EXA40 SERIES Application Note 101 Rev. 01 - Feb. 1999 NEW Product * Ultra high efficiency topology, 91% typical at 5V * Operating ambient temperature of -40C to +70C (natural convection) * Approved to EN60950, UL1950, CSA C22.2 No. 234/950 * Complies with ETS 300 019-1-3/2-3 * Complies with ETS 300 132-2 input voltage and current requirements * Fully compliant with ETS 300 386-1 1. Introduction 1. Introduction . . . . . . . . . . . . . . . . . . . . . .1 2. Models and Features . . . . . . . . . . . . . .1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 3. General Description . . . . . . . . . . . . . . .1 Electrical Description . . . . . . . . . . . . . . . . . . . .1 Physical Construction . . . . . . . . . . . . . . . . . . .2 4. Safety . . . . . . . . . . . . . . . . . . . . . . . . . .3 Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Input Fusing . . . . . . . . . . . . . . . . . . . . . . . . . . .3 6. 7. The EXA40 comprises eight separate models as shown in Table 1. All popular integrated circuit operating voltages are covered by the entire range. Model Input Voltage Output Voltage EXA40-24S05 18-36VDC 4.5 to 5.5V EXA40-24S3V3 18-36VDC 3.0 to 3.6V Radiated . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Conducted . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 EXA40-24S2V75 18-36VDC 2.5 to 3.0V Use in a Manufacturing Environment . .5 EXA40-24S1V8 18-36VDC 1.5 to 2.0V EXA40-48S05 36-75VDC 4.5 to 5.5V EXA40-48S3V3 36-75VDC 3.0 to 3.6V EXA40-48S2V75 36-75VDC 2.5 to 3.0V EXA40-48S1V8 36-75VDC 1.5 to 2.0V Applications . . . . . . . . . . . . . . . . . . . . .6 Optimum PCB Layout . . . . . . . Optimum Thermal Performance Remote ON/OFF Control . . . . . Output Voltage Adjustment . . . 9. 2. Models and Features EMC . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Resistance to Soldering Heat . . . . . . . . . . . . . .5 Water Washing . . . . . . . . . . . . . . . . . . . . . . . . .5 ESD Control . . . . . . . . . . . . . . . . . . . . . . . . . . .5 8. In addition the automated manufacture methods and use of planar magnetics together with an extensive qualification program have produced one of the most reliable range of converters. Features and Functions . . . . . . . . . . . .2 Overvoltage Protection . . . . . . . . . . . . . . . . . .2 Over Temperature Protection . . . . . . . . . . . . . .3 Current Limit and Short Circuit . . . . . . . . . . . . .3 Remote ON/OFF . . . . . . . . . . . . . . . . . . . . . . .3 Output Voltage Adjustment . . . . . . . . . . . . . . .3 5. The EXA40 Series is a new generation of DC/DC converters which were designed in response to the growing need for low operating voltage and higher efficiencies. They offer unprecedented efficiency figures and the greatest range of low output voltages on the market. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 .6 .7 .7 Appendix 1 . . . . . . . . . . . . . . . . . . . . . .8 Output Voltage Trim Curves . . . . . . . . . . . . . . .9 10. Appendix 2 . . . . . . . . . . . . . . . . . . . . .11 Output TVS Rating . . . . . . . . . . . . . . . . . . . . .11 Table 1 - EXA40 Models Features * Overtemperature shutdown * Optional latching OVP * Primary remote On/Off * Output voltage adjustability * Continuous short circuit protection * Overcurrent limiting 11. Appendix 3 . . . . . . . . . . . . . . . . . . . . .13 Recommended PCB Layouts . . . . . . . . . . . . .13 3. General Description Electrical Description The EXA40 is a resonant reset Forward converter with synchronous rectification. A simplified schematic is shown in Figure 1. The significant gain in efficiency has been achieved by optimum driving of the synchronous rectifiers. PAGE 1 EXA40 SERIES | Application Note Input LC Filter OTP A separate paper discussing the benefits of "open frame low to medium DC/DC converters" Design Note 102 is available from Artesyn Technologies. The effective elimination of potting and a case has been made possible by the use of modern automated manufacturing techniques and in particular the 100% use of SMT components, the use of planar magnetics and the exceptionally high efficiencies. + Synchronous Rectifiers PWM Control OptoCoupler Feedback & Adjustability OptoCoupler OVP Detection Trim On/Off Figure 1 - Simplified Schematic The DC input is filtered by an LC filter before it reaches the main transformer. A PWM controller is used to regulate the output. The main power switch is a MOSFET running at a control frequency of 300KHz. The output is