External Use

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Modernizing RF and Microwave

Power Applications

Solid State Heating Solutions

FTF-IND-F0408

A P R . 2 0 1 4

Dan Viza | RF Product Manager

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External Use 1

Session Introduction

• Evolution of RF Power Solutions:

− Solid state RF power is evolving to a level of performance suitable for

effective use as an alternative to traditional magnetrons in a range of

heating applications from cooking food to plastic welding

• Enabling New and Differentiated Heating & Cooking Solutions:

− Appliance and commercial kitchen OEM’s can begin creating

differentiated solutions and new end product types enabled by RF power

which enable closed loop operation

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Agenda

• Freescale RF Power Introduction

• Traditional RF Power Devices

• Key Differences Between Magnetron and Solid State

• Implications For Microwave Cooking Application

• Summary

• Contacts For More Information

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RF Power: In Your Daily Life

Amplify RF Signals and Deliver:

• High Power

• High Linearity

• High Efficiency

Portfolio Range:

• From 2.8 MHz to 4.0 GHz

• From 0.1W to 1.25kW

Healthcare Cooking Cellular

Air Traffic Control FM Radio

Professional

Mobile Radio

Wafer Plasma Etch

Freescale RF Power

Products

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Freescale Leads Industry In RF Power Innovation

BILLIONS Watts/Year Delivered

Modernization of RF Power

Innovative Application of RF Power

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Traditional RF Power Devices

• Vacuum Electron Devices (VED’s)

can be divided into several types:

− Magnetrons

− Power Grid Device (Triode, Tetrode)

− Traveling Wave tubes (TWTs)

− Klystrons

− Crossed-field Amplifiers (CFAs)

− Gyrotrons

• Covering frequencies from DC to

95GHz and from 10s of watts to

megawatts.

• Size: 4x3 36x36x120

• Weight: 2# 5600#

• Scary voltages: 1KW ~ 3KV min

• 5s 5m warmup

Klystrons

Magnetrons

Traveling Wave Tubes

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Modernizing RF Power Heating: Magnetron To Solid State

Magnetron

• 4,000V supply voltage

• 500 – 1000 hours lifetime,

degrades over time

• Bulky, heavy

• Simple On-off control

RF Transistor

• 28-50V supply voltage

• Up to 20 years lifetime, no

degradation

• Small, low mass

• High resolution control

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Microwave Oven Background & Fundamentals

• Microwave oven commercially

introduced 1947 (Raytheon)

• Dielectric heating due to dipole

rotation

• 2.4GHz typical (ISM)

− 915MHz also used

• Magnetron microwave energy

source

− Self oscillating device

− Filament warm up time required

− Relatively broadband

Turntable

Waveguide Stirrer

Magnetron

High Voltage

Transformer (Hidden)

• Stirrer, turntable used to

“distribute” energy

• System efficiency > 56%;

degrades over time

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Solid State Cooking: How Is It Different? More Than A Magnetron Replacement

Turntable

Waveguide Stirrer

Magnetron

Solid State Oven Magnetron Oven

• Selective cooking

• Versatile: complex food

combinations

• Improved consistency

• Reduced time

• “Floods” and heats cavity

• Crude On/Off control

• Electro-mech BOM

• Degrades over time

Solid State

RF Power

Closed loop, controlled RF power

• Direct energy to load

• Reflected energy received

• Absorbed energy analyzed

• Multiple sources

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Power Control

• Fine control at low levels

− Power can be set to any level from

less than 1% to 100%

− Enables effective heating of low mass

objects

• Magnetron uses PWM with ~10

second minimum on time

− Magnetron filament requires initial

heat up time

− Best in Class magnetron can vary to

60% then goes to PWM

• Precise cooking, warming,

defrosting, thawing through control

of power

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 50% 100%

Required Power

De

live

red

Po

we

r

Magnetron

Solid State

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Phase Control Location Optimization

• Detecting “load” location and shifting phase in multi-feed system

− Optimize energy to load location

• Output is coherent, allowing phase and amplitude control of multiple sources

− Enable selective combining of the energy

• Analogous to laser vs flood light

• Reduces random ‘hot spots’

