Philips bf908-r_n Datasheet

BF908; BF908R

Dual-gate MOS-FETs

Rev. 03 — 14 November 2007 Product data sheet

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NXP Semiconductors

NXP Semiconductors Product specification

Rev. 03 - 14 November 2007

2 of 9

Dual-gate MOS-FETs BF908; BF908R

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

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

43

Top view

BF908 marking code: %M1.

Fig.1 Simplified outline (SOT143) and

handbook, halfpage

34

21

symbol; BF908.

MAM039

g
g

d

g

2

g

1

s,b

d

2

1

PINNING

PIN SYMBOL DESCRIPTION

1 s, b source
2 d drain
3g
4g

2
1

gate 2
gate 1

Top view

BF908R marking code: %M2.

Fig.2 Simplified outline (SOT143R) and

12

symbol; BF908R.

MAM040

s,b

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

DS

I

D

P

tot

T

j

 forward transfer admittance 36 43 50 mS

y

fs

C

ig1-s

C

rs

drain-source voltage −−12 V
drain current −−40 mA
total power dissipation −−200 mW
operating junction temperature −−150 °C

input capacitance at gate 1 2.4 3.1 4 pF
reverse transfer capacitance f = 1 MHz 20 30 45 pF

F noise figure f = 800 MHz − 1.5 2.5 dB

NXP Semiconductors Product specification

Rev. 03 - 14 November 2007

3 of 9

Dual-gate MOS-FETs BF908; BF908R

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC 134).

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

V

DS

I

D

±I

G1

±I

G2

P

tot

T

stg

T

j

Note

1. Device mounted on a printed-circuit board.

drain-source voltage − 12 V
drain current − 40 mA
gate 1 current − 10 mA
gate 2 current − 10 mA
total power dissipation see Fig.3; note 1

BF908 up to T
BF908R up to T

=50°C − 200 mW

amb

=40°C − 200 mW

amb

storage temperature −65 +150 °C
operating junction temperature − 150 °C

250

handbook, halfpage

P

tot

(mW)

200

150

100

50

0

0 50 100 150 200

BF908

BF908R

T

Fig.3 Power derating curves.

amb

MRC275

o

( C)

NXP Semiconductors Product specification

Rev. 03 - 14 November 2007

4 of 9

Dual-gate MOS-FETs BF908; BF908R

THERMAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS VALUE UNIT

R

th j-a

Note

1. Device mounted on a printed-circuit board.

STATIC CHARACTERISTICS

=25°C; unless otherwise specified.

T

j

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

±V

(BR)G1-SS

±V

(BR)G2-SS

−V

(P)G1-S

−V

(P)G2-S

I

DSS

±I

G1-SS

±I

G2-SS

thermal resistance from junction to ambient note 1

BF908 500 K/W
BF908R 550 K/W

gate 1-source breakdown voltage V
gate 2-source breakdown voltage V
gate 1-source cut-off voltage V
gate 2-source cut-off voltage V
drain-source current V
gate 1 cut-off current V
gate 2 cut-off current V

G2-S=VDS
G1-S=VDS
G2-S
G1-S
G2-S
G2-S=VDS
G1-S=VDS

= 0; I
= 0; I

=10mA 8 − 20 V

G1-S

=10mA 8 − 20 V

G2-S

=4V; VDS=8V; ID=20µA −−2V
=4V; VDS=8V; ID=20µA −−1.5 V
=4V; VDS=8V; V

= 0; V

G1-S

= 0; V

G2-S

=03 1527mA

G1-S

=5V −−50 nA
=5V −−50 nA

DYNAMIC CHARACTERISTICS

Common source; T

=25°C; VDS=8V; V

amb

=4V; ID= 15 mA; unless otherwise specified.

G2-S

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

y

 forward transfer admittance pulsed; Tj=25°C; f = 1 MHz 36 43 50 mS

fs

C

ig1-s

C

ig2-s

C

os

C

rs

F noise figure f = 200 MHz; G

input capacitance at gate 1 f = 1 MHz 2.4 3.1 4 pF
input capacitance at gate 2 f = 1 MHz 1.2 1.8 2.5 pF
output capacitance f = 1 MHz 1.2 1.7 2.2 pF
reverse transfer capacitance f = 1 MHz 20 30 45 fF

f = 800 MHz; G

= 2 mS; BS=B

S
S=GSopt

; BS=B

Sopt
Sopt

− 0.6 1.2 dB

− 1.5 2.5 dB

NXP Semiconductors Product specification

Rev. 03 - 14 November 2007

5 of 9

Dual-gate MOS-FETs BF908; BF908R

40

handbook, halfpage

ID

(mA)

30

20

10

0

−0.6 −0.4 0 0.2−0.2 0.4

VDS= 8V; Tj=25°C.

V

V

G2-S

G1-S

Fig.4 Transfer characteristics; typical values.

MRC281

= 4 V

3 V

2 V

1.5 V
1 V

0.5 V

0 V

(V)

0.6

30

handbook, halfpage

ID

(mA)

20

10

0

048 16

V

= 4 V; Tj=25°C.

G2-S

V

G1-S

12

Fig.5 Output characteristics; typical values.

MRC282

= 0.3 V

0.2 V

0.1 V

0 V

−0.1 V

−0.2 V

−0.3 V

VDS (V)

50

Y

fs

(mS)

40

30

20

10

V

G2-S

0

0 5 10 15 20 25

VDS= 8 V; Tj=25°C.

0.5 V

= 0 V

MRC280

4 V

3 V
2 V

1.5 V

1 V

ID(mA)

Fig.6 Forward transfer admittance as a function

of drain current; typical values.

