AEE Series Te c h n i c a l R e f e r e n c e N o t e s 3.3V,5V,5.2V,8V,12V,15V Single Output 10W DC-DC Converter REV02 USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 -1www.astec.com AEE-24S/48S DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Introduction Design Features The AEE series of switching DC-DC converters 2" X 1" package is one of the most cost effective options avail- High efficiency able in component power. The AEE uses an industry standard package size and pinout con- High power density figuration, but has a lower profile than most 10 watts of output power competitive products. This allows users the additional headroom often needed in card cage 2:1 wide input of 18-36V and 36-72V configurations, or can be used to improve air- Output short circuit protection flow and cooling efficiency. Output current limiting AEE converters come in 24V or 48V input ver- Wide operating case temperature range: sions, each of which uses a 2:1 input range. -25C~ +95C Outputs are isolated from the input and single or dual output versions are available.AEE converters are capable of providing up to 10 watts of output power. Application At startup, input current passes through an DATACOM equipment input filter designed to help meet CISPR 22 level A radiated emissions, and Bellcore Computer equipment GR1089 conducted emissions. A fuse should be used in line with the input to the module. Distributed power architecture Communications equipment The AEE converters are pulse width modulated (PWM) and operate at a nominal fixed frequency of 330 kHz. Feedback to the PWM controller uses an opto-isolator, maintaining complete isolation between primary and secondary. Caution should be taken to avoid ground loops when connecting the converter to ground. USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -2- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Typical Application Fuse L1 +Vin Vin C2 +Vo C1 C4 C3 Load -Vo -Vin Note: For the min. load requirement of AV10-24S/48S series, see ordering information on Page 4. Recommended : L1: 10-12H C1: m 47F/100V electrolytic capacitor C2: 1F/100V metal film or ceramic high frequency capacitor (The detailed information about C1 and C2 can refer to the paragraph " Input Filter" on page 16.) C3: See the "Output Filter" on page 18. C4: 1F ceramic capacitor Block Diagram USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -3- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Model Numbering A E E 01 - L 24 24: Input Voltage Output Voltage: 8V Output Current: 1A 1 X 2 Thru Hole Enhanced Thermals Series Ordering Information ModeI Number Input Voltage (V) Input Current(A) Max Output Current(A) Min Max Ripple (mV rms) Max Noise (mV pp) Max Efficiency typ (%) Output Voltage (V) Output Capacitor (uF) AEE02F24 24 0.62 0.13 2.5 20 75 77 3.3 1000 AEE02A24 24 0.72 0.1 2 20 100 78 5 1000 AEE01L24 24 0.72 0.02 1.25 20 100 80 8 100 AEE00B24 24 0.7 20 100 82 12 100 AEE00C24 24 0.7 0.03 0.67 20 100 82 15 100 AEE02F48 48 0.31 0.13 2.5 20 75 77 3.3 1000 AEE02A48 48 0.36 0.1 2 20 100 80 5 2200 AEE02A48-5.2 48 AEE01L48 48 AEE00B48 AEE00C48 0.04 0.05 2 20 100 78 5.2 100 0.72 0.02 1.25 20 100 80 8 100 48 0.35 0.04 0.84 20 100 85 12 330 48 0.35 0.03 0.67 20 100 85 15 100 USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 0.36 0.84 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -4- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Absolute Maximum Rating Characteristic Min Typ Max Units Notes Input Voltage(continuous) 40/80 Vdc 24Vin/48Vin Input Voltage(peak/surge) 50/100 Vdc 24Vin/48Vin,100ms non-repetitive Case temperature -25 95 C storage temperature -40 105 C Input Characteristics Characteristic Min Typ Max Units Notes Input Voltage Range 18 24 36 Vdc For 24Vin 36 48 72 Vdc For 48Vin 10 %Iin Input Reflected Current Turn-off Input Voltage Vdc Turn-on Input Voltage Vdc Turn On Time 250 ms General Specifications Characteristic Min MTBF Typ Max 3,730 Isolation 500 Hand Soldering Time TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 k Hrs Bellcore TR332, Tcase=30C 260 C wave solder < 10 s 5 s iron temperature 425C 24 USA Notes