======================PACKAGE_THERMALS===================== as costly as germanium. Package_Thermals silicon (physical data) Atomic number: 14 Atomic weight: 28.086 Density: 2329 [293 K];2525 [at m.p.] kg m-3 Molar volume: 12.06 cm3 Velocity of sound: 2200 m s-1 Hardness Mineral: 6.5 Melting point: 1683K Boiling point: 2628K Thermal conductivity: 148 [300 k] W m-1 K-1 Water Standard: 2.42W Specific Heat: 0.76joule/gm*C Fusion: 39.6 kJ mol-1 Thermal_Feed_back silicon (physical data) Atomic number: 14 Atomic weight: 28.086 Density: 2329 [293 K]; 2525 [liquid at m.p.] kg m-3 Molar volume: 12.06 cm3 Velocity of sound: 2200 m s-1 Hardness Mineral: 6.5 Melting point: 1683K Boiling point: 2628K Thermal conductivity: 148 [300 k] W m-1 K-1 Coefficient of linear thermal expansion: K-1 Water Standard: 2.42W Fusion: 39.6 kJ mol-1 Vaporization: 383.3 kJ mol-1 thermal resistance for a 1mil cube geometry of Silicon? Therm_Conduct = 148 W/(m*K) = 148uW/(um*K) = 3.76mW/(mil*K) which means ... __ 3.76mWatt /\ -> ______ Delta Temp / /| If L =1mil,A = 1mil^2,and 3.76mWat 1 deg_K /L / | Delta Temp = 1 deg_K -> /_____/ | ________________________________ |__ A | / | R_th = 266 deg_K/W for 1mil^3 | | /\ | / |________________________________| |/____|/ / R_th = Rho*L/A 3.76mWatt Rho = 266mil*deg_K/W If you have a single transistor which is powered at 5mA*5V =25mW such that its temperature is uniform over a half shell 1 mil in radius temperature? 25mW of power | - - - - |- - - - _ -|- _ - - - - - \|/ - - - - - - _- V -_ - - _ - - - - - _____________________ - - - - -_ /1mil/ | | | - - - - -/_|_/ / / | - - - - _/ 2mil__/ _/ / - - - /\__|__/ / / - - - /_ |3mil __/ _/ - - / \__|____/ _/ - /\_ 4mil __/ - / \___|______/ _/ /\__ |5mil __/ / \____|_______/ The thermal resistance can be modeled in terms of half shells of silicon. Given that the thermal gradients will follow this pattern, the following gives the area of a half sphere. A = 2*PI()*R^2 If you look at a 1mil thick shell which is 1mil away from the heat source, its thermal resistance should be about one sixth the thermal resistance of a 1mil cube. And thermal resistance should drop with the square of the distance since because of R_th ={1_mil*(266 deg_K/W)/6.28}/R_mils^2 R_th =(42 deg_K/W)*1_mil/R_mils^2 At 5mA current at 5volts supply, the temperature gradient works out very close to 1 deg_C. ___________________________________ | delta_Temp_1mil_@25mW = 1.05deg_K | |___________________________________| >From 1 mils to 15mils, the total resistance and thermal gradient follows.. R_th = (42 deg_K/W)*( 1/1mils + 1/2mils + 1/3mils ..etc) T_delta =( 1 +0.25 +0.11 +0.06 +etc) =1.58 deg_K 25mW*(63deg_K/W) = 1.58deg_K ____________________________________ | 25mW of power from 1mil to 15mils | |sees a thermal R of 63 degree/watt | |____________________________________| | - - - - |- - - - _ -|- _ - - - - - \|/ - - - - - - _- V -_ - - _ - - - - - _____________________ - - - - -_ /1mil/ | | | - - - - -/_|_/1.6C/ / | - - - - _/ 2mil__/.6C_/ / - - - /\__|__/ / / - - - /_ |3mil __/ _/ - - / \__|____/ .3C _/ .2C - /\_ 4mil __/ - / \___|______/ _/ /\__ |5mil __/ / \____|_______/ Once you exceed the thickness of the wafer (15mils), the thermal resistance of die bonded to metal is of course is much lower. It is common practice to layout a die such that anything sensitive to thermal gradients is on isothermal lines with anything that can dissipate power. It also does not hurt to put somes distance (say 15mils) between them. Cross coupling