C31 L22
L23
L24
L20L18L12
D.U.T. L15
C32
C34
R10
L6 L8 L10
L5L3
L2
50 Ω
input 50 Ω
output
L7 L9 L11
C8
C15
C10
C11
C16
+VDD1
,,,
,,,
,,,
,,,,
,,,,
,,,
,,
,,
A
A
+VDD1
+VDD2

2003 Sep 19 16
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
List of components (see Figs 21 and 22).
COMPONENT DESCRIPTION VALUE DIMENSIONS CATALOGUE NO.
C1, C2 multilayer ceramic chip capacitor;
note 1 27 pF, 500 V
C3, C4, C31, C32 multilayer ceramic chip capacitor;
note 1 3×18 pF in parallel, 500 V
C5 film dielectric trimmer 4 to 40 pF 2222 809 08002
C6, C30 film dielectric trimmer 2 to 18 pF 2222 809 09006
C7 multilayer ceramic chip capacitor;
note 1 100 pF, 500 V
C8, C9, C15, C18 MKT film capacitor 1 µF, 63 V 2222 371 11105
C10, C13, C14,
C19, C36 multilayer ceramic chip capacitor 100 nF, 50 V 2222 852 47104
C11, C12 multilayer ceramic chip capacitor;
note 1 2×1 nFinparallel, 500 V
C16, C17 electrolytic capacitor 220 µF, 63 V
C20 multilayer ceramic chip capacitor;
note 1 3×33 pF in parallel, 500 V
C21 film dielectric trimmer 2 to 9 pF 2222 809 09005
C22, C27, C37,
C38 multilayer ceramic chip capacitor; note 1 1 nF, 500 V
C23, C26, C35 electrolytic capacitor 10 µF, 63 V
C24, C25 multilayer ceramic chip capacitor;
note 1 2×470 pF in parallel, 500 V
C28 multilayer ceramic chip capacitor;
note 1 2×10 pF + 1×18 pF in
parallel, 500 V
C29 multilayer ceramic chip capacitor;
note 1 2×5.6 pF in parallel, 500 V
C33, C34 multilayer ceramic chip capacitor;
note 1 5.6 pF, 500 V
L1, L3, L22, L24 stripline; note 2 50 Ωlength 80 mm
width 4.8 mm
L2, L23 semi-rigid cable; note 3 50 Ωext. dia. 3.6 mm
outer conductor
length 80 mm
L4, L5 stripline; note 2 43 Ωlength 24 mm
width 6 mm
L6, L7 stripline; note 2 43 Ωlength 14.5 mm
width 6 mm
L8, L9 stripline; note 2 43 Ωlength 4.4 mm
width 6 mm
L10, L11 stripline; note 2 43 Ωlength 3.2 mm
width 6 mm
L12, L13 stripline; note 2 43 Ωlength 15 mm
width 6 mm

2003 Sep 19 17
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Notes
1. American Technical Ceramics capacitor, type 100B or other capacitor of the same quality.
2. L1, L3 to L13, L18 to L22 and L24 are microstriplines on a double copper-clad printed-circuit board, with fibre-glass
reinforced PTFE dielectric (εr= 2.2), thickness 1⁄16 inch; thickness of copper sheet 2 ×35 µm.
3. L2 and L23 are soldered on to striplines L1 and L24 respectively.
L14, L17 2 ×grade 3B Ferroxcube
wideband HF chokes in parallel 4312 020 36642
L15, L16 13⁄4turns enamelled 2 mm copper
wire 40 nH int. dia. 10 mm leads 2 ×7mm
space 1 mm
L18, L19 stripline; note 2 43 Ωlength 13 mm
width 6 mm
L20, L21 stripline; note 2 43 Ωlength 29.5 mm
width 6 mm
R1 metal film resistor 10 Ω, 0.4 W
R2, R7 10 turns potentiometer 50 kΩ
R3, R6 metal film resistor 1 kΩ, 0.4 W
R4, R5 metal film resistor 2 ×5.62 Ω, in
parallel, 0.4 W
R8, R9 metal film resistor 10 Ω±5%, 1 W
R10 metal film resistor 4 ×42.2 Ωin
parallel, 1 W
R11 metal film resistor 5.11 kΩ, 1W
IC1 voltage regulator 78L05
COMPONENT DESCRIPTION VALUE DIMENSIONS CATALOGUE NO.

