Available at http://freescale.com/RFbroadcast
Freescale Semiconductor
Technical Data
> Design Support > Reference Designs
Rev. 0, 6/2011
High Ruggedness N--Channel Enhancement--Mode
Lateral MOSFETs
170--230 MHz, 225 W AVG., 50 V
VHF DIGITAL TV BROADCAST
REFERENCE DESIGN
VGG
BIAS
Reference Design Characteristics
Solid--state broadcast transmitters require transistors that are broadband,
highly efficient and very rugged. There is also demand for transistors with
higher power capability to minimize device count and combining losses. This
document describes the design and performance of a VHF DVB--T power
amplifier using the MRFE6VP61K25H LDMOS transistor.
• Frequency Band: 170--230 MHz
• Output Power: 225 Watts Avg. DVB--T
RF
INPUT
• Supply Voltage: 50 Vdc
• Power Gain (Typ): 25 dB
+
The MRFE6VP61K25H device is capable of 1250 watts CW operation and
suitable for high power applications between 1.8 and 600 MHz. The LDMOS
technology used is designed to operate at 50 volts, thereby increasing the
power capability per device and reducing the number of devices needed per
system. A temperature compensation circuit has been included in the amplifier
design to keep the quiescent current stable over temperature.
M = Match
M
M
RF
OUTPUT
+
-
M
BIAS
• Drain Efficiency (Typ): 30%
VDD
BIAS
VHF Digital TV Broadcast Reference Design
MRFE6VP61K25H
MRFE6VP61K25HS
VHF Broadcast
VGG
M
BIAS
RF Power Reference Design Library
VDD
VHF DIGITAL TV BROADCAST REFERENCE DESIGN
This reference design is designed to demonstrate the RF
performance characteristics of the MRFE6VP61K25H/HS
devices when applied to the 170--230 MHz VHF broadcast
frequency band. The reference design is tuned for
performance at 225 watts avg. output power, VDD = 50 volts
and IDQ = 2.0 A.
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.
REFERENCE DESIGN LIBRARY TERMS
AND CONDITIONS
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.
Freescale is pleased to make this reference design
available for your use in development and testing of your
HEATSINKING
Figure 1. VHF Broadcast Reference Design Fixture
© Freescale Semiconductor, Inc., 2011. All rights reserved.
RF Reference Design Data
Freescale Semiconductor
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
1
MEASUREMENTS
or over their rated temperature at such high power. Therefore
a pulsed signal is used to measure power, gain and efficiency
of the amplifier.
As shown in Figure 3, the P1dB is more than 1250 watts
with an IDQ of 150 mA. The results with IDQ = 2.0 A is shown
in Figure 4.
The power capability and P1dB with a pulsed signal gives
an indication of the average DVB--T power that the amplifier
is capable of with a PAR above 8 dB (0.01% probability,
CCDF) and a (non--corrected) shoulder distance below
--30 dBc. A rough estimation is that the available DVB--T
average power is about 7 dB below the pulsed P1dB power.
SMALL SIGNAL
The amplifier is first measured with a small signal over a
large frequency range to verify that there are no resonances
or gain peaks due to the transistor matching or decoupling
network. The small signal measurement can be seen in
Figure 2.