is also preferred if possible. ___________________________________________________ | ---___ | | \__ | | \_ ISOTHERMAL LAYOUT | | \ | | \ \ | | \ \ | | +1.6deg_C \ \ | | ___ |_| | | |5mA| |T| | | |@5V|<- 15mils ->|_| Input | | |___| |T| transistors | | Output |_| | | transistors / /<--5mdeg_C gradient | | / /<---across 1mil | | / / | | _/ 0.5mdeg_C*3uV/deg_C =1.5nV | | _/ | | ___/ | |___________________________________________________| If the input TC is about 3uV/deg_C, and if the isothermal layout reduces the gradient by 1/10th, the thermal feedback will induce 1.8nV of thermal induced offset. Compare this TC to the effects of thermalcouples on the PC board. Their TC can be as high as 15uV/deg_C compared to the 1nV/deg_C example given above. It is common for this thermal couple error to have an impact around the one Hertz frequency range. When there is a need for microvolt accuracy, there are a lot more things to consider. Package_Thermals silicon (physical data) Atomic number: 14 Atomic weight: 28.086 Density: 2329 [293 K];2525 [at m.p.] kg m-3 Molar volume: 12.06 cm3 Velocity of sound: 2200 m s-1 Hardness Mineral: 6.5 Melting point: 1683K Boiling point: 2628K Thermal conductivity: 148 [300 k] W m-1 K-1 Water Standard: 2.42W Specific Heat: 0.76joule/gm*C Fusion: 39.6 kJ mol-1 Vaporization: 383.3 kJ mol-1 thermal mass (thermal capacitance) of a 200mil by 200mil by 15mil thick die. __________ / /| 200mils / / / 200mils*25.4u =>.5cm / / / 15mils*25.4u =>.038cm /_________/ / 15mils|_________|/ 200mils 0.5cm*0.5cm*.038cm=.0095cc_Si Silicon Volume .0095cc*2.42Water= .0229gm Thermal Mass 0.0229gm*0.76joule/gm*C =.0174J/deg_C In other words, it takes about 1/60 of a Joule to raise the chip temperature 1deg_C. The package in still air can have a thermal resistance around 200deg_C/W. So there is nothing stopping the modeling of the packaged silicon as a thermal RC. Applying 25mW for 1sec is 25mJoules. You would expect the die temperature to increase 1.47deg_C over that time. 1sec / __ 200deg_C/W _/ ____| |_________/\ /\___ _|_ |__| _|_ \/ | / _ \ ___ | Tau = R*C \/ \/ ^ 25mW | 17.4mJ/deg_C| /\_/\ /|\ | | \___/ | _|_ _|_ _|_ /// /// /// Tau_still_air = 200deg_C/W * 17.4mJ/deg_C = 3.5seconds Of course any air movement across the package will greatly influence this time constant. plastic dip 100C/W to5 120C/w cer dip 70C/w Si melt 1420C Cu melts 1083 Gold 1030 Alum 660 Si storaage 300 50/50 solder melts 200 indium melts 156 Silcon operates 175 mil spec 155 -65 industrial 125 -25 commerical 85 0C Rth of square_Si 56C/W to 70C/W drops 13.6db per thickness distance about 12dB/10mils drops 86.6% per mil ======================SILICON_PACKAGE=============================== Package_Thermals silicon (physical data) Atomic number: 14 Atomic weight: 28.086 Density: 2329 [293 K];2525 [at m.p.] kg m-3 Molar volume: 12.06 cm3 Velocity of sound: 2200 m s-1 Hardness Mineral: 6.5 Melting point: 1683K Boiling point: 2628K Thermal conductivity: 148 [300 k] W m-1 K-1 Water Standard: 2.42W Specific Heat: 0.76joule/gm*C Fusion: 39.6 kJ mol-1 Vaporization: 383.3 kJ mol-1 thermal mass (thermal capacitance) of a 200mil by 200mil by 15mil thick die. __________ / /| 200mils / / / 200mils*25.4u =>.5cm / / / 15mils*25.4u =>.038cm /_________/ / 15mils|_________|/ 200mils 0.5cm*0.5cm*.038cm=.0095cc_Si Silicon Volume .0095cc*2.42Water= .0229gm Thermal Mass 0.0229gm*0.76joule/gm*C =.0174J/deg_C In other words, it takes about 1/60 of a Joule to raise the chip temperature 1deg_C. The package