MRF137
The RF MOSFET Line
N–Channel Enhancement–Mode
. . . designed for wideband large–signal output and driver stages up to
400 MHz range.
•Guaranteed 28 Volt, 150 MHz Performance
Output Power = 30 Watts
Minimum Gain = 13 dB
Efficiency — 60% (Typical)
•Small–Signal and Large–Signal Characterization
•Typical Performance at 400 MHz, 28 Vdc, 30 W
Output = 7.7 dB Gain
•100% Tested For Load Mismatch At All Phase Angles
With 30:1 VSWR
•Low Noise Figure — 1.5 dB (Typ) at 1.0 A, 150 MHz
•Excellent Thermal Stability, Ideally Suited For Class A
Operation
•Facilitates Manual Gain Control, ALC and Modulation
Techniques
MAXIMUM RATINGS
Rating Symbol Value Unit
Drain–Source Voltage VDSS 65 Vdc
Drain–Gate Voltage
(RGS = 1.0 MΩ)VDGR 65 Vdc
Gate–Source Voltage VGS ±40 Vdc
Drain Current — Continuous ID5.0 Adc
Total Device Dissipation @ TC = 25°C
Derate above 25°CPD100
0.571 Watts
W/°C
Storage Temperature Range Tstg –65 to +150 °C
Operating Junction Temperature TJ200 °C
THERMAL CHARACTERISTICS
Characteristic Symbol Max Unit
Thermal Resistance, Junction to Case RθJC 1.75 °C/W
Handling and Packaging — MOS devices are susceptible to damage from electrostatic charge. Reasonable precautions in handling and
packaging MOS devices should be observed.
30 W, to 400 MHz
N–CHANNEL MOS
BROADBAND RF POWER
FET
CASE 211–07, STYLE 2
Order this document
by MRF137/D
SEMICONDUCTOR TECHNICAL DATA
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ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted.)
Characteristic Symbol Min Typ Max Unit
OFF CHARACTERISTICS
Drain–Source Breakdown Voltage (VGS = 0, ID = 10 mA) V(BR)DSS 65 — — Vdc
Zero Gate Voltage Drain Current (VDS = 28 V, VGS = 0) IDSS — — 4.0 mAdc
Gate–Source Leakage Current (VGS = 20 V, VDS = 0) IGSS — — 1.0 µAdc
ON CHARACTERISTICS
Gate Threshold Voltage (VDS = 10 V, ID = 25 mA) VGS(th) 1.0 3.0 6.0 Vdc
Forward Transconductance (VDS = 10 V, ID = 500 mA) gfs 500 750 — mmhos
DYNAMIC CHARACTERISTICS
Input Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Ciss — 48 — pF
Output Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Coss — 54 — pF
Reverse Transfer Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Crss —11 — pF
FUNCTIONAL CHARACTERISTICS
Noise Figure
(VDS = 28 Vdc, ID = 1.0 A, f = 150 MHz) NF — 1.5 — dB
Common Source Power Gain
(VDD = 28 Vdc, Pout = 30 W, f = 150 MHz (Figure 1)
IDQ = 25 mA) f = 400 MHz (Figure 14)
Gps 13
—16
7.7 —
—
dB
Drain Efficiency (Figure 1)
(VDD = 28 Vdc, Pout = 30 W, f = 150 MHz, IDQ = 25 mA) η50 60 — %
Electrical Ruggedness (Figure 1)
(VDD = 28 Vdc, Pout = 30 W, f = 150 MHz, IDQ = 25 mA,
VSWR 30:1 at All Phase Angles)
ψNo Degradation in Output Power
Figure 1. 150 MHz Test Circuit
C1 — Arco 403, 3.0–35 pF, or equivalent
C2 — Arco 406, 15–115 pF, or equivalent
C3 — 56 pF Mini–Unelco, or equivalent
C4 — Arco 404, 8.0–60 pF, or equivalent
C5 — 680 pF, 100 Mils Chip
C6 — 0.01 µF, 100 V, Disc Ceramic
C7 — 100 µF, 40 V
C8 — 0.1 µF, 50 V, Disc Ceramic
C9, C10 — 680 pF Feedthru
D1 — 1N5925A Motorola Zener
L1 — 2 Turns, 0.29″ ID, #18 AWG Enamel, Closewound
L2 — 1–1/4 Turns, 0.2″ ID, #18 AWG Enamel, Closewound
L3 — 2 Turns, 0.2″ ID, #18 AWG Enamel, Closewound
RFC1 — 20 Turns, 0.30″ ID, #20 AWG Enamel, Closewound
RFC2 — Ferroxcube VK–200 — 19/4B
R1 — 10 kΩ, 1/2 W Thin Film
R2 — 10 kΩ, 1/4 W
R3 — 10 Turns, 10 kΩ
R4 — 1.8 kΩ, 1/2 W
Board — G10, 62 Mils
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Figure 2. Output Power versus Input Power Figure 3. Output Power versus Input Power
Figure 4. Output Power versus Input Power Figure 5. Output Power versus Supply Voltage
Figure 6. Output Power versus Supply Voltage Figure 7. Output Power versus Supply Voltage