2003 Sep 19 18
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.22 Printed-circuit board and component layout for 225 MHz class-AB test circuit.
The circuit and components are situated on one side of the PTFE fibre-glass board, the other side being fully metallized to serve as an earth.
Earth connections are made by means of copper straps for a direct contact between upper and lower sheets.
Dimensions in mm.
handbook, full pagewidth
MBC436
119 130
100
Hollow
rivets Hollow
rivets
strap
strap
strap
strap
strap
strap
strap
strap
R11
C38 C35 C37
C36 C16
IC1
L2
L1
R1
C1
C2
C3
C4
C5
L4
L5
C6
slider R2
slider R7
C13 R6
C12
C17
L10
L11
R4
R5
L8L6
L7 L9
VDD1
C10 R3
C11 C8
to R2,R7
VDD1
VDD2
C9
C7
L17
R9
L17
C18
C25 C27
C26
C19
L12
C20
L13 C21 C28
L18
L19
L20
L21
C29
C31
C32
C30 C33
C34
R10
50 Ω
output
50 Ω
input
L23 L24
L3
L22
C14 C22
C23
L14
R8
L14
C15
C24
L15
L16

2003 Sep 19 19
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
Fig.23 Input impedance as a function of frequency
(series components); typical values per
section.
Class-AB operation; VDS = 50 V; IDQ =2×0.5 A;
RGS = 2.8 Ω(per section); PL= 250 W.
handbook, halfpage
150 200 250
2
1
−1
–2
0
MGE611
ri
zi
(Ω)
xi
f (MHz)
Fig.24 Load impedance as a function of frequency
(series components); typical values per
section.
Class-AB operation; VDS = 50 V; IDQ =2×0.5 A;
RGS = 2.8 Ω(per section); PL= 250 W.
handbook, halfpage
150 250200 f (MHz)
3
2
1
0
MGE625
XL
RL
ZL
(Ω)
Fig.25 Definition of MOS impedance.
handbook, halfpage
MBA379
ZiZL
Fig.26 Power gain as a function of frequency;
typical values per section.
Class-AB operation; VDS = 50 V; IDQ =2×0.5 A;
RGS = 2.8 Ω(per section); PL= 250 W.
handbook, halfpage
150 200 250
20
0
10
MGE624
Gp
(dB)
f (MHz)

2003 Sep 19 20
Philips Semiconductors Product Specification
VHF push-pull power MOS transistor BLF278
BLF278 scattering parameters
VDS = 50 V; ID= 500 mA; note 1
Note
1. For more extensive s-parameters see internet:
http://www.semiconductors.philips.com/markets/communications/wirelesscommunications/broadcast.
f (MHz) s11 s21 s12 s22
|s11|∠Φ |s21|∠Φ |s12|∠Φ |s22|∠Φ
5 0.87 −142.1 60.05 104.3 0.00 −19.4 0.83 160.9
10 0.88 −159.8 32.09 91.4 0.00 0.68 167.5 165.8
20 0.88 −169.0 15.70 77.3 0.01 13.4 0.62 177.6
30 0.88 −171.2 9.98 68.4 0.01 3.4 0.64 −175.8
40 0.89 −172.2 6.99 61.0 0.01 −4.4 0.66 −171.2
50 0.91 −172.9 5.24 55.0 0.01 −10.3 0.70 −168.1
60 0.92 −173.5 4.08 49.6 0.01 −15.0 0.74 −166.8
70 0.93 −174.1 3.26 44.9 0.01 −18.3 0.78 −166.5
80 0.94 −174.7 2.66 41.0 0.01 −19.8 0.80 −166.5
90 0.95 −175.2 2.22 37.5 0.00 −19.7 0.83 −166.7
100 0.95 −175.7 1.88 34.0 0.00 −18.0 0.85 −167.4
125 0.97 −176.9 1.27 26.8 0.00 −1.9 0.88 −169.4
150 0.97 −177.9 0.91 22.7 0.00 35.3 0.91 −170.0
175 0.98 −178.7 0.69 19.5 0.00 65.3 0.94 −170.8
200 0.98 −179.5 0.54 16.0 0.00 78.0 0.95 −172.4
250 0.99 179.2 0.35 12.1 0.01 86.7 0.96 −174.0
300 0.99 178.1 0.25 9.1 0.01 87.8 0.98 −175.5
350 0.99 177.1 0.19 8.2 0.01 90.3 0.98 −176.5
400 0.99 176.1 0.14 7.2 0.01 91.4 0.99 −177.6
450 0.99 175.1 0.11 8.1 0.02 92.2 0.99 −178.3
500 0.99 174.2 0.09 9.7 0.02 91.5 0.99 −179.2
600 0.99 172.4 0.07 14.8 0.02 91.4 0.99 179.5
700 0.99 170.7 0.05 24.0 0.03 91.6 0.99 178.3
800 0.99 168.9 0.04 35.6 0.03 92.5 1.00 177.1
900 0.99 167.1 0.04 46.0 0.04 93.1 1.00 176.0
1000 0.99 165.2 0.04 60.3 0.04 94.1 1.00 175.0