PULSED
Although the MRFE6VP61K25H device is capable of
1250 watts CW operation, some of the matching components,
e.g. capacitors used in this DVB--T amplifier, could be close to
40
30
20
Gps
20
10
0
IRL (dB)
10
--10
0
IRL
--10
--20
--30
--20
VDD = 50 Vdc
IDQ = 2.0 A
--30
--40
--40
0
50
100
Gps, POWER GAIN (dB)
30
150
200
250
300
--50
400
350
f, FREQUENCY (MHz)
Figure 2. Small Signal Characteristics
170 MHz
230 MHz
80
26.5
70
26
24
170 MHz 60
23
50
22
40
230 MHz
21
VDD = 50 Vdc, IDQ = 150 mA
Pulse Width = 50 μsec
Duty Cycle = 2.5%
ηD
20
19
0
200
30
400
600
800
1000
1200 1400 1600
20
10
1800
Gps
230 MHz
170 MHz
25.5
80
200 MHz 70
60
200 MHz
170 MHz
25
230 MHz
24.5
50
40
24
30
23.5
23
20
VDD = 50 Vdc, IDQ = 2.0 A
Pulse Width = 50 μsec
Duty Cycle = 2.5%
ηD
10
22.5
0
200
400
600
800
1000
ηD, DRAIN EFFICIENCY (%)
Gps
200 MHz
Gps, POWER GAIN (dB)
Gps, POWER GAIN (dB)
25
200 MHz
ηD, DRAIN EFFICIENCY (%)
26
1200 1400 1600
0
1800
Pout, OUTPUT POWER (WATTS) PULSED
Pout, OUTPUT POWER (WATTS) PULSED
Figure 3. Pulsed Power Gain and Drain Efficiency
versus Output Power
Figure 4. Pulsed Power Gain and Drain Efficiency
versus Output Power
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
2
RF Reference Design Data
Freescale Semiconductor
A DVB--T signal with a 9.6 dB peak--to--average (PAR)
ratio at 0.01% probability on CCDF was used to quantify the
broadband performance of the MRFE6VP61K25H device
under a digital modulation scheme. The circuit is air--cooled
and the device bolted down to the heatsink with thermal
grease (Figure 1).
Figure 5 illustrates typical broadband performance at
225 watts avg. DVB--T power. The PAR is above 8 dB across
the VHF band of 170--230 MHz with a 30% efficiency and
gain of 25 dB.
10
40
35
9.5
ηD
9
30
PAR
25
8
27
7.5
7
6.5
6
170
26
Gps
25
VDD = 50 Vdc
IDQ = 2.0 A
Pout = 225 W Avg. DVB--T
180
190
24
200
210
Gps, POWER
GAIN (dB)
PAR (dB)
8.5
ηD, DRAIN
EFFICIENCY (%)
The drive up data in Figures 6 and 7 shows that it is
reasonable to use the device up to 250 watts avg. DVB--T
power and still have a PAR above 8 and shoulder distance
below --30 dBc. This is in line with the rough estimation that
the average DVB--T power is about 7 dB below the pulsed
P1dB. The shoulder distance is measured using delta
marker at ±4.2 MHz offset.
The device can be used at lower supply voltage for lower
output power or to optimize the tradeoff between linearity and
efficiency. Decreasing the supply voltage will improve
efficiency and decrease the linearity.
DVB--T
23
230
220
f, FREQUENCY (MHz)
Figure 5. DVB--T Peak--to--Average Ratio, Power Gain and
Drain Efficiency versus Frequency
9.5
9
230 MHz
PAR (dB)
7.5
35
30
230 MHz
200 MHz
6.5
6
150
--22
40
ηD
7
55
45
200 MHz
8
--20
50
PAR
8.5 170 MHz
60
25
170 MHz
170
190
210
230
20
250
Pout, OUTPUT POWER (WATTS) DVB--T AVG.
Figure 6. DVB--T Peak--to--Average Ratio and
Drain Efficiency versus Output Power
--24
SHOULDER (dBc)
VDD = 50 Vdc
IDQ = 2.0 A
ηD, DRAIN EFFICIENCY (%)
10
--26
--28
--30
--32
+4.2 MHz
--34
--4.2 MHz
--36
--38
--40
150 160
170 180 190
200
210 220 230
240 250
Pout, OUTPUT POWER (WATTS) DVB--T AVG.
Figure 7. Power Sweep DVB--T Signal
Frequency @ 200 MHz
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
RF Reference Design Data
Freescale Semiconductor
3
AMPLIFIER DESIGN
MATCHING NETWORK
The first element in the output matching is a LC network
made of microstrip lines and capacitors. The LC section is
followed by a 4:1 coaxial transformer. The impedance of the
coaxial cable is 25 Ω, which is the optimum impedance for a
transformation from 12.5 to 50 Ω, following the equation
Z = Z in × Z out.
A 1:1 balun made of a 50 Ω coaxial cable together with
capacitors are finalizing the matching network to 50 Ω at the
output of the demo board.
Due to the relatively high power of the amplifier, several
capacitors were used in parallel instead of using only one. By
using multiple capacitors, the total ESR (Equivalent Series
Resistance) will be lower which improves the current
handling capability.