sensed and compared with a secondary side reference and an error signal is fed back via an optocoupler to the PWM controller. The trim pin on the secondary side allows the output to be adjusted by connecting a resistor between trim and either the positive or negative output depending on whether you wish to trim up or down. The optional latching Over-Voltage Protection (OVP) circuit sends back a signal to the PWM controller to turn off if the output rises above a pre-determined limit for longer than 1ms. OVP transients less than this are eliminated through the use of an output TVS. More details on the OVP section can be found in the applications section. The controller latches off until the power is re-cycled or the remote pin is toggled. An Over-Temperature Protection (OTP) circuit on the primary side shuts down the PWM controller if the converter is in danger of being damaged. Unlike the OVP circuit the OTP circuit does not latch off the controller. There is however a considerable amount of thermal hysteresis which is used to protect the unit. The output synchronous rectifiers are controlled by circuitry on the secondary side which optimise the driving scheme. Physical Construction The EXA40 is constructed using a single multi-layer FR4 PCB. SMT components are placed on both sides of the PCB and in general, the heavier power components are mounted on the top side in order to optimise heat dissipation. The converter is sold as an open-frame product and no case is required. The open frame design has several advantages over encapsulated closed devices. Among these advantages are: * Cost: No potting compound, case or associated Process costs involved. * Thermals: The heat is removed from the heat generating components without heating more sensitive, less tolerant components such as opto-couplers. * Environmental: Some encapsulants are not kind to the environment and create problems in incinerators. In addition open frame converters are more easily re-cycled. * Reliability: Open Frame modules are more reliable for a number of reasons. http://www.artesyn.com 4. Features and Functions Overvoltage Protection A TVS is used across all models to clamp all transients of short duration that may occur. The levels of these transients are given in Table 2. Output Voltage TVS Value 5V 6.8V 3.3V 4.0V 2.75V 4.0V 1.8V 4.0V Table 2 - Output TVS Clamping Voltages The maximum duration of these pulses and their peak power is dependent on a number of factors. Appendix 2 contains details of the output TVS ratings. For a single Pulse the maximum Peak Power at 1ms is 600W at 25C (see Figure A2-1). As the ambient temperature increases so the Peak Pulse power derates as shown in Figure A2-2. Repetitive Pulses are not as straightforward and an extra derating chart is supplied in Figure A2-3. The derating is expressed here as a function of the pulse duty cycle and pulse width. Note that these derating factors are quoted at 25C and must be further derated for temperature by referring to Figure A2-2. The OVP function is an optional function that is used to protect the users circuitry from damage should the converter fail or if an externally induced transient occurs on the output. The trip points are set quite accurately at 125% of Vout nominal and are given in Table 3. The OVP function has a discrimination circuit to prevent it tripping due to small duration transients. This filter eliminates any pulses of between 500s and 1ms duration over the trip point level. Output Voltage TVS Value 5V 6.2V 3.3V 4.2V 2.75V 3.6V 1.8V 2.5V Table 3 - OVP Trip Point When the unit trips the PWM controller shuts down the output within 1ms. PAGE 2 EXA40 SERIES | Application Note Over Temperature Protection This feature is included as standard in order to protect the converter and the circuitry it powers from overheating in the event of a runaway thermal condition such as a fan failure at high temperatures. or continuous operation above Tmax at full power. The actual ambient temperature it trips at is dependent on quite a number of factors The airflow over the unit is the most dominant parameter. The trip point is also affected by the input voltage, output trim voltage, user PCB layout, output load and model. For all models under full load conditions the trip point will be at a minimum of 75C in still air using the recommended layout in the Applications section. Still Air or natural convection is defined as 0.1m/s airflow. As the load is decreased and the unit is operated at higher temperatures, the trip point also rises. This trip point will at all times protect the unit and will be a minimum of 5C away from the safe operating temperature of the device. 