60

Y

fs

(mS)

40

20

0

VDS= 8 V; V

0 40 80 120 16040

= 4 V; ID=15mA.

G2-S

MRC276

o

Tj( C)

Fig.7 Forward transfer admittance as a function

of junction temperature; typical values.

NXP Semiconductors Product specification

Rev. 03 - 14 November 2007

6 of 9

Dual-gate MOS-FETs BF908; BF908R

Table 1 Scattering parameters

f

(MHz)

V

DS

MAGNITUDE

=8V; V

s

11

ANGLE

(ratio)

=4V; ID= 10 mA; T

G2-S

MAGNITUDE

(deg)

amb

(ratio)

=25°C.

s

21

ANGLE

MAGNITUDE

(deg)

(ratio)

s

12

ANGLE

MAGNITUDE

(deg)

(ratio)

s

22

ANGLE

(deg)

50 0.998 −5.1 3.537 173.5 0.001 98.2 0.996 −2.4
100 0.994 −10.4 3.502 167.7 0.001 88.8 0.994 −4.9
200 0.979 −20.8 3.450 154.9 0.003 74.6 0.987 −9.5
300 0.962 −30.3 3.318 143.7 0.004 69.5 0.983 −13.9
400 0.939 −40.1 3.234 131.9 0.005 65.6 0.980 −18.5
500 0.914 −49.1 3.093 120.7 0.006 64.4 0.974 −22.8
600 0.892 −57.1 2.912 111.1 0.005 63.1 0.969 −27.0
700 0.865 −64.4 2.774 101.0 0.005 65.2 0.966 −31.2
800 0.837 −71.6 2.616 91.4 0.004 70.8 0.965 −35.4
900 0.811 −78.1 2.479 81.9 0.004 87.4 0.965 −39.4

1000 0.785 −84.5 3.329 72.5 0.003 108.0 0.966 −43.7

V

DS

=8V; V

=4V; ID= 15 mA; T

G2-S

amb

=25°C.

50 0.998 −5.3 3.983 173.4 0.001 95.5 0.994 −2.4
100 0.994 −10.9 3.943 167.5 0.001 93.6 0.991 −5.0
200 0.976 −21.6 3.878 154.7 0.003 74.3 0.984 −9.7
300 0.957 −31.7 3.722 143.3 0.004 70.0 0.979 −14.2
400 0.934 −41.7 3.614 131.6 0.005 63.5 0.975 −18.8
500 0.907 −51.1 3.446 120.4 0.006 62.2 0.969 −23.2
600 0.885 −59.1 3.240 110.9 0.005 59.6 0.964 −27.4
700 0.851 −66.8 3.072 100.9 0.005 64.8 0.961 −31.6
800 0.826 −73.9 2.891 91.3 0.004 67.8 0.959 −35.9
900 0.797 −80.7 2.733 81.9 0.004 85.0 0.958 −40.0

1000 0.773 −87.0 2.569 72.8 0.004 102.9 0.958 −44.2

Table 2 Noise data

(MHz)

=8V; V

V

DS

V

=8V; V

DS

Γ

f

=4V; ID= 10 mA; T

G2-S

F

min

(dB)

amb

(ratio) (deg)

=25°C.

opt

r

n

800 1.50 0.720 56.7 0.580

=4V; ID= 15 mA; T

G2-S

amb

=25°C.

800 1.50 0.700 59.2 0.520

NXP Semiconductors Product specification

Rev. 03 - 14 November 2007

7 of 9

Dual-gate MOS-FETs BF908; BF908R

PACKAGE OUTLINES

handbook, full pagewidth

Dimensions in mm.

10

max

3.0

0.150

30

max

0.090

0.1

max

max

o

o

10

0.88

0.75

0.60

o

1.1

max

2.8

1.9

43

1

2

0

0.1

TOP VIEW

0.48

1.7

0

0.1

B

A

1.4

1.2

M0.1 AB

2.5

max

0.2

MBC845

M

AB

Fig.8 SOT143.

handbook, full pagewidth

Dimensions in mm.

0.40

0.25

10

max

3.0

0.150

0.090

30

max

o

0.1

max

10

max

o

0.48

0.38

o

1.1

max

2.8

1.9

34

2

1

0.88

0.78

1.7

M0.1 B

TOP VIEW

B

A

1.4

1.2

MBC844

2.5

max

0.2

A

M

Fig.9 SOT143R.

NXP Semiconductors

Rev. 03 - 14 November 2007

8 of 9

Legal information

Data sheet status

BF908; BF908R

Dual-gate MOS-FETs

Document status

Objective [short] data sheet Development This document contains data from the objective specification for product development.
Preliminary [short] data sheet Qualification This document contains data from the preliminary specification.
Product [short] data sheet Production This document contains the product specification.

[1] Please consult the most recently issued document before initiating or completing a design.
[2] The term ‘short data sheet’ is explained in section “Definitions”.
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information is available on the Internet at URL

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NXP Semiconductors

BF908; BF908R

Dual-gate MOS-FETs

Revision history

Revision history

Document ID Release date Data sheet status Change notice Supersedes

BF908-R_N_3 20071114 Product data sheet - BF908-R_2
Modifications:
BF908-R_2 19960730 Product specification - BF908R_1
BF908R_1 - - - -

• Fig. 1 and 2 on page 2; Figure note changed

Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.

© NXP B.V. 2007. All rights reserved.

For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]

Date of release: 14 November 2007
Document identifier: BF908-R_N_3