MOTOROLA MRF176GU

Order this document
by MRF176GU/D
SEMICONDUCTOR TECHNICAL 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
200/150 W, 50 V, 500 MHz
N–CHANNEL MOS
BROADBAND
RF POWER FETs
D
• 100% Ruggedness Tested At Rated Output Power
• Low Thermal Resistance
• Low Crss — 7.0 pF Typ @ VDS = 50 V
G
S
(FLANGE)
G
CASE 375–04, STYLE 2
D
MAXIMUM RATINGS
Symbol
Value
Unit
Drain–Source Voltage
Rating
VDSS
125
Vdc
Gate–Source Voltage
VGS
± 40
Vdc
Drain Current — Continuous
ID
16
Adc
Total Device Dissipation @ TC = 25°C
Derate above 25°C
PD
400
2.27
Watts
W/°C
Storage Temperature Range
Tstg
– 65 to +150
°C
TJ
200
°C
Symbol
Max
Unit
RθJC
0.44
°C/W
Operating Junction Temperature
THERMAL CHARACTERISTICS
Characteristic
Thermal Resistance, Junction to Case
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)
Symbol
Min
Typ
Max
Unit
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
Characteristic
OFF CHARACTERISTICS (1)
Drain–Source Breakdown Voltage
(VGS = 0, ID = 100 mA)
NOTE:
1. Each side of device measured separately.
REV 8
RF DEVICE DATA
MOTOROLA
Motorola, Inc. 1995
MRF176GU MRF176GV
1
ELECTRICAL CHARACTERISTICS — continued (TC = 25°C unless otherwise noted)
Characteristic
Symbol
Min
Typ
Max
Unit
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)
1.0
3.0
5.0
Vdc
Forward Transconductance (VDS = 10 V, ID = 2.5 A)
gfs
2.0
3.0
—
mhos
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
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)
η
50
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)
ψ
ON CHARACTERISTICS (1)
DYNAMIC CHARACTERISTICS (1)
FUNCTIONAL CHARACTERISTICS — MRF176GV (2) (Figure 1)
No Degradation in Output Power
NOTES:
1. Each side of device measured separately.
2. Measured in push–pull configuration.
R1
BIAS 0 – 6 V
C8
C3
C10
C9
C4
D.U.T.
R2
+
50 V
–
T2
T1
C5
C1
C6
C2
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 Turns 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
C7
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 Transformer.
T1 — Can Be Made of 25 Ohm Semirigid
T1 — Co–Ax, 47 – 62 Mils O.D.
T2 — 1:4 Impedance Ratio RF Transformer.
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.
Figure 1. 225 MHz Test Circuit
MRF176GU MRF176GV
2
MOTOROLA RF DEVICE DATA
ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted)
Characteristic
Symbol
Min
Typ
Max
Unit
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)
η
45
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)
ψ
FUNCTIONAL CHARACTERISTICS — MRF176GU (1) (Figure 2)
No Degradation in Output Power
NOTE:
1. Measured in push–pull configuration.
A
B
L7
C17
C18
L8
BIAS
C11
C12
R1
C13
C19
C15
50 V
R2
C9
L1
Z1
Z3
L3
C1
B1
C3
C6
C5
C4
C8
B2
C7
C10
L2
Z2
Z4
C2
L4
D.U.T.
L6
R3
A
B
C14
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
.200
C19 — 10 µF 100 V Tantalum Cap
L1, L2 — Hairpin Inductor #18 W
L3, L4 — Hairpin Inductor #18 W
.200″
C16
.400″
.200″
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
Figure 2. 400 MHz Test Circuit
MOTOROLA RF DEVICE DATA
MRF176GU MRF176GV
3
TYPICAL CHARACTERISTICS
100
VDS = 30 V
I D, DRAIN CURRENT (AMPS)
f T, UNITY GAIN-FREQUENCY (MHz)
4000
3000
15 V
2000
1000
0
0
1
2
3
4
5
6
7
ID, DRAIN CURRENT (AMPS)
8
9
10
TC = 25°C
1
10
2
Figure 3. Common Source Unity Current Gain*
Gain–Frequency versus Drain Current
10
50
VDS, DRAIN–SOURCE VOLTAGE (VOLTS)
200
Figure 4. DC Safe Operating Area
* Data shown applies to each half of MRF176GU/GV
INPUT AND OUTPUT IMPEDANCE
MRF176GU/GV
VDD = 50 V, IDQ = 2 x 100 mA
f
MHz
Zin
400
300
f = 500 MHz
f = 500 MHz
400
ZOL*
225
100
225
300
400
500
2.05 – j2.50
2.00 – j1.10
1.85 + j0.75
1.60 + j2.70
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
150
ZOL*
6.50 – j3.50
4.80 – j3.10
3.00 – j1.90
2.60 + j0.10
(Pout = 200 W)
300
225
50
ZOL*
OHMS
(Pout = 150 W)
225
150
Zin
OHMS
17.00 – j4.00
14.00 – j5.00
11.00 – j5.20
8.20 – j5.00
5.00 – j4.20
30
100
Zo = 10 Ω
50
30
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.