− Lab tests show as many as 5 hot spot locations Position

Antenna Antenna

Phase

Control

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Frequency Control – Managing IoT Interference

Conventional microwave oven emission

covers virtually complete Wifi spectrum (all

channels simultaneously) Detection and frequency shifting enable

elimination of smart home device

interference

Conventional MWO Emission Solid State MWO Emission

Vs. WiFi Router

Frequency

Po

we

r

WiFi Signal

SS MWO Signal MWO Signal

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Electro-Mechanical Simplification

• Reduced electro-mechanical

component BOM

− Stirrer

− Waveguide

− Turntable

• Reduced Weight

− Magnetron ~1.6 lbs

− High voltage power supply

• Enabling design flexibility

− Antenna location flexibility

− Flush mounted antenna

1 in3 vs. 31.5 in3

Turntable

Waveguide Stirrer

Magnetron

2”

1” 1/2”

Deep

3”

3”

3 1/2”

Deep

Antenna

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Solid State Cooking & Heating Advantages

Feature Benefit

High Resolution Control

• Precise cooking/heating

• Highly efficient

• Higher quality nutrition

• Faster meal preparation

• Versatile food preparation

• Low noise

• IoT interference management

Durability • Consistent heating parameters over lifetime

• Reduced maintenance

Reduced Size & Weight • Form factor design flexibility

• Lower logistics costs

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Freescale Microwave Solutions

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Microwave Heating Device Roadmap

Available Now 2013 2014

75W

250W

500W

MHT2000N

MHT1001H

MHT1000H 140W @ 2.45 GHz, 45% eff.

25W @ 2.45 GHz IC

190W @ 2.45GHz, 45% eff.

Production

Proposal

Planning

Execution

28-32 V LDMOS

300W @ 2.45GHz, 65% eff.

MHT2001N

50 V LDMOS

Plastic

2015

175W @ 900MHz IC, 70% 2nd stage eff.

250W @ 2.45GHz, 55% eff.

48V GaN

350-300W @ 900-1300MHz, 55% eff.

MHT2002N

50W @ 2.45 GHz IC

MHT1007H

RF & Microwave Heating Products

1: Discrete

2: IC

3. System

H: ceramic

N: plastic

MHT1002N

Right edge

= launch

MHT1003N

MHT1004N

15W driver @ 2.4 GHz

MHT1006N

MHT2003N

50W@ 2.4 GHz; >60% Eff

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RFPT-MHT3003 Eval Board250W Power Amplifier Configuration

RFPT-MHT3003

High Gain PA

SMA

N-F

I O

F R

MHT2000N MHT1003N

Log Amp

Current Shunt

Amp

Log Amp

Current Shunt

Amp

2 Wire Temp

sensor

50mV at Imax Shunt

Temp1

Temp 2

RF Det 2

RF Det 3

I1

I2

V1

Temp sensor

Vg1

Vg2 Vg3

Log Amp

RF Det1

Input r dividert

Coupler

Log Amp

LT5534 or

AD8314 RF Det 4

28-32V

Supply

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Freescale Microwave Oven Reference Designs

All reference designs include:

• Integrated MCU

• Kinetis MCU + Signal Generator + Receive

Path

• High performance microwave power amplification

• Closed loop features

• Real time delivered power measurement

• Mismatch detection

• Temperature and voltage sensing

250W @ 2.45GHz

Single antenna or feed interface

500W @ 2.45GHz with Power

Boost

Single antenna or feed interface

500W @ 2.45GHz

Dual antenna or feed interface

Components Eval Boards

Ref Designs

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Summary

Modernizing Microwave Ovens Solid state RF power technology proving capable of delivering differentiated perfomance

High Resolution Control Enabling new functions and applications

Improved Size, Weight, and Mechanical Complexity Opening the door for design freedom and durability

Freescale Leading The Evolution With components, eval boards, tools, reference designs

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For Further Information

• www.freescale.com/RFheating

• RFheating@freescale.com

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