Vdc Pin solder temperature Weight Units grams Asia 852-2437-9662 852-2402-4426 www.astec.com -5- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t AEE02F24 / F48 Output Characteristics Characteristic Min Power Output Current Output Setpoint Voltage 3.23 Typ Max Units 10 W 2.55 A 3.3 Notes 3.37 Vdc Vin=24V/48V, Io=2.5A Line Regulation 0.2 %Vo Vin=18~36V/36~72V, Io=2.5A Load Regulation 1 %Vo Io=0~2.5A, Vin=24V/48V 250 mV Ta=25C, di/dt=1A/10s 500 s Ta=25C, di/dt=1A/10s 250 mV 500 s 3.6 A Dynamic Response 50-75% load 50-25% load Current Limit Threshold 2.8 3.0 Short Circuit Current Ta=25C, di/dt=1A/10s Ta=25C, di/dt=1A/10s A Efficiency 75 77 % Trim Range Vin=24V/48V, Io=2.5A, Ta=25C %Vo Over Voltage Protection Setpoint V Temperature Regulation 0.02 Ripple (rms) 20 mV ( 0 to 20MHz Bandwidth ) Noise (p-p) 75 mV ( 0 to 20MHz Bandwidth ) Switching Frequency USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 330 Europe 44-(0)1384-842-211 44-(0)1384-843-355 %Vo/C kHz Asia 852-2437-9662 852-2402-4426 www.astec.com -6- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t AEE02A24/A48 Output Characteristics Characteristic Min Typ Max Units Power 10 W Output Current 2 A Output Setpoint Voltage 4.95 5 Notes 5.05 Vdc Vin=24V/48, Io=2A Line Regulation 0.2 %Vo Vin=18~36V/36~72V, Io=2A Load Regulation 0.5 %Vo Io=0~2A, Vin=24V/36V 100 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 100 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 3 A Dynamic Response 50-75% load 50-25% load Current Limit Threshold 2.2 Short Circuit Current A Efficiency 77/76 78/80 % Trim Range Vin=24Vor48V, Io=2A, Ta=25C %Vo Over Voltage Protection Setpoint V Temperature Regulation 0.02 %Vo/C Ripple (rms) 20 mV ( 0 to 20MHz Bandwidth ) Noise (p-p) 100 mV ( 0 to 20MHz Bandwidth ) Switching Frequency USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 330 Europe 44-(0)1384-842-211 44-(0)1384-843-355 kHz Asia 852-2437-9662 852-2402-4426 www.astec.com -7- AV 1 0 - 2 4 S / 4 8 S D C - D C C o n v e r t e r s 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t AV1048S5V2 Output Characteristics Characteristic Min Typ Max Units Power 10 W Output Current 2 A Output Setpoint Voltage 5.5 5.2 5.25 Vdc Notes Vin=24V/48, Io=2A Line Regulation 0.2 %Vo Vin=18~36V/36~72V, Io=2A Load Regulation 0.5 %Vo Io=0~2A, Vin=24V/36V 200 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 200 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 3 A Dynamic Response 50-75% load 50-25% load Current Limit Threshold 2.2 Short Circuit Current Efficiency A 76 78 % Trim Range Vin=24Vor48V, Io=2A, Ta=25C %Vo Over Voltage Protection Setpoint V Temperature Regulation 0.02 %Vo/C Ripple (rms) 20 mV ( 0 to 20MHz Bandwidth ) Noise (p-p) 100 mV ( 0 to 20MHz Bandwidth ) Switching Frequency 330 kHz Tel: 28780808 www.emersonnetworkpower.com.cn fax: 28788578 -8- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t AEE01L24/L48 Output Characteristics Characteristic Min Power Output Current Output Setpoint Voltage 7.92 Typ Max Units 10 W 1.25 A 8 9.08 Vdc Notes Vin=24V/48v, Io=1.25A Line Regulation 0.2 %Vo Vin=18~36V/36~48, Io=0.84A Load Regulation 0.5 %Vo Io=0~0.84A, Vin=24V/48V 120 mV 200 s Ta=25C, di/dt=1A/10s 120 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 2 A Dynamic Response 50-75% load 50-25% load Current Limit Threshold 1.5 Short Circuit Current Ta=25C, di/dt=1A/10s A Efficiency 78 80 % Trim Range Vin=24/48V, Io=1.25A,Ta=25C %Vo Over Voltage Protection Setpoint V Temperature Regulation 0.02 %Vo/C Ripple (rms) 20 mV ( 0 to 20MHz Bandwidth ) Noise (pp) 100 mV ( 0 to 20MHz Bandwidth ) Switching Frequency 330 kHz USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -9- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t AEE00B24/B48 Output Characteristics Characteristic Min Power Output Current Output Setpoint Voltage 11.88 Typ Max Units 10 W 0.84 A 12 Notes 12.12 Vdc Vin=24V/48v, Io=0.84A Line Regulation 0.2 %Vo Vin=18~36V/36~48, Io=0.84A Load Regulation 0.5 %Vo Io=0~0.84A, Vin=24V/48V 100 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 100 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 1.26 A Dynamic