A printed circuit board (PCB) with high thermal
conductivity was also selected to improve the thermal
capability of the amplifier and reduce the temperature of the
components used in the matching network.
The input matching network is made in a similar way.
Simulation software was used to get a first approach of the
values needed and to understand the impact of each
matching element.
In addition to the matching network, the decoupling circuits
for gate and drain bias supply needs to be carefully
designed. Small signal measurement and a low frequency
probe was used to verify that the decoupling was adequate
and without resonances.
A nonlinear electro--thermal transistor model for the
MRFE6VP61K25H transistor is available for customers to
optimize their design. The model is available online from
Freescale’s RF High Power Model Library at
http://freescale.com/rf/models. Supported CAD tools include
Agilent EEsof’s ADS and Microwave OfficeR from AWR
Corporation.
TEMPERATURE COMPENSATED BIAS CIRCUIT
Temperature Coefficient of the Transistor
The RF performance of a power amplifier depends on the
quiescent current, IDQ. For a fixed gate bias voltage, VGS, the
IDQ increases with temperature. A thermal tracking circuit is
introduced to compensate for the quiescent current variation
versus temperature. Figure 13 shows the PCB layout with
components for the amplifier including the thermal tracking
circuit.
The tracking circuit is using a voltage regulator (U1) to
provide a stable +5 volts.(1) A resistor network including a
potentiometer (R7) sets VGS to the desired IDQ. The resistor
values are selected to have a tuning range for the VGS to be
between 1.1 and 3.2 volts, hence covering both Class AB
and Class C operation.
The bipolar NPN transistor (Q1) is used as a thermal
tracking device. If the current through the transistor Q1 is
kept constant, the base--emitter voltage decreases with
increasing temperature. The temperature coefficient of the
transistor (Q1) depends on the collector current, IC, and can
be found in the data sheet for Q1. For IC = 4 mA, the
temperature coefficient is around --2.1 mV/°C. This reduction
in voltage is used to compensate for the increase in IDQ of
the LDMOS device due to temperature.
The temperature coefficient for the MRFE6VP61K25H
was measured using a heat and cooling plate. The VHF
amplifier with its copper heatsink was placed on the plate
and the temperature varied between 0°C and 100°C. The
temperature was measured close to the transistor. The gate
voltage was adjusted to keep the quiescent current constant
over temperature. The measurement was done for quiescent
currents of 150 mA, 1.0 A and 2.0 A. The results are plotted
in Figure 9. To keep the IDQ constant at 2.0 A, the gate
voltage needs to be reduced with 2.1 mV/°C.
The temperature coefficient of the device is depending on
the bias point, which explains the difference in thermal
coefficient for IDQ = 150 mA (--2.4 mV/°C), IDQ = 1.0 A
(--2.3 mV/°C) and IDQ = 2.0 A (--2.1 mV/°C).(2)
The next step is to measure the thermal compensation
circuit when the temperature is varied between 0°C and
100°C. The temperature coefficient for the compensation
circuit is --2.1 mV/°C. As can be seen in Figure 10, the circuit
compensates well the thermal coefficient of the LDMOS
device.
Figure 11 shows the behavior for the amplifier with the
temperature compensation circuit. The temperature variation
is less than 5% between 25°C and 115°C.
FIXTURE IMPEDANCE
VDD = 50 Vdc, IDQ = 2.0 A, Pout = 225 W Avg. DVB--T
f
MHz
Zsource
Ω
Zload
Ω
170
1.1 + j4.5
2.7 -- j0.2
200
2.1 + j5.1
2.2 + j1.1
230
1.6 + j4.1
2.1 + j2.1
Zsource = Test circuit impedance as measured from
gate to gate, balanced configuration.
Zload
= Test circuit impedance as measured from
drain to drain, balanced configuration.