5. Safety Isolation The EXA40 has been submitted to independent safety agencies and has EN60950 and UL1950 Safety approvals. Basic insulation is provided and the unit is approved for use between the classes of circuits listed in Table 4. Insulation Between And TNV-1 Circuit Earthed SELV Circuit Unearthed SELV Circuit TNV-2 Circuit TNV-3 Circuit Earthed SELV Circuit Unearthed SELV Circuit or or TNV-1 Circuit Earthed or Unearthed Hazardous Voltage Secondary Circuit Earthed SELV Circuit ELV Circuit Unearthed Hazardous Voltage Secondary Circuit TNV-1 Circuit Current Limit and Short Circuit All models of the EXA40 have a built in current limit function and full continuous short circuit protection. Table 4 Insulation categories for Basic The current limit inception point is dependent on the input voltage, ambient temperature and has a parametric spread also. For all models the inception point is typically 140% or 11.2A. It may go as high as 180% or as low as 100% over all operating conditions and the lifetime of the product. The TNV or Telecommunication Voltage definitions are given in Table V.1 of IEC950 from which EN60950 and UL1950 are derived. None of the specifications are guaranteed when the unit is operated in an overcurrent condition. The unit will not be damaged in an overcurrent condition as it will protect itself through the use of the OTP function before any damage occurs. However the lifetime of the unit will be reduced. In order for the user to maintain the insulation requirements of these safety standards it is necessary for the required creepage and clearance distances to be maintained between the input and output. In short circuit the unit enters a `hiccup' foldback current mode and may be operated continuously in this condition. The duty cycle of this hiccup is dependent on input voltage, temperature etc. The RMS value of the short circuit current is guaranteed to be a maximum of 12A RMS over all operating conditions and the lifetime of the product. While the unit is specified to operate into a continuous short circuit, extended or frequent short circuits will reduce the lifetime of the converter. A short circuit is defined as a resistance of 20m or less. The EXA40 has an approved insulation system that satisfies the requirements of the safety standards. Creepage is the distance along a surface such as a PCB and for the EXA40 the creepage requirement between primary and secondary is 1.4mm or 55 thou. Clearance is the distance through air and the requirement is 0.7mm or 27 thou. Input Fusing In order to comply with safety requirements the user must provide a fuse in the unearthed input line if an earthed input is used. The reason for putting the fuse in the unearthed line is to avoid earth being disconnected in the event of a failure. If an earthed input is not being used then the fuse may be in either input line. Remote On/Off The remote On/Off function allows the unit to be controlled by an external signal which puts the module into a low power dissipating sleep mode. Methods of applying are given in the applications section. For the 48V input models a 2A Anti-Surge Fuse should be used and for the 24V models a 3.15A Anti-Surge fuse is required. High Rupture Capacity (HRC) fuses are recommended. Output Voltage Adjustment The output voltage on all models except for the 1.8V output is trimmable by 10%. The 1.8V output is asymmetrically trimmable by +13% and -18%. Details on how to do trim all models are provided in the applications section. 6. EMC PAGE 3 The EXA40 has been designed to comply with the EMC requirements of ETSI 300-386-1. It meets the most stringent requirements of Table 5; Public telecommunications equipment, locations other than telecommunication centres, High Priority of Service. Following is the list of standards which apply and which it has complied with. EXA40 SERIES | Application Note Radiated emissions The applicable standard is EN55022 Class B (FCC Part 15). Testing DC/DC converters as a stand-alone component to the exact requirements of EN55022 (FCC Part 15) is very difficult to do as the standard calls for 1m leads to be attached to the input and output ports and aligned such as to maximise the disturbance. In such a set-up it is possible to from a perfect dipole antenna that very few DC/DC