TM AMPSS Astec Modular Power Supply System APA501 Series Heatsinks for Power Modules Technical Reference Manual Series Highlights * Horizontal, Vertical and Low Profile fin options * Full range of mounting accessories Heatsinks ............................................................................ 3 "60" Size Heatsink Dimensions & Characteristics ............................................ 4 "80" Size Heatsink Dimensions & Characteristics ............................................ 7 Thermal Design Process and Example .......................... 11 Rev. 01 Jan 96 AMPSS(R) Reference Manual Table of Contents Contents 1 Heatsinks for AMPSS modules are available in a variety of sizes and fin orientation. Mounting kits and thermal pads are also available. The table below shows the options available for "80" and "60" module sizes. A heatsink mounting kit provides the most convenient way to mount the heatsink to the module and then mount the assembly onto a circuit board 1 AMPSS modules may be retained by their input and output pins only, or may be fixed to the board using bolts screwed into the tapped studs which are provided as part of the mounting kit. In both cases the studs provide clearance between the module and the circuit board to facilitate PCB cleaning operations. Note: baseplate and heatsink must be connected to protective earth 2 Description Model Number Heatsink, "60" size, vertical fin. Heatsink, "60" size, horizontal fin Heatsink, "60" size, vertical fin. Heatsink, "60" size, horizontal fin Heatsink, "60" size, vertical fin. Heatsink, "60" size, horizontal fin Heatsink, "60" size, low profile APA501-60-001 APA501-60-002 APA501-60-003 APA501-60-004 APA501-60-005 APA501-60-006 APA501-60-007 Dimensions Free air thermal inches mm resistance 2.26x2.32x0.6 57.5x59x15 3.8C/W 2.26x2.32x0.6 57.5x59x15 3.9C/W 2.26x2.32x0.9 57.5x59x22.5 3.3C/W 2.26x2.32x0.9 57.5x59x22.5 3.7C/W 2.26x2.32x1.5 57.5x59x37 2.8C/W 2.26x2.32x1.5 57.5x59x37 2.8C/W 2.25x3.50x0.5 57.2x89x12 3.6C/W Heatsink, "80" size, vertical fin. Heatsink, "80" size, horizontal fin Heatsink, "80" size, vertical fin. Heatsink, "80" size, horizontal fin Heatsink, "80" size, vertical fin. Heatsink, "80" size, horizontal fin Heatsink, "80" size, low profile APA501-80-001 APA501-80-002 APA501-80-003 APA501-80-004 APA501-80-005 APA501-80-006 APA501-80-007 4.53x2.32x0.6 4.53x2.32x0.6 4.53x2.32x0.9 4.53x2.32x0.9 4.53x2.32x1.5 4.53x2.32x1.5 4.55x3.50x0.5 Thermal Pad, "60" size Thermal Pad, "80" size Mounting Kit, Tapped Studs Mounting Kit, Solder Studs Mounting Kit, Tapped Studs for low profile heatsink Mounting Kit, Solder Studs for low profile heatsink Spring Sockets (20 cont. 15pwr) APA502-60-001 APA502-80-001 APA503-00-001 APA503-00-002 APA503-00-007 Rev. 01 Jan 96 115x59x15 115x59x15 115x59x22.5 115x59x22.5 115x59x37 115x59x37 115.6x89x12 AMPSS (R) Accessories Heatsinks 2.7C/W 2.4C/W 2.2C/W 2.0C/W 2.0C/W 1.7C/W 2.2C/W APA503-00-008 APA504-00-001 AMPSS(R) Reference Manual 3 APA501-60-001 o 3.80 (0.15) Forced Convection for APA501-60-001 at 100W Output 50.80 (2.00) 59.00 (2.32) Thermal Resistance Baseplate to Ambient (C/W) 2.5 12.0 (0.47) Heatsinks "60" Size Heatsink Dimensions & Characteristics 15.0 (0.6) 48.26 (1.90) 57.50 (2.26) 2 1.5 1 0.5 0 4.0 (0.16) 0 200 400 600 800 1000 V air (LFM) APA501-60-002 Forced Convection for APA501-60-002 at 100W Output o 3.80 (0.15) 2 1.5 1 0.5 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 15.0 (0.6) 48.26 (1.90) 57.50 (2.26) Thermal Resistance Baseplate to Ambient (C/W) 12.0 (0.47) 50.80 (2.00) 59.00 (2.32) 2.5 APA501-60-003 o 3.80 (0.15) Forced Convection for APA501-60-003 at 100W Output 4.0 (0.16) 4 AMPSS(R) Reference Manual Thermal Resistance Baseplate to Ambient (C/W) 24.0 (0.9) 48.26 (1.90) 57.50 (2.26) 12.0 (0.47) 50.80 (2.00) 59.00 (2.32) 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 1000 V air (LFM) Rev. 01 Jan 96 o 3.80 (0.15) Forced