Input
Matching
Network
+
Device
Under
Test
--
-Z
source
Output
Matching
Network
+
Z
load
Figure 8. Series Equivalent Source and Load
Impedance
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
4
RF Reference Design Data
Freescale Semiconductor
TEMPERATURE COMPENSATED BIAS CIRCUIT
2.8
2.75
2.7
2.7
2.5
2.4
1.0 A
2.6
Compensation Circuit
2.55
2.3
150 mA
2.2
VGS to keep IDQ = 2.0 A
2.65
IDQ = 2.0 A
VGS (V)
VGS (V)
2.6
VDD = 50 Vdc
IDQ = 2.0 A
2.5
2.1
2.45
0
20
40
60
TEMPERATURE (°C)
80
100
20
0
Figure 9. VGS versus Temperature to keep IDQ Constant
40
60
TEMPERATURE (°C)
80
100
Figure 10. Temperature Compensation Circuit
versus VGS to keep IDQ = 2.0 A
2.5
2.4
IDQ (A)
2.3
2.2
2.1
2.0
1.9
1.8
20
VDD = 50 Vdc
VGS = 2.65 V
40
60
80
100
120
TEMPERATURE (°C)
Figure 11. IDQ Drift with Temperature Compensation
Circuit
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
RF Reference Design Data
Freescale Semiconductor
5
CIRCUIT DESCRIPTION
U1
VGS
C2
R3
C1 C4
R5
R4
R8
R7
R6
C3 C5
C6
C7
L1
R2
Q1
COAX2
R1
RF
INPUT
C9
COAX1
C12
C13
C11
C8
L3
C14
C15
C10
COAX3
C33 C34 C35 C36 C37 C38
VDD
L2
COAX4
C19
C17
C16
C18
C20
C21
C22
C23
C24
C25
C26
C27
C28
COAX6
RF
OUTPUT
C29
C30
C31
C32
COAX5
Figure 12. VHF Broadcast Reference Design Schematic Diagram
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
6
RF Reference Design Data
Freescale Semiconductor
R6
C3
R4
R7
C5 R5
C2
C6
R1
R8
R3
VGS
R2
Q1
C35 C36
U1
C34
VDS
C33
C1
C19
C20
C7
C13 C12
L1
COAX2
C9
COAX4
CUT OUT AREA
C8
L3
C10
C11
C38
C37
C4
C14
C15
COAX1
L2
C16*
C17*
C26* C27*
C28*
C23*
C29*
C30*
C18*
C24*
C21
C22
COAX5
COAX3
C25*
C31*
C32*
COAX6
MRFE6VP61K25H_VHF
Rev. 1
*C16, C17, C18, C23, C24, C25, C26, C27, C28, C29, C30, C31, C32 are mounted vertically.
Figure 13. VHF Broadcast Reference Design Component Layout
Table 1. VHF Broadcast Reference Design Component Designations and Values
Part
Description
Part Number
Manufacturer
C1
2.2 μF, 100 V Chip Capacitor
HMK432B7225KM--T
Taiyo Yuden
C2, C12, C13, C14, C15
1 μF Chip Capacitors
GRM21BR71H105KA12L
Murata
C3
10 nF Chip Capacitor
C0805C103J5RAC--TU
Kemet
C4
220 μF, 63 V Electrolytic Capacitor
227CKS050M
Illinois Capacitor
C5
100 nF Chip Capacitor
CDR33BX104AKWS
Kemet
C6, C25, C26, C27, C28,
C29, C30, C31, C32, C33
1000 pF Chip Capacitors
ATC800B102JT50XT
ATC
C7
2.2 μF, 50 V Chip Capacitor
C3225X7R1H225KT
TDK
C8
22 pF Chip Capacitor
ATC800B220JT500XT
ATC
C9, C10
5.1 nF Chip Capacitors
ATC700B512JT50XT
ATC
C11
36 pF Chip Capacitor
ATC100B360JT500XT
ATC
C16, C17
39 pF Chip Capacitors
ATC800B390JT500XT
ATC
C18
47 pF Chip Capacitor
ATC800B470JT500XT
ATC
C19, C22
1 μF Chip Capacitors
GRM32CR72A105KA35L
Murata
C20, C21, C36
2.2 μF Chip Capacitors
HMK432B7225KM--T
Taiyo Yuden
C23, C24
8.2 pF Chip Capacitors
ATC800B8R2CT500XT
ATC
C34
10 nF Chip Capacitor
ATC200B103MT50XT
ATC
C35
100 nF Chip Capacitor
C1812F104K1RAC
Kemet
C37, C38
470 μF, 63 V Electrolytic Capacitors
MCGPR63V477M13X26--RH
Multicomp
L1
10 Turns, #22 AWG Magnetic Wire
8077
Belden
L2
10 Turns, #16 AWG Magnetic Wire
8074
Belden
L3
2.5 nH Inductor
A01TKL
Coilcraft
(continued)
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
