SLUA271C June   2002  – December 2023 ADS1013 , ADS1014 , ADS1015 , ADS1018 , ADS1112 , ADS1113 , ADS1114 , ADS1115 , ADS1118 , ADS1120 , ADS1148 , ADS114S06 , ADS114S06B , ADS114S08 , ADS114S08B , ADS1158 , ADS1191 , ADS1192 , ADS1203 , ADS1204 , ADS1205 , ADS1220 , ADS1225 , ADS1226 , ADS124S06 , ADS124S08 , ADS1257 , ADS1258 , ADS1261 , ADS1283 , ADS1287 , ADS1287D , ADS1291 , ADS1292 , ADS1292R , ADS1293 , ADS6222 , ADS6224 , ADS6242 , ADS6243 , ADS6244 , ADS6245 , ADS6422 , ADS6423 , ADS6424 , ADS6425 , ADS6442 , ADS6443 , ADS6444 , BQ24010 , BQ24012 , BQ24013 , BQ24020 , BQ24022 , BQ24023 , CC2560 , CC2564C , CSD13202Q2 , CSD15571Q2 , CSD16301Q2 , CSD16321Q5 , CSD16322Q5 , CSD16323Q3 , CSD16325Q5 , CSD16327Q3 , CSD16340Q3 , CSD16342Q5A , CSD16401Q5 , CSD16403Q5A , CSD16404Q5A , CSD16406Q3 , CSD16407Q5 , CSD16408Q5 , CSD16409Q3 , CSD16410Q5A , CSD16411Q3 , CSD16412Q5A , CSD16413Q5A , CSD16414Q5 , CSD16415Q5 , CSD16556Q5B , CSD16570Q5B , CSD17301Q5A , CSD17302Q5A , CSD17303Q5 , CSD17304Q3 , CSD17305Q5A , CSD17306Q5A , CSD17307Q5A , CSD17308Q3 , CSD17309Q3 , CSD17310Q5A , CSD17311Q5 , CSD17312Q5 , CSD17313Q2 , CSD17318Q2 , CSD17322Q5A , CSD17327Q5A , CSD17501Q5A , CSD17505Q5A , CSD17506Q5A , CSD17507Q5A , CSD17510Q5A , CSD17522Q5A , CSD17527Q5A , CSD17551Q3A , CSD17551Q5A , CSD17552Q3A , CSD17552Q5A , CSD17553Q5A , CSD17555Q5A , CSD17556Q5B , CSD17559Q5 , CSD17570Q5B , CSD17571Q2 , CSD17573Q5B , CSD17575Q3 , CSD17576Q5B , CSD17577Q3A , CSD17577Q5A , CSD17578Q3A , CSD17578Q5A , CSD17579Q3A , CSD17579Q5A , CSD17581Q3A , CSD17581Q5A , CSD18501Q5A , CSD18502Q5B , CSD18503Q5A , CSD18504Q5A , CSD18509Q5B , CSD18510Q5B , CSD18511Q5A , CSD18512Q5B , CSD18513Q5A , CSD18514Q5A , CSD18531Q5A , CSD18532NQ5B , CSD18532Q5B , CSD18533Q5A , CSD18534Q5A , CSD18537NQ5A , CSD18540Q5B , CSD18543Q3A , CSD18563Q5A , CSD19502Q5B , CSD19531Q5A , CSD19532Q5B , CSD19533Q5A , CSD19534Q5A , CSD19537Q3 , CSD19538Q2 , CSD19538Q3A , CSD25310Q2 , CSD25402Q3A , CSD25404Q3 , CSD85301Q2 , CSD85312Q3E , CSD86330Q3D , CSD86336Q3D , CSD86350Q5D , CSD86356Q5D , CSD86360Q5D , CSD87312Q3E , CSD87313DMS , CSD87330Q3D , CSD87331Q3D , CSD87333Q3D , CSD87334Q3D , CSD87335Q3D , CSD87350Q5D , CSD87351Q5D , CSD87351ZQ5D , CSD87352Q5D , CSD87353Q5D , CSD87355Q5D , CSD87502Q2 , CSD87503Q3E , CSD88584Q5DC , CSD88599Q5DC , DAC3482 , DAC3484 , LMR10510 , LMR10515 , LMR10520 , LMR10530 , MSC1202Y2 , MSC1202Y3 , MSP430F1122 , MSP430F1132 , MSP430F122 , MSP430F1222 , MSP430F123 , MSP430F1232 , MSP430F2001 , MSP430F2002 , MSP430F2003 , MSP430F2011 , MSP430F2012 , MSP430F2013 , MSP430F2013-EP , MSP430F2112 , MSP430F2122 , MSP430F2132 , MSP430FR5969 , MSP430G2001 , MSP430G2101 , MSP430G2102 , MSP430G2111 , MSP430G2112 , MSP430G2121 , MSP430G2131 , MSP430G2132 , MSP430G2152 , MSP430G2201 , MSP430G2201-Q1 , MSP430G2211 , MSP430G2212 , MSP430G2221 , MSP430G2231 , MSP430G2231-Q1 , MSP430G2232 , MSP430G2252 , MSP430G2302 , MSP430G2312 , MSP430G2332 , MSP430G2352 , MSP430G2402 , MSP430G2432 , MSP430G2452 , TLA2021 , TLA2022 , TLA2024 , TLV62065 , TLV62080 , TLV62085 , TLV62090 , TLV62130 , TLV62130A , TLV62150 , TLV62150A , TPS60150 , TPS60151 , TPS61020 , TPS61021A , TPS61024 , TPS61025 , TPS61026 , TPS61027 , TPS61028 , TPS61029 , TPS61029-Q1 , TPS61030 , TPS61031 , TPS61032 , TPS61042 , TPS61045 , TPS61086 , TPS61087 , TPS61087-Q1 , TPS61088 , TPS61089 , TPS61090 , TPS61091 , TPS61092 , TPS61093 , TPS61093-Q1 , TPS61100 , TPS61107 , TPS61120 , TPS61130 , TPS61170 , TPS61170-Q1 , TPS61200 , TPS61201 , TPS61202 , TPS61240 , TPS61240-Q1 , TPS61251 , TPS61252 , TPS61260 , TPS61261 , TPS61291 , TPS62020 , TPS62021 , TPS62026 , TPS62040 , TPS62042 , TPS62043 , TPS62044 , TPS62046 , TPS62060 , TPS62061 , TPS62063 , TPS62065 , TPS62067 , TPS62080 , TPS62080A , TPS62081 , TPS62082 , TPS62085 , TPS62086 , TPS62087 , TPS62090 , TPS62090-Q1 , TPS62091 , TPS62092 , TPS62093 , TPS62095 , TPS62097 , TPS62097-Q1 , TPS62110 , TPS62110-EP , TPS62110-Q1 , TPS62111 , TPS62111-EP , TPS62112 , TPS62112-EP , TPS62113 , TPS62122 , TPS62125 , TPS62130 , TPS62130A , TPS62131 , TPS62132 , TPS62133 , TPS62134A , TPS62134B , TPS62134C , TPS62134D , TPS62135 , TPS62136 , TPS62140 , TPS62141 , TPS62142 , TPS62143 , TPS62150 , TPS62150A , TPS62151 , TPS62152 , TPS62153 , TPS62160 , TPS62161 , TPS62162 , TPS62163 , TPS62170 , TPS62171 , TPS62172 , TPS62173 , TPS62175 , TPS62177 , TPS62230 , TPS62231-Q1 , TPS622314-Q1 , TPS62240 , TPS62242 , TPS62243 , TPS62250 , TPS62260 , TPS62260-Q1 , TPS62261 , TPS62261-Q1 , TPS62262 , TPS62262-Q1 , TPS62263 , TPS62263-Q1 , TPS62270 , TPS62272 , TPS62273 , TPS62290 , TPS62290-Q1 , TPS62291 , TPS62293 , TPS62293-Q1 , TPS62300 , TPS62301 , TPS62302 , TPS62303 , TPS62304 , TPS62305 , TPS62320 , TPS62321 , TPS62352 , TPS62355 , TPS62400 , TPS62400-Q1 , TPS62401 , TPS62402 , TPS62403 , TPS62404 , TPS62404-Q1 , TPS62406-Q1 , TPS62407-Q1 , TPS62410 , TPS62410-Q1 , TPS62420 , TPS62420-Q1 , TPS62421 , TPS62422-Q1 , TPS62423-Q1 , TPS62424-Q1 , TPS62510 , TPS62560 , TPS62562 , TPS62590 , TPS62590-Q1 , TPS62730 , TPS62732 , TPS62733 , TPS62740 , TPS62750 , TPS62751 , TPS62821 , TPS62822 , TPS62823 , TPS62825 , TPS62826 , TPS62840 , TPS62870 , TPS62870-Q1 , TPS62871 , TPS62871-Q1 , TPS62872 , TPS62872-Q1 , TPS62873 , TPS62873-Q1 , TPS62874-Q1 , TPS62875-Q1 , TPS62876-Q1 , TPS62877-Q1 , TPS63000 , TPS63000-Q1 , TPS63001 , TPS63002 , TPS63020 , TPS63021 , TPS63030 , TPS63031 , TPS63050 , TPS63051 , TPS63060 , TPS63061 , TPS63070 , TPS63700 , TPS63710 , TPS84620 , TPSM82810 , TPSM82813 , TPSM82816 , TPSM82821 , TPSM82822 , TPSM82864A , TPSM82866A , TPSM82866C , TPSM8287A06 , TPSM8287A10 , TPSM8287A12 , TPSM8287A15 , TUSB7320 , TUSB7340 , TUSB8040A , TUSB8040A1

