SIMPLE SWITCHER PCB 布局指南SIMPLE SWITCHER PCB SIMPLE SWITCHER PCB PCB , EMCEMI CAD/ , CAD, PCB , , /CAD 1229 Sanjaya Maniktala 20027 LM267x LM259xLM257x2 Simple Switcher EMI , ICEMI SIMPLE SWITCHER PCB a) b) c) d) e) f) g) h) 2 LM267x/0.1 μF-0.47 μF2 2 X (SMT) , SMT()2 AN-1229 SIMPLE SWITCHER is a Registered Trademark of National Semiconductor. 2002 National Semiconductor Corporation AN200426 www.national.com AN-1229 20042601 1. 1a CBYPASSCIN 1b 1c www.national.com 2 PCB PWM , AN-