Convection for APA501-60-004 at 100W Output 2.5 2 1.5 1 0.5 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 24.0 (0.9) 48.26 (1.90) 57.50 (2.26) Thermal Resistance Baseplate to Ambient (C/W) 12.0 (0.47) 50.80 (2.00) 59.00 (2.32) 3 APA501-60-005 AMPSS (R) Accessories APA501-60-004 Forced Convection for APA501-60-005 at 100W Output o 3.80 (0.15) 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 37.0 (1.5) 48.26 (1.90) 57.50 (2.26) Thermal Resistance Baseplate to Ambient (C/W) 12.0 (0.47) 50.80 (2.00) 59.00 (2.32) 1.6 200 400 600 800 1000 4.0 (0.16) V air (LFM) APA501-60-006 o 3.80 (0.15) Forced Convection for APA501-60-006 at 100W Output Thermal Resistance Baseplate to Ambient (C/W) 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 37.0 (1.5) 48.26 (1.90) 57.50 (2.26) 12.0 (0.47) 50.80 (2.00) 59.00 (2.32) 1.8 Rev. 01 Jan 96 AMPSS(R) Reference Manual 5 4.47(0.18) Forced Convection for APA501-80-007 at 200W Output 2.5 A A Thermal Resistance Baseplate to Ambient (C/W) 19.10 (0.75) 48.26 (1.90) 50.80 (2.00) 57.2 (2.25) Heatsinks APA501-60-007 2 1.5 1 0.5 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 0.1 45 o7.5 (0.30) (4X) o3.8 (0.15) (4X) 12.0 (0.47) 4.2 (0.17) 3.5 (0.14) 0 o4.2 (0.17) (4X) 63.0 (2.48) 89.0 (3.50) Section A-A 6 AMPSS(R) Reference Manual Rev. 01 Jan 96 APA501-80-001 o 3.80 (0.15) Forced Convection for APA501-80-001 at 200W Output Thermal Resistance Baseplate to Ambient (C/W) 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 15.0 (0.6) 106.68 (4.20) 115.0 (4.53) 12.0 (0.47) 50.80(2.00) 59.0 (2.32) 1.2 AMPSS (R) Accessories "80" Size Heatsink Dimensions & Characteristics APA501-80-002 o 3.80 (0.15) Forced Convection for APA501-80-002 at 200W Output Thermal Resistance Baseplate to Ambient (C/W) 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 15.0 (0.6) 106.68 (4.20) 115.0 (4.53) 12.0 (0.47) 50.80(2.00) 59.0 (2.32) 1.2 Rev. 01 Jan 96 AMPSS(R) Reference Manual 7 o 3.80 (0.15) Forced Convection for APA501-80-003 at 200W Output 12.0 (0.47) 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 22.5 (0.89) 106.68 (4.20) 115.0 (4.53) Thermal Resistance Baseplate to Ambient (C/W) 1.2 50.80(2.00) 59.0 (2.32) Heatsinks APA501-80-003 APA501-80-004 o 3.80 (0.15) Forced Convection for APA501-80-004 at 200W Output Thermal Resistance Baseplate to Ambient (C/W) 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 V air (LFM) 4.0 (0.16) 22.5 (0.89) 106.68 (4.20) 115.0 (4.53) 12.0 (0.47) 50.80(2.00) 59.0 (2.32) 1.2 8 AMPSS(R) Reference Manual Rev. 01 Jan 96 1000 o 3.80 (0.15) Forced Convection for APA501-80-005 at 200W Output Thermal Resistance Baseplate to Ambient (C/W) 12.0 (0.47) 50.80(2.00) 59.0(2.32) 1.4 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 37.0 (1.5) 106.68 (4.20) 115.0 (4.53) 1.2 AMPSS (R) Accessories APA501-80-005 APA501-80-006 o 3.80 (0.15) Forced Convection for APA501-80-006 at 200W Output Thermal Resistance Baseplate to Ambient (C/W) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 200 400 600 800 1000 V air (LFM) 4.0 (0.16) 37.0 (1.5) 106.68 (4.20) 115.0 (4.53) 12.0 (0.47) 50.80(2.00) 59.0(2.32) 0.9 Rev. 01 Jan 96 AMPSS(R) Reference Manual 9 19.1 (0.75) 4.47 (0.18) 50.8 (2.00) Forced Convection for APA501-80-007 at 200W Output 106.68 (4.20) Thermal Resistance Baseplate to Ambient (C/W) 1.4 115.6 (4.55) 0.2 Heatsinks APA501-80-007 1.2 1 0.8 0.6 0.4 0.2 0 0 200 400 600 800 V air (LFM) A 12.0 (0.47) 4.2 (0.17) 3.5 (0.14) A 4.0 (0.16) 0.1 45 o7.5 (0.30) (4X) o3.8 (0.15) (4X) o4.2 (0.17) (4X) 63.0 (2.48) 89.0 (3.50) Section A-A 10 AMPSS(R) Reference Manual Rev. 01 Jan 96 1000 Temperature & MTBF APMSS modules are designed to be able to run at baseplate temperatures of 100C in the case of the AM80 series and 85C for other series. However, for normal operation the modules should not be run at the maximum allowable temperature since the Mean Time Between Failures (MTBF) will reduce sharply as temperature