1
MRF175GU MRF175GVMOTOROLA RF DEVICE DATA
The RF MOSFET Line
N–Channel Enhancement–Mode
Designed for broadband commercial and military applications using push pull
circuits at frequencies to 500 MHz. The high power, high gain and broadband
performance of these devices makes possible solid state transmitters for FM
broadcast or TV channel frequency bands.
•Guaranteed Performance
MRF175GV @ 28 V, 225 MHz (“V” Suffix)
Output Power — 200 Watts
Power Gain — 14 dB Typ
Efficiency — 65% Typ
MRF175GU @ 28 V, 400 MHz (“U” Suffix)
Output Power — 150 Watts
Power Gain — 12 dB Typ
Efficiency — 55% Typ
•100% Ruggedness Tested At Rated Output Power
•Low Thermal Resistance
•Low Crss — 20 pF Typ @ VDS = 28 V
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 ID26 Adc
Total Device Dissipation @ TC = 25°C
Derate above 25°CPD400
2.27 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 0.44 °C/W
ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted)
Characteristic Symbol Min Typ Max Unit
OFF CHARACTERISTICS (1)
Drain–Source Breakdown Voltage
(VGS = 0, ID = 50 mA) V(BR)DSS 65 — — Vdc
Zero Gate Voltage Drain Current
(VDS = 28 V, VGS = 0) IDSS — — 2.5 mAdc
Gate–Source Leakage Current
(VGS = 20 V, VDS = 0) IGSS — — 1.0 µAdc
(continued)
Handling and Packaging — MOS devices are susceptible to damage from electrostatic charge. Reasonable precautions in handling and
packaging MOS devices should be observed.
Order this document
by MRF175GU/D
SEMICONDUCTOR TECHNICAL DATA
200/150 WATTS, 28 V, 500 MHz
N–CHANNEL MOS
BROADBAND
RF POWER FETs
CASE 375–04, STYLE 2
Motorola, Inc. 1995
D
GS
(FLANGE)
D
G
REV 7
MRF175GU MRF175GV
2MOTOROLA RF DEVICE DATA
ELECTRICAL CHARACTERISTICS — continued (TC = 25°C unless otherwise noted)
Characteristic Symbol Min Typ Max Unit
ON CHARACTERISTICS (1)
Gate Threshold Voltage (VDS = 10 V, ID = 100 mA) VGS(th) 1.0 3.0 6.0 Vdc
Drain–Source On–Voltage (VGS = 10 V, ID = 5.0 A) VDS(on) 0.1 0.9 1.5 Vdc
Forward Transconductance (VDS = 10 V, ID = 2.5 A) gfs 2.0 3.0 — mhos
DYNAMIC CHARACTERISTICS (1)
Input Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Ciss — 180 — pF
Output Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Coss — 200 — pF
Reverse Transfer Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Crss — 20 — pF
FUNCTIONAL CHARACTERISTICS — MRF175GV (2) (Figure 1)
Common Source Power Gain
(VDD = 28 Vdc, Pout = 200 W, f = 225 MHz, IDQ = 2.0 x 100 mA) Gps 12 14 — dB
Drain Efficiency
(VDD = 28 Vdc, Pout = 200 W, f = 225 MHz, IDQ = 2.0 x 100 mA) η55 65 — %
Electrical Ruggedness
(VDD = 28 Vdc, Pout = 200 W, f = 225 MHz, IDQ = 2.0 x 100 mA,
VSWR 10:1 at all Phase Angles)
ψNo Degradation in Output Power
NOTES:
1. Each side of device measured separately.
2. Measured in push–pull configuration.
Figure 1. 225 MHz Test Circuit
C1 — Arco 404, 8.0–60 pF
C2, C3, C7, C8 — 1000 pF Chip
C4, C9 — 0.1 µF Chip
C5 — 180 pF Chip
C6 — 100 pF and 130 pF Chips in Parallel
C10 — 0.47 µF Chip, Kemet 1215 or Equivalent
L1 — 10 Turns AWG #16 Enamel Wire, Close
L1 — Wound, 1/4″ I.D.
L2 — Ferrite Beads of Suitable Material for
L2 — 1.5–2.0 µH Total Inductance
Board material — .062″ fiberglass (G10),
Two sided, 1 oz. copper, εr
^
5
Unless otherwise noted, all chip capacitors
are ATC Type 100 or Equivalent.
R1 — 100 Ohms, 1/2 W
R2 — 1.0 k Ohm, 1/2 W
T1 — 4:1 Impedance Ratio RF Transformer.
T1 — Can Be Made of 25 Ohm Semirigid Coax,
T1 — 47–52 Mils O.D.
T2 — 1:9 Impedance Ratio RF Transformer.
T2 — Can Be Made of 15–18 Ohms Semirigid
T2 — Coax, 62–90 Mils O.D.
