SOLDER PAD FOR SURFACE MOUNT

1、solder pad for surface mount 关于dpak元件焊盘开窗方式 application report sbfa015a - january 1998 - revised may 2021 solder pad recommendations for surface-mount devices by wm. p. klein, p.e. cost and performance requirements continue to push thepackaging of electronic systems into smaller and smallerspaces. a

2、t one time, the standard center-to-center pin spac-ing was 100 mils (0.1) on through-hole parts (dips).the advent of surface-mount devices (smd) has brought pinspacings that differ from one package series to the next.the solder joint of pin-foot to printed circuit board (pcb) mustprovide the strengt

3、h to hold the device in place. the closelead spacings make lead-to-lead solder bridges more preva-lent. these factors increase the importance of an optimizedpcb design. the criteria for a well-designed solder joint is based on bothempirical data and reliability testing. solder-joint strength isdirec

4、tly related to the total solder volume. an observablesolder fillet is evidence of proper wetting. therefore, apositive solder fillet is usually specified. a joint can bedescribed by the solder fillets formed between the devicepins and the pcb pads. figure 1 shows the three fillets: toe,heel, and sid

5、e. a properly designed solder pad minimizes solder bridgingwhile affording a strong and easily inspected joint.these goals have conflicting dimensional requirements. factors to consider when determining the dimensions of thesolder pads include part dimension tolerances, pcb produc-tion tolerances, a

6、nd accuracy-of-placement tolerances.figure 2 shows how placement accuracy can affect solderbridge formation. the designer should also consider thelimitations of the soldering process. boards designed forwave soldering usually have slightly wider pads than thosedesigned for reflow techniques. two tra

7、de organizations provide industry standards. the elec-tronic industries association (eia)1 represents manufacturers inall areas of the electronics industry. the eias joint electrondevice engineering council (jedec)2 establishes standardpackage dimensions. the institute for interconnecting andpackagi

8、ng electronic circuits (ipc)3 has established standardsfor pcb design. the surface mount land pattern subcommit-tee of the printed board design committee of ipc has devel-oped standard pad dimensions for the packages defined by thejedec committee. the ipc document surface-mount designand land patter

9、n standard is designated ipc-sm-782.to further assist the designer, the mathematical relationshipsin the standard have been programmed in a spreadsheetcalculator. access to this program is available at the ipc figure 1. solder joint fillets. ab-132ccopyright 1998-2021, texas instruments incorporated

10、 关于dpak元件焊盘开窗方式 figure 2. device placements. internet web site3. surface-mount land patterns are given formany jedec standard packages. capability to customizethe patterns for special designs is also provided. the resultsof this program are tabulated in the appendices of this paperfor some of the mo

11、re popular packages currently supplied bytexas instruments. the values listed in the following tables are based on theassumptions shown in table i. performance will also dependon process variables. while an effort has been made toselect nominal values for these variables, the design engi-neer should

12、 determine the optimum value through experi-mentation. fabrication toleranceplacement tolerancetoe joint minimumheel joint minimumside joint minimum 0.1mm0.1mm0.4mm0.5mm0.0mm notes: (1)electronic industries association (eia) 2500 wilson boulevardarlington, va 22201/ (2)joint electron device engineer

13、ing council (jedec) (3) the institute for interconnecting and packaging electronic circuits (ipc)2215 sanders road northbrook, il 60062-6135 phone: 847-509-9700 fax: 847-509-9798 /index.html table i. assumed basic dimensions. 2 sbfa015a 关于dpak元件焊盘开窗方式 figure 3. package dimensions. pkg#18223526521121

14、9221239217331332348337334338324322333346 lmin0.2280.2280.2280.3940.3940.3940.3940.3980.1020.1020.1020.1890.2910.2910.2910.2280.3950.395 lmax0.2440.2440.2440.4190.4190.4190.4190.4190.1180.1180.1180.1970.3230.3230.3230.2440.4200.420 wmin0.0130.0130.0130.0130.0130.0130.0130.0130.0100.0100.0110.0110.009

15、0.0090.0090.0080.0080.008 wmax0.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.0180.0150.0150.0150.0150.0120.0130.013 tmin0.0160.0160.0160.0160.0160.0160.0160.0200.0140.0140.0040.0180.0220.0220.0220.0160.0200.020 tmax0.0500.0500.0500.0500.0500.0500.0500.0400.0220.0220.0240.0260.0370.0370.0370.050

