开关电源的PCB布局指南

1、 AN-1229© 2002 National Semiconductor Corporation AN200426SIMPLE SWITCHER ®PCB 2A N -1229 200426011.1a CBYPASS CIN 1b 1c PCB PWM , AN-12293 V IR 1.4 0.5 1 20 1 1A 2.5 IC PCB 20 SIMPLE SWITCHER V L*dI/dt 1A dI/dt 1a 1b 1c dI/dt 1.2 0.8 FET , LM267x 30ns , LM259x 75ns 30ns 1 1A 0.7V 2.5mV 2

2、3A 4V 1c 1a 1b , IC SW , VIN 1c VIN , Np/Ns RCD , EMI IC IC V*dtL*dI , L V*dt , COMP IC , 4A N -1229 dI/dt 1 FET FET / IC IC IC CBYPASS IC acap , X Y Z 1c CIN CBYPASS - - IC / Cuk Cuk - LM267x / ESR ESL VIN 1 FET IC IC / VIN 100kHz 260kHz 10MHz 30MHz / PWM FET 1 CBYPASS IC VIN GND 0.1F 0.47F X7R 120

3、6 , 0612 ESR/ESL CIN 1 IC LM267x AN-12295 acap IC IC SW GND RC 10: 100: 470pF 2.2nF 1/2 C V 2 f RC IC GND 1c IC IC SMT IC 2 PCB X 6A N -1229 AN-1229 7 w PCB L 1 2 3 x PCB x PCB 1.78AWG20 32 0.081 1 1000 2.54 , L 21 L 0.16 L 17 21 3 PCB / / 10 L d 3.20042606 EMI SMT PCB FR4 IC PCB / PCB FR4 EMI , EMI

4、 PCB / , 45 90 , A , , 8A N -1229 20C 30C 40C 4 4. MIL-STD-275E20042607, PCB 1 2 1 1.4 35m 2 2 1 1.4 20C 4A 75/1.454 1.4 2 0.7 1 /PTH 1.4 PCB 10 Buck 1c IC Io D Io D Io 1D 3A |Vo/Vin 0.41.2A 1.8A 3A 30C FR4 120C , 30C 5A 1 12 2 7 B 1 2 / PCB PCB PCB , , PCB AN-1229 9 C PCB 1 1 3 2 30C/W SMT FR4 GF G

5、10 CEM1CEM2CEM3 FR4 10% 20% 50% 70% Simple Switcher EMI IC GND 2 IC X PCB 0.3 0.33 , 1 1.2 / / IC Buck Boost Buck-Boost / EMI EMI Mica Sil-pads SMT EMI Buck , 0.5V 5A 0.4 5 0.5 (1-0.4=1.5W 100C 55C, 1005545C 1.5W 45/1.530C/W PCB AP Rth C/W 6.790.52.6 1 2 , 2 , , PCB PCB EMI 10A N -1229 2 X , IC SMT

6、2 PCB SIMPLE SWITCHER , Simple Switcher 1. AND/OR2. SMT / IC IC5a 5b , 5b IC 5c IC Io R 5d 5c 5d 5d AN-1229 20042608 5. 11 SIMPLE SWITCHER® PCB a 1. / b CSP-9-111C2 CSP-9-111S2CSP-9-111S2 RoHS National Semiconductor Americas Customer Support Center Email: new.feedback Tel: 1-800-272-9959 National Semiconductor Europe Customer Support Center Fax: +49 (0 180-530 85 86 Email: europe.support Deutsch Tel: +49 (0 69 9508 6208 English Tel: +44 (0 870 24 0 2171 Français Tel: +33 (0 1 41 91 8790 National Semiconductor #UKC2CEKE%WUVQOGT Support Center Email: ap.support National Semico