NOTE: For stability, the input transformer T1 should be loaded
NOTE: with ferrite toroids or beads to increase the common
NOTE: mode inductance. For operation below 100 MHz. The
NOTE: same is required for the output transformer.
BIAS 0–6 V
R1
C3 C4
R2
C1 C2
T1
C5
D.U.T.
C6
T2
C7
L1
C8 C9
L2
C10 +
–28 V
3
MRF175GU MRF175GVMOTOROLA RF DEVICE DATA
ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted)
Characteristic Symbol Min Typ Max Unit
FUNCTIONAL CHARACTERISTICS — MRF175GU (1) (Figure 2)
Common Source Power Gain
(VDD = 28 Vdc, Pout = 150 W, f = 400 MHz, IDQ = 2.0 x 100 mA) Gps 10 12 — dB
Drain Efficiency
(VDD = 28 Vdc, Pout = 150 W, f = 400 MHz, IDQ = 2.0 x 100 mA) η50 55 — %
Electrical Ruggedness
(VDD = 28 Vdc, Pout = 150 W, f = 400 MHz, IDQ = 2.0 x 100 mA,
VSWR 10:1 at all Phase Angles)
ψNo Degradation in Output Power
NOTE:
1. Measured in push–pull configuration.
Figure 2. 400 MHz Test Circuit
B1 — Balun 50 Ω Semi Rigid Coax 0.086″ O.D. 2″ Long
B2 — Balun 50 Ω Semi Rigid Coax 0.141″ O.D. 2″ Long
C1, C2, C8, C9 — 270 pF ATC Chip Cap
C3, C5, C7 — 1.0–20 pF Trimmer Cap
C4 — 15 pF ATC Chip Cap
C6 — 33 pF ATC Chip Cap
C10, C12, C13, C16, C17 — 0.01 µF Ceramic Cap
C11 — 1.0 µF 50 V Tantalum
C14, C15 — 680 pF Feedthru Cap
C18 — 20 µF 50 V Tantalum
L1, L2 — Hairpin Inductor #18 Wire
L3, L4 — 12 Turns #18 Enameled Wire 0.340″ I.D.
L5 — Ferroxcube VK200 20/4B
L6 — 3 Turns #16 Enameled Wire 0.340″ I.D.
R1 — 1.0 kΩ 1/4 W Resistor
R2, R3 — 10 kΩ 1/4 W Resistor
Z1, Z2 — Microstrip Line 0.400″ x 0.250″
Z3, Z4 — Microstrip Line 0.870″ x 0.250″
Z5, Z6 — Microstrip Line 0.500″ x 0.250″
Board material — 0.060″ Teflon–fiberglass,
εr = 2.55, copper clad both sides, 2 oz. copper.
BIAS C10 C11 R1 C12 C13
C14 C15
L5 L6
C18 28 V
B1 C3 C4 C5 C6 C7 B2
C2 L2
R3 L4
C16 C17 BA
Z2
Z1 Z3 Z5
Z4 Z6
0.180
″
0.200
″
AB
D.U.T.
R2 L3
C9
C1 L1 C8
MRF175GU MRF175GV
4MOTOROLA RF DEVICE DATA
Figure 3. Common Source Unity Current Gain
Frequency versus Drain Current Figure 4. DC Safe Operating Area
Figure 5. Drain Current versus Gate Voltage
(Transfer Characteristics) Figure 6. Gate–Source Voltage versus
Case Temperature
TYPICAL CHARACTERISTICS
Figure 7. Capacitance versus Drain–Source Voltage*
*Data shown applies to each half of MRF175GU/GV.