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Figure 8. Output Power versus Supply Voltage Figure 9. Output Power versus Gate Voltage
Figure 10. Drain Current versus Gate Voltage
(Transfer Characteristics) Figure 11. Gate Source Voltage versus
Case Temperature
Figure 12. Capacitance versus
Drain–Source Voltage Figure 13. DC Safe Operating Area
°
°
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Figure 14. 400 MHz Test Circuit
C1, C2, C3, C4 — 0–20 pF Johanson, or equivalent
C5, C8 — 270 pF, 100 Mil Chip
C6, C7 — 24 pF Mini–Unelco, or equivalent
C9 — 0.01 µF, 100 V, Disc Ceramic
C10 — 100 µF, 40 V
C11 — 0.1 µF, 50 V, Disc Ceramic
C12, C13 — 680 pF Feedthru
D1 — 1N5925A Motorola Zener
R1, R2 — 10 kΩ, 1/4 W
R3 — 10 Turns, 10 kΩ
Figure 15. Large–Signal Series Equivalent Input and Output Impedance, Zin, ZOL*
R4 — 1.8 kΩ, 1/2 W
Z1 — 2.9″ x 0.166″ Microstrip
Z2, Z4 — 0.35″ x 0.166″ Microstrip
Z3 — 0.40″ x 0.166″Microstrip
Z5 — 1.05″ x 0.166″Microstrip
Z6 — 1.9″ x 0.166″ Microstrip
RFC1 — 6 Turns, 0.300″ ID, #20 AWG Enamel, Closewound
RFC2 — Ferroxcube VK–200 — 19/4B
Board — Glass Teflon, 62 Mils
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f
S11 S21 S12 S22
f
(MHz) |S11|∠φ|S21|∠φ|S12|∠φ|S22|∠φ
2.0 0.977 –32 59.48 163 0.011 67 0.661 –36
5.0 0.919 –70 48.67 142 0.024 44 0.692 –78
10 0.852 –109 33.50 122 0.032 29 0.747 –117
20 0.817 –140 19.05 106 0.037 16 0.768 –146
30 0.814 –153 13.11 99 0.038 14 0.774 –157
40 0.811 –159 9.88 95 0.038 13 0.782 –162
50 0.812 –164 7.98 92 0.038 12 0.787 –165
60 0.813 –166 6.66 89 0.038 12 0.787 –168
70 0.815 –168 5.708 86 0.038 11 0.787 –169
80 0.816 –170 5.003 84 0.038 11 0.787 –170
90 0.817 –171 4.560 83 0.038 12 0.787 –171
100 0.817 –172 4.170 81 0.039 13 0.787 –172
110 0.818 –173 3.670 80 0.039 13 0.788 –172
120 0.820 –173 3.420 79 0.039 13 0.788 –173
130 0.821 –173 3.170 79 0.039 13 0.788 –173
140 0.822 –174 2.980 78 0.039 13 0.788 –173
150 0.823 –175 2.826 77 0.039 14 0.788 –173
160 0.824 –175 2.650 76 0.039 14 0.790 –174
170 0.825 –176 2.438 75 0.039 14 0.792 –174
180 0.827 –176 2.325 73 0.039 15 0.793 –174
190 0.829 –177 2.175 72 0.039 16 0.796 –174
200 0.831 –177 2.084 71 0.039 16 0.799 –174
225 0.836 –178 1.824 69 0.039 18 0.805 –174
250 0.846 –178 1.621 66 0.039 21 0.816 –174
275 0.853 –179 1.462 64 0.039 23 0.822 –174
300 0.853 –179 1.319 61 0.040 25 0.833 –174
325 0.856 –179 1.194 59 0.040 27 0.828 –174
350 0.857 +179 1.089 56 0.040 30 0.842 –174
375 0.861 +179 1.014 54 0.042 32 0.849 –174
400 0.865 +178 0.927 51 0.043 35 0.856 –174
425 0.875 +178 0.876 49 0.045 37 0.866 –174
450 0.881 +178 0.810 46 0.046 40 0.870 –174
475 0.886 +177 0.755 44 0.046 43 0.875 –174
500 0.887 +177 0.694 41 0.051 43 0.888 –174
525 0.888 +176 0.677 39 0.052 43 0.890 –174
550 0.896 +176 0.625 36 0.055 45 0.898 –174
575 0.907 +175 0.603 34 0.058 45 0.913 –174
600 0.910 +175 0.585 32 0.061 45 0.918 –174
625 0.910 +174 0.563 30 0.065 45 0.945 –174
650 0.920 +174 0.543 28 0.069 46 0.952 –174
675 0.938 +173 0.533 26 0.074 47 0.974 –174
700 0.943 +171 0.515 24 0.078 47 0.958 –176
725 0.934 +170 0.491 22 0.079 46 0.953 –177
750 0.940 +170 0.475 22 0.084 48 0.943 –177
775 0.953 +169 0.477 21 0.090 48 0.957 –177
800 0.959 +168 0.467 17 0.093 48 0.957 –179
Table 1. Common Source Scattering Parameters
50 Ω System
VDS = 28 V, ID = 0.75 A
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Figure 16. S11, Input Reflection Coefficient
versus Frequency
VDS = 28 V ID = 0.75 A
Figure 17. S12, Reverse Transmission Coefficient
versus Frequency
VDS = 28 V ID = 0.75 A
Figure 18. S21, Forward Transmission Coefficient
versus Frequency
