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

3.4 Exposed Pad PCB Design

The construction of the exposed pad enables enhanced thermal and electrical characteristics. To take full advantage of this feature, the pad must be physically connected to the PCB substrate with solder. The published data for thermal performance, θJA, is based on a four-layer PCB incorporating vias that act as the thermal path to the layers, also known as a JEDEC High K board design per JESD51-7.

The dimensions of the thermal pad on the PCB should be equal to the exposed pad on the QFN and SON. Adequate clearance (CPL) is necessary to prevent solder bridging. Experiments have concluded that a minimum clearance of 0,2 mm is satisfactory for most designs.