RF Reference Design Data
Freescale Semiconductor
7
Table 1. VHF Broadcast Reference Design Component Designations and Values (continued)
Part
Description
Part Number
Manufacturer
R1
2.2 kΩ, 1/8 W Chip Resistor
CRCW08052K20FKEA
Vishay
R2
1.2 kΩ, 1/8 W Chip Resistor
CRCW08051K20FKEA
Vishay
R3
10 Ω, 1/8 W Chip Resistor
CRCW080510R0FKEA
Vishay
R4
1 kΩ, 1/8 W Chip Resistor
CRCW08051K00FKEA
Vishay
R5
3.9 kΩ, 1/8 W Chip Resistor
CRCW08053R90FKEA
Vishay
R6
200 Ω, 1/8 W Chip Resistor
CRCW0805200RFKEA
Vishay
R7
5 kΩ Potentiometer CMS Cermet Multi--turn
3224W--1--502E
Bourns
R8
10 Ω, 1/4 W Chip Resistor
CRCW120610R0FKEA
Vishay
Q1
Bipolar NPN Transistor
BC847ALT1G
On--Semiconductor
U1
Voltage Regulator
LP2951ACDMR2G
On--Semiconductor
Coax1
50 Ω, 5.11″
RG--316
Micro--Coax
Coax2, Coax3
24 Ω, 2.75″
TC--24
RF Power Systems
Coax4, Coax5
25 Ω, Semi Rigid RF Cable, .118″ Line, 2.56″ length.
UT141--25
Micro--Coax
Coax6
50 Ω, 4.72″
EC141--50 Quickform/Hand Formable
NEXANS
PCB*
0.030″, εr = 3.5
TC350
Arlon
Heatsink
NI--1230 Copper Heatsink
C193X280T970
Machine Shop
*PCB artwork for this reference design is available at http://freescale.com/RFbroadcast > Design Support > Reference Designs.
FREESCALE RF POWER 50 V TECHNICAL ADVANTAGES
ENHANCED VHV6
The MRFE6VP61K25H is fabricated using Freescale’s
sixth--generation, very high voltage 50 V LDMOS process
technology with enhanced ruggedness (VHV6E). The VHV6
technology was introduced by Freescale several years ago
and was a breakthrough for high power devices used for
broadcast and other applications like industrial, scientific and
medical (ISM) and commercial aerospace, where high power
density is required. The high power capability per device
allows the MRFE6VP61K25H to reach more than 1.25 kW
peak power over the entire VHF band. The VHV6E
technology is a further development of the VHV6 technology
with improved ruggedness.
RUGGEDNESS
Ruggedness, the ability of the transistor to withstand
severe load mismatch conditions under high output power
without device failure or degradation in device performance,
is a very important parameter when designing a broadcast
amplifier. Although the matching circuit plays a role in
determining the ruggedness of the amplifier, the intrinsic
LDMOS ruggedness of the device is the foundation for the
overall amplifier ruggedness.
The ruggedness failure of the MOSFET is the result of a
drain breakdown (impact ionization) event. As described in
Freescale’s 50 V RF LDMOS White Paper, there are three
ruggedness failure mechanisms that can occur as a result of
a drain impact ionization event.(3) The first two mechanisms
involve the basic breakdown of the MOSFET drain junction,
either laterally across the channel or vertically across the
drain to source junction isolation. The third mechanism is
triggered by an impact ionization event and is the self biasing
“snapback” of the parasitic bipolar device.
The MRFE6VP61K25H device has been designed to
address the three failure mechanisms resulting in extremely
rugged devices. The MRFE6VP61K25H is capable of
handling a load mismatch of 65:1 VSWR @ 50 Vdc.