converters could pass. However the standard also states that `An attempt should be made to maximise the disturbance consistent with the typical application by varying the configuration of the test sample'. In addition ETS 300 386-1 states that the testing should be carried out on the enclosure. The EXA40 is primarily intended for PCB mounting in Telecommunication Rack systems. Conducted emissions The required standard for conducted is EN55022 Class A (FCC Part 15). The EXA40 has quite a substantial LC filter on board to enable it to meet this standard with just the addition of one external component for the 48V models and two for some of the 24V models. The conducted noise graphs for the EXA40-48S05 are given in Figure 2 & Figure 3 . The graphs of all other models are available on request. For the purpose of the radiated test the unit was mounted on a 6U high PCB with a 40W load on board and connections to the remote on/off and trim pins. The recommended PCB layouts were used on the test PCB. The unit was then mounted in an ETSI standard 19" rack system and the position of the card was varied to achieve maximum emissions. There was a 4F capacitor connected across the input and the ground plane was connected to the output (pin 7). However the difference between the ground plane being connected to the input or output is minimal. Details of the capacitor and optimum groundplane can be found in later sections. The test results for the 48S05 and 24S05 models are shown in tables 5 and 6 below as these are the models with the highest switching voltages and currents. The testing was carried out by an independent test house and a copy of the report is available on request. Frequency (MHz) Figure 2 - EXA40-48S05 Class A Conducted Noise Response (dBV/m) 30.00 14.80 102.53 23.75 108.50 21.80 109.09 22.85 110.67 23.00 Table 5 - Radiated Emissions on EXA40-48S05 Frequency (MHz) Response (dBV/m) 30.00 14.80 108.56 15.80 108.81 16.85 110.62 19.00 111.50 21.20 Figure 3 - EXA40-48S05 Class B Conducted Noise Table 6 - Radiated Emissions on EXA40-24S05 In both cases the unit passed the Class B limit which is 30 dBV/m with a significant margin. http://www.artesyn.com The required Filters to meet Class A & Class B for all models shown in Figure 4 to Figure 7. Table 7 is a cross-reference which indicates which filter is required for which model. PAGE 4 EXA40 SERIES Model | Application Note Class A Class B The part numbers of the parts used in each case are given below. 48S1V8 Filter A Filter C 48S2V75 Filter A Filter C 48S3V3 Filter A Filter C Surface Mount Ferrite Bead part no; MMG DS52-9K3F-R1ES2. 48S05 Filter A Filter B 24S1V8 Filter A Filter C 24Vin models use 10H TDK inductor part no; SLF10145T100M2R5. 24S2V75 Filter B Filter C 24S3V3 Filter B Filter C 24S05 Filter B Filter D Table 7 - Model/Filter cross-reference E.U.T. 2 x 4F Film Caps Inductor Dependent on Input Voltage + Vin E.U.T. 2 x 4F Film Caps Figure 5 - Filter B SM Ferrite Resistance to Soldering Heat The EXA40 is intended for PCB mounting. Artesyn has determined how well it can resist the temperatures associated with the soldering of PTH components without affecting its performance or reliability. The method used to verify this is MIL-STD-202 method 210D. Within this method two test conditions were specified, Soldering Iron condition A and Wave Solder condition C. For the soldering iron test the UUT was placed on a PCB with the recommended PCB layout pattern shown in the applications section. A soldering iron set to 350C 10C was applied to each terminal for 5 seconds. The UUT was then removed from the test PCB and was examined under a microscope for any reflow of the pin solder or physical change to the terminations. None was found. Figure 4 - Filter A - Vin 48Vin models use 47H TDK inductor part no; SLF10145T470M1R4. 