f , UNITY GAIN FREQUENCY (MHz)
T
ID, DRAIN CURRENT (AMPS)
VGS, GATE-SOURCE VOLTAGE (NORMALIZED) ID, DRAIN CURRENT (AMPS)
C, CAPACITANCE (pF)
4000
3000
2000
1000
020181614121086420 ID, DRAIN CURRENT (AMPS)
VDS = 10 V
VDS = 20 V
100
101 VDS, DRAIN–SOURCE VOLTAGE (VOLTS)
10
1100
TC = 25
°
C
1VGS, GATE–SOURCE VOLTAGE (VOLTS)
1
2
3
4
5
2 3 4 5 6
VDS = 10 V
TYPICAL DEVICE SHOWN, VGS(th) = 3 V
–25 TC, CASE TEMPERATURE (
°
C)
1.2
0 25 50 75 100 125 150 175
1.1
1
0.9
0.8
VDD = 28 V
ID = 4 A 3 A
2 A
100 mA
1000
50 VDS, DRAIN–SOURCE VOLTAGE (VOLTS)
10 15 20 25
500
200
100
10
20
50
Ciss
Crss
Coss
VGS = 0 V
f = 1 MHz
5
MRF175GU MRF175GVMOTOROLA RF DEVICE DATA
Figure 8. Power Input versus Power Output Figure 9. Output Power versus Supply Voltage
TYPICAL CHARACTERISTICS
MRF175GV
Figure 10. Output Power versus Supply Voltage Figure 11. Output Power versus Input Power
MRF175GU
Figure 12. Power Gain versus Frequency
MRF175GV
P , POWER OUTPUT (WATTS)
out
P , OUTPUT POWER (WATTS)
out
P , OUTPUT POWER (WATTS)
out
P , OUTPUT POWER (WATTS)
out
0Pin, POWER INPUT (WATTS)
12 24
300
200
100
0
VDD = 28 V
IDQ = 2 x 100 mA
f = 225 MHz
VDD, SUPPLY VOLTAGE (VOLTS)
12
320
014 16 18 20 22 24 26 28
280
240
200
160
120
80
40
8 W
Pin = 12 W
4 W
VDD, SUPPLY VOLTAGE (VOLTS)
12
200
14 16 18 20 22 24 26 28
180
0
160
120
80
40
140
100
60
20
Pin = 14 W
10 W
6 W
Pin, INPUT POWER (WATTS)
0
200
5 10 15 20 25
180
0
160
120
80
40
140
100
60
20
VDS = 28 V
IDQ = 2 x 100 mA
f = 400 MHz 500 MHz
POWER GAIN (dB)
f, FREQUENCY (MHz)
30
5 10 20 50 100 200 500
25
20
15
10
5
Pout = 200 W
VDS = 28 V
IDQ = 2 x 100 mA 150 W
IDQ = 2 x 100 mA
f = 225 MHz
f = 400 MHz
MRF175GU MRF175GV
6MOTOROLA RF DEVICE DATA
INPUT AND OUTPUT IMPEDANCE
Figure 13. Series Equivalent Input/Output Impedance
NOTE: Input and output impedance values given are measured from gate to gate and drain to drain respectively.
ZOL*
Zin
f = 500 MHz
f = 500 MHz
400
400
300
225
150
100
50
30
225 300
225
150
100
5030
ZOL*
Zo = 10
Ω
ZOL* = Conjugate of the optimum load
impedance into which the device
operates at a given output power,
voltage and frequency.
f
MHz Zin
OHMS ZOL*
OHMS
225
300
400
500
1.95 – j2.30
1.75 – j0.20
1.60 + j2.20
1.35 + j4.00
3.10 – j0.25
2.60 + j0.20
2.00 + j1.20
1.70 + j2.70
(Pout = 150 W)
30
50
100
150
225
6.50 – j5.10
5.00 – j4.80
3.60 – j4.20
2.80 – j3.60
1.95 – j2.30
6.30 – j2.50
5.75 – j2.75
4.60 – j2.65
2.60 – j2.20
2.60 – j0.60
(Pout = 200 W)
VDD = 28 V, IDQ = 2 x 100 mA
RF POWER MOSFET CONSIDERATIONS
MOSFET CAPACITANCES
The physical structure of a MOSFET results in capacitors
between the terminals. The metal oxide gate structure deter-
mines the capacitors from gate–to–drain (Cgd), and gate–to–
source (Cgs). The PN junction formed during the fabrication
of the MOSFET results in a junction capacitance from drain–
to–source (Cds).
These capacitances are characterized as input (Ciss), out-
put (Coss) and reverse transfer (Crss) capacitances on data
sheets. The relationships between the inter–terminal capaci-
tances and those given on data sheets are shown below . The
Ciss can be specified in two ways:
1. Drain shorted to source and positive voltage at the gate.
2. Positive voltage of the drain in respect to source and zero
volts at the gate. In the latter case the numbers are lower.
However, neither method represents the actual operat-
ing conditions in RF applications.
Cgd
GATE
SOURCE
Cgs
DRAIN
Cds Ciss = Cgd + Cgs
Coss = Cgd + Cds
Crss = Cgd
The Ciss given in the electrical characteristics table was
measured using method 2 above. It should be noted that
Ciss, Coss, Crss are measured at zero drain current and are
provided for general information about the device. They are
not RF design parameters and no attempt should be made to
use them as such.
LINEARITY AND GAIN CHARACTERISTICS
In addition to the typical IMD and power gain, data pres-
ented in Figure 3 may give the designer additional informa-
tion on the capabilities of this device. The graph represents
the small signal unity current gain frequency at a given drain
current level. This is equivalent to fT for bipolar transistors.
Since this test is performed at a fast sweep speed, heating of
the device does not occur. Thus, in normal use, the higher
temperatures may degrade these characteristics to some ex-
tent.
