6. Thermal Performance Information Design Guide & Applications Manual For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies Simplified thermal management is one of the benefits of using Vicor converters. High operating efficiency minimizes heat loss, and the low-profile package features an easily accessible, electrically isolated thermal interface surface. Consideration should be given to the module baseplate temperature during operation. The maximum baseplate temperature specification for Maxi, Mini, and Micro is 100°C. Proper thermal management pays dividends in terms of improved converter and system MTBFs, smaller size, and lower product life-cycle costs. The following pages provide guidelines for achieving effective thermal management of Vicor converters. Enhanced module cooling can be achieved with free or forced convection by using the appropriate heat sink. The available Vicor heat sinks and thermal interface options are available on the Vicor website. The relevant nomenclature for the tabulated thermal information supplied in this section for the Maxi, Mini, and Micro modules is defined as follows: Tb = baseplate temperature Ta = ambient temperature Pout = module output power Pin = module input power η = module efficiency = Pout / Pin Pdiss = module power dissipation = Pin – Pout = (1/η – 1) • Pout Supplied thermal resistance values: θbs = baseplate-to-heatsink thermal resistance θba = baseplate-to-ambient thermal resistance Basis of output power versus ambient temperature derating curves: (Ta)max = (Tb)max – θba • Pdiss = (Tb)max – θba • (1/η – 1) • Pout Additional Thermal Data The following pages contain temperature derating curves. For additional thermal data, see the following link: http://asp.vicorpower.com/calculators/calculators.asp?calc=5 Maxi, Mini, Micro Design Guide Page 25 of 88 Rev 4.9 Apps. Eng. 800 927.9474 vicorpower.com 800 735.6200 6. Thermal Performance Information Design Guide & Applications Manual For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies THERMAL PERFORMANCE CURVES (Maxi) Table Usage: The forced convection thermal impedance data shown in the tables on the next three pages assumes airflow through the heat sink fins. Actual airflow through the fins should be verified. For purposes of heat sink calculation, assume efficiencies listed on Maxi data sheets. Use as a design guide only. Verify final design by actual temperature measurement. Maxi θba (Baseplate-to-Ambient Thermal Resistance Values) vs. Airflow θbs = 0.07°C/W Free Air 200 LFM 400 LFM 600 LFM 800 LFM 1,000 LFM 1,200 LFM Baseplate 4.98 3.23 2.17 1.73 1.46 1.27 1.14 0.9'' Longitudinal Fins 2.89 1.30 0.90 0.72 0.59 0.51 0.46 0.9'' Transverse Fins 2.24 1.02 0.72 0.60 0.51 0.44 0.41 0.4'' Longitudinal Fins 3.72 2.14 1.48 1.10 0.86 0.71 0.61 0.4'' Transverse Fins 3.49 1.53 1.08 0.87 0.70 0.60 0.55 Maxi Output Power vs. Ambient Temperature Derating Curves Baseplate (No Heat Sink) 0.4'' (10,1 mm) Heat Sink 80 60 40 20 400 300 300 600 500 500 400 400 400 300 400 LFM Rev 4.9 Apps. Eng. 800 927.9474 600 LFM 800 LFM vicorpower.com 800 735.6200 95 90 100 85 80 75 70 65 60 55 50 40 45 100 95 90 85 80 75 70 65 60 55 50 45 40 100 95 90 85 80 75 70 65 60 55 1000 LFM 100 95 90 85 80 Ambient Temperature (deg C) 75 70 