Communication Concepts FM-1KW User Manual

Freescale Semiconductor

Technical Data

 REFERENCE DESIGN IN 1st REVIEW -- 06/03/11

Available at http://www.freescale.com. Go to Support/Software & Tools/

Additional Resources/Reference Designs/Networking

Rev . 1.1, 6/2011

RF Power Reference Design Library

FM Broadcast Reference Design

High Ruggedness N--Channel Enhancement--Mode
Lateral MOSFETs

Reference Design Characteristics

The MRFE6VP61K25H/HS are versatile devices and are well suited for a
wide range of applications. They are capable of delivering 1.2 kW under
continuous wave test signaling as a result of their high efficiency and low
thermal resistance. This document focuses on FM broadcast radio applications
for both analog and complex modulation waveforms.

 Frequency Band: 87.5--108 MHz
 Output Power: 1100 Watts CW
 Supply Voltage: 50 Vdc
 Power Gain (Typ): 25 dB
 Drain Efficiency (Min): 79% (at fundamental frequency)

The MRFE6VP61K25H/HS products are enhanced ruggedness 50 volt
LDMOS power transistors that can operate in harsh environments and in highly
mismatched applications (within the limit of maximum junction temperature).
These parts are designed for high voltage operation and are fabricated using
Freescale’s very high voltage 6th generation (VHV6E) platform.

MRFE6VP61K25H

MRFE6VP61K25HS

FM Broadcast

87.5--108 MHz, 1100 W CW, 50 V
FM BROADCAST

REFERENCE DESIGN

V

DD

BIAS

M

OUTPUT

+

-

M

BIAS

V

DD

RF

INPUT

M=Match

V

GG

BIAS

M

­+

M

BIAS

V

GG

RF

FM BROADCAST REFERENCE DESIGN

This reference design is designed to demonstrate the RF
performance characteristics of the MRFE6VP61K25H/HS
devices when applied to the 87.5--108 MHz FM broadcast
frequency band. The reference design is tuned for
performance at 1100 watts CW output power, V
and IDQ= 200 mA.

=50volts

DD

REFERENCE DESIGN LIBRARY TERMS

AND CONDITIONS

Freescale is pleased to make this reference design
available for your use in development and testing of your

own product or products. The reference design contains an
easy--to--copy, fully functional amplifier design. It consists of
“no tune” distributed element matching circuits designed to
be as small as possible, and is designed to be used as a
“building block” by our customers.

HEATSINKING

When operating this fixture it is critical that adequate heat­sinking is provided for the device. Excessive heating of the
device may prevent duplication of the included measurements
and/or destruction of the device.

Figure 1. FM Broadcast Reference Design Fixture

 Freescale Semiconductor, Inc., 2011.All rights reserved.

RF Reference Design Data
Freescale Semiconductor

MRFE6VP61K25H MRFE6VP61K25HS FM Broadcast

1

MEASUREMENTS

31

30

29

28

f = 108 MHz

108 MHz



D

87.5 MHz

98 MHz

90

80

70

32

30



D

28

60

26

27

, POWER GAIN (dB)

ps

26

G

25

VDD=50V
I

DQ

= 200 mA

87.5 MHz
98 MHz

G

ps

24

300 500 700 1100

200 400 600 800 900 1000

100

, OUTPUT POWER (WATTS)

P

out

Air--Cooled, CW, 87.5--108 MHz, Low Pass Filter

Figure 2. Continuous Wave Performance Graph

with Low Pass Filter versus Output Power

1200

50

24

, POWER GAIN (dB)

DRAIN EFFICIENCY (%)

40

30

20

ps

G

D,



22

P

out

V

DD

I

DQ

= 1100 W
=50V

= 200 mA

20

88 92 96 100 102 104

86

G

ps

f, FREQUENCY (MHz)

Air--Cooled, CW, 87.5--108 MHz, Low Pass Filter

Figure 3. Continuous Wave Performance Graph

with Low Pass Filter versus Frequency

Table 1. CW Drive--Up at 87.5 MHz

P

in

(W)