16、0.0400.040 amin0.1500.1500.1500.2910.2910.2910.2910.2910.0590.0590.0590.1140.1970.1970.1970.1490.2910.291 amax0.1570.1570.1570.2990.2990.2990.2990.2990.0690.0690.0690.1220.2200.2200.2200.1570.2990.299 bmin0.1890.3370.3860.3980.4470.4960.5980.6970.1100.1100.1100.1140.2720.3110.3900.1880.6130.720 bmax

17、0.1960.3440.3940.4130.4630.5120.6140.7130.1180.1180.1180.1220.2950.3350.4130.1970.6300.730 hmin0.0530.0530.0530.0930.0930.0930.0930.0930.0350.0350.0350.0320.0770.0770.0770.0530.0530.095 hmax0.0690.0690.0690.1040.1040.1040.1040.1040.0570.0570.0570.0480.0790.0790.0790.0690.0690.110 pnom0.05000.05000.0

18、5000.05000.05000.05000.05000.05000.03740.03740.02560.02560.02560.02560.02560.02500.02500.0250 leadcount8141616182024285688202428164856 packageso-8so-14 so-16so-16wso-18so-20so-24so-28sot-23-5sot-23-6sot-23-8msop-8ssop-20ssop-24ssop-28ssop-16ssop-48ssop-56 table ii . package dimensionsinches. pkg#182

19、235265211219221239217331332348337334338324322333346 lmin5.795.795.7910.0110.0110.0110.0110.112.592.592.604.807.397.397.395.7910.0310.03 lmax6.206.206.2021.6410.6410.6410.6410.643.003.003.005.008.208.208.206.2021.6710.67 wmin0.330.330.330.330.330.330.330.330.250.250.280.280.230.230.230.200.200.20 wma

20、x0.510.510.510.510.510.510.510.510.510.510.460.380.380.380.380.300.330.33 tmin0.410.410.410.410.410.410.410.510.360.360.100.460.560.560.560.410.510.51 tmax1.271.271.271.271.271.271.271.020.560.560.610.660.940.940.941.271.021.02 amin3.813.813.817.397.397.397.397.391.501.501.502.905.005.005.003.787.39

21、7.39 amax3.993.993.997.597.597.597.597.591.751.751.753.105.595.595.593.997.597.59 bmin4.808.569.8010.1111.3512.6015.1917.702.792.792.802.906.917.909.914.7815.5718.29 bmax4.988.7410.0110.4911.7613.0015.6018.113.003.003.003.107.498.5110.495.0016.0018.54 hmin1.351.351.352.362.362.362.362.360.890.890.90

22、0.811.961.961.961.351.352.41 hmax1.751.751.752.642.642.642.642.641.451.451.451.222.012.012.011.751.752.79 pnom1.2701.2701.2701.2701.2701.2701.2701.2700.9500.9500.6500.6500.6500.6500.6500.6350.6350.635 leadcount8141616182024285688202428164856 packageso-8so-14so-16so-16wso-18so-20so-24so-28sot-23-5sot

23、-23-6sot-23-8msop-8ssop-20ssop-24ssop-28ssop-16ssop-48ssop-56 table iii. package dimensionsmillimeters. sbfa015a 3 关于dpak元件焊盘开窗方式 figure 4. pad dimensions. pkg#182235265211219221239217331332348337334338324322333346 zmin0.2730.2730.2730.4470.4470.4470.4470.4480.1470.1470.1470.2260.3510.3510.3510.2730

24、.4480.448 zmax0.2770.2770.2770.4510.4510.4510.4510.4510.1510.1510.1510.2300.3550.3550.3550.2770.4520.452 gmin0.0890.0890.0890.2540.2540.2540.2540.2780.0340.0340.0150.0970.1770.1770.1770.0890.2750.275 gmax0.0930.0930.0930.2580.2580.2580.2580.2820.0380.0380.0190.1010.1810.1810.1810.0930.2790.279 xmin0

