SMT 50 W TRANSFORMER For use with Semtech's SC4905A/B ! W E N Power Rating: 50W Height: 10.3 mm Max Footprint: 28.8 mm x 20.5 mm Max Electrical Specifications @ 25°C — Operating Temperature -40°C to 130°C Part Number Power Rating 1 Turns Ratio (with 7T Pri. Aux.) Primary Secondary Isolation Primary Inductance (µH MIN) Leakage Inductance (µH MAX) Primary (mΩ MAX) DCR Primary Aux. (mΩ MAX) Secondary (mΩ MAX) PA0273 50 W 1.6:1:1 1500 Vdc Basic 230 .35 65 225 27 Mechanical PA0273 Schematic .850 21,59 .850 21,59 12X PA0273 Date Code Country of Origin .028 0,71 1,2 .930 1.190 23,62 30,23 1.150 MAX 29,21 PRI 1 3,4 SEC 2 5 12X .060 1,52 .118 3,00 .590 15,00 AUX 6 .118 3,00 .590 15,00 .005/0,13 12 SURFACES 10,11,12 Weight . . . . . . . . . . . . . .13.2 grams Tape & Reel . . . . . . . . . . . .100/reel Tray . . . . . . . . . . . . . . . . . . .45/tray SUGGESTED PAD LAYOUT .450 MAX 11,43 .010 ± .002 0,25 ± 0,05 7,8,9 Dimensions: Inches mm Unless otherwise specified, all tolerances are ± .010 0,25 12X .080 2,03 Application Notes • The PA0273 was designed for use with Semtech's SC4905A/B IC datasheet application which details the solution for a low cost, discrete component alternative to 50 W telecom power modules. • The PA0273 transformer was designed for (but not limited to) the following application: Topology: Two-switch forward Frequency: 250 kHz Pri./Sec. Isolation: Basic Insulation (1500 Vdc) Input Voltage: 36-72 v telecom input Output Voltage(s): 12 v / 4.5 A output (with an auxilary primary side control winding - 12 v/100 mA) To determine if the transformer is suitable for your application it is necessary to ensure that the temperature rise of the component (ambient plus temp. rise) does not exceed its operating temperature. To determine the temperature rise of the component it is necessary to calculate the total power losses (core and copper) in the application. Total Copper Losses (Pcu_total(W)) Pcu_total(W) = sum of the losses in each winding The losses in each winding can be calculated by: Pcu(W)= .001* DCR(mΩ) * (Irms2) Core Losses (Pcore(W)) To calculate core loss, use the following formula: CoreLoss (W) = 2.298 E-12 * (Freq_kHz)1.6 * (^B/2)2.5 Where: ^B = (Minimum_Input_Voltage)*(Maximum_DutyCycle)* 105 / (4.96 * Freq_kHz) Temperature Rise Temp.Rise (°C) = 27.27*CoreLoss(W) + 47.4*Pcu_Total Operating Temperature (°C) = Max.Ambient (°C) + Temp.Rise(°C) For More Information : UNITED STATES (Worldwide) UNITED KINGDOM (Northern Europe) FRANCE SINGAPORE (Southern Europe) (Southern Asia) TAIWAN, R.O.C. (Northern Asia) HONG KONG (China/Hong Kong) 12220 World Trade Drive San Diego, CA 92128 U.S.A. http://www.pulseeng.com TEL: 858 674 8100 FAX: 858 674 8262 1 & 2 Huxley Road The Surrey Research Park Guildford, Surrey GU2 5RE United Kingdom TEL: 44 1483 401700 FAX: 44 1483 401701 Zone Industrielle F-39270 Orgelet France TEL: 33 3 84 35 04 04 FAX: 33 3 84 25 46 41 3F-4, No. 81, Sec. 1 HsinTai Wu Road Hsi-Chih, Taipei Hsien Taiwan, R.O.C. Tel: 886 2 2698 0228 FAX: 886 2 2698 0948 19/F, China United Plaza 1008 Tai Nan West Street Cheung Sha Wan, Kowloon Hong Kong, China TEL: 852 2788 6588 FAX: 852 2776 1055 150 Kampong Ampat #07-01/02 KA Centre Singapore 368324 TEL: 65 287 8998 FAX: 65 280 0080 DISTRIBUTOR Performance warranty of products offered on this data sheet is limited to the parameters specified. Data is subject to change without notice. Other brand and product names mentioned herein may be trademarks or registered trademarks of their respective owners. Printed on recycled paper. ©2002, Pulse Engineering, Inc. PRELIMINARY P564.P (8/02)