Datasheet MRF151G Datasheet (Motorola)

Page 1

SEMICONDUCTOR TECHNICAL DATA
The RF MOSFET Line
   
N–Channel Enhancement–Mode MOSFET
Designed for broadband commercial and military applications at frequencies to 175 MHz. The high power, high gain and broadband performance of this device makes possible solid state transmitters for FM broadcast or TV channel frequency bands.
Guaranteed Performance at 175 MHz, 50 V:
Output Power — 300 W Gain — 14 dB (16 dB Typ) Efficiency — 50%
Low Thermal Resistance — 0.35°C/W
Ruggedness Tested at Rated Output Power
Nitride Passivated Die for Enhanced Reliability
D
Order this document
by MRF151G/D

300 W, 50 V, 175 MHz
N–CHANNEL
BROADBAND
RF POWER MOSFET
G G
D
S
(FLANGE)
CASE 375–04, STYLE 2
MAXIMUM RATINGS
Rating Symbol Value Unit
Drain–Source Voltage V Drain–Gate Voltage V Gate–Source Voltage V Drain Current — Continuous I Total Device Dissipation @ TC = 25°C
Derate above 25°C Storage Temperature Range T Operating Junction Temperature T
DSS
DGO
GS
D
P
D
stg
J
125 Vdc 125 Vdc ±40 Vdc
40 Adc
500
2.85
–65 to +150 °C
200 °C
THERMAL CHARACTERISTICS
Characteristic Symbol Max Unit
Thermal Resistance, Junction to Case R
NOTE — CAUTION — MOS devices are susceptible to damage from electrostatic charge. Reasonable precautions in handling and packaging MOS devices should be observed.
θJC
0.35 °C/W
Watts
W/°C
REV 8
Motorola, Inc. 1997
MRF151GMOTOROLA RF DEVICE DATA
1
Page 2
ELECTRICAL CHARACTERISTICS (T
Characteristic Symbol Min Typ Max Unit
= 25°C unless otherwise noted.)
C
OFF CHARACTERISTICS (Each Side)
Drain–Source Breakdown Voltage (VGS = 0, ID = 100 mA) V Zero Gate Voltage Drain Current (VDS = 50 V, VGS = 0) I Gate–Body Leakage Current (VGS = 20 V, VDS = 0) I
ON CHARACTERISTICS (Each Side)
Gate Threshold Voltage (VDS = 10 V, ID = 100 mA) V Drain–Source On–Voltage (VGS = 10 V, ID = 10 A) V Forward Transconductance (VDS = 10 V, ID = 5.0 A) g
DYNAMIC CHARACTERISTICS (Each Side)
Input Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) C Output Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) C Reverse Transfer Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) C
FUNCTIONAL TESTS
Common Source Amplifier Power Gain
(VDD = 50 V, P Drain Efficiency
(VDD = 50 V, P Load Mismatch
(VDD = 50 V, P
VSWR 5:1 at all Phase Angles)
= 300 W, IDQ = 500 mA, f = 175 MHz)
out
= 300 W, f = 175 MHz, ID (Max) = 11 A)
out
= 300 W, IDQ = 500 mA,
out
(BR)DSS
DSS GSS
GS(th)
DS(on)
fs
iss
oss
rss
G
ps
η 50 55 %
ψ
125 Vdc
5.0 mAdc — 1.0 µAdc
1.0 3.0 5.0 Vdc
1.0 3.0 5.0 Vdc
5.0 7.0 mhos
350 pF — 220 pF — 15 pF
14 16 dB
No Degradation in Output Power
C2
R1
C1
C1
C5C4
R2
T1
C6
C3
+
BIAS 0–6 V
INPUT
R1 — 100 Ohms, 1/2 W R2 — 1.0 kOhm, 1/2 W C1 — Arco 424 C2 — Arco 404 C3, C4, C7, C8, C9 — 1000 pF Chip C5, C10 — 0.1 µF Chip C6 — 330 pF Chip C11 — 0.47 µF Ceramic Chip, Kemet 1215 or
C11 — Equivalent (100 V)
C12 — Arco 422 L1 — 10 Turns AWG #18 Enameled Wire,
L1 — Close Wound, 1/4 I.D.
L2 — Ferrite Beads of Suitable Material for
L2 — 1.5–2.0 µH Total Inductance
Unless Otherwise Noted, All Chip Capacitors are ATC Type 100 or Equivalent.
Figure 1. 175 MHz Test Circuit
L2
C10C9
D.U.T.
T1 — 9:1 RF Transformer. Can be made of 15–18 Ohms
T1 — Semirigid Co–Ax, 62–90 Mils O.D.
T2 — 1:4 RF Transformer. Can be made of 16–18 Ohms
T2 — Semirigid Co–Ax, 70–90 Mils O.D.
Board Material — 0.062 Fiberglass (G10), 1 oz. Copper Clad, 2 Sides, εr = 5.0
NOTE: For stability, the input transformer T1 must 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.
See Figure 6 for construction details of T1 and T2.
T2
L1
C7 C8
C11
C12
+
50 V
OUTPUT
MRF151G 2
MOTOROLA RF DEVICE DATA
Page 3
TYPICAL CHARACTERISTICS
1000
C
500
200
100
50
C, CAPACITANCE (pF)
20
0
0 1020304050
VDS, DRAIN–SOURCE VOLTAGE (VOL TS)
iss
C
oss
C
rss
Figure 2. Capacitance versus
Drain–Source Voltage*
*Data shown applies to each half of MRF151G.
1.04
1.03
1.02
1.01 1
0.99
0.98
0.97
0.96
0.95
0.94
0.93
0.92
, DRAIN-SOURCE VOLTAGE (NORMALIZED)
0.91
GS
0.9
V
–25 0 25 50 75 100
TC, CASE TEMPERATURE (
250 mA
100 mA
°
C)
ID = 5 A
4 A
2 A
1 A
2000
VDS = 30 V
1000
, UNITY GAIN FREQUENCY (MHz)
T
f
0
048121620
2 6 10 14 18
I
, DRAIN CURRENT (AMPS)
D
15 V
Figure 3. Common Source Unity Gain Frequency
versus Drain Current*
100
TC = 25°C
10
, DRAIN CURRENT (AMPS)
D
I
1
2 20 200
