Philips BLF278 User Guide

DISCRETE SEMICONDUCTORS

DATA SH EET

M3D091

BLF278

VHF push-pull power MOS
transistor

Product Specification
Supersedes data of 1996 Oct 21

2003 Sep 19

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.

CAUTION

This productis 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.

PINNING - SOT262A1

PIN DESCRIPTION

1 drain 1
2 drain 2
3 gate 1
4 gate 2
5 source

12

55

34

Top view

Fig.1 Simplified outline and symbol.

d

g

s

g

d

MAM098

QUICK REFERENCE DATA

RF performance at Th=25°C in a push-pull common source test circuit.

MODE OF OPERATION

f

(MHz)

V

(V)

DS

P

(W)

L

G

(dB)

p

η

D

(%)

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 2

Philips Semiconductors Product Specification

VHF push-pull power MOS transistor BLF278

LIMITING VALUES

In accordance with the Absolute Maximum System (IEC 60134).

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

Per transistor section

V

DS

V

GS

I

D

P

tot

T

stg

T

j

THERMAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS VALUE UNIT

R

th j-mb

R

th mb-h

drain-source voltage − 125 V
gate-source voltage −±20 V
drain current (DC) − 18 A
total power dissipation Tmb≤ 25 °C; total device; both

− 500 W

sections equally loaded
storage temperature −65 150 °C
junction temperature − 200 °C

thermal resistance from junction
to mounting base

thermal resistance from
mounting base to heatsink

total device; both sections

equally loaded.

total device; both sections

equally loaded.

max. 0.35 K/W

max. 0.15 K/W

100

handbook, halfpage

I

D

(A)

(1)

10

1

1 10 100

Total device; both sections equally loaded.
(1) Current is this area may be limited by R
(2) Tmb=25°C.

Fig.2 DC SOAR.

(2)

DSon

MRA988

V (V)

DS

.

500

500

handbook, halfpage

P

tot

(W)

400

300

200

100

0

0 40 80 160

Total device; both sections equally loaded.
(1) Continuous operation.
(2) Short-time operation during mismatch.

(1)

Fig.3 Power derating curves.

(2)

120

MGE616

Th (°C)

2003 Sep 19 3

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

I

DSS

I

GSS

V

GSth

∆V

GS

g

fs

g

fs1/gfs2

R

DSon

I

DSX

C

is

C

os

C

rs

C

d-f

drain-source breakdown voltage VGS= 0; ID= 100 mA 125 −−V
drain-source leakage current VGS= 0; VDS=50V −−2.5 mA
gate-source leakage current VGS= ±20 V; VDS=0 −−1µA
gate-source threshold voltage VDS= 10 V; ID=50mA 2 − 4.5 V
gate-source voltage difference

VDS= 10 V; ID=50mA −−100 mV
of both sections

forward transconductance VDS= 10 V; ID= 5 A 4.5 6.2 − S
forward transconductance ratio

VDS= 10 V; ID=5A 0.9 − 1.1
of both sections

drain-source on-state resistance VGS= 10 V; ID=5A − 0.2 0.3 Ω
drain cut-off current VGS= 10 V; VDS=10V − 25 − A
input capacitance VGS= 0; VDS= 50 V; f = 1 MHz − 480 − pF
output capacitance VGS= 0; VDS= 50 V; f = 1 MHz − 190 − pF
feedback capacitance VGS= 0; VDS= 50 V; f = 1 MHz − 14 − pF
drain-flange capacitance − 5.4 − pF

VGS group indicator

GROUP

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

LIMITS

(V)

GROUP

LIMITS

(V)

MIN. MAX. MIN. MAX.

2003 Sep 19 4

Philips Semiconductors Product Specification

VHF push-pull power MOS transistor BLF278

handbook, halfpage

0

T.C.

(mV/K)

−1

−2

−3

−4

−5

10

VDS=10V.

−2

−1

10

110

ID (A)

Fig.4 Temperature coefficient of gate-source

voltageasafunctionofdraincurrent;typical
values per section.

MGE623

30

handbook, halfpage

I

D

(A)

20

10

0

0

VDS= 10 V; Tj=25°C.

5

10

MGE622

VGS (V)

Fig.5 Drain current as a function of gate-source

voltage; typical values per section.

15

400

handbook, halfpage

R

DSon

(mΩ)

300

200

100

0

0 50 100 150

VGS= 10 V; ID=5A.

Tj (°C)

Fig.6 Drain-source on-state resistance as a

function of junction temperature; typical
values per section.

MGE621

C

is

C

os

VDS (V)

MGE615

1200

handbook, halfpage

C

(pF)

800

400

0

0

VGS= 0; f = 1 MHz.

20

40

Fig.7 Input and output capacitance as functions

of drain-source voltage; typical values per
section.

60

2003 Sep 19 5

Philips Semiconductors Product Specification

VHF push-pull power MOS transistor BLF278

400

handbook, halfpage

C

rs

(pF)

300

200

100

0

010 50

VGS= 0; f = 1 MHz.

20 30 40

VDS (V)

Fig.8 Feedback capacitance as a function of

drain-source voltage; typical values per
section.

MGE620

APPLICATION INFORMATION
Class-B operation

RF performance in CW operation in a common source push-pull test circuit. Th=25°C; R
otherwise specified. R

MODE OF OPERATION

=4Ω per section; optimum load impedance per section = 3.2 + j4.3 Ω (VDS= 50 V).

GS

f

(MHz)

V

(V)

DS

I

DQ

(A)

P

(W)

L

CW, class-B 108 50 2 × 0.1 300 >20

= 0.15 K/W unless

th mb-h

G

p

(dB)

typ. 22

η

D

(%)

>60

typ. 70

CW, class-C 108 50 VGS= 0 300 typ. 18 typ. 80

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: V

= 50 V; f = 108 MHz at rated load power.

DS

2003 Sep 19 6

Philips Semiconductors Product Specification

VHF push-pull power MOS transistor BLF278

30

handbook, halfpage

G

p

(dB)

20

10

0

0

Class-B operation; VDS=50V;IDQ=2×0.1 A; f = 108 MHz;

= 3.2 + j4.3 Ω (per section); RGS=4Ω (per section).

Z

L

(1) Th=25°C.
(2) Th=70°C.

(1)

(2)

200 400 600

MGE682

PL (W)

Fig.9 Power gain as a function of load power;

typical values.

80

handbook, halfpage

η

D

(%)

60

(1)

40

20

0

0 200 400

Class-B operation; VDS=50V;IDQ=2×0.1 A; f = 108 MHz;

= 3.2 + j4.3 Ω (per section); RGS=4Ω (per section).

Z

L

(1) Th=25°C.
(2) Th=70°C.

(2)

(2)

(1)

PL (W)

Fig.10 Efficiency as a function of load power;

typical values.

MGE683

600

600

handbook, halfpage

P

L

(W)

400

200

0

0

Class-B operation; VDS=50V;IDQ=2×0.1 A; f = 108 MHz;

= 3.2 + j4.3 Ω (per section); RGS=4Ω (per section).

Z

L

(1) Th=25°C.
(2) Th=70°C.

(1)

(2)

51015

MGE684

Pi (W)

Fig.11 Load power as a function of input power;

typical values.

2003 Sep 19 7