RELIABILITY
In addition to ruggedness, the MRFE6VP61K25H
transistor has been developed to meet quality and reliability
standards demanded by transmitter manufacturers and
operators. There is an MTTF (Median--Time--To--Failure)
calculator(4) available to assist the customers in estimating
the MRFE6VP61K25H device reliability in terms of
electromigration wear--out mechanism. The MTTF is more
than 1000 years when operated at VDS = 50 V, Pout = 1250 W
CW, efficiency = 75%, Tcase = 63°C and TJ = 128°C.
The device is qualified for a maximum operating junction
temperature, TJ, of 225°C.
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
8
RF Reference Design Data
Freescale Semiconductor
Enhanced ESD
Operational reliability is also an important aspect of design
as reflected in stability of the device performance over its
lifetime. All MOSFETs suffer from degradation due to hot
carrier injection (HCI). In the case of NMOS FETs, high
energy electrons are generated due to high electric fields
near the drain corner of the gate. These “hot” carriers can be
injected and trapped in the nearby oxide layers over time and
impact device performance such as threshold voltage. A shift
in threshold voltage will decrease the quiescent current (IDQ)
and alter the RF performance. Several device design
innovations have been incorporated into the 50 volt VHV6
platform to result in IDQ drift for the MRFE6VP61K25H of less
than 5% over 20 years.
2.E--02
IESD (A)
1.E--02
5.E--03
0.E+00
--5.E--03
--1.E--02
--2.E--02
--15 --10 --5
0
5 10
VGS (V)
15
20
25
15
20
25
Standard ESD
2.E--02
1.E--02
IESD (A)
ESD PROTECTION
The MRFE6VP61K25H device incorporates enhanced
protection against electrostatic discharge (ESD), which
makes it less susceptible to damage during handling and
manufacturing. As shown in Figure 14, the enhanced ESD
protection also increases the maximum rating for the
Gate--Source Voltage to --6.0 to +10 Vdc, which in turn allows
a greater negative voltage swing without turning on the ESD
structure. One example where this feature is very beneficial
is Class C operation at high input RF power levels.
5.E--03
0.E+00
--5.E--03
--1.E--02
--2.E--02
--15 --10 --5
0
5 10
VGS (V)
Figure 14. Gate Voltage Breakdown with ESD
THERMAL BEHAVIOR
THERMAL RESISTANCE
Accurate thermal characterization of the RF power
transistor as well as the circuit components is necessary to
analyze the reliability of the system in which the device is
used. To calculate the junction--to--case thermal resistance
(RθJC), the maximum die surface temperature (TJ) during
amplifier operation, the case temperature (TC) and the
dissipated power (Pdiss) must be known.
Total dissipated power is calculated as:
Pdiss = [RF input power + DC power (ID*VD)]
-- (RF output power + RF reflected power)
Junction--to--case thermal resistance is calculated as:
RθJC = (TJ --TC)/Pdiss
The maximum die surface temperature, TJ, of the device is
measured with infrared (IR) microscopy, and a thermocouple
element is used to measure the case temperature, TC.
The thermal resistance of the MRFE6VP61K25H
measured under CW signal:
Tcase = 63°C, Pout = 1250 W CW, RθJC = 0.15°C/W
The thermal resistance, RθJC, depends on both test
condition and method. The thermal measurement
methodology used by Freescale is described in Freescale
Application Note AN1955, Thermal Measurement
Methodology of RF Power Amplifiers.(5)
REFLOW MOUNTING
All RF performance data in this reference design
document is taken with an air cooled copper heatsink and the
device bolted down using a clamp and thermal grease as
interface material. Reflow mounting, i.e. the device soldered
to the heatsink, can be used to lower the overall thermal
resistance which reduces the junction temperature and
improves RF performance and reliability. For Si--based
devices, each 15°C to 20°C reduction in junction
temperature typically results in a doubling of the MTTF.
Reflow mounting also improves the electrical contact. Proper
grounding makes the power amplifier less susceptible to
oscillation type damage.
The MRFE6VP61K25HS is a version of the transistor with
an earless package for optimal reflow mounting.
More information can be found in Freescale Application
Note AN1908, Solder Reflow Attach Method for High Power
RF Devices in Air Cavity Packages.(6)
CONCLUSION
The design and performance of a VHF DVB--T power
amplifier using the MRFE6VP61K25H has been presented.
