1
MRF176GU MRF176GVMOTOROLA 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.
•Electrical Performance
MRF176GU @ 50 V, 400 MHz (“U” Suffix)
Output Power — 150 Watts
Power Gain — 14 dB Typ
Efficiency — 50% Typ
MRF176GV @ 50 V, 225 MHz (“V” Suffix)
Output Power — 200 Watts
Power Gain — 17 dB Typ
Efficiency — 55% Typ
•100% Ruggedness Tested At Rated Output Power
•Low Thermal Resistance
•Low Crss — 7.0 pF Typ @ V DS = 50 V
MAXIMUM RATINGS
Rating Symbol Value Unit
Drain–Source Voltage VDSS 125 Vdc
Gate–Source Voltage VGS ±40 Vdc
Drain Current — Continuous ID16 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
Handling and Packaging — MOS devices are susceptible to damage from electrostatic charge. Reasonable precautions in handling and
packaging MOS devices should be observed.
ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted)
Characteristic Symbol Min Typ Max Unit
OFF CHARACTERISTICS (1)
Drain–Source Breakdown Voltage
(VGS = 0, ID = 100 mA) V(BR)DSS 125 — — Vdc
Zero Gate Voltage Drain Current
(VDS = 50 V, VGS = 0) IDSS — — 2.5 mAdc
Gate–Body Leakage Current
(VGS = 20 V, VDS = 0) IGSS — — 1.0 µAdc
NOTE:
1. Each side of device measured separately.
Order this document
by MRF176GU/D
SEMICONDUCTOR TECHNICAL DATA
200/150 W, 50 V, 500 MHz
N–CHANNEL MOS
BROADBAND
RF POWER FETs
CASE 375–04, STYLE 2
Motorola, Inc. 1995
D
GS
(FLANGE)
D
G
REV 8
MRF176GU MRF176GV
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–V oltage (VGS = 10 V, ID = 5.0 A) VDS(on) 1.0 3.0 5.0 Vdc
Forward T ransconductance (VDS = 10 V, ID = 2.5 A) gfs 2.0 3.0 — mhos
DYNAMIC CHARACTERISTICS (1)
Input Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Ciss —180 — pF
Output Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Coss —100 — pF
Reverse Transfer Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Crss —6.0 — pF
FUNCTIONAL CHARACTERISTICS — MRF176GV (2) (Figure 1)
Common Source Power Gain
(VDD = 50 Vdc, Pout = 200 W, f = 225 MHz, IDQ = 2.0 x 100 mA) Gps 15 17 — dB
Drain Efficiency
(VDD = 50 Vdc, Pout = 200 W, f = 225 MHz, IDQ = 2.0 x 100 mA) η50 55 — %
Electrical Ruggedness
(VDD = 50 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, C6, C8 — 1000 pF Chip
C4, C9 — 0.1 µF Chip
C5 — 180 pF Chip
C7 — Arco 403, 3.0–35 pF
C10 — 0.47 µF Chip, Kemet 1215 or Equivalent
L1 — 10 T urns AWG #16 Enameled Wire,
L1 — Close Wound, 1/4″ I.D.
Board material — .062″ fiberglass (G10),
Two sided, 1 oz. copper, εr
^
5
Unless otherwise noted, all chip capacitors
are ATC Type 100 or Equivalent
L2 — Ferrite Beads of Suitable Material
L2 — for 1.5–2.0 µH, Total Inductance
R1 — 100 Ohms, 1/2 W
R2 — 1.0 kOhms, 1/2 W
T1 — 4:1 Impedance Ratio RF T ransformer.
T1 — Can Be Made of 25 Ohm Semirigid
T1 — Co–Ax, 47–62 Mils O.D.
T2 — 1:4 Impedance Ratio RF T ransformer.
