MRF151A - Tyco Electronics - Datasheet.Directory

ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted.)

Characteristic Symbol Min Typ Max Unit

OFF CHARACTERISTICS

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 — — 5.0 mAdc

Gate–Body Leakage Current (VGS = 20 V, VDS = 0) IGSS — — 1.0 µAdc

ON CHARACTERISTICS

Gate Threshold Voltage (VDS = 10 V, ID = 100 mA) VGS(th) 1.0 3.0 5.0 Vdc

Drain–Source On–V oltage (VGS = 10 V, ID = 10 A) VDS(on) 1.0 3.0 5.0 Vdc

Forward T ransconductance (VDS = 10 V, ID = 5.0 A) gfs 5.0 7.0 — mhos

DYNAMIC CHARACTERISTICS

Input Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Ciss — 350 — pF

Output Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Coss — 220 — pF

Reverse Transfer Capacitance (VDS = 50 V, VGS = 0, f = 1.0 MHz) Crss — 15 — pF

FUNCTIONAL TESTS

Common Source Amplifier Power Gain, f = 30; 30.001 MHz

(VDD = 50 V, Pout = 150 W (PEP), IDQ = 250 mA) f = 175 MHz Gps 18

—22

13 —

—dB

Drain Efficiency

(VDD = 50 V, Pout = 150 W (PEP), f = 30; 30.001 MHz,

ID (Max) = 3.75 A)

η40 45 — %

Intermodulation Distortion (1)

(VDD = 50 V, Pout = 150 W (PEP), f = 30 MHz,

f2 = 30.001 MHz, IDQ = 250 mA) IMD(d3)

IMD(d11) —

—–32

–60 –30

—

Load Mismatch

(VDD = 50 V, Pout = 150 W (PEP), f1 = 30; 30.001 MHz,

IDQ = 250 mA, VSWR 30:1 at all Phase Angles)

ψNo Degradation in Output Power

CLASS A PERFORMANCE

Intermodulation Distortion (1) and Power Gain

(VDD = 50 V, Pout = 50 W (PEP), f1 = 30 MHz,

f2 = 30.001 MHz, IDQ = 3.0 A)

GPS

IMD(d3)

IMD(d9–13)

—

–50

–75

—

NOTE:

1. To MIL–STD–1311 V ersion A, Test Method 2204B, Two Tone, Reference Each Tone.

Figure 1. 30 MHz Test Circuit

C1 — 470 pF Dipped Mica

C2, C5, C6, C7, C8, C9 — 0.1 µF Ceramic Chip or

Monolythic with Short Leads

C3 — 200 pF Unencapsulated Mica or Dipped Mica

with Short Leads

C4 — 15 pF Unencapsulated Mica or Dipped Mica

with Short Leads

C10 — 10 µF/100 V Electrolytic

L1 — VK200/4B Ferrite Choke or Equivalent, 3.0 µH

L2 — Ferrite Bead(s), 2.0 µH

R1, R2 — 51 Ω/1.0 W Carbon

R3 — 3.3 Ω/1.0 W Carbon (or 2.0 x 6.8 Ω/1/2 W in Parallel)

T1 — 9:1 Broadband Transformer Communication Concepts, Inc. RF800-9 material 43 or equiv.

T2 — 1:9 Broadband Transformer

Board Material — 0.062″ Fiberglass (G10),

1 oz. Copper Clad, 2 Sides,

r = 5

BIAS

0–12 V +

–

C5 C6 C7 C8 C9 C10 50 V

D.U.T.

T1 C2

C1 C3

INPUT

L2 +

–

OUTPUT

REV 1

VGS, DRAIN-SOURCE VOLT AGE (NORMALIZED)

Figure 2. 175 MHz Test Circuit

Figure 3. Capacitance versus

Drain–Source Voltage

TYPICAL CHARACTERISTICS

Figure 4. Gate–Source Voltage versus

Case Temperature

BIAS

0–12 V

C11

+50 V

D.U.T.