Response 50-75% load 50-25% load Current Limit Threshold 0.93 Short Circuit Current A Efficiency 81/81 82/85 % Trim Range Vin=24/48V, Io=0.84A,Ta=25C %Vo Over Voltage Protection Setpoint V Temperature Regulation 0.02 %Vo/C Ripple (rms) 20 mV ( 0 to 20MHz Bandwidth ) Noise (pp) 100 mV ( 0 to 20MHz Bandwidth ) Switching Frequency 330 kHz USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -10- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t AEE00C24/C48 Output Characteristics Characteristic Min Power Output Current Output Setpoint Voltage 14.85 Typ Max Units 10 W 0.67 A 15 Notes 15.15 Vdc Vin=24/48V, Io=0.67A Line Regulation 0.2 %Vo Vin=18~36V/36~72V, Io=0.67A Load Regulation 0.5 %Vo Io=0~0.67A, Vin=24V/48V 100 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 100 mV Ta=25C, di/dt=1A/10s 200 s Ta=25C, di/dt=1A/10s 1 A Dynamic Response 50-75% load 50-25% load Current Limit Threshold 0.74 Short Circuit Current A Efficiency 81/81 82/85 % Trim Range Vin=24/48V, Io=0.67A, Ta=25C %Vo Over Voltage Protection Setpoint V Temperature Regulation 0.02 %Vo/C Ripple (rms) 20 mV ( 0 to 20MHz Bandwidth ) Noise (pp) 100 mV ( 0 to 20MHz Bandwidth ) Switching Frequency 330 kHz USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -11- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Characteristic Curves AEE02F24 AEE02A24 AEE01L24 AEE00B24 AEE00C24 Typical Efficiency Curves AEE 48V input Series Efficiency (%) Efficiency (%) Typical Efficiency Curves AEE 24V input Series Output Current (amps) Output Current (amps) Typical Input Current AEE 48input Series Input Current (amps) Input Current (amps) Typical Input Current AEE 24input Series AEE02F24 AEE02A24 AEE00B24 AEE00C24 AEE01L24 USA AEE02F48 AEE02A48-5V2 AEE01L48 AEE00B48 AEE00C48 Input Voltage (volts) TEL: 1-760-930-4600 FAX: 1-760-930-0698 AEE02F48 AEE02A48/5V2 AEE01L48 AEE00BF48 AEE00C48 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Input Voltage (volts) Asia 852-2437-9662 852-2402-4426 www.astec.com -12- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Characteristic Curves Typical Overcurrent Curves AEE02-01 F/A/L 48 Typical Overcurrent Curves AEE02-01 F/A/L 24 8 7 7 Output Voltage (volts) Output Voltage (volts) 8 AEE02F48 AEE02A48/-5V2 AEE01L48 AEE02F24 AEE02A24 AEE01L24 Output Current (amps) Output Current (amps) Typical Overcurrent Curves AEE 00B/C 24 Output Voltage (volts) Output Voltage (volts) Typical Overcurrent Curves AEE 00B/C 48 AEE00B48 AEE00C48 AEE00B24 AEE00C24 Output Current (amps) Output Current (amps) USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -13- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t T ransient response (rated input voltage, step load, at 25 C) Typical Transient Response to Step Load Change from 50%-25%Iomax AEE00B24 Typical Transient Response to Step Load Change from 50%-75%Iomax AEE00B24 Typical Output Startup From Power On AEE00B24 Typical Output Startup From Power On AEE00B48 USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -14- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Characteristic Measurement of reflected noise current (with an simulated source impedance of 12 uH, and current is detected at the input of the module) Measurement of output ripple (p-p) ground wire loop L C2 C1 Derating Curves AEE 48V Input 100 Maximum Case Temperature Percent maximum output power Typical Output Ripple and Noise AEE 48V Input 80 Safe Operating Area 60 40 20 0 -20 -10 0 10 20 30 40 50 60 70 80 90 100 Ambient Temperature in degrees C USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -15- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Table 1 Pin Location The +Vin and -Vin input connection pins are located as shown in Figure 1. AEE converters have a 2:1 input voltage range of 18-36V or 3672V. Care should be taken to avoid applying reverse polarity to the input which can damage the converter. Series Fuse Rating 24Vin 48Vin 2A 1A Input Reverse Voltage Voltage Protection Under installation and cabling conditions where reverse polarity across the input may occur, reverse polarity protection is recommended. Protection can easily be provided as shown