VDS, DRAIN–TO–SOURCE VOL TAGE (VOL TS)
Figure 4. Gate–Source V oltage versus
Case T emperature*
HIGH IMPEDANCE
WINDINGS
CENTER
CENTER
TAP
TAP
IMPEDANCE
Figure 6. RF Transformer
4:1
RATIO
Figure 5. DC Safe Operating Area
9:1
IMPEDANCE
RATIO
CONNECTIONS
TO LOW IMPEDANCE
WINDINGS
MRF151GMOTOROLA RF DEVICE DATA
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Page 4
TYPICAL CHARACTERISTICS
350
f = 150 MHz
300
250
200
150
, OUTPUT POWER (WATTS)
100
out
P
50
0
0510
P
, INPUT POWER (WATTS)
in
VDD = 50 V IDQ = 2 x 250 mA
175 MHz
200 MHz
30
25
20
15
, POWER GAIN (dB)
PS
G
10
5
VDD = 50 V
IDQ = 2 x 250 mA
P
= 150 W
out
2 5 10 30 100 200
Figure 7. Output Power versus Input Power Figure 8. Power Gain versus Frequency
f, FREQUENCY (MHz)
f = 175 MHz
150
125
INPUT, Z
in
150
125
f = 175 MHz
OUTPUT, ZOL*
(DRAIN TO DRAIN)
ZOL* = Conjugate of the optimum load impedance
ZOL* = into which the device output operates at a ZOL* = given output power, voltage and frequency.
Zo = 10
30
100
(GATE TO GATE)
100 30
Figure 9. Input and Output Impedance
MRF151G 4
MOTOROLA RF DEVICE DATA
Page 5
RF POWER MOSFET CONSIDERA TIONS
MOSFET CAPACITANCES
The physical structure of a MOSFET results in capacitors between the terminals. The metal anode gate structure de­termines the capacitors from gate–to–drain (Cgd), and gate– to–source (Cgs). The PN junction formed during the fabrication of the RF MOSFET results in a junction capaci­tance from drain–to–source (Cds).
These capacitances are characterized as input (C put (C
) and reverse transfer (C
oss
) capacitances on data
rss
iss
), out-
sheets. The relationships between the inter–terminal capaci­tances and those given on data sheets are shown below. The C
can be specified in two ways:
iss
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
C
ds
SOURCE
C
C
C
iss
oss
rss
= Cgd = C
= Cgd = C
= C
gd
gs
ds
GATE
C
gd
C
gs
LINEARITY AND GAIN CHARACTERISTICS
In addition to the typical IMD and power gain data pres­ented, 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, V
DS(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, V
has a positive temperature
DS(on)
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, V
GS(th)
.
Gate Voltage Rating — Never exceed the gate voltage rating. Exceeding the rated VGS can result in permanent damage to the oxide layer in the gate region.
Gate Termination — The gates of these devices are es­sentially capacitors. Circuits that leave the gate open–cir-
cuited 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 protec­tion 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 ap­plied. As a final note, when placing the FET into the system it is designed for, soldering should be done with a grounded iron.
DESIGN CONSIDERATIONS
The MRF151G is an RF Power, MOS, N–channel en­hancement mode field–effect transistor (FET) designed for HF and VHF power amplifier applications.
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 MOSFETs 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.
DC BIAS
The MRF151G 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. RF power FETs require forward bias for optimum perfor­mance. The value of quiescent drain current (IDQ) is not criti­cal for many applications. The MRF151G was characterized at IDQ = 250 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 MRF151G 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.
MRF151GMOTOROLA RF DEVICE DATA
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Page 6
P ACKAGE DIMENSIONS
R
K
E
H
U G
12
5
34
D
N
–A–
Q
RADIUS 2 PL
0.25 (0.010) B
–B–
J
–T–
C
CASE 375–04
ISSUE D
M
T
SEATING PLANE
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
M
A
M
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
STYLE 2:
PIN 1. DRAIN
2. DRAIN
3. GATE
4. GATE
5. SOURCE
MILLIMETERSINCHES
DIM MIN MAX MIN MAX
A 1.330 1.350 33.79 34.29 B 0.370 0.410 9.40 10.41 C 0.190 0.230 4.83 5.84 D 0.215 0.235 5.47 5.96 E 0.050 0.070 1.27 1.77 G 0.430 0.440 10.92 1 1.18 H 0.102 0.112 2.59 2.84 J 0.004 0.006 0.1 1 0.15 K 0.185 0.215 4.83 5.33 N 0.845 0.875 21.46 22.23 Q 0.060 0.070 1.52 1.78 R 0.390 0.410 9.91 10.41 U 1.100 BSC 27.94 BSC
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MRF151G 6
MOTOROLA RF DEVICE DATA
*MRF151G/D*
MRF151G/D
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