RF INPUT C8

RF OUTPUT

C4 C5

C2 C3

C10

RFC2

1000

500

200

100

0 1020304050

C, CAPACIT ANCE (pF)

VDS, DRAIN–SOURCE VOLT AGE (VOLTS)

1.04

0.9–25 0 25 50 75 100

TC, CASE TEMPERATURE (°C)

1.03

1.02

1.01

0.99

0.98

0.97

0.96

0.95

0.94

0.93

0.92

0.91

Ciss

Coss

Crss

1D = 5 A

4 A

2 A

1 A

250 mA

100 mA

C1, C2, C8 — Arco 463 or equivalent

C3 — 25 pF, Unelco

C4 — 0.1 µF, Ceramic

C5 — 1.0 µF, 15 WV Tantalum

C6 — 15 pF, Unelco J101

C7 — 25 pF, Unelco J101

C9 — Arco 262 or equivalent

C10 — 0.05 µF, Ceramic

C11 — 15 µF, 60 WV Electrolytic

D1 — 1N5347 Zener Diode

L1 — 3/4″, #18 A WG into Hairpin

L2 — Printed Line, 0.200″ x 0.500″

L3 — 1″, #16 A WG into Hairpin

L4 — 2 T urns, #16 AWG, 5/16 ID

RFC1 — 5.6 µH, Choke

RFC2 — VK200–4B

R1 — 150 Ω, 1.0 W Carbon

R2 — 10 kΩ, 1/2 W Carbon

R3 — 120 Ω, 1/2 W Carbon

Board Material — 0.062″ Fiberglass (G10),

1 oz. Copper Clad, 2 Sides, εr = 5.0

REV 1

Figure 5. DC Safe Operating Area Figure 6. Common Source Unity Gain Frequency

versus Drain Current

Figure 7. Power Gain versus Frequency Figure 8. Output Power versus Input Power

Figure 9. IMD versus Pout

100

12 20 200

VDS, DRAIN–TO–SOURCE VOLTAGE (VOLTS)

2000

00 4 8 12 16 20

ID, DRAIN CURRENT (AMPS)

1000

VDS = 30 V

ID, DRAIN CURRENT (AMPS)

2 6 10 14 18

VDS = 15 V

TC = 25°C

52 5 10 30 100 200

f, FREQUENCY (MHz)

VDD = 50 V

IDQ = 250 mA

Pout = 150 W

300

0012345

Pin, INPUT POWER (W ATTS)

200

100

00 5 10 15 20 25

300

200

100 f = 30 MHz

IDQ = 250 mA

f = 175 MHz

IDQ = 250 mA

VDD = 50 V

40 V

55 0 40 80 120 160 200

Pout, OUTPUT POWER (WATTS PEP)

IDQ = 250 mA

IDQ = 500 mA

20 60 100 140 180

VDD = 50 V, f = 30 MHz, TONE SEPARATION = 1 kHz

GPS, POWER GAIN (dB)

Pout, OUTPUT POWER (WATTS) fT, UNITY GAIN FREQUENCY (MHz)

IMD, INTERMODULA TION DISTOR TION

TYPICAL CHARACTERISTICS

REV 1

Figure 10. Series Equivalent Impedance

150

7.5

ZOL*

Zin

f = 175 MHz

100

15 7.5 Zo = 10 Ω

VDD = 50 V

IDQ = 250 mA

Pout = 150 W

ZOL* = Conjugate of the optimum load impedance

ZOL* = into which the device output operates at a

ZOL* = given output power, voltage and frequency .

f = 175 MHz

150

100

NOTE: Gate Shunted by 25 Ohms.

Table 1. Common Source S–Parameters (VDS = 50 V, ID = 2 A)