in Figure 2. In both cases the diode rating is rated for 2A/100V. Placing the diode across the inputs rather than in-line with the input offers an advantage in that the diode only conducts in a reverse polarity condition, which increases circuit efficiency and thermal performance. Fig.1 Pin Location Input Characteristic TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 +Vin -Vin -Vin Fig.2 Reverse Polarity Protection Circuits Fusing The AEE series power module has no internal fuse. An external fuse must always be employed! To meet international safety requirements, a 250 Volt rated fuse should be used. If one of the input lines is connected to chassis ground, then the fuse must be placed in the other input line. Standard safety agency regulations require input fusing. Recommended fuse ratings for the AEE series are shown in Table 1. USA +Vin Input Filter Input filters are included in the converters to help achieve standard system emissions certifications. Some users however, may find that additional input filtering is necessary. The AEE series has an internal switching frequency of 330 kHz so a high frequency capacitor mounted close to the input terminals produces the best results. To reduce reflected noise, a capacitor can be added across the input as shown in Figure 3, forming a filter. A Asia 852-2437-9662 852-2402-4426 www.astec.com -16- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t certain rules must be followed in the design of the system using the module. In particular, all of the creepage and clearance requirements of the end-use safety requirement must be observed. These documents include EN60950, UL-1950, and CSA 22.2-960. Also specific applications need to receive other or additional requirements. +Vin C1 -Vin Fig.3 Ripple Rejection Input Filter 47F/100V electrolytic capacitor is recommended for C1. For conditions where EMI is a concern, a different input filter can be used. Figure 4 shows an input filter designed to reduce EMI effects. L1 is a 12 H differential inductor, C1is a 47F/100V electrolytic capacitor, and C2 is a 1F/100V metal film or ceramic high frequency capacitor. When a filter inductor L1 is connected in series with the power converter input, an input capacitor C2 should be added. An input capacitor C2 should also be used when the input wiring is long, since the wiring can act as an inductor. Failure to use an input capacitor under these conditions can produce large input voltage spikes and an unstable output. L1 C2 Safety Consideration For safety-agency approval of the system in which the power module is used, the power module must be installed in compliance with the spacing and separation requirements of the end-use safety agency standard, i.e., UL1950, CSA C22.2 No. 950-95, and EN60950. The input-to-output 500VDC isolation is an operational insulation. The DC/DC power module should be installed in end-use equipment, in compliance with the requirements of the ultimate application, and is intended to be supplied by an isolated secondary circuit. When the supply to the DC/DC power module meets all the requirements for SELV(<60Vdc), the output is considered to remain within SELV limits (level 3). If connected to a 60Vdc power system, double or reinforced insulation must be provided in the power supply that isolates the input from any hazardous voltages, including the ac mains. One Vi pin and one Vo pin are to be grounded or both the input and output pins are to be kept floating. Single fault testing in the power supply must be performed in combination with the DC/DC power module to demonstrate that the output meets the requirement for SELV. The input pins of the module are not operator accessible. +Vin C1 -Vin Fig.4 EMI Reduction Input Filter Input-Output Characteristic Isolation The isolation voltage between input to output, input to case and case to output are all greater than 500 Volt DC. If the system using the power module needs to meet safety agency approval, USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Note: Do not ground either of the input pins of the module, without grounding one of the output pins. This may