The MRFE6VP61K25H is a 1250 watt device fabricated
using Freescale’s sixth--generation VHV6E 50 V LDMOS
process technology. Under a DVB--T signal using OFDM
modulation, the MRFE6VP61K25H achieves 225 watts avg.
power at --30 dBc shoulder performance (±4.2 MHz offset)
with 30% efficiency and 25 dB gain across the VHF band of
170 to 230 MHz. In addition to very good RF performance,
the transistor is also designed for excellent ruggedness and
reliability. A thermal compensation circuit is included in the
amplifier design to keep the quiescent current constant over
temperature.
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
RF Reference Design Data
Freescale Semiconductor
9
REFERENCES
1. “RF LDMOS Power Modules for GSM Base Station
Application: Optimum Biasing Circuit.” (Document
Number: AN1643) Application Note, 1998.
2. O. Lembeye and J. C. Nanan, “Effect of Temperature on
High Power RF LDMOS Transistors,” Applied Microwave
& Wireless (2002).
3. 50 V RF LDMOS White Paper: “An Ideal RF Power
Technology for ISM, Broadcast and Radar Applications”.
Ref.
50VRFLDMOSWP.
Av ailable
at
http://freescale.com/RFpower.
4. MRFE6VP61K25H MTTF c alc ulator av ailable at
http://freescale.com/RFpower > Software & Tools >
Dev elopment Tools > Simulations and Models >
Calculators. Enter the “part number” into the Search field
for quickest results.
5. “Thermal Measurement Methodology of RF Power
Amplifiers.” (Document Number: AN1955) Application
Note, 2004.
6. “Solder Reflow Attach Method for High Power RF
Devices in Air Cavity Packages.” (Document Number:
AN1908) Application Note, 2011.
Technical documentation, including data sheets and application notes, for Freescale RF Power product can be found at:
http://freescale.com/RFpower. Enter the applicable Document Number into “Keyword” search for quickest results.
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
10
RF Reference Design Data
Freescale Semiconductor
APPENDIX A
1.929 (48.98)
8x
#4--40
0.300″ deep
2.737 (69.51)
0.41 (10.41)
1.813 (46.04)
2.719 (69.07)
E
F
A
D
A
B
D
A
2.882 (73.19)
A
D
E
0.813 (20.64)
0.140 (3.56)
1.309 (33.26)
B
0.611 (15.52)
F
D
1.668 (42.38)
1.489 (37.83)
∅0.188 (∅4.76)
1.129 (28.69)
0.950 (24.14)
B
A
D
0.130 (3.32)
0.125 (3.17)
4.725 (120.02)
4.499 (114.28)
2.929 (74.38)
2.283 (57.98)
1.724 (43.78)
2.134 (54.19)
AA
1.929 (48.99)
1.558 (39.58)
0.929 (23.59)
0.000 (0.00)
0.00 (0.00)
0.177 (4.50)
0.000 (0.00)
A
2.011 (51.08)
0.000 (0.00)
0.128 (3.25)
0.324 (8.23)
D
4.548 (115.52)
Copper Heatsink for VHF Broadcast Fixture
inches (mm)
C, Device Channel
0.038 (0.97)
0 (0.00)
0.300 (7.62)
0.720 (18.29)
E
Gutter is 0.030 wide
and 0.046 deep, both
sides
2.929 (74.39)
0.929 (23.59)
E
0.720″ Copper Heatsink Hole Details
Designators
Details
A
2 places, both sides, drill and tap, #2--56 screw depth 0.300″
B
2 places, both sides, 0.1875″ diameter notch 0.020″ deep
C
NI--1230 channel 0.410″ wide by 0.0380″ deep
D
2 places, both sides, drill depth 0.250″ and tap for #4--40 screw
E
Locator holes from bottom diameter = 0.257″, depth = 0.400″
F
2 places, drill through and tap for #4--40 screw
Figure 15. NI--1230 Heatsink
MRFE6VP61K25H MRFE6VP61K25HS VHF Broadcast
RF Reference Design Data
Freescale Semiconductor
11
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> Design Support > Reference Designs
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Rev. 0, 6/2011
RF Reference Design Data
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