S11 S21 S12 S22

MHz |S11|φ|S21|φ|S12|φ|S22|φ

ÁÁÁÁÁ

0.877

ÁÁÁÁ

–174

ÁÁÁÁÁ

10.10

ÁÁÁÁÁ

ÁÁÁÁ

0.008

ÁÁÁÁÁ

ÁÁÁÁ

0.707

ÁÁÁÁÁ

–169

ÁÁÁÁÁ

0.886

ÁÁÁÁ

–175

ÁÁÁÁÁ

7.47

ÁÁÁÁÁ

ÁÁÁÁ

0.009

ÁÁÁÁÁ

ÁÁÁÁ

0.715

ÁÁÁÁÁ

–172

ÁÁÁÁÁ

0.895

ÁÁÁÁ

–175

ÁÁÁÁÁ

5.76

ÁÁÁÁÁ

ÁÁÁÁ

0.008

ÁÁÁÁÁ

ÁÁÁÁ

0.756

ÁÁÁÁÁ

–171

ÁÁÁÁÁ

0.902

ÁÁÁÁ

–176

ÁÁÁÁÁ

4.73

ÁÁÁÁÁ

ÁÁÁÁ

0.009

ÁÁÁÁÁ

ÁÁÁÁ

0.764

ÁÁÁÁÁ

–171

ÁÁÁÁÁ

0.912

ÁÁÁÁ

–176

ÁÁÁÁÁ

3.86

ÁÁÁÁÁ

ÁÁÁÁ

0.009

ÁÁÁÁÁ

ÁÁÁÁ

0.784

ÁÁÁÁÁ

–172

ÁÁÁÁÁ

0.918

ÁÁÁÁ

–177

ÁÁÁÁÁ

3.19

ÁÁÁÁÁ

ÁÁÁÁ

0.010

ÁÁÁÁÁ

ÁÁÁÁ

0.802

ÁÁÁÁÁ

–171

ÁÁÁÁÁ

0.925

ÁÁÁÁ

–177

ÁÁÁÁÁ

2.69

ÁÁÁÁÁ

ÁÁÁÁ

0.011

ÁÁÁÁÁ

ÁÁÁÁ

0.808

ÁÁÁÁÁ

–171

ÁÁÁÁÁ

100

ÁÁÁÁÁ

0.932

ÁÁÁÁ

–177

ÁÁÁÁÁ

2.34

ÁÁÁÁÁ

ÁÁÁÁ

0.013

ÁÁÁÁÁ

ÁÁÁÁ

0.850

ÁÁÁÁÁ

–173

ÁÁÁÁÁ

110

ÁÁÁÁÁ

0.936

ÁÁÁÁ

–178

ÁÁÁÁÁ

2.06

ÁÁÁÁÁ

ÁÁÁÁ

0.014

ÁÁÁÁÁ

ÁÁÁÁ

0.865

ÁÁÁÁÁ

–175

ÁÁÁÁÁ

120

ÁÁÁÁÁ

0.942

ÁÁÁÁ

–178

ÁÁÁÁÁ

1.77

ÁÁÁÁÁ

ÁÁÁÁ

0.015

ÁÁÁÁÁ

ÁÁÁÁ

0.875

ÁÁÁÁÁ

–173

ÁÁÁÁÁ

130

ÁÁÁÁÁ

0.946

ÁÁÁÁ

–179

ÁÁÁÁÁ

1.55

ÁÁÁÁÁ

ÁÁÁÁ

0.017

ÁÁÁÁÁ

ÁÁÁÁ

0.874

ÁÁÁÁÁ

–172

ÁÁÁÁÁ

140

ÁÁÁÁÁ

0.950

ÁÁÁÁ

–179

ÁÁÁÁÁ

1.39

ÁÁÁÁÁ

ÁÁÁÁ

0.019

ÁÁÁÁÁ

ÁÁÁÁ

0.884

ÁÁÁÁÁ

–174

ÁÁÁÁÁ

150

ÁÁÁÁÁ

0.954

ÁÁÁÁ

–180

ÁÁÁÁÁ

1.23

ÁÁÁÁÁ

ÁÁÁÁ

0.021

ÁÁÁÁÁ

ÁÁÁÁ

0.909

ÁÁÁÁÁ

–175

ÁÁÁÁÁ

160

ÁÁÁÁÁ

0.957

ÁÁÁÁ

–180

ÁÁÁÁÁ

1.13

ÁÁÁÁÁ

ÁÁÁÁ

0.023

ÁÁÁÁÁ

ÁÁÁÁ

0.911

ÁÁÁÁÁ

–176

ÁÁÁÁÁ

170

ÁÁÁÁÁ

0.960

ÁÁÁÁ

180

ÁÁÁÁÁ

1.01

ÁÁÁÁÁ

ÁÁÁÁ

0.024

ÁÁÁÁÁ

ÁÁÁÁ

0.904

ÁÁÁÁÁ

–177

ÁÁÁÁÁ

180

ÁÁÁÁÁ

0.962

ÁÁÁÁ

179

ÁÁÁÁÁ

0.90

ÁÁÁÁÁ

ÁÁÁÁ

0.026

ÁÁÁÁÁ

ÁÁÁÁ

0.931

ÁÁÁÁÁ

–176

ÁÁÁÁÁ

190

ÁÁÁÁÁ

0.964

ÁÁÁÁ

179

ÁÁÁÁÁ

0.84

ÁÁÁÁÁ

ÁÁÁÁ

0.028

ÁÁÁÁÁ

ÁÁÁÁ

0.929

ÁÁÁÁÁ

–178

ÁÁÁÁÁ

200