7. Use in a Manufacturing Environment + Vin - Vin Film Capacitor ITW Paktron part number 405K100CS4G. Inductor dependent on Input Voltage For the wave soldering test the UUT was again mounted on a test PCB. The unit was wave soldered using the conditions shown in Table 8. Temperature Time Temperature Ramp 260C 5C 10s1 Preheat 4C/s to 160C. 25mm/s rate Table 8 Wave Solder Test Conditions + Vin E.U.T. 2 x 4F Film Caps - Vin Figure 6 - Filter C SM Ferrite Inductor dependent on Input Voltage The UUT was inspected after soldering and no physical change on pin terminations was found. Water Washing The EXA40 is suitable for water washing as it doesn't have any pockets where water may congregate long-term. The user should ensure that a sufficient drying process and period is available to remove the water from the unit after washing + Vin - Vin 2 x 4F Film Caps Figure 7 - Filter D PAGE 5 ESD Control The EXA40's are manufactured in an ESD controlled environment and supplied in conductive packaging to prevent ESD damage occurring before or during shipping. It is essential that they are unpacked and handled using an approved ESD control procedures. Failure to do so could affect the lifetime of the converter. | Application Note 8. Applications Optimum PCB Layout The recommended PCB layout for a double and single sided PCB's are given in Appendix 3. At a minimum 2oz/ft2 or 70m copper should be used. The PCB acts as a heatsink and draws heat from the unit via conduction through the pins and radiation. The two layers also act as EMC shields. If 2oz/ft copper or the recommended layout isn't used then the user needs to ensure that the unit always operates within correct temperature limits by measuring the hotspots indicated in the thermal section. 2 For a double-sided PCB Figure A3-1 and Figure A3-2 should be used Figure A3-4 should be used for single-sided PCB's. Figure A3-5 show locations where via should not be placed on the user application to avoid solder mounds causing isolation problems. Optimum Thermal Performance All models of the EXA40 except the EXA40-24S05 can operate in still air up to a maximum ambient temperature of 70C using the recommended PCB layout shown in the previous section. The EXA40-24S05 is limited to 60C without airflow. Still air which is sometimes called natural convection is defined as 0.1m/s airflow. Above 70C the output power may be derated so that the maximum ambient operating temperature can be extended to 100C as shown in Figure 8 and Figure 9. If forced air cooling is used then the converter may be used up to 95C at full output power dependent on the airflow. Figure 10 is a graph of the maximum allowed ambient temperature at full power versus the airflow across the converter. 100 Max. Ambient Max. Ambient (C) EXA40 SERIES 90 24S05 Only 80 70 60 0 0.5 1.0 Airflow (m/s) 1.5 2.0 Figure 10 - Max. Ambient Temperature at full Power with Forced Airflow If the unit is operated with forced airflow then it may be operated to 100C with linear derating from the maximum ambient specified in Figure 10. Figure 11 shows the derating for a converter operating with 1.5m/s forc ed airflow for all models except the EXA40-24S05. 120% OUTPUT POWER 100% 120% 100% 80% 60% 40% 80% 60% 40% 20% 0% 0 20% 20 0% 40 60 80 88 100 Maximum Ambient (C) -40 -20 0 20 40 60 80 100 Figure 11 - Thermal Derating for 1.5m/s Forced Airflow. Figure 8 - Output Power versus Ambient Temperature in natural Convection Figure 12 shows the derating for an EXA40-24S05 120% 120% 100% 100% OUTPUT POWER 80% 60% 40% 20% 0% -40 -20 0 20 40 60 80 90 100 Figure 9 - Output Power versus Ambient Temperature in natural Convection for the EXA40-24S05 80% 60% 40% 20% 0% 0 20 40 60 78 100 Maximum Ambient (C) Figure 12 - Thermal Derating for 1.5m/s Forced Airflow. http://www.artesyn.com PAGE 6 EXA40 SERIES | Application Note The most accurate method of ensuring that the converter is operating within its guidelines in a chosen application is to measure the temperature of a hot-spot. There are three such spots on the EXA40 and which is the hottest is dependent on the input line voltage, output load and the ambient temperature. In general they will be within 10C of each other. These hot spots are shown in Figure 13. They are the main primary switch and the two secondary synchronous rectifiers, each of which is a D2PAK. Other Suitable Devices: 74LS15 74LS03 74LS26 74LS12 74LS22 74LS136 74LS266 Input + Input 74LSO1 Remote On/Off Hot Spots Figure 15 Implementation of Remote On/Off with TTL Devices Input + Input - Output + Output - Figure 13 Hot Spot Locations When measuring the temperature of these points the thermocouple should be mounted as closely as possible to the tab of the device. In order to maintain the Artesyn Derating criteria the temperatures of the devices should never exceed 120C. Remote On/Off Control The remote On/Off control is a primary referenced function which allows the converter to be put into a low power dissipating sleep mode. The maximum current taken by unit during this mode is 2mA over all line and temperature conditions. The remote On/Off pin can source typically 70A of current into the collector of a