VDS = 28 V ID = 0.75 A
Figure 19. S22, Output Reflection Coefficient
versus Frequency
VDS = 28 V ID = 0.75 A
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DESIGN CONSIDERATIONS
The MRF137 is a RF power N–Channel enhancement
mode field–effect transistor (FET) designed especially for
VHF power amplifier applications. M/A-COM RF MOS FETs
feature a vertical structure with a planar design, thus avoiding
the processing difficulties associated with V–groove vertical
power FETs.
M/A-COM Application Note AN211A, FETs in Theory and
Practice, is suggested reading for those not familiar with the
construction and characteristics of FETs.
The major advantages of RF power FETs include high gain,
low noise, simple bias systems, relative immunity from ther-
mal runaway, and the ability to withstand severely mis-
matched loads without suffering damage. Power output can
be varied over a wide range with a low power dc control signal,
thus facilitating manual gain control, ALC and modulation.
DC BIAS
The MRF137 is an enhancement mode FET and, therefore,
does not conduct when drain voltage is applied. Drain current
flows when a positive voltage is applied to the gate. See Figure
10 for a typical plot of drain current versus gate voltage. RF
power FETs require forward bias for optimum performance.
The value of quiescent drain current (IDQ) is not critical for
many applications. The MRF137 was characterized at IDQ =
25 mA, which is the suggested minimum value of IDQ. For
special applications such as linear amplification, IDQ may
have to be selected to optimize the critical parameters.
The gate is a dc open circuit and draws no current.
Therefore, the gate bias circuit may generally be just a simple
resistive divider network. Some special applications may
require a more elaborate bias system.
GAIN CONTROL
Power output of the MRF137 may be controlled from its
rated value down to zero (negative gain) by varying the dc gate
voltage. This feature facilitates the design of manual gain
control, AGC/ALC and modulation systems. (See Figure 9.)
AMPLIFIER DESIGN
Impedance matching networks similar to those used with bi-
polar VHF transistors are suitable for MRF137. See M/A-COM
Application Note AN721, Impedance Matching Networks Ap-
plied to R F Power Transistors. The higher input impedance of
RF MOS FETs helps ease the task of broadband network de-
sign. Both small signal scattering parameters and large signal
impedances are provided. While the s–parameters will not
produce an exact design solution for high power operation,
they do yield a good first approximation. This is an additional
advantage of RF MOS power FETs.
RF power FETs are triode devices and, therefore, not
unilateral. This, coupled with the very high gain of the
MRF137, yields a device capable of self oscillation. Stability
may be achieved by techniques such as drain loading, input
shunt resistive loading, or output to input feedback. Two port
parameter stability analysis with the MRF137 s–parameters
provides a useful tool for selection of loading or feedback
circuitry to assure stable operation. See M/A-COM Application
Note AN215A for a discussion of two port network theory and
stability.
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PACKAGE DIMENSIONS
CASE 211–07
ISSUE N
A
UM
M
Q
RB
D
K
E
C
J
H
S
9
Specifications subject to change without notice.
n North America: Tel. (800) 366-2266, Fax (800) 618-8883
n Asia/Pacific: Tel.+81-44-844-8296, Fax +81-44-844-8298
n Europe: Tel. +44 (1344) 869 595, Fax+44 (1344) 300 020
Visit www.macom.com for additional data sheets and product information.
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