ÁÁÁÁÁ

0.967

ÁÁÁÁ

179

ÁÁÁÁÁ

0.75

ÁÁÁÁÁ

ÁÁÁÁ

0.030

ÁÁÁÁÁ

ÁÁÁÁ

0.922

ÁÁÁÁÁ

–179

ÁÁÁÁÁ

210

ÁÁÁÁÁ

0.967

ÁÁÁÁ

178

ÁÁÁÁÁ

0.71

ÁÁÁÁÁ

ÁÁÁÁ

0.032

ÁÁÁÁÁ

ÁÁÁÁ

0.937

ÁÁÁÁÁ

–180

ÁÁÁÁÁ

220

ÁÁÁÁÁ

0.969

ÁÁÁÁ

178

ÁÁÁÁÁ

0.67

ÁÁÁÁÁ

ÁÁÁÁ

0.035

ÁÁÁÁÁ

ÁÁÁÁ

0.949

ÁÁÁÁÁ

180

ÁÁÁÁÁ

230

ÁÁÁÁÁ

0.971

ÁÁÁÁ

178

ÁÁÁÁÁ

0.60

ÁÁÁÁÁ

ÁÁÁÁ

0.038

ÁÁÁÁÁ

ÁÁÁÁ

0.950

ÁÁÁÁÁ

179

ÁÁÁÁÁ

240

ÁÁÁÁÁ

0.970

ÁÁÁÁ

177

ÁÁÁÁÁ

0.57

ÁÁÁÁÁ

ÁÁÁÁ

0.037

ÁÁÁÁÁ

ÁÁÁÁ

0.950

ÁÁÁÁÁ

179

REV 1

Table 1. Common Source S–Parameters (VDS = 50 V, ID = 2 A) continued

S11 S21 S12 S22

MHz |S11|φ|S21|φ|S12|φ|S22|φ

ÁÁÁÁÁ

250

ÁÁÁÁÁ

0.972

ÁÁÁÁ

177

ÁÁÁÁÁ

0.51

ÁÁÁÁÁ

ÁÁÁÁ

0.039

ÁÁÁÁÁ

ÁÁÁÁ

0.935

ÁÁÁÁÁ

179

ÁÁÁÁÁ

260

ÁÁÁÁÁ

0.973

ÁÁÁÁ

177

ÁÁÁÁÁ

0.47

ÁÁÁÁÁ

ÁÁÁÁ

0.041

ÁÁÁÁÁ

ÁÁÁÁ

0.954

ÁÁÁÁÁ

178

ÁÁÁÁÁ

270

ÁÁÁÁÁ

0.972

ÁÁÁÁ

176

ÁÁÁÁÁ

0.45

ÁÁÁÁÁ

ÁÁÁÁ

0.044

ÁÁÁÁÁ

ÁÁÁÁ

0.953

ÁÁÁÁÁ

176

ÁÁÁÁÁ

280

ÁÁÁÁÁ

0.974

ÁÁÁÁ

176

ÁÁÁÁÁ

0.41

ÁÁÁÁÁ

ÁÁÁÁ

0.046

ÁÁÁÁÁ

ÁÁÁÁ

0.965

ÁÁÁÁÁ

175

ÁÁÁÁÁ

290

ÁÁÁÁÁ

0.974

ÁÁÁÁ

176

ÁÁÁÁÁ

0.40

ÁÁÁÁÁ

ÁÁÁÁ

0.046

ÁÁÁÁÁ

ÁÁÁÁ

0.944

ÁÁÁÁÁ

175

ÁÁÁÁÁ

300

ÁÁÁÁÁ

0.975

ÁÁÁÁ

176

ÁÁÁÁÁ

0.39

ÁÁÁÁÁ

ÁÁÁÁ

0.048

ÁÁÁÁÁ

ÁÁÁÁ

0.929

ÁÁÁÁÁ

176

ÁÁÁÁÁ

310

ÁÁÁÁÁ

0.976

ÁÁÁÁ

175

ÁÁÁÁÁ

0.36

ÁÁÁÁÁ

ÁÁÁÁ

0.049

ÁÁÁÁÁ

ÁÁÁÁ

0.943

ÁÁÁÁÁ

176

ÁÁÁÁÁ

320

ÁÁÁÁÁ

0.974

ÁÁÁÁ

175

ÁÁÁÁÁ

0.33

ÁÁÁÁÁ

ÁÁÁÁ

0.053

ÁÁÁÁÁ

ÁÁÁÁ

0.954

ÁÁÁÁÁ

173

ÁÁÁÁÁ

330

ÁÁÁÁÁ

0.975

ÁÁÁÁ

174

ÁÁÁÁÁ

0.31

ÁÁÁÁÁ

ÁÁÁÁ

0.056

ÁÁÁÁÁ

ÁÁÁÁ

0.935

ÁÁÁÁÁ

172

ÁÁÁÁÁ

340

ÁÁÁÁÁ

0.976

ÁÁÁÁ

174

ÁÁÁÁÁ

0.30

ÁÁÁÁÁ

ÁÁÁÁ

0.056

ÁÁÁÁÁ

ÁÁÁÁ

0.948

ÁÁÁÁÁ

172

ÁÁÁÁÁ

350

ÁÁÁÁÁ

0.975

ÁÁÁÁ

174

ÁÁÁÁÁ

0.29

ÁÁÁÁÁ

ÁÁÁÁ

0.058

ÁÁÁÁÁ

ÁÁÁÁ

0.950

ÁÁÁÁÁ