65 60 55 50 45 40 35 30 25 20 5 15 10 0 0 100 95 90 85 80 Ambient Temperature (deg C) 75 70 65 60 55 50 45 40 35 30 25 20 5 15 10 100 Ambient Temperature (deg C) 200 LFM 35 30 25 20 200 0 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 0 25 0 20 100 5 100 15 5 300 200 200 10 15 Power Output (Watts) Power Output (Watts) 600 500 300 50 100 Ambient Temperature (deg C) Ambient Temperature (deg C) 600 0 12 - 48V Maxi Thermal Performance Curves - .9" Heat Sink 45 0 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 5 20 12 - 48V Maxi Thermal Performance Curves - .4" Heat Sink 15 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 Ambient Temperature (deg C) 10 0 100 50 50 12 - 48V Maxi Thermal Performance Curves - No Heat Sink 150 40 100 200 30 150 250 25 200 20 250 5 50 Maxi, Mini, Micro Design Guide 10 350 15 100 35 0 Output Power (Watts) 100 95 90 85 80 75 400 10 150 Free Air 30 95 100 90 85 80 75 70 65 55 50 45 40 60 65 60 55 50 45 40 70 Ambient Temperature (deg C) Output Power (Watts) 200 15 50 0 Output Power (Watts) 250 10 100 0 350 0 150 Ambient Temperature (deg C) 300 0 35 30 25 20 100 5 0 15 50 0 Output Power (Watts) 35 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 0 15 50 150 10 100 0 150 0 Output Power (Watts) 200 350 Output Power (Watts) 30 25 20 5 15 0 10 95 90 100 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 15 10 200 10 Output Power (Watts) 250 200 400 Page 26 of 88 Ambient Temperature (deg C) 250 Ambient Temperature (deg C) 12 – 54 V 0 Ambient Temperature (deg C) 250 0 5V 40 0 Ambient Temperature (deg C) 3.3 V 60 20 0 0 80 25 20 100 35 40 120 100 20 60 140 120 5 80 160 140 15 100 160 10 120 Output Power (Watts) 2V Output Power (Watts) 140 Output Power (Watts) 160 0.9'' (22,8 mm) Heat Sink 1200 LFM 6. Thermal Performance Information Design Guide & Applications Manual For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies THERMAL PERFORMANCE CURVES (Mini) Table Usage: The forced convection thermal impedance data shown in the tables on the next three pages assumes airflow through the heat sink fins. Actual airflow through the fins should be verified. For purposes of heat sink calculation, assume efficiencies listed on Mini data sheets. Use as a design guide only. Verify final design by actual temperature measurement. Mini θba (Baseplate-to-Ambient Thermal Resistance Values) vs. Airflow θbs = 0.14°C/W Free Air 200 LFM 400 LFM 600 LFM 800 LFM 1,000 LFM 1,200 LFM Baseplate 7.94 4.50 3.20 2.52 2.15 1.89 1.69 0.9'' Longitudinal Fins 4.10 1.72 1.26 1.02 0.86 0.75 0.68 0.9'' Transverse Fins 3.93 1.93 1.38 1.06 0.89 0.77 0.70 0.4'' Longitudinal Fins 6.28 2.81 1.98 1.55 1.24 1.05 0.94 2V Mini Thermal Performance Curves - .9" Heat Sink 2V Mini Thermal Performance Curves - .4" Heat Sink 2V Mini Thermal Performance Curves - No Heat Sink 0.4'' Transverse Fins 6.34 3.00 2.09 1.59 1.31 1.11 0.99 Mini Output Power vs. Ambient Temperature Derating Curves Baseplate (No Heat Sink) 0.4'' (10,1 mm) Heat Sink 100 100 80 80 30 20 40 160 160 200 LFM 95 90 100 85 80 70 65 60 55 50 45 40 35 75 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 100 95 90 85 80 75 70 65 60 55 50 45 40 30 25 150 400 LFM Rev 4.9 Apps. Eng. 800 927.9474 600 LFM 800 LFM vicorpower.com 800 735.6200 1000 LFM 100 95 