Figure 5. Series Equivalent Input/Output Impedance
MRF176GU MRF176GV
4
MOTOROLA RF DEVICE DATA
TYPICAL CHARACTERISTICS
30
200
Ciss
100
Coss
25
Pout = 200 W
50
POWER GAIN (dB)
C, CAPACITANCE (pF)
500
VGS = 0 V
f = 1 MHz
20
5
0
15
150 W
VDS = 50 V
IDQ = 2 x 100 mA
10
Crss
10
20
10
20
30
40
VDS, DRAIN–SOURCE VOLTAGE (VOLTS)
5
50
10
5
Figure 6. Capacitance versus Drain–Source Voltage*
20
50
100
f, FREQUENCY (MHz)
200
500
Figure 7. Power Gain versus Frequency
* Data shown applies to each half of MRF176GU/GV
MRF176GV
320
Pout , OUTPUT POWER (WATTS)
Pout, POWER OUTPUT (WATTS)
300
VDD = 50 V
200
40 V
100
IDQ = 2 x 100 mA
f = 225 MHz
280
IDQ = 2 x 100 mA
f = 225 MHz
240
Pin = 6 W
200
4W
160
120
2W
80
40
0
0
6
Pin, POWER INPUT (WATTS)
Figure 8. Power Input versus Power Output
MOTOROLA RF DEVICE DATA
12
0
30
32
34
36
38
40
42
44
VDS, SUPPLY VOLTAGE (VOLTS)
46
48
50
Figure 9. Output Power versus Supply Voltage
MRF176GU MRF176GV
5
200
200
180
180
160
Pout , OUTPUT POWER (WATTS)
Pout , OUTPUT POWER (WATTS)
TYPICAL CHARACTERISTICS
MRF176GU
f = 400 MHz
140
120
500 MHz
100
80
60
VDD = 40 V
IDQ = 2 x 100 mA
40
20
0
0
2
4
6
8
10
12
Pin, INPUT POWER (WATTS)
14
Figure 10. Output Power versus Input Power
f = 400 MHz
160
500 MHz
140
120
100
80
60
VDD = 50 V
IDQ = 2 x 100 mA
40
20
16
0
0
2
4
6
8
10
12
Pin, INPUT POWER (WATTS)
14
16
Figure 11. Output Power versus Input Power
Pout , OUTPUT POWER (WATTS)
200
Pin = 12 W
180
8W
160
140
4W
120
100
80
60
40
IDQ = 2 x 100 mA
f = 400 MHz
20
0
20
30
40
VDD, SUPPLY VOLTAGE (VOLTS)
50
Figure 12. Output Power versus Supply Voltage
MRF176GU MRF176GV
6
MOTOROLA 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 determines 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), output (Coss) and reverse transfer (Crss) capacitances on data
sheets. The relationships between the inter–terminal capacitances 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 operating conditions in RF applications.
DRAIN
Cgd
GATE
Cds
Cgs
Ciss = Cgd + Cgs
Coss = Cgd + Cds
Crss = Cgd
SOURCE
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 presented in Figure 3 may give the designer additional information 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 extent.
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 under 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.
MOTOROLA 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). Exceeding the rated VGS can result in permanent damage to
the oxide layer in the gate region.
Gate Termination — The gates of this device are essentially 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 required, 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 susceptible 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 capacitance to ensure the complete perforation of the gate oxide. To avoid the possibility of device failure caused by static
discharge, precautions similar to those taken with small–signal 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 applied. 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 after the device is placed in the intended circuit. If the gate may
see voltage transients which exceed VGS(max), the circuit designer 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 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.
DESIGN CONSIDERATIONS
The MRF176G is a RF power N–channel enhancement
mode field–effect transistor (FETs) designed for VHF and
MRF176GU MRF176GV
7
UHF power amplifier applications. Motorola RF MOSFETs
feature a vertical structure with a planar design, thus avoiding 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 mismatched 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 MRF176G is an enhancement mode FET and, therefore, does not conduct when drain voltage is applied. Drain
MRF176GU MRF176GV
8
current flows when a positive voltage is applied to the gate.
RF power FETs require forward bias for optimum performance. The value of quiescent drain current (IDQ) is not critical 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 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 be just a simple resistive divider 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.
MOTOROLA RF DEVICE DATA
PACKAGE DIMENSIONS
U
G
1
Q
RADIUS 2 PL
0.25 (0.010)
M
T A
B
M
2
DIM
A
B
C
D
E
G
H
J
K
N
Q
R
U
–B–
R
5
K
M
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3
4
D
N
E
J
H
–T–
–A–
SEATING
PLANE
C
STYLE 2:
PIN 1.
2.
3.
4.
5.
INCHES
MIN
MAX
1.330
1.350
0.370
0.410
0.190
0.230
0.215
0.235
0.050
0.070
0.430
0.440
0.102
0.112
0.004
0.006
0.185
0.215
0.845
0.875
0.060
0.070
0.390
0.410
1.100 BSC
MILLIMETERS
MIN
MAX
33.79
34.29
9.40
10.41
4.83
5.84
5.47
5.96
1.27
1.77
10.92
11.18
2.59
2.84
0.11
0.15
4.83
5.33
21.46
22.23
1.52
1.78
9.91
10.41
27.94 BSC
DRAIN
DRAIN
GATE
GATE
SOURCE
CASE 375–04
ISSUE D
MOTOROLA RF DEVICE DATA
MRF176GU MRF176GV
9
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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”
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Mfax is a trademark of Motorola, Inc.
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INTERNET: http://motorola.com/sps
MRF176GU MRF176GV
10
◊
MRF176GU/D
MOTOROLA RF DEVICE
DATA