Order this document by MRF141G/D 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, 28 V: Output Power — 300 W Gain — 12 dB (14 dB Typ) Efficiency — 50% 300 W, 28 V, 175 MHz N–CHANNEL BROADBAND RF POWER MOSFET • Low Thermal Resistance — 0.35°C/W • Ruggedness Tested at Rated Output Power • Nitride Passivated Die for Enhanced Reliability D G S (FLANGE) G CASE 375–04, STYLE 2 D MAXIMUM RATINGS Rating Symbol Value Unit Drain–Source Voltage VDSS 65 Vdc Drain–Gate Voltage VDGO 65 Vdc VGS ± 40 Vdc Drain Current — Continuous ID 32 Adc Total Device Dissipation @ TC = 25°C Derate above 25°C PD 500 2.85 Watts W/°C Storage Temperature Range Tstg – 65 to +150 °C TJ 200 °C Symbol Max Unit RθJC 0.35 °C/W Gate–Source Voltage Operating Junction Temperature THERMAL CHARACTERISTICS Characteristic Thermal Resistance, Junction to Case NOTE — CAUTION — MOS devices are susceptible to damage from electrostatic charge. Reasonable precautions in handling and packaging MOS devices should be observed. REV 2 RF DEVICE DATA MOTOROLA Motorola, Inc. 1997 MRF141G 1 ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted) Characteristic Symbol Min Typ Max Unit V(BR)DSS 65 — — Vdc Zero Gate Voltage Drain Current (VDS = 28 V, VGS = 0) IDSS — — 5.0 mAdc Gate–Body Leakage Current (VGS = 20 V, VDS = 0) IGSS — — 1.0 µAdc Gate Threshold Voltage (VDS = 10 V, ID = 100 mA) VGS(th) 1.0 3.0 5.0 Vdc Drain–Source On–Voltage (VGS = 10 V, ID = 10 A) VDS(on) 0.1 0.9 1.5 Vdc Forward Transconductance (VDS = 10 V, ID = 5.0 A) gfs 5.0 7.0 — mhos Input Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Ciss — 350 — pF Output Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Coss — 420 — pF Reverse Transfer Capacitance (VDS = 28 V, VGS = 0, f = 1.0 MHz) Crss — 35 — pF Gps 12 14 — dB Drain Efficiency (VDD = 28 V, Pout = 300 W, f = 175 MHz, ID (Max) = 21.4 A) η 45 55 — % Load Mismatch (VDD = 28 V, Pout = 300 W, IDQ = 500 mA, f = 175 MHz, VSWR 5:1 at all Phase Angles) ψ OFF CHARACTERISTICS (1) Drain–Source Breakdown Voltage (VGS = 0, ID = 100 mA) ON CHARACTERISTICS (1) DYNAMIC CHARACTERISTICS (1) FUNCTIONAL TESTS (2) Common Source Amplifier Power Gain (VDD = 28 V, Pout = 300 W, IDQ = 500 mA, f = 175 MHz) No Degradation in Output Power NOTES: 1. Each side measured separately. 2. Measured in push–pull configuration. MRF141G 2 MOTOROLA RF DEVICE DATA R1 + BIAS 0 – 6 V – L2 C4 C5 C10 C2 + 28 V – OUTPUT C12 L1 T2 DUT INPUT C11 T1 HIGH IMPEDANCE WINDINGS 9:1 IMPEDANCE RATIO CENTER TAP CENTER TAP C13 C6 C7 C1 C3 CONNECTIONS TO LOW IMPEDANCE WINDINGS 4:1 IMPEDANCE RATIO C8 C9 T1 — 9:1 RF Transformer. Can be made of 15 – 18 Ohms T1 — Semirigid Co–Ax, 62 – 90 Mils O.D. T2 — 1:9 RF Transformer. Can be made of 15 – 18 Ohms T2 — Semirigid Co–Ax, 70 – 90 Mils O.D. C1 — Arco 402, 1.5 – 20 pF C2 — Arco 406, 15 – 115 pF C3, C4, C8, C9, C10 — 1000 pF Chip C5, C11 — 0.1 µF Chip C6 — 330 pF Chip C7 — 200 pF and 180 pF Chips in Parallel C12 — 0.47 µF Ceramic Chip, Kemet 1215 or Equivalent C13 — Arco 403, 3.0 – 35 pF L1 — 10 Turns AWG #16 Enameled Wire, L1 — Close Wound, 1/4″ I.D. L2 — Ferrite Beads of Suitable Material for L2 — 1.5 – 2.0 µH Total Inductance R1 — 100 Ohms, 1/2 W R2 — 1.0 kOhm, 1/2 W Board Material — 0.062″ Fiberglass (G10), 1 oz. Copper Clad, 2 Sides, εr = 5 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 pictures for construction details. Unless Otherwise Noted, All Chip Capacitors are ATC Type 100 or Equivalent. Figure 1. 