allow a non-SELV voltage to appear between the output pin and ground. Asia 852-2437-9662 852-2402-4426 www.astec.com -17- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Figure 6. The recommended output capacitor is 100uF/25V aluminum (or tantalum) electrolytic capacitor. Extra care should be taken when long leads or traces are used to provide power to the load. Long lead lengths increase the chance for noise to appear on the lines. Under these conditions a capacitor C4 can be added across the load as shown in Figure 7. The recommended component for C4 is 1F ceramic capacitor. Output Characteristics Minimum Load Requirements There is 3% minimum load required for the AEE series modules. Overcurrent Protection (OCP) AEE series DC/DC converters feature foldback current limiting as part of their Overcurrent Protection (OCP) circuits. When output current exceeds 110 to 150% of rated current, such as during a short circuit condition, the output will shutdown. Note: If input voltage exceeds 60V, the continuous shortcircuit may damage the module or decrease its life. When the overcurrent condition is removed, the converter will automatically restart. +Vout C3 Load -Vout Fig.6 Output Ripple Filter +Vout C3 C4 Load -Vout Output Voltage (volts) Fig.7 Output Ripple Filter For a Distant Load Decoupling Noise on the power distribution system is not always created by the converter. High speed analog or digital loads with dynamic power demands can cause noise to cross the power inductor back onto the input lines. Noise can be reduced by decoupling the load. In most cases, connecting a 10 F tantalum capacitor in parallel with a 0.1F ceramic capacitor across the load will decouple it. The capacitors should be connected as close to the load as possible. AEE00B24 AEE00C24 Fig.5 Overcurrent Foldback Output Filters When the load is sensitive to ripple and noise, an output filter can be added to minimize the effects. A simple output filter to reduce output ripple and noise can be made by connecting a capacitor C3 across the output as shown in USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -18- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Design Considerations I1 + I2 + I3 I2 + I3 I3 RL2 RL1 RL3 +Vout Ground Loops Ground loops occur when different circuits are given multiple paths to common or earth ground, as shown in Figure 8. Multiple ground points can slightly different potential and cause current flow through the circuit from one point to another. This can result in additional noise in all the circuits. To eliminate the problem, circuits should be designed with a single ground connection as shown in Figure 9. RLine Load 1 Load 3 RG2 RG1 RG3 RL = Lead Resistance RG = Ground Lead Resistance Fig.10 Parallel Power Distribution Radial Power Distribution Radial power distribution is the preferred method of providing power to the load. Figure 11 shows how individual loads are connected directly to the power source. This arrangement requires additional power leads, but it avoids the voltage variation problems associated with the parallel power distribution technique. RLine +Vout Load Load 2 -Vout Load RLine -Vout RLine RLine RLine Ground Loop +Vout RL3 RL1 RL2 Load 1 RL = Lead Resistance RG = Ground Lead Resistance Fig.11 Radial Power Distribution RLine +Vout Load Load RLine -Vout Mixed Distribution In the real world a combination of parallel and radial power distribution is often used. Dynamic and high current loads are connected using a radial design, while static and low current loads can be connected in parallel. This combined approach minimizes the drawbacks of a parallel design when a purely radial design is not feasible. RLine RLine Fig.9 Single Point Ground Parallel Power Distribution Figure 10 shows a typical parallel power distribution design. Such designs, sometimes called daisy chains, can be used for very low output currents, but are not normally recommended. The voltage across loads far from the source can vary greatly depending on the IR drops along the leads and changes in the loads closer to the source. Dynamic load conditions increase the potential