in still air can have a thermal resistance around 200deg_C/W. So there is nothing stopping the modeling of the packaged silicon as a thermal RC. Applying 25mW for 1sec is 25mJoules. You would expect the die temperature to increase 1.47deg_C over that time. 1sec / __ 200deg_C/W _/ ____| |_________/\ /\___ _|_ |__| _|_ \/ | / _ \ ___ | Tau = R*C \/ \/ ^ 25mW | 17.4mJ/deg_C| /\_/\ /|\ | | \___/ | _|_ _|_ _|_ /// /// /// Tau_still_air = 200deg_C/W * 17.4mJ/deg_C = 3.5seconds Of course any air movement across the package will greatly influence this time constant. plastic dip 100C/W to5 120C/w cer dip 70C/w Si melt 1420C Cu melts 1083 Gold 1030 Alum 660 Si storaage 300 50/50 solder melts 200 indium melts 156 Silcon operates 175 mil spec 155 -65 industrial 125 -25 commerical 85 0C Rth of square_Si 56C/W to 70C/W drops 13.6db per thickness distance about 12dB/10mils drops 86.6% per mil fusing current I Konstant*Dia_in^(3/2) Konstant cu 10244 gold 1mil 1Amp Fusing Currents Wires in amperes which wire melt calculated from I = K*d^(3/2) FUSING CURRENTS IN AMPERES. AWG B & S Diam d Copper Alumin GermSilv Iron Tin Gauge Inches K=10244 K=7585 K=5230 K=3148 K=1642 40 0.0031 1.77 1.31 0.90 0.54 0.28 38 0.0039 2.50 1.85 1.27 0.77 0.40 36 0.0050 3.62 2.68 1.85 1.11 0.58 34 0.0063 5.12 3.79 2.61 1.57 0.82 32 0.0070 7.19 5.32 3.67 2.21 1.15 30 0.0100 10.2 7.58 5.23 3.15 1.64 28 0.0126 14.4 10.7 7.39 4.45 2.32 26 0.0159 20.5 15.2 10.5 6.31 3.29 24 0,0201 29.2 21.6 14.9 8.97 4.68 22 0,0253 41.2 30.5 21.0 12.7 6.61 20 0,0319 58.4 43.2 29.8 17.9 9.36 19 0 0359 69.7 51.6 35.5 21.4 11.2 18 0.0403 82.9 61.4 42.3 25.5 13.3 17 0.0452 98.4 72.9 50.2 30.2 15.8 16 0.6508 117 86.8 59.9 36.0 18.8 15 0.0571 140 103 71.4 43.0 22.4 14 0.0641 166 123 84.9 51.1 26.6 13 0.0719 197 146 101 60.7 31.7 12 0.0808 235 174 120 72.3 37.7 11 0.0907 280 207 143 86.0 44.9 10 0.1019 333 247 170 102 53.4 9 0.1144 396 293 202 122 63.5 8 0.1285 472 349 241 145 75.6 7 0.1443 561 416 287 173 90.0 6 0.1620 668 495 341 205 107 ------------------------------------------------------------- Gold in plastic 2mile 100% 5Amps 14% dc faile 5.5Amps 63% failure 6Amp (.5 to 3sec) 29% survival 8Amp 1mil gold 1-1.5Amp 3mil gold 100% 8amps ------------------------------------------------------------- Si 1.00 to 1.46 Watts/cm*C GaAS 0.44 Cu 4.05 Gold 3.09 BeO 2.34 Kovar 0.2 Silver 4.14 saphire 0.25 Al2O3 0.188 Conductivity electrical conductivity 376.676 1/mohm-cm 2.65e-6uohms-cm Gold 2.24uohms-cm Al 376.67 1mil = 25.4um 1e6_um = 1e2_cm 1e0_um = 1e-4_cm 1mil = 25.4e-4_cm 1_cm=394mils wire at lease 100mils long Gold 2.24uohms_cm AL 2.65uohms-cm A 2*PI*(.5mils)^2 = =1.57mil2 L = 1cm = 394mils R = rho*L/A = rho*394mils/1.57mils2 2.24uohms-cm*394(/1.57*25.4e-4cm) .221ohms/cm for Au .261ohms/cm for Al 1mils 25.4um = =2.54e-3cm 100mils = .254cm 66mohms M1 40 mohm/sq M2 24 mohm/sq ----------------------SOT23------------------------ Thermal Resistance is 327 deg per Watt _______ ______ -IN | 4 | 46 X 38 | 5 | V+ |______\| |/_____| \___________________/ /\________________ /\ ||\ /|| ____|| -IN V+||____ | | GND ___|__ | |____ | | ____| || +IN VOUT || ||/_______________\|| \/_____ _____\/ _______/ | | \______ +IN | 3 /| | 2 | |\ 1 | VOUT |_______| |_____| |______| GND ____________ | | ___| |___ VOUT |___| 1 5 |___| V+ | | ___| | GND |___| 2 | | | ___| |___ +IN |___| 3 4 |___| -IN+ | | |____________| 1 __ 8 |_______| | | |_______| __ __________| |__________ ____ | | 46 X 38 | | 2 | | ______________ | | 7 _|_|____|_ -IN V+ _|____|_|_ -IN | | | DieID | | | V+ __| | | GND ___|__ | |____ ___ | | | | _____ _|_|____|_ +IN VOUT _|____|_|_ 3 | | |______________| | | 6 +IN | | | | VOUT __| |_____/____ __________| |_____ ____/__ | | _______ | / | |__| | | 4 GND 5 ______________ | |__| | ___| |___ |___| 1 8 |___| | | ___| |___ -IN |___| 2 7 |___| V+ | | ___| |___ +IN |___| 3 6 |___| VOUT | | ___| |___ GND |___| 4 5 |___| | | |______________| Plastic Small Outline Transistor (SOT) _______________ |\ \ __| \ \ _/\__\ \ \___ |\_/ __| \ \__\__ \|__/ \ \ \_ \__\ _\_ \ \\____| _/\__\ \______________\ |\_/ __|| | \|__/ \|______________| --------------------- ------------------------------------------------ Package| Mkt |JEDEC |Body Size|L/F |Die Size|Rja (C/W) | Rjc Type | Dwg |/EIAJ |mils |Mt'l|Sq. mils|Aie Flow-LFM | C/W | |Spec | | | |Linear Feet/Minute| | | | | | |------------------| | | | | | | 0|225|500|1000| -------------------- ------------------------------------------------- SOT-23 |M03A |TO-236 | 51x115 |A-42| 900|405|353|325| 294| 140 -3/5 | |-AA | x36.5 | | | | | | | |------------ ---------------------------------------------- |M03B |TO-236 | 51x115 |A-42| 900|405|353|325| 294| 140 | |-AB | x36.5 | | | | | | | |------------ ---------------------------------------------- |M05A |None | 63x115 |A-42| 1748|325| | | | | | | x45 | | | | | | | Plastic Package Dimensional/Thermal Data Body Board SizeLead FrameArea Typical Thermal Data¿ JA (¡C/Watt) Mkt JEDEC Wide Long Max. Max. Die * Dwg Spec Pitch Size Air Flow-LFM ¿ JC Nom. Nom Mat'l mils mils Linear mils Sq Feet/Minute ¡C/W) mils mils (X) (Y) Mils 225 500 1000 Package Type Small Outline Transistor (SOT-23) M03A TO-236-AA 55 120 A-42 50 98 120 900 405 353 325 294 140 M03B TO-236-AB 55 120 A-42 50 98 120 900 405 353 325 294 140 SOT-5lead (Drawing #SOT 23-5). ______________ |\ \ __| \ \ _/\__\ \ \__ |\_/ __| \ \__\__ \|__/ \ \ \_ \__\ _\_ \ \\____| _/\__\ \______________\ |\_/ __|| | \|__/ \|______________| CAPACITANCE MATRIX (pf) 1 2 3 1 0.11775 -0.05827 -0.00299 2 -0.05827 0.26750 -0.05827 3 -0.00299 -0.05827 0.11775 INDUCTANCE MATRIX (nh) 1 2 3 1 0.86549 0.30572 0.15341 2 0.30572 0.78615 0.30576 3 0.15341 0.30576 0.86549 CAPACITANCE MATRIX (pf) 4 5 4 0.10445 -0.00443 5 -0.00443 0.10445 INDUCTANCE MATRIX (nh) 4 5 4 0.85659 0.04967 5 0.04967 0.85659 * Since the leadframe material is Alloy42, the inductance values in low frequency range are bigger than values listed above. NOTES: In each of matrices above the diagonal elements are the Self capacitance and the SelfInductance Values. Absolute values mutual capacitance should be considered. off diagonal elements are mutual capacitance and inductan lead lengths provided at bottom of each Inductance matrix. The bond wire Inductance are not considered. Typically the bond wire inductance is in the range of 0.8nh-1.0nh for a 50 mil wire length. numbers in the top row and first column are lead numbers. Metal this process, under passivation appears to harder to blow up than expected. From the DRC rules, you would not expect minimm geometry dimensions metal and via to be able to take DC currents greater than 200mA. appears that it takes blowing a hole in the passitivation is what it takes to open a link of metal or via. Up until that happens, looks like metal is being melted, but passivation is holding it in place. \ <--hole---> / 5um X 5um typical hole inpassivation \ / ____________ MET2 /| takes about 200mA => 160mW in 25um_sq ___________/ | ___________|/_______ / |_| MET1 /_______________ |_______________ easiest metal link to blow was two min size metals jointed together by one via. resistance of the via gets high enough around 170mA->350mA to blow hole in passivation , at which point metal sprays out as liguid around the crater. Whenever more metal close by , this appears to conduct away soem of hea that more current is needed to create same size hole in the passivation. Another data point 600mA DC can blow a 30um by 30um hole in the passivation above a strip of 30um MET2 GND 1 __ 8 OUT |______\| | | |__/__| __ _______\__| |____/___ ____ | | \28 X 40 / | | 2 | | ____\______/_ | | 7 | | | \ / | | | VCC -|-|----|-[ ] [ ] [ ] | | | | | | ^ | | | __| | | | | | |____ ___ | | ID | | _____ | | | | | | -|-|----|-[ ] [ ] [ ] | | | 3 | | |_____/_____\_| | | 6 OFF | | / \ | | __| |________/_ ____\___| |_____ _______/ | | __\____ | /| |__| | \ | 4 INN 5 INPP ______________ | |__| | ___| |___ Trim |___| 1 8 |___| | | ___| LM741 |___ -IN |___| 2 7 |___| V+ | | ___| |___ +IN |___| 3 6 |___| VOUT | | ___| |___ GND |___| 4 5 |___| Trim | | |______________| ______________ | |__| | ___| |___ GND |___| 1 8 |___| OUT | | ___| 10uA |___ VCC |___| 2 7 |___| | | ___| |___ OFF |___| 3 6 |___| | | ___| |___ INN |___| 4 5 |___| INNP | | |______________| SOT 23-6 46 X 38 Pad _______ _______ ______ OUT | 4 | | 5 |SD | 6 | VCC |______\| |___|___| |/_____| \_________|_________/ /\________|_______ /\ ||\ | /|| ____|| OUT SD V+||____ | | | | |____ | | ____| || +IN GND -IN || ||/_______|_______\|| \/_____ | _____\/ _______/ | | \______ +IN | 3 /| | 2 | |\ 1 | -IN |_______| |_____| |______| GND _____________ | | | ___| | |___ |___| | 1 6 |___| IN- | | SOT6 | V+ ___| | |___ |___| | 2 5 |___| GND | | | SDT ___| | |___ |___| | 3 4 |___| IN+ | | | OUT |_|___________| __________________________________________ | | | VIN CLK | | 2 1 14 13 | | |__| |__| |__| |__| | | \ / | | GND ..\.........../.. DOUT | | ___ :[ ] [ ]: ___ | | 3 ___|-___: <=id :___-|___ 12 | | -[ ] [ ]- | | ___ : : ___ | | 4 ___| :[ ] [ ]: |___ 11 | | _-...............-_ | | ___ _- -_ ___ | | 5 ___|- -|___ 10 | | VCC CS | | | | __ __ __ __ | | | | | | | | | | | | 6 7 8 9 | |__________________________________________| Build_Sheet_14_Pin_side_braze __________________________________________ | | | 2 1 14 13 | | |__| |__| |__| |__| | | \ | | / | | ..\...|...|.../.. | | ___ :[ ] [ ] [ ] [ ]: ___ | | 3 ___|-___: Pin1 :___-|___ 12 | | -[ ] [ ]- | | ___ : <=id : ___ | | 4 ___|-----[ ] [ ]-----|___ 11 | | : : | | ___ ___-[ ] [ ]-___ ___ | | 5 ___|- : : -|___ 10 | | :[ ] [ ] [ ] [ ]: | | :./...|...|...\.: | | __/ _| |_ \__ | | | | | | | | | | | | 6 7 8 9 | |__________________________________________| 1 __ 8 |_______| | | |_______| __ __________| |__________ ____ | | 46 X 38 | | 2 | | ______________ | | 7 _|_|____|_ -IN V+ _|____|_|_ -IN | | | | | | V+ __| | |[DieID] GND _|___ | |____ ___ | | | | _____ _|_|____|_ +IN VOUT _|____|_|_ 3 | | |______________| | | 6 +IN | | | | VOUT __| |_____/____ __________| |_____ ____/__ | | _______ | / | |__| | | 4 GND 5 ____________ | | ___| |___ VCC |___| 1 6 |___| CS | | ___| |___ GND |___| 2 5 |___| DATA_OUT | | ___| |___ VIN |___| 3 4 |___| CLK | | |____________| ___||_______________|| NC \\ L| L|\ NC \\ || SOT_PIN1 || NC \\ L| | L|\ NC \\ || V _____ || V+ \\ L| <=\\ \=> L|\ CS \\ || \\ \ || NC \\ L| <=\\ \=> L|\ NC \\ || \\ \ || GND \\ L| <=\\____\=> L|\ DOUT \\ || ----- || VIN \\ L| L|\ CLK \\ || || NC \\ L| <==PIN1 L|\ NC \\____________________\ ---------------------