transistor and can be directly connected to an optocoupler open collector output. The following three figures provide details of methods of connecting to the remote on/off pin. Remote On/Off Trim Secondary Side Control Circuitry Figure 16 Secondary Side control of Remote On/Off Output Voltage Adjust The output voltage can be adjusted by connecting a resistor between the output trim pin and either the output high or low pin. For the 2.75V, 3.3V and 5V outputs the trim function has a range of approximately 10%. For the 1.8V output the trim range is typically +13%/-18%. The following three figures show how the output may be trimmed either high or low while Appendix 1 contains graphs which plot the output voltage against the trim resistor for all models. Input + Input Remote On/Off Output + Output Trim Figure 14 Implementation of Remote On/Off with a single Transistor PAGE 7 Figure 17 Output Trim Low using a Fixed resistor or Potentiometer EXA40 SERIES | Application Note Output + Output Trim Figure 18 Output Trim High using a Fixed resistor or Potentiometer Output + Output Trim Figure 19 Variable Output Trim using a Potentiometer http://www.artesyn.com PAGE 8 EXA40 SERIES | Application Note Appendix 1 Output Voltage Trim Curves 2.1 2.0 1.9 1.8 1.7 1.6 1.5 1.4 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 32000 36000 40000 Figure A1-1 - 1.8V Output Voltage vs. Trim Resistor Value 3.1 3.0 2.9 2.8 2.7 2.6 2.5 2.4 0 4000 8000 12000 16000 20000 24000 28000 Figure A1-2 - 2.75V Output Voltage vs. Trim Resistor Value PAGE 9 EXA40 SERIES | Application Note Appendix 1 Output Voltage Trim Curves 3.8 3.7 3.6 3.5 3.4 3.3 3.2 3.1 3.0 2.9 0 4000 8000 12000 16000 20000 Figure A1-3 - 3.3V Output Voltage vs. Trim Resistor Value 5.6 5.4 5.2 5.0 4.8 4.6 4.4 0 8000 16000 24000 32000 40000 48000 56000 Figure A1-4 - 5V Output Voltage vs. Trim Resistor Value http://www.artesyn.com PAGE 10 EXA40 SERIES | Application Note Appendix 2 Output TVS Rating Peak Power, Pp (kW) 100 10 1 0.1 0.1 1 10 100 1,000 10,000 Pulse Width, Tp (s) Figure A2-1 - TVS Output Rating vs. Pulse Width @ 25C Ambient Peak Pulse Derating (%) 120% 100% 80% 60% 40% 20% 0% 0 25 50 75 Ambient Temperature (C) Figure A2-2 - Output TVS Peak Pulse Derating vs. Ambient Temperature PAGE 11 100 EXA40 SERIES | Application Note Appendix 2 Output TVS Rating Derating Factor 1.00 Pulse Width 0.10 10ms 1ms 10us 100us 0.01 0.1 0.2 0.5 1 2 5 10 20 50 100 Duty Cycle (%) Figure A2-3 3.3V Output Voltage vs. Trim Resistor Value Appendix 3 Recommended PCB Layouts VIEW IS FROM TOP SIDE BOTTOM SIDE LAYER 2 OF 2 VIEW IS FROM TOP SIDE TOP SIDE LAYER 1 OF 2 VIEW IS FROM TOP SIDE BOTTOM SIDE LAYER 1 OF 1 2.20 (55.88) 2.20 (55.88) 0.08 (2.00) Isolation Remote On/Off 2.20 (55.88) 0.08 (2.00) Isolation 0.08 (2.00) Isolation Trim -Vin +Vin +Vout -Vout 2.20 (55.88) 2.20 (55.88) Remote On/Off Trim -Vin -Vout +Vin +Vout 2.20 (55.88) 0.04 (1.00) 2 Places THERMAL RELIEF IN CONDUCTOR PLANES REFERENCE IPC-D-275 SECTION 5.3.2.3 THERMAL RELIEF IN CONDUCTOR PLANES REFERENCE IPC-D-275 SECTION 5.3.2.3 ALL DIMENSIONS IN INCHES (mm) ALL TOLERANCES ARE 0.10 (0.004) ALL DIMENSIONS IN INCHES (mm) ALL TOLERANCES ARE 0.10 (0.004) Figure A3-1 - Recommended Top Layer Footprint Figure A3-2 - Recommended Bottom Layer Footprint http://www.artesyn.com THERMAL RELIEF IN CONDUCTOR PLANES REFERENCE IPC-D-275 SECTION 5.3.2.3 ALL DIMENSIONS IN INCHES (mm) ALL TOLERANCES ARE 0.10 (0.004) Figure A3-3 - Recommended Single Sided PCB Layout PAGE 12 EXA40 SERIES | Application Note Appendix 3 Recommended PCB Layouts ROUTE VIA HOLES AWAY FROM SHADED AREAS 2.20 (55.88) 2.09 (53.14) 1.91 (48.46) o0.12 (o3.00) 4 Places 2.20 (55.88) 2.10 (53.39) Typ. 1.21 (30.83) 0.98 (24.90) 0.88 (22.46) 0.10 (2.50) 0.92 Typ. (23.48) 0.08 (2.00) Typ. 0.78 (19.80) 0.25 (6.35) 0.90 (22.86) 1.02 (25.92) 1.26 (32.00) 1.57 (40.01) 2.00 (50.80) 2.13 (54.07) Typ. ALL DIMENSIONS IN INCHES (mm) ALL TOLERANCES ARE 0.10 (0.004) Figure A3-4 Footprint Via Keep-out Areas PAGE 13 1.22 (30.98) http://www.artesyn.com PAGE 14 AN_EXA40_19990209_PRE.PDF Data Sheet (c) Artesyn Technologies(R) 2000 The information and specifications contained in this data sheet are believed to be correct at time of publication. However, Artesyn Technologies accepts no responsibility for consequences arising from printing errors or inaccuracies. Specifications are subject to change without notice. No rights under any patent accompany the sale of any such product(s) or information contained herein.