problems. USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Load 3 RG3 -Vout Fig.8. Ground Loops RLine Load 2 RG2 RG1 Europe 44-(0)1384-842-211 44-(0)1384-843-355 +Vout RL3 RL1 RL4 RL2 Load 1 RG1 Load 2 Load 3 Load 4 RG2 RG3 -Vout RG4 RL = Lead Resistance RG = Ground Lead Resistance Fig.12 Mixed Power Distribution Asia 852-2437-9662 852-2402-4426 www.astec.com -19- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t +Vout Percent maximum output power Figure 14, or airflow over the converter must be provided. When airflow is provided, the case temperature of the converter should be used to determine maximum temperature limits. The minimum operating temperature for the AEE is -25C. Operation at temperatures as low as -40C is possible, but output performance below -25C is not specified. 100 Maximum Case Temperature Redundant Operation A common requirement in high reliability systems is to provide redundant power supplies. The easiest way to do this is to place two converters in parallel, providing fault tolerance but not load sharing. Oring diodes should be used to ensure that failure of one converter will not cause failure of the second. Figure 13 shows such an arrangement. Upon application of power, one of the converters will provide a slightly higher output voltage and will support the full load demand. The second converter will see a zero load condition and will "idle". If the first converter should fail, the second converter will support the full load. When designing redundant converter circuits, Shottky diodes should be used to minimize the forward voltage drop. The voltage drop across the Shottky diodes must also be considered when determining load voltage requirements. 80 Safe Operating Area 60 40 20 0 -20 -10 0 10 20 30 40 50 60 70 80 90 100 Ambient Temperature in degrees C Fig.14 Derating Curves Mechanical Considerations -Vout Load Installation Although AEE series converters can be mounted in any orientation, free air-flowing must be taken. Normally power components are always put at the end of the airflow path or have the separate airflow paths. This can keep other system equipment cooler and increase component life spans. +Vout -Vout Fig.13 Redundant Operation Module Derating Soldering AEE series converters are compatible with standard wave soldering techniques. When wave soldering, the converter pins should be preheated for 20-30 seconds at 110 C, and wave soldered at 260C for less than 10 seconds. When hand soldering, the iron temperature Thermal Derating AEE single and dual output converters are rated for full power up to a case temperature of 95C. Under typical conditions this equates to an ambient temperature of 65C. For operation above ambient air temperatures of 65C, output power must be derated as shown in USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Asia 852-2437-9662 852-2402-4426 www.astec.com -20- AEE01L24/L48 DC-DC Converters 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t should be maintained at 425C and applied to the converter pins for less than 5 seconds. Longer exposure can cause internal damage to the converter. Cleaning can be performed with cleaning solvent IPA or with water. MTBF The MTBF, calculated in accordance with Bellcore TR-NWT-000332 is 3,730,000 hours. Obtaining this MTBF in practice is entirely possible. If the ambient air temperature is expected to exceed +25C, then we also advise a oriented for the best possible cooling in the air stream. Emerson Network Power can supply replacements for converters from other manufacturers, or offer custom solutions. Please contact the company for details. Mechanical Chart (pin-side view) -Vo -Vin +Vin +Vo Tolerances: Inches .xx !0.020 .xxx !0.010 Pins >4mm <4mm USA TEL: 1-760-930-4600 FAX: 1-760-930-0698 Europe 44-(0)1384-842-211 44-(0)1384-843-355 Millimeters .x !0.5 .xx !0.25 !0.02inch ( !0.5mm) !0.01inch ( !0.25mm) Asia 852-2437-9662 852-2402-4426 www.astec.com -21- AV 1 0 - 2 4 S / 4 8 S D C - D C C o n v e r t e r s 1 8 - 3 6 V d c a n d 3 6 - 7 2 V d c I n p u t , 1 0 Wa t t S i n g l e O u t p u t Tel: 28780808 www.emersonnetworkpower.com.cn fax: 28788578 -22-