T2 — Can Be Made of 25 Ohm Semirigid
T2 — Co–Ax, 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. T2
C6 C7
50 V
+
–
C10
C9C8
3
MRF176GU MRF176GVMOTOROLA RF DEVICE DATA
ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted)
Characteristic Symbol Min Typ Max Unit
FUNCTIONAL CHARACTERISTICS — MRF176GU (1) (Figure 2)
Common Source Power Gain
(VDD = 50 Vdc, Pout = 150 W, f = 400 MHz, IDQ = 2.0 x 100 mA) Gps 12 14 — dB
Drain Efficiency
(VDD = 50 Vdc, Pout = 150 W, f = 400 MHz, IDQ = 2.0 x 100 mA) η45 50 — %
Electrical Ruggedness
(VDD = 50 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 Semirigid Coax .086 OD 2″ Long
B2 — Balun, 50 Ω Semirigid Coax .141 OD 2″ Long
C1, C2, C9, C10 — 270 pF ATC Chip Capacitor
C3 — 15 pF ATC Chip Cap
C4, C8 — 1.0–20 pF Piston Trimmer Cap
C5 — 27 pF ATC Chip Cap
C6, C7 — 22 pF Mini Unelco Capacitor
C11, C13, C14, C15, C16 — 0.01 µF Ceramic Capacitor
C12 — 1.0 µF 50 V Tantalum Cap
C17, C18 — 680 pF Feedthru Capacitor
C19 — 10 µF 100 V Tantalum Cap
L1, L2 — Hairpin Inductor #18 W
L3, L4 — Hairpin Inductor #18 W
L5, L6 — 13T #18 W .250 ID
L7 — Ferroxcube VK–200 20/4B
L8 — 3T #18 W .340 ID
R1 — 1.0 kΩ 1/4 W Resistor
R2, R3 — 10 kΩ 1/4 W Resistor
Z1, Z2 — Microstrip Line .400L x .250W
Z3, Z4 — Microstrip Line .450L x .250W
Ckt Board Material — .060″ teflon–fiberglass, copper clad both sides, 2 oz. copper,
εr = 2.55
.200
.400
″
.200
″
.200
″
C11 C12 R1 C13 C15
R2
AB
C17 L7 C18 L8
C19 50 V
L1
L2
C1
C2
B1 B2
Z1
Z2
C3 C4
R3D.U.T.
AB
C14 C16
L6
Z4
Z3 L3
L4
C10
C9
C5 C6
C7 C8
BIAS
MRF176GU MRF176GV
4MOTOROLA RF DEVICE DATA
Figure 3. Common Source Unity Current Gain*
Gain–Frequency versus Drain Current Figure 4. DC Safe Operating Area
TYPICAL CHARACTERISTICS
*Data shown applies to each half of MRF176GU/GV
4000
3000
2000
1000
010012 345 67 89
I
D
, DRAIN CURRENT (AMPS)
f , UNITY GAIN-FREQUENCY (MHz)
T
ID, DRAIN CURRENT (AMPS)
100
2002 VDS, DRAIN–SOURCE VOLTAGE (VOL TS)
10
110 50
15 V
VDS = 30 V
TC = 25
°
C
Figure 5. Series Equivalent Input/Output Impedance
Zin
f = 500 MHz
400
100
30
225
50
ZOL*
Zo = 10
Ω
150
150
f = 500 MHz
300
225
50
225
100
30
300
400
ZOL*
f
MHz Zin
OHMS ZOL*
OHMS
225
300
400
500
2.05 – j2.50
2.00 – j1.10
1.85 + j0.75
1.60 + j2.70
6.50 – j3.50
4.80 – j3.10
3.00 – j1.90
2.60 + j0.10
(Pout = 150 W)
30
50
100
150
225
7.50 – j6.50
5.50 – j7.00
3.20 – j6.00
2.50 – j4.80
2.05 – j2.50
17.00 – j4.00
14.00 – j5.00
11.00 – j5.20
8.20 – j5.00
5.00 – j4.20
(Pout = 200 W)
INPUT AND OUTPUT IMPEDANCE
MRF176GU/GV
VDD = 50 V, IDQ = 2 x 100 mA
ZOL* = Conjugate of the optimum load
impedance into which the device output
operates at a given output power, voltage
and frequency.
NOTE: Input and output impedance values given are measured from gate to gate and drain to drain respectively.