174

ÁÁÁÁÁ

360

ÁÁÁÁÁ

0.977

ÁÁÁÁ

174

ÁÁÁÁÁ

0.28

ÁÁÁÁÁ

ÁÁÁÁ

0.059

ÁÁÁÁÁ

ÁÁÁÁ

0.978

ÁÁÁÁÁ

172

ÁÁÁÁÁ

370

ÁÁÁÁÁ

0.976

ÁÁÁÁ

173

ÁÁÁÁÁ

0.26

ÁÁÁÁÁ

ÁÁÁÁ

0.061

ÁÁÁÁÁ

ÁÁÁÁ

0.981

ÁÁÁÁÁ

170

ÁÁÁÁÁ

380

ÁÁÁÁÁ

0.976

ÁÁÁÁ

173

ÁÁÁÁÁ

0.26

ÁÁÁÁÁ

ÁÁÁÁ

0.065

ÁÁÁÁÁ

ÁÁÁÁ

0.944

ÁÁÁÁÁ

171

ÁÁÁÁÁ

390

ÁÁÁÁÁ

0.977

ÁÁÁÁ

173

ÁÁÁÁÁ

0.24

ÁÁÁÁÁ

ÁÁÁÁ

0.066

ÁÁÁÁÁ

ÁÁÁÁ

0.960

ÁÁÁÁÁ

171

ÁÁÁÁÁ

400

ÁÁÁÁÁ

0.976

ÁÁÁÁ

172

ÁÁÁÁÁ

0.23

ÁÁÁÁÁ

ÁÁÁÁ

0.068

ÁÁÁÁÁ

ÁÁÁÁ

0.955

ÁÁÁÁÁ

173

ÁÁÁÁÁ

410

ÁÁÁÁÁ

0.976

ÁÁÁÁ

172

ÁÁÁÁÁ

0.22

ÁÁÁÁÁ

ÁÁÁÁ

0.071

ÁÁÁÁÁ

ÁÁÁÁ

0.999

ÁÁÁÁÁ

170

ÁÁÁÁÁ

420

ÁÁÁÁÁ

0.977

ÁÁÁÁ

172

ÁÁÁÁÁ

0.21

ÁÁÁÁÁ

ÁÁÁÁ

0.071

ÁÁÁÁÁ

ÁÁÁÁ

0.962

ÁÁÁÁÁ

168

ÁÁÁÁÁ

430

ÁÁÁÁÁ

0.976

ÁÁÁÁ

171

ÁÁÁÁÁ

0.19

ÁÁÁÁÁ

ÁÁÁÁ

0.073

ÁÁÁÁÁ

ÁÁÁÁ

0.950

ÁÁÁÁÁ

168

ÁÁÁÁÁ

440

ÁÁÁÁÁ

0.976

ÁÁÁÁ

171

ÁÁÁÁÁ

0.20

ÁÁÁÁÁ

ÁÁÁÁ

0.075

ÁÁÁÁÁ

ÁÁÁÁ

0.953

ÁÁÁÁÁ

168

ÁÁÁÁÁ

450

ÁÁÁÁÁ

0.978

ÁÁÁÁ

171

ÁÁÁÁÁ

0.19

ÁÁÁÁÁ

ÁÁÁÁ

0.080

ÁÁÁÁÁ

ÁÁÁÁ

0.982

ÁÁÁÁÁ

168

ÁÁÁÁÁ

460

ÁÁÁÁÁ

0.978

ÁÁÁÁ

170

ÁÁÁÁÁ

0.18

ÁÁÁÁÁ

ÁÁÁÁ

0.082

ÁÁÁÁÁ

ÁÁÁÁ

0.990

ÁÁÁÁÁ

165

ÁÁÁÁÁ

470

ÁÁÁÁÁ

0.978

ÁÁÁÁ

170

ÁÁÁÁÁ

0.18

ÁÁÁÁÁ

ÁÁÁÁ

0.081

ÁÁÁÁÁ

ÁÁÁÁ

0.953

ÁÁÁÁÁ

168

ÁÁÁÁÁ

480

ÁÁÁÁÁ

0.974

ÁÁÁÁ

170

ÁÁÁÁÁ

0.18

ÁÁÁÁÁ

ÁÁÁÁ

0.085

ÁÁÁÁÁ

ÁÁÁÁ

0.944

ÁÁÁÁÁ

167

ÁÁÁÁÁ

490

ÁÁÁÁÁ

0.973

ÁÁÁÁ

169

ÁÁÁÁÁ

0.17

ÁÁÁÁÁ

ÁÁÁÁ

0.086

ÁÁÁÁÁ

ÁÁÁÁ

0.966

ÁÁÁÁÁ

165

ÁÁÁÁÁ

500

ÁÁÁÁÁ

0.972

ÁÁÁÁ

169

ÁÁÁÁÁ

0.17

ÁÁÁÁÁ

ÁÁÁÁ

0.089

ÁÁÁÁÁ

ÁÁÁÁ

0.980

ÁÁÁÁÁ

165

REV 1

RF POWER MOSFET CONSIDERATIONS

MOSFET CAPACITANCES

The physical structure of a MOSFET results in capacitors

between the terminals. The metal anode gate structure de-