25、.0180.0180.0180.0180.0180.0180.0180.0180.0170.0170.0160.0140.0130.0130.0130.0110.0120.012 xmax0.0220.0220.0220.0220.0220.0220.0220.0220.0210.0210.0200.0180.0170.0170.0170.0150.0160.016 yref0.0940.0940.0940.0990.0990.0990.0990.0990.0580.0580.0680.0660.0890.0890.0890.0940.0890.089 c/cref0.1830.1830.18

26、30.3530.3530.3530.3530.3650.0930.0930.0830.1640.2660.2660.2660.1830.3640.364 dref0.1500.3000.3500.3500.4000.4500.5500.6500.0750.0750.0770.0770.2300.2810.3330.1750.5750.675 enom0.05000.05000.05000.05000.05000.05000.05000.05000.03740.03740.02560.02560.02560.02560.02560.02500.02500.0250 packageso-8so-1

27、4so-16so-16wso-18wso-20wso-24wso-28wsot-23-5sot-23-6sot-23-8msop-8ssop-20ssop-24ssop-28ssop-16ssop-48ssop-56 table iv. pad dimensionsinches. pkg#182235265211219221239217331332348337334338324322333346 zmin6.9346.9346.93411.35411.35411.35411.35411.3793.7343.7343.7345.7408.9158.9158.9156.93411.37911.37

28、9 zmax7.0367.0367.03611.45511.45511.45511.45511.4683.8353.8353.8355.8429.0179.0179.0177.03611.48111.481 gmin2.2612.2612.2616.4526.4526.4526.4527.0610.8640.8640.3812.4644.4964.4964.4962.2616.9856.985 gmax2.3622.3622.3626.5536.5536.5536.5537.1630.9650.9650.4832.5654.5974.5974.5972.3627.0877.087 xmin0.

29、4570.4570.4570.4570.4570.4570.4570.4570.4320.4320.4060.3560.3300.3300.3300.2790.3050.305 xmax0.5590.5590.5590.5590.5590.5590.5590.5590.5330.5330.5080.4570.4320.4320.4320.3730.4060.406 yref2.3882.3882.3882.5152.5152.5152.5152.5151.4731.4731.7271.6762.2612.2612.2612.3882.2612.261 c/cref4.6484.6484.648

30、8.9668.9668.9668.9669.2712.3622.3622.1084.1666.7566.7566.7564.6489.2469.246 dref3.8107.6208.8908.89010.16011.43013.97016.5101.9051.9051.9501.9505.8427.1378.4584.44514.60517.145 enom1.2701.2701.2701.2701.2701.2701.2701.2700.9500.9500.6500.6500.6500.6500.6500.6350.6350.635 packageso-8so-14so-16so-16ws

31、o-18wso-20wso-24wso-28wsot-23-5sot-23-6sot-23-8msop-8ssop-20ssop-24ssop-28ssop-16ssop-48ssop-56 table v . pad dimensionsmillimeters. 4 sbfa015a 关于dpak元件焊盘开窗方式 sot223 figure 6. pcb pad dimensions for sot223inches (mm). # ofpkga and eleadsdesignatorfigures 5 and 635 dcydcq 0.0905 (2.30)0.05 (1.27) bfi

32、gure 50.03 (0.76)0.017 (0.43) xfigure 60.032 (0.81)0.020 (0.51) note: pad sizes are the minimum recommended and maybe increased for improved heat dissipation. table vi. dimensions for sot-223inches (mm). sbfa015a 5 关于dpak元件焊盘开窗方式 ddpak devices the three ddpak surface-mount power package types allhav

33、e the same body dimensions. they differ only in the number of leads and their associated lead dimensions.these values are given in table viii. figure 8. pcb pad dimensions for ddpakinches (mm). # ofpkga and eleadsdesignatorfigures 5 and 6357 kttkttktt 0.10 (2.54)0.067 (1.70)0.05 (1.27) bfigure 50.05

34、 (1.27)0.032 (0.81)0.028 (0.71) xfigure 60.055 (1.35)0.038 (0.97)0.035 (0.89) note: pad sizes are the minimum recommended and maybe increased for improved heat dissipation. table vii. dimensions for ddpakinches (mm). 6 sbfa015a 关于dpak元件焊盘开窗方式 important notice texas instruments incorporated and its s

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37、warranty. testing and other quality control techniques are used to the extent tideems necessary to support this warranty. except where mandated by government requirements, testing of allparameters of each product is not necessarily performed. ti assumes no liability for applications assistance or cu

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