175 MHz Test Circuit VGS, GATE-SOURCE VOLTAGE (NORMALIZED) TYPICAL CHARACTERISTICS I D, DRAIN CURRENT (AMPS) 100 10 TC = 25°C 1 1 10 VDS, DRAIN–TO–SOURCE VOLTAGE (VOLTS) Figure 2. DC Safe Operating Area MOTOROLA RF DEVICE DATA 100 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 0.91 0.9 – 25 ID = 5 A 4A 2A 1A 0.5 A 0 25 50 TC, CASE TEMPERATURE (°C) 0.25 A 75 100 Figure 3. Gate–Source Voltage versus Case Temperature MRF141G 3 TYPICAL CHARACTERISTICS 2000 Coss VDS = 20 V C, CAPACITANCE (pF) f T, UNITY GAIN FREQUENCY (MHz) 2000 10 V 1000 0 0 2 4 6 8 10 12 14 ID, DRAIN CURRENT (AMPS) 16 18 Ciss 200 Crss 20 20 0 NOTE: Data shown applies to each half of MRF141G. 5 10 15 20 VDS, DRAIN–TO–SOURCE VOLTAGE (VOLTS) NOTE: Data shown applies to each half of MRF141G. Figure 4. Common Source Unity Gain Frequency versus Drain Current Figure 5. Capacitance versus Drain–Source Voltage 400 Pout , OUTPUT POWER (WATTS) G PS , POWER GAIN (dB) 30 25 20 15 VDD = 28 V IDQ = 2 x 250 mA Pout = 300 W 10 5 25 2 5 350 Pin = 30 W f = 175 MHz 300 20 W IDQ = 250 mA x 2 250 10 W 200 150 100 50 10 30 f, FREQUENCY (MHz) 100 200 0 12 Figure 6. Power Gain versus Frequency 100 18 20 22 SUPPLY VOLTAGE (VOLTS) 24 26 28 f = 175 MHz INPUT, Zin (GATE TO GATE) 125 100 150 f = 175 MHz 30 30 16 Figure 7. Output Power versus Supply Voltage 150 125 14 OUTPUT, ZOL* (DRAIN TO DRAIN) Zo = 10 Ω ZOL* = Conjugate of the optimum load impedance ZOL* = into which the device output operates at a ZOL* = given output power, voltage and frequency. Figure 8. Input and Output Impedances MRF141G 4 MOTOROLA RF DEVICE DATA RF POWER MOSFET CONSIDERATIONS 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 (C gs ). 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 LINEARITY AND GAIN CHARACTERISTICS In addition to the typical IMD and power gain data presented, Figure 4 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. 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. Exceeding the rated VGS can result in permanent damage to the oxide layer in the gate region. Gate Termination — The gate of this device is essentially capacitor. Circuits that leave the gate open–circuited or floatMOTOROLA RF DEVICE DATA ing should be avoided. These conditions can result in turn– on of the device 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. 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 MRF141G 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 MRF141G 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 MRF141G 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 MRF141G 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. MRF141G 5 PACKAGE DIMENSIONS U G Q RADIUS 2 PL 0.25 (0.010) 1 M T A M DIM A B C D E G H J K N Q R U –B– 5 3 4 D E B 2 R K M NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. J N H –T– –A– SEATING PLANE C 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 STYLE 2: PIN 1. 2. 3. 4. 5. 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 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. 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Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer. How to reach us: USA / EUROPE: Motorola Literature Distribution; P.O. Box 20912; Phoenix, Arizona 85036. 1–800–441–2447 JAPAN: Nippon Motorola Ltd.; Tatsumi–SPD–JLDC, Toshikatsu Otsuki, 6F Seibu–Butsuryu–Center, 3–14–2 Tatsumi Koto–Ku, Tokyo 135, Japan. 03–3521–8315 MFAX: [email protected] – TOUCHTONE (602) 244–6609 INTERNET: http://Design–NET.com HONG KONG: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park, 51 Ting Kok Road, Tai Po, N.T., Hong Kong. 852–26629298 MRF141G 6 ◊ *MRF141G/D* MRF141G/D MOTOROLA RF DEVICE DATA