90 85 80 Ambient Temperature (deg C) 75 70 65 60 55 50 45 40 30 25 20 100 95 90 85 80 Ambient Temperature (deg C) 75 70 65 60 55 50 45 40 35 30 25 20 5 15 0 10 50 0 15 100 50 0 100 95 90 85 80 75 70 65 60 55 50 45 40 50 35 20 200 100 30 15 250 0 100 25 0 100 300 150 20 12 - 48V Mini Thermal Performance Curves - .9" Heat Sink Ambient Temperature (deg C) Output Power (Watts) 150 5 0 5 20 5 200 15 40 10 250 200 10 60 Output Power (Watts) 300 250 Output Power (Watts) 300 0 80 Ambient Temperature (deg C) Ambient Temperature (deg C) Maxi, Mini, Micro Design Guide 100 95 90 85 80 75 70 65 60 55 50 45 40 0 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 15 0 120 12 - 48V Mini Thermal Performance Curves - .4" Heat Sink 35 20 30 40 140 10 60 12 - 48V Mini Thermal Performance Curves - No Heat Sink 0 Output Power (Watts) 80 25 60 100 20 80 5 100 120 15 120 140 10 Output Power (Watts) 140 Free Air 20 180 180 Ambient Temperature (deg C) 5 Ambient Temperature (deg C) Ambient Temperature (deg C) 200 0 5V Mini Thermal Performance Curves - .9" Heat Sink 15 100 95 90 0 200 0 30 60 20 85 80 75 70 65 60 55 50 45 40 35 30 25 20 100 5 0 0 15 5V Mini Thermal Performance Curves - .4" Heat Sink 80 10 40 95 90 Output Power (Watts) 60 160 40 25 0 95 90 100 85 80 75 70 65 60 55 50 45 100 80 200 10 Output Power (Watts) 40 120 100 20 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 0 15 5V Mini Thermal Performance Curves - No Heat Sink 140 120 10 60 20 Page 27 of 88 Ambient Temperature (deg C) 0 Output Power (Watts) 80 180 12 – 54 V 20 140 Ambient Temperature (deg C) 5V 35 30 25 20 5 0 15 95 100 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 15 10 100 10 Output Power (Watts) 120 0 3.3V Mini Thermal Performance Curves - .9" Heat Sink 30 Ambient Temperature (deg C) 140 20 40 0 Ambient Temperature (deg C) 40 50 10 10 0 0 3.3 V 60 10 10 0 3.3V Mini Thermal Performance Curves - .4" Heat Sink 35 40 70 35 3.3V Mini Thermal Performance Curves - No Heat Sink 20 50 20 40 60 5 50 Output Power (Watts) 60 30 70 Output Power (Watts) 70 15 80 Output Power (Watts) 90 90 90 2V 0.9'' (22,8 mm) Heat Sink 10 100 1200 LFM 6. Thermal Performance Information Design Guide & Applications Manual For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies THERMAL PERFORMANCE CURVES (Micro) Table Usage: The forced convection thermal impedance data shown in the tables on the next three pages assumes airflow through the heat sink fins. Actual airflow through the fins should be verified. For purposes of heat sink calculation, assume efficiencies listed on Micro data sheets. Use as a design guide only. Verify final design by actual temperature measurement. Micro θba (Baseplate-to-Ambient Thermal Resistance Values) vs. Airflow θbs = 0.21°C/W Free Air 200 LFM 400 LFM 600 LFM 800 LFM 1,000 LFM 1,200 LFM Baseplate 10.90 6.90 4.78 3.74 3.15 2.79 2.49 0.9'' Longitudinal Fins 5.37 2.51 1.79 1.42 1.20 1.06 0.93 0.9'' Transverse Fins 5.04 2.31 1.68 1.31 1.10 0.97 0.88 0.4'' Longitudinal Fins 7.77 3.87 2.68 2.13 1.78 1.48 1.32 2V Micro Thermal Performance Curves - .4" Heat Sink 2V Micro Thermal Performance Curves - No Heat Sink 0.4'' Transverse Fins 7.76 3.58 2.52 2.01 1.67 1.45 1.29 2V Micro Thermal Performance Curves - .9" Heat Sink Micro Output Power