 

  1.   1
  2.   QFN and SON PCB Attachment
  3.   Trademarks
  4. 1Texas Instruments Quad Flatpack No Leads and Small-Outline No Leads
    1. 1.1 Introduction
  5. 2Manufacturing Considerations
    1. 2.1 SMT Process
  6. 3Printed Circuit Board (PCB) Design Guidelines
    1. 3.1 Land Pad Styles
    2. 3.2 Land Pad Design
    3. 3.3 Lead Finger Pad PCB Design
    4. 3.4 Exposed Pad PCB Design
      1. 3.4.1 Thermal Pad Via Design
    5. 3.5 Solder Mask
    6. 3.6 Surface Finishes
    7. 3.7 Board Layout Considerations
  7. 4Solder Paste Screen Printing Process
    1. 4.1 Solder Paste
    2. 4.2 Solder Stencils
    3. 4.3 Lead Finger Stencil Design
    4. 4.4 Exposed-Pad Stencil Design
  8. 5Package to Board Assembly Process
    1. 5.1 Placement and Alignment
    2. 5.2 Solder Reflow
    3. 5.3 PCB Cleaning
    4. 5.4 Inspection
  9. 6Rework Guidelines (Hot Gas Convection and Manual)
    1. 6.1 Compound Removal
    2. 6.2 Site Redress
    3. 6.3 Component Replacement and Reflow
    4. 6.4 Manual Rework Considerations
  10. 7Revision History

5.2 Solder Reflow

There are no special requirements necessary when reflowing QFN and SON components. As with all SMT components, it is important that profiles be checked on all new board designs. In addition, if there are multiple packages on the board, the profile must be checked at different locations on the board. Component temperatures can vary because of surrounding components, location of the device on the board, and package densities.

To maximize the self-alignment effect of QFN and SON, it is recommended that the maximum reflow temperature specified for the solder paste not be exceeded. A good guide is to subject the PCB to a temperature ramp not exceeding 4°C per second.

The reflow profile guidelines (see Figure 5-2) are based on the temperature at the actual solder-pad to PCB land-pad solder joint location. The actual temperature at the solder joint is often different than the temperature settings in the reflow/rework system, due to the location of the system thermocouple used to monitor the temperature.

Specific production reflow and rework systems vary depending on manufacturer and model. Therefore, system specific profiles must be established using thermocouples at the actual solder joint locations.

TI has tested and qualified QFNs and SONs for three reflow operations according to JEDEC J-STD-020. This allows one reflow operation per side of the PCB (assuming the use of a double-sided PCB) and one rework operation if necessary.

TI recommends use of the temperature profile from the solder-paste manufacturer to optimize flux activity within the MSL guidelines for the most thermally sensitive component. See J-STD-033 for more details on MSL classification.

GUID-E256C8DD-FB9D-4AA1-8660-E562A9C349FE-low.gifFigure 5-1 Package Self Alignment at Reflow
GUID-5A0F2C1B-073A-47C5-8F6A-476C1740E988-low.gif Figure 5-2 QFN and SON Pb and Pb-Free Example Reflow Profiles