5
MRF176GU MRF176GVMOTOROLA RF DEVICE DATA
Figure 6. Capacitance versus Drain–Source Voltage* Figure 7. Power Gain versus Frequency
TYPICAL CHARACTERISTICS
*Data shown applies to each half of MRF176GU/GV
MRF176GV
Figure 8. Power Input versus Power Output Figure 9. Output Power versus Supply Voltage
C, CAPACITANCE (pF)
POWER GAIN (dB)
P , POWER OUTPUT (WATTS)
out
P , OUTPUT POWER (WATTS)
out
500
0VDS, DRAIN–SOURCE VOLTAGE (VOL TS)
10
200
100
50
20
10
520 30 40 50 f, FREQUENCY (MHz)
10
20
10
520
30
25
15
5 50 100 200 500
300
0Pin, POWER INPUT (WATTS)
200
100
0612
320
VDS, SUPPLY VOLTAGE (VOLTS)
30
280
240
200
160
120
80
40
032 34 36 38 40 42 44 46 48 50
Coss
Crss
Ciss
VGS = 0 V
f = 1 MHz
Pout = 200 W
150 W
VDS = 50 V
IDQ = 2 x 100 mA
VDD = 50 V
40 V
IDQ = 2 x 100 mA
f = 225 MHz
IDQ = 2 x 100 mA
f = 225 MHz Pin = 6 W
4 W
2 W
MRF176GU MRF176GV
6MOTOROLA RF DEVICE DATA
TYPICAL CHARACTERISTICS
MRF176GU
Figure 10. Output Power versus Input Power Figure 11. Output Power versus Input Power
Figure 12. Output Power versus Supply Voltage
P , OUTPUT POWER (WATTS)
out
200
Pin, INPUT POWER (WATTS)
0
180
160
140
120
100
80
60
02
40
20
4 6 810121416
P , OUTPUT POWER (WATTS)
out
200
Pin, INPUT POWER (WATTS)
0
180
160
140
120
100
80
60
02
40
20
4 6 81012 1416
P , OUTPUT POWER (WATTS)
out
200
VDD, SUPPLY VOLTAGE (VOLTS)
180
160
140
120
100
80
60
020
40
20
30 40 50
f = 400 MHz
VDD = 40 V
IDQ = 2 x 100 mA VDD = 50 V
IDQ = 2 x 100 mA
500 MHz
f = 400 MHz
500 MHz
Pin = 12 W
4 W
IDQ = 2 x 100 mA
f = 400 MHz
8 W
7
MRF176GU MRF176GVMOTOROLA RF DEVICE DATA
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.
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 — This device does not have an internal
monolithic zener diode from gate–to–source. The addition of
an internal zener diode may result in detrimental effects on
the reliability of a power MOSFET. If gate protection is re-
quired, an external zener diode is recommended.
HANDLING CONSIDERATIONS
The gate of the MOSFET, which is electrically isolated
from the rest of the die by a very thin layer of SiO2, may be
damaged if the power MOSFET is handled or installed
improperly. Exceeding the 40 V maximum gate–to–source
voltage rating, VGS(max), can rupture the gate insulation and
destroy the FET. RF Power MOSFETs are not nearly as sus-
ceptible as CMOS devices to damage due to static discharge
because the input capacitances of power MOSFETs are
much larger and absorb more energy before being charged
to the gate breakdown voltage. However, once breakdown
begins, there is enough energy stored in the gate–source ca-
pacitance to ensure the complete perforation of the gate ox-
ide. To avoid the possibility of device failure caused by static
discharge, precautions similar to those taken with small–sig-
nal MOSFET and CMOS devices apply to power MOSFETs.
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.
The gate of the power MOSFET could still be in danger af-
ter the device is placed in the intended circuit. If the gate may
see voltage transients which exceed VGS(max), the circuit de-
signer should place a 40 V zener across the gate and source
terminals to clamp any potentially destructive spikes. Using a
resistor to keep the gate–to–source impedance low also
helps damp transients and serves another important func-
tion. 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.
DESIGN CONSIDERATIONS
The MRF176G is a RF power N–channel enhancement
mode field–effect transistor (FETs) designed for VHF and
MRF176GU MRF176GV
8MOTOROLA RF DEVICE DATA
UHF power amplifier applications. Motorola RF MOSFETs
feature a vertical structure with a planar design, thus avoid-
ing the processing difficulties associated with V–groove
MOS power FETs.
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, thus facilitating manual gain control, ALC and modula-
tion.
DC BIAS
The MRF176G 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 MRF176G 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.
9
MRF176GU MRF176GVMOTOROLA RF DEVICE DATA
PACKAGE DIMENSIONS
CASE 375–04
ISSUE D
STYLE 2:
PIN 1. DRAIN
2. DRAIN
3. GATE
4. GATE
5. SOURCE
12
34
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.
MRF176GU MRF176GV
10 MOTOROLA RF DEVICE DATA
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 which may be provided in Motorola
data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals”
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. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal
Opportunity/Af firmative Action Employer .
Mfax is a trademark of Motorola, Inc.
How to reach us:
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MRF176GU/D
◊