vs. Ambient Temperature Derating Curves Baseplate (No Heat Sink) 0.4'' (10,1 mm) Heat Sink 50 50 40 40 40 45 5 40 20 100 80 80 90 60 40 20 95 90 100 85 80 75 70 65 60 55 50 45 40 30 25 35 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 15 80 60 40 400 LFM Rev 4.9 Apps. Eng. 800 927.9474 600 LFM 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 0 5 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 Ambient Temperature (deg C) 20 Ambient Temperature (deg C) 200 LFM 100 20 15 0 5 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 0 10 20 20 10 100 95 90 85 80 75 70 65 60 55 50 45 40 80 15 40 120 100 10 60 5 12 - 48V Micro Thermal Performance Curves - .9" Heat Sink Ambient Temperature (deg C) Output Power (Watts) 80 15 20 0 Output Power (Watts) 100 10 30 140 0 Output Power (Watts) 40 0 120 120 0 50 10 140 140 Maxi, Mini, Micro Design Guide 60 Ambient Temperature (deg C) Ambient Temperature (deg C) Page 28 of 88 35 30 12 - 48V Micro Thermal Performance Curves - .4" Heat Sink 25 10 70 0 20 20 100 Output Power (Watts) 30 0 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 15 0 12 - 48V Micro Thermal Performance Curves - No Heat Sink 40 5 30 50 15 40 60 10 Output Power (Watts) 50 90 70 0 60 10 Output Power (Watts) 70 Free Air 15 Ambient Temperature (deg C) 100 0 10 0 100 95 0 Ambient Temperature (deg C) 80 10 5V Micro Thermal Performance Curves - .9" Heat Sink 30 100 20 20 95 90 100 85 80 75 70 65 60 0 50 10 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5V Micro Thermal Performance Curves - .4" Heat Sink 0 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 0 25 10 20 55 20 0 5 50 30 10 15 45 40 5 5V Micro Thermal Performance Curves - No Heat Sink Ambient Temperature (deg C) 60 15 40 10 10 0 50 10 Output Power (Watts) 50 90 12 – 54 V 15 70 Ambient Temperature (deg C) 5V 3.3V Micro Thermal Performance Curves - .9 Heat Sink 20 Output Power (Watts) 60 20 40 35 30 25 20 5 15 0 95 100 70 60 0 Output Power (Watts) 70 30 25 Ambient Temperature (deg C) Ambient Temperature (deg C) 3.3 V 30 5 0 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 15 0 3.3V Micro Thermal Performance Curves - .4" Heat Sink 10 3.3V Micro Thermal Performance Curves - No Heat Sink 5 0 15 10 10 20 35 5 15 25 15 20 30 10 25 Output Power (Watts) 30 45 35 Output Power (Watts) 35 10 Output Power (Watts) 45 2V 0.9'' (22,8 mm) Heat Sink 50 Ambient Temperature (deg C) 800 LFM vicorpower.com 800 735.6200 1000 LFM 1200 LFM 6. Thermal Performance Information Design Guide & Applications Manual For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies Typical Examples — Thermal Equations (Maxi, Mini, Micro) EXAMPLE 1 Determine the maximum output power for a Maxi module without a heat sink delivering 5 V in 400 LFM airflow at a maximum ambient temperature of 40ºC. Maximum output power = (Tbmax – Tamax) / [θba • (1/η – 1)] Tbmax = 100ºC Tamax = 40ºC For Maxi module without a heat sink @ 400 LFM, θba = 2.17ºC/W For the 5 V Maxi module the typical value for η = 0.83 Maximum output power = (100 – 40) / [2.17 (1/0.83 – 1)] ~135 W Or, the same answer could be obtained by using the output power versus ambient temperature derating curves for the Maxi modules. For the case with no heat sink the baseplate chart for the 5 V module would be used. At