0.3 150 27.0 -- 6 . 1 33.6 50 8.9 0.2

0.5 314 28.0 -- 6 . 5 48.0 50 13.1 0.2

1.0 639 28.1 -- 8 . 1 65.8 50 19.4 0.2

1.5 844 27.5 -- 10.1 72.6 50 23.2 0.2

2.0 975 26.9 -- 1 1 . 9 76.1 50 25.6 0.2

2.5 1056 26.3 --13.0 78.1 50 27.0 0.2

3.0 1100 25.6 --13.3 79.1 50 27.8 0.2

3.5 111 6 25.0 -- 13.6 79.2 50 28.2 0.2

P

(W)

out

Gain

(dB)

IRL

(dB)

Eff

(%)

V

(V)

DD

I
(A)

Table 2. CW Drive--Up at 98 MHz

P

in

(W)

0.3 168 27.5 -- 1 1 . 0 36.8 50 9.1 0.2

0.5 343 28.4 -- 1 1 . 8 52.0 50 13.2 0.2

1.0 660 28.2 -- 14.9 68.5 50 19.3 0.2

1.5 864 27.6 -- 19.4 75.3 50 22.9 0.2

2.0 999 27.0 -- 22.4 78.7 50 25.4 0.2

2.5 1058 26.3 --22.0 80.1 50 26.4 0.2

3.0 1085 25.6 --22.0 80.2 50 27.0 0.2

3.5 1094 24.9 --22.6 80.4 50 27.2 0.2

P

(W)

out

Gain

(dB)

IRL

(dB)

Eff

(%)

V

(V)

DD

I
(A)

Table 3. CW Drive--Up at 108 MHz

P

in

(W)

0.3 193 28.1 -- 14.2 40.9 50 9.4 0.2

0.5 377 28.8 -- 14.9 56.1 50 13.4 0.2

1.0 695 28.4 -- 15.6 72.9 50 19.1 0.2

1.5 881 27.7 -- 13.5 78.6 50 22.4 0.2

2.0 980 26.7 -- 14.1 79.2 50 22.9 0.2

2.5 1018 26.1 --12.2 81.6 50 24.9 0.2

3.0 1066 25.5 -- 11 . 8 82.4 50 25.9 0.2

3.5 1092 24.9 -- 11 . 8 82.7 50 26.4 0.2

1. IDQis set by adjusting a variable gate--source voltage while maintaining a constant 50 volts at the drain.

P

(W)

out

Gain

(dB)

IRL

(dB)

Eff

(%)

V

(V)

DD

I
(A)

DD

DD

DD

108

90

80

70

60

50

DRAIN EFFICIENCY (%)

D,



40

30

11090 94 98 106

(1)

I

DQ

(A)

(1)

I

DQ

(A)

(1)

I

DQ

(A)

MRFE6VP61K25H MRFE6VP61K25HS FM Broadcast

2

RF Reference Design Data

Freescale Semiconductor

AMPLIFIER DESIGN

MATCHING NETWORK

As a first order approximation, the typical maximum
efficiency impedance point corresponds to a 25% power
degradation from the maximum P3dB impedance. The
maximum output power impedance value on this device
corresponds to a 1.25 kW output capability from

87.5--108 MHz. This puts the targeted P1dB compression
value at 800 watts of output power total, or 400 watts per
side. The initial load impedance is determined using the
following equation:

out

2

=

)

(0.85  50 V)

(2  400 W)

(0.85  VDD)

R=

(2  P

R (drain to drain) = 2.25  x2=4.5

The coaxial transformer turns ratio was chosen to meet
this required impedance level and the length of the coax
(series inductance) was tuned to attain maximum efficiency
and maximum power transfer between the device and its
complex conjugate test fixture load impedance.

