Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

AN1955 Datasheet(PDF) 1 Page - Freescale Semiconductor, Inc

Part # AN1955
Description  Thermal Measurement Methodology of RF Power Amplifiers
Download  5 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  FREESCALE [Freescale Semiconductor, Inc]
Direct Link  http://www.freescale.com
Logo FREESCALE - Freescale Semiconductor, Inc

AN1955 Datasheet(HTML) 1 Page - Freescale Semiconductor, Inc

  AN1955 Datasheet HTML 1Page - Freescale Semiconductor, Inc AN1955 Datasheet HTML 2Page - Freescale Semiconductor, Inc AN1955 Datasheet HTML 3Page - Freescale Semiconductor, Inc AN1955 Datasheet HTML 4Page - Freescale Semiconductor, Inc AN1955 Datasheet HTML 5Page - Freescale Semiconductor, Inc  
Zoom Inzoom in Zoom Outzoom out
 1 / 5 page
background image
AN1955
1
RF Application Information
Freescale Semiconductor
Thermal Measurement Methodology
of RF Power Amplifiers
By: Mali Mahalingam and Edward Mares
INTRODUCTION
This document explains the methodology used by
Freescale for thermal measurement of high power RF (Radio
Frequency) power amplifiers (RFPA). Semiconductor device
reliability heavily depends on device operating temperature so
the accurate thermal characterization of these high power
devices is crucial in establishing the reliability of the systems
that use such devices.
DIE SURFACE TEMPERATURE (TJ )
MEASUREMENT
Infrared (IR) microscopy is used to determine the die
surface temperature (TJ) during amplifier operation. Because
this IR measurement method requires a direct view of the die,
the protective ceramic lid is removed and replaced with a
modified lid that has an opening to view the die. In the case of
overmolded plastic packages, the center portion of the mold
compound is etched away until the die is sufficiently exposed.
Because the heat flow from the device to the heatsink is
dominated by conduction, the measurement error caused by
the removal of the lid or removal of the mold compound around
the die surface is negligible. The exposed die is coated with
a high emissivity coating (see Appendix) to obtain a fixed
emissivity value for IR thermal measurement. This coating
greatly improves the accuracy of the IR measurement
because it eliminates the need for any emissivity correction
procedure used by the IR microscope. The emissivity
correction procedure recommended by IR microscope
manufacturers is ineffective at compensating for the
translucent nature of silicon [1]. With the IR microscopy
procedure, the maximum die surface temperature (“hot spot”)
in the measurement field can be located. The hot spot
temperature is selected as the die temperature (TJ) for thermal
resistance (θJC). The thermal resistance calculations are
described later.
CASE TEMPERATURE (TC) MEASUREMENT
The case temperature (TC) of the package is measured by
a 0.020″ diameter stainless steel sheath thermocouple (Type
J; Omega part # JMQSS-020G-12) that is mounted within the
heatsink of the RF circuit. It is mounted from the bottom and
protrudes through the mounting interface to contact with the
bottom surface of the package (Figure 1). A 0.032″ diameter
hole is drilled through the circuit heatsink to permit
thermocouple passage. This small hole provides minimal
disturbance to the heat flow path and interface integrity. The
thermocouple model is selected based on its sensitivity
combined with excellent durability. A spring mechanism is
added to the thermocouple to guarantee constant mechanical
contact with the bottom side of the flange. The placement for
this thermocouple is centered relative to the centermost active
transistor in the package (Figure 2).
Die
Package
Temperature of Case (TC) Measured with Spring−
Loaded Thermocouple Making Direct Contact
Heatsink
Die Temperature (TJ) Measured
with IR Microscope
4 Active Die
Thermocouple Centered Relative to
Centermost Active Die in Package
Figure 1. Case Temperature Measurement
Figure 2. Positioning of Thermocouple
AN1955
Rev. 0, 1/2004
Freescale Semiconductor
Application Note
© Freescale Semiconductor, Inc., 2004, 2006. All rights reserved.


Similar Part No. - AN1955

ManufacturerPart #DatasheetDescription
logo
Freescale Semiconductor...
AN1950 FREESCALE-AN1950 Datasheet
307Kb / 24P
   Water Level Monitoring
logo
STMicroelectronics
AN1953 STMICROELECTRONICS-AN1953 Datasheet
222Kb / 20P
   PFC for ST7MC starter kit
AN1957 STMICROELECTRONICS-AN1957 Datasheet
252Kb / 22P
   Microprocessor Supervisor Functions
More results

Similar Description - AN1955

ManufacturerPart #DatasheetDescription
logo
Lumileds Lighting Compa...
AB33 LUMILEDS-AB33 Datasheet
1Mb / 8P
   Thermal Measurement Guidelines
logo
Polyfet RF Devices
MADK21 POLYFET-MADK21 Datasheet
75Kb / 2P
   Power RF Amplifiers
MADQ02 POLYFET-MADQ02 Datasheet
85Kb / 2P
   Power RF Amplifiers
MBDQ01 POLYFET-MBDQ01 Datasheet
58Kb / 2P
   Power RF Amplifiers
PHM017-3 POLYFET-PHM017-3 Datasheet
42Kb / 2P
   Power RF Amplifiers
MDDQ02 POLYFET-MDDQ02 Datasheet
85Kb / 2P
   Power RF Amplifiers
PHM022 POLYFET-PHM022 Datasheet
41Kb / 2P
   Power RF Amplifiers
PHM017 POLYFET-PHM017 Datasheet
44Kb / 2P
   Power RF Amplifiers
PHM020 POLYFET-PHM020 Datasheet
46Kb / 2P
   Power RF Amplifiers
MADL01 POLYFET-MADL01 Datasheet
42Kb / 2P
   Power RF Amplifiers
More results


Html Pages

1 2 3 4 5


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com