DRAIN CHARACTERISTICS
One figure of merit for a FET is its static resistance in the
full–on condition. This on–resistance, VDS(on), occurs in the
linear region of the output characteristic and is specified un-
der specific test conditions for gate–source voltage and drain
current. For MOSFETs, VDS(on) has a positive temperature
coefficient and constitutes an important design consideration
at high temperatures, because it contributes to the power
dissipation within the device.
GATE CHARACTERISTICS
The gate of the MOSFET is a polysilicon material, and is
electrically isolated from the source by a layer of oxide. The
input resistance is very high — on the order of 109 ohms —
resulting in a leakage current of a few nanoamperes.
7
MRF175GU MRF175GVMOTOROLA RF DEVICE DATA
Gate control is achieved by applying a positive voltage
slightly in excess of the gate–to–source threshold voltage,
VGS(th).
Gate Voltage Rating — Never exceed the gate voltage
rating (or any of the maximum ratings on the front page). Ex-
ceeding the rated VGS can result in permanent damage to
the oxide layer in the gate region.
Gate Termination — The gates of this device are essen-
tially capacitors. Circuits that leave the gate open–circuited
or floating should be avoided. These conditions can result in
turn–on of the devices due to voltage build–up on the input
capacitor due to leakage currents or pickup.
Gate Protection — These devices do not have an internal
monolithic zener diode from gate–to–source. If gate protec-
tion is required, an external zener diode is recommended.
Using a resistor to keep the gate–to–source impedance
low also helps damp transients and serves another important
function. Voltage transients on the drain can be coupled to
the gate through the parasitic gate–drain capacitance. If the
gate–to–source impedance and the rate of voltage change
on the drain are both high, then the signal coupled to the gate
may be large enough to exceed the gate–threshold voltage
and turn the device on.
HANDLING CONSIDERATIONS
When shipping, the devices should be transported only in
antistatic bags or conductive foam. Upon removal from the
packaging, careful handling procedures should be adhered
to. Those handling the devices should wear grounding straps
and devices not in the antistatic packaging should be kept in
metal tote bins. MOSFETs should be handled by the case
and not by the leads, and when testing the device, all leads
should make good electrical contact before voltage is ap-
plied. As a final note, when placing the FET into the system it
is designed for, soldering should be done with grounded
equipment.
DESIGN CONSIDERATIONS
The MRF175G is a RF power N–channel enhancement
mode field–effect transistor (FETs) designed for HF, VHF and
UHF power amplifier applications. Motorola RF MOSFETs
feature a vertical structure with a planar design.
Motorola 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
thermal 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 sig-
nal.
DC BIAS
The MRF175G is an enhancement mode FET and, there-
fore, does not conduct when drain voltage is applied. Drain
current flows when a positive voltage is applied to the gate.
RF power FETs require forward bias for optimum perfor-
mance. The value of quiescent drain current (IDQ) is not criti-
cal for many applications. The MRF175G was characterized
at IDQ = 100 mA, each side, which is the suggested minimum
value of IDQ. For special applications such as linear amplifi-
cation, IDQ may have to be selected to optimize the critical
parameters.
The gate is a dc open circuit and draws no current. There-
fore, the gate bias circuit may be just a simple resistive divid-
er network. Some applications may require a more elaborate
bias sytem.
GAIN CONTROL
Power output of the MRF176 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.
MRF175GU MRF175GV
8MOTOROLA RF DEVICE DATA
PACKAGE DIMENSIONS
CASE 375–04
ISSUE D
STYLE 2:
PIN 1. DRAIN
2. DRAIN
3. GATE
4. GATE
5. SOURCE
1 2
3 4
5
D
Q
U
G
R
K
RADIUS 2 PL
–B–
–T–
E
H
J
C
SEATING
PLANE
N
M
A
M
0.25 (0.010) B M
T
–A–
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A1.330 1.350 33.79 34.29
B0.370 0.410 9.40 10.41
C0.190 0.230 4.83 5.84
D0.215 0.235 5.47 5.96
E0.050 0.070 1.27 1.77
G0.430 0.440 10.92 11.18
H0.102 0.112 2.59 2.84
J0.004 0.006 0.11 0.15
K0.185 0.215 4.83 5.33
N0.845 0.875 21.46 22.23
Q0.060 0.070 1.52 1.78
R0.390 0.410 9.91 10.41
U1.100 BSC 27.94 BSC
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty , representation or guarantee regarding
the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit,
and specifically disclaims any and all liability , including without limitation consequential or incidental damages. “Typical” parameters can and do vary in different
applications. All operating parameters, including “T ypicals” must be validated for each customer application by customer’s technical experts. Motorola does
not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in
systems intended for surgical implant into the body , or other applications intended to support or sustain life, or for any other application in which the failure of
the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such
unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless
against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part.
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MRF175GU/D
*MRF175GU/D*
◊