2

=2.25

FIXTURE IMPEDANCE

VDD=50Vdc,IDQ= 200 mA, P

f

MHz

87.5 2.20 + j6.70 4.90 + j2.90

98 2.30 + j6.90 4.10 + j2.50

108 2.30 + j7.00 4.40 + j3.60

Z

= Test circuit impedance as measured from

source

= Test circuit impedance as measured from

Z

load

Input
Matching
Network

Z

source



gate to gate, balanced configuration.

drain to drain, balanced configuration.

Device
Under

+

Tes t

-- +

Z

source

Figure 4. Series Equivalent Source and Load

Impedance

= 1100 W CW

out

--

Z

load

Z

load



Output
Matching
Network

RF Reference Design Data
Freescale Semiconductor

Figure 5. FM Broadcast Reference Design Fixture Impedance

MRFE6VP61K25H MRFE6VP61K25HS FM Broadcast

3

CIRCUIT DESCRIPTION

C1

C3

V

GS

B1

R1

RF

INPUT

T1

L1

C2

C15 C16 C17 C19 C18

B2

COAX1

C4

L2

L3

V

DD

C7

C8

C9

COAX3

RF

OUTPUT

COAX2

B3

C22 C23 C24 C21 C20

Figure 6. FM Broadcast Reference Design Schematic Diagram

MRFE6VP61K25H MRFE6VP61K25HS FM Broadcast

4

C10

C11

C12

C5

V

DD

RF Reference Design Data

Freescale Semiconductor

C1

COAX1

C15

C16

C17

C19 C18

+

+

B1

C3

R1

L1

C2

MRFE6VP61K25H Rev. 1

Note: Component numbers C6, C13 and

C14 are not used.

T1

L2

L3

CUT OUT AREA

C4

L4

L5

C22

COAX2

C11

C24

C23

COAX3

C7
C8
C9

C10

C12

+

C21 C20

C5

+

Figure 7. FM Broadcast Reference Design Component Layout

Table 4. FM Broadcast Reference Design Component Designations and Values

Part Description Part Number Manufacturer

B1 Long Ferrite Bead 2743021447 Fair--Rite

C1

C2 27 pF Chip Capacitor ATC100B270JT500XT ATC

C3, C7, C8, C9, C10,
C11, C12

C4 39 pF Mica Capacitor MIN02--002DC390J--F Cornell Dubilier

C5 3 pF Chip Capacitor ATC100B3R0CT500XT ATC

C15, C22 10K pF Chip Capacitors ATC200B103KT500XT ATC

C16, C23 1 F, 100 V Chip Capacitors C3225JB2A105KT TDK

C17, C24 10 F, 100 V Chip Capacitors C5750X7S2A106MT TDK

C18, C19, C20, C21 470 F, 63 V Electrolytic Capacitors 477KXM063M Illinois Capacitor

L1 39 nH Inductor 1812SMS--39NJLC Coilcraft

L2, L3 2.5 nH Inductors A01TKLC Coilcraft

L4, L5 7 Turn, #16 AWG, ID = 0.3 Inductors Copper Wire

R1 11 , 1/4 W Chip Resistor CRCW120611R0FKEA Vishay

T1 Balun TUI--9 Comm Concepts

Coax1, Coax2 Flex Cables, 12 ,5.9 TC--12 Comm Concepts

Coax3 Coax Cable, Quickform 50 ,8.7 SUCOFORM 250--01 Huber+Suhner

PCB* 0.030, r=3.5 TC--350 Arlon

Heatsink NI--1230 Copper Heatsink C193X280T970 Machine Shop

6.8 F, 50 V Chip Capacitor C4532X7R1H685K TDK

1000 pF Chip Capacitors ATC100B102JT50XT ATC

*PCB artwork for this reference design is available at http://freescale.com/RFbroadcast > Design Support > Reference Designs.

Note: See Appendix A for Tuning Tips.

MRFE6VP61K25H MRFE6VP61K25HS FM Broadcast

RF Reference Design Data
Freescale Semiconductor

5