termines 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

LINEARITY AND GAIN CHARACTERISTICS

In addition to the typical IMD and power gain data pres-

ented, Figure 6 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 cur-

rent 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. 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 float-

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 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 a grounded

iron.

DESIGN CONSIDERATIONS

The MRF151A is an RF Power, MOS, N–channel enhance-

ment mode field–effect transistor (FET) designed for HF and

VHF power amplifier applications.

M/A-COM 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 MRF151A 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 MRF151A was characterized at

IDQ = 250 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 system.

GAIN CONTROL

Power output of the MRF151A 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.

REV 1

PACKAGE DIMENSIONS

CASE P-244

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

ESEATING

PLANE

DIM MIN MAX MIN MAX

MILLIMETERSINCHES

A0.960 0.990 24.39 25.14

B0.465 0.510 11.82 12.95

C0.229 0.275 5.82 6.98

D0.216 0.235 5.49 5.96

E0.084 0.110 2.14 2.79

H0.144 0.178 3.66 4.52

J0.003 0.007 0.08 0.17

K0.435 ––– 11.05 –––

M45 NOM 45 NOM

Q0.115 0.130 2.93 3.30

R0.246 0.255 6.25 6.47

U0.720 0.730 18.29 18.54

STYLE 2:

PIN 1. SOURCE

2. GATE

3. SOURCE

4. DRAIN

Specifications subject to change without notice.

n North America: Tel. (800) 366-2266, Fax (800) 618-8883

n Asia/Pacific: Tel.+81-44-844-8296, Fax +81-44-844-8298

n Europe: Tel. +44 (1344) 869 595, Fax+44 (1344) 300 020

Visit www.macom.com for additional data sheets and product information.

REV 1