increases. For example, an AM80-300L-050F40 operating at 5V@40A output, with a baseplate temperature of 50C, has an MTBF of over one million hours. If the temperature is doubled to 100C this figure drops to 155,000 hours. The following rules should be followed to ensure reliable operation * At the maximum system ambient temperature the APMSS baseplate temperature rating should not be exceeded. * At the normal system ambient operating temperature the APMSS baseplate temperature must be low enough to meet MTBF requirements. The Thermal Design Process 1. Determine heat generated by module from its losses. The minimum efficiency at relevant line and load conditions should be used in calculating the losses. 2. Determine maximum baseplate temperature rise to stay within module temperature rating at maximum system ambient. 3. Define maximum system baseplate temperature to meet MTBF in normal system operating conditions or at the temperature at which the MTBF is specified. 4. Select/design heatsink and airflow requirement. 5. Test using the APMSS imbedded TEMP-MON feature which allows direct and convenient monitoring of baseplate temperature. (BM/AM/ AL/AK Series) 1. Heat generated = Power Out x [(1/Efficiency)-1] = 150 x [(1/0.83)-1] = 31 Watt 2. Maximum baseplate temperature 100C (from AM80 specifications). At 60 C (max. ambient temp.) the maximum baseplate temperature rise is 40C. 3. To achieve 800,000 hours MTBF, baseplate temperature must not exceed 61C. Maximum baseplate temperature rise (from 25C operating ambient) is 36C. 4. Choose the lowest temperature rise of or i.e. 36C. The cooling system must dissipate 31 Watts with a maximum baseplate temperature rise of 36C. Thermal resistance = 36/31 = 1.16C/Watt. AMPSS (R) Accessories Thermal Design Process and Example To ensure good thermal contact Astec recommends the use of Thermstrate(R) thermal mounting pads. Thermal resistance of the Thermstrate(R) interface between baseplate and heatsink is 0.1C/W. For this example (overall thermal resistance 1.16 C/ W) the heatsink thermal resistance should be a maximum of 1.06C/W. A 10% safety margin is desirable so a heatsink achieving 0.95C/W is chosen. To achieve this level of cooling using natural convection would require an very large heatsink. It would therefore be better to employ forced air cooling. A thermal resistance vs air flow characteristic should be referenced to determine the required airflow for the heatsink you are using. Thermal Design Example This example is for the following parameters: * Single 5V AM80 module used in a distributed power system. * Average load 30A (150 Watts) * Normal operating ambient temperature 25C * Maximum ambient temperature 60C * MTBF required - 800,000 hours (from system requirements) * Efficiency measured at 83% (Efficiency = Output power/ Input power) Rev. 01 Jan 96 AMPSS(R) Reference Manual 11 Heatsinks Tips on installation of AMPSS modules 1.Ensure that the module/heatsink interface smooth, flat and free of debris. Always use either thermal grease or APMSS thermal pads. 2. Fit modules and other heat generating devices at the top of the cabinet where possible. 3. Stagger modules to improve cooling and facilitate even heat distribution between modules. AIRFLOW AIRFLOW 4. Avoid blocking the airflow to the modules with other components. AIRFLOW AIRFLOW 5. Use a heatsink with fins running vertically for natural convection cooling. 12 AMPSS(R) Reference Manual Rev. 01 Jan 96 For further information contact : NORTH AMERICA ASTEC AMERICA, INC. 5810 Van Allen Way Carlsbad, CA 92008 USA Tel : 760-930-4600 Fax : 760-930-4700 EUROPE ASTEC EUROPE LTD. Astec House, Waterfront Bus. Park Merry Hill, Dudley West Midlands DY5 1LX U.K. Tel : 44-1384-842211 Fax : 44-1384-843355 ASIA ASTEC ASIA 6F., China Dyeing Works Building 382-392 Castle Peak Road Tsuen Wan N.T. Hong Kong Tel : 852-2437-9662 Fax : 852-2402-4426 APA701-VRM Rev. 04 May 97