a 40ºC ambient and 400 LFM airflow this chart indicates a maximum output power of approximately 135 W. For full output power of 400 W the required thermal resistance is; θba = (100 – 40) / [400 (1/0.83 – 1)] = 0.73ºC/W What size heat sink would be necessary to operate at full output power (400 W) under the same conditions? From the θba versus airflow charts for the Maxi, the thermal resistance at 400 LFM airflow requires the use of a 0.9"(22,8 mm) transverse fin heat sink. EXAMPLE 2 Determine the maximum ambient for a Mini module with a 0.9” (22,8 mm) heat sink in 400 LFM of airflow delivering 200 W at 5 V. From the output power versus ambient temperature chart for the 5 Vout Mini with a 0.9’’ (22,8 mm) heat 5V Mini Thermal Performance Curves - .9" Heat Sink sink, the 200 W at 400 LFM data point results in a Tamax of approximately 48ºC. 200 180 140 120 100 80 60 40 95 90 100 85 80 75 70 65 60 55 50 45 40 35 30 25 20 5 15 0 10 20 0 5 V Mini with 0.9” (22,8 mm) heat sink Output Power (Watts) 160 Ambient Temperature (deg C) Maxi, Mini, Micro Design Guide Page 29 of 88 Rev 4.9 Apps. Eng. 800 927.9474 vicorpower.com 800 735.6200 6. Thermal Performance Information Design Guide & Applications Manual For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies THERMAL MANAGEMENT ACCESSORIES (All parts are RoHS compliant unless otherwise noted) Transverse Fins Longitudinal Fins Maxi Heat Sinks Mini Heat Sinks Micro Heat Sinks Threaded Through Hole Threaded Through Hole Threaded Through Hole 0.4" (10,1 mm) Fin P/N 30482 0.4" (10,1 mm) Fin P/N 30718 0.4" (10,1 mm) Fin P/N 32188 0.4" (10,1 mm) Fin P/N 30195 0.4" (10,1 mm) Fin P/N 32174 0.4" (10,1 mm) Fin P/N 30719 0.9" (22,8 mm) Fin P/N 30188 0.9" (22,8 mm) Fin P/N 30181 0.9" (22,8 mm) Fin P/N 30189 0.9" (22,8 mm) Fin P/N 30182 0.9" (22,8 mm) Fin P/N 30190 0.9" (22,8 mm) Fin P/N 30183 0.4" (10,1 mm) Fin P/N 30778 0.4" (10,1 mm) Fin P/N 30720 0.4" (10,1 mm) Fin P/N 30184 0.4" (10,1 mm) Fin P/N 30721 0.4" (10,1 mm) Fin P/N 32173 0.4" (10,1 mm) Fin P/N 30722 0.9" (22,8 mm) Fin P/N 30196 0.9" (22,8 mm) Fin P/N 30723 0.9" (22,8 mm) Fin P/N 30269 0.9" (22,8 mm) Fin P/N 30724 0.9" (22,8 mm) Fin P/N 30270 0.9" (22,8 mm) Fin P/N 30725 Standoffs and Screws Low-profile Side-fin Heat Sinks Height only 0.125" (3,17 mm) above module baseplate* 0.55" (13,97 mm) Side Fins P/N 30096 0.55" (13,97 mm) Side Fins P/N 32190 Bulk and single-module kits compatible with all standard mounting configurations. 0.55" (13,97 mm) Side Fins P/N 30095 See the specific products on the Vicor website for more information. Not compatible with standoff kits. ThermMate Thermal Pads 20263 For use with Vicor modules, ThermMate thermal pads are a “dry” alternative to thermal compound and are pre-cut to the outline dimensions of the module. THERMAL PAD 20265 20264 PART NUMBER THICKNESS Maxi (10 pc. pkg.) 20263 0.007" (0,177 mm) Mini (10 pc. pkg.) 20264 0.007" (0,177 mm) Micro (10 pc. pkg.) 20265 0.007" (0,177 mm) * For thermal curves of low-profile side-fin heat sinks and on-line capability for thermal curve calculations, see the following link: http://asp.vicorpower.com/calculators/calculators.asp?calc=5 Maxi, Mini, Micro Design Guide Page 30 of 88 Rev 4.9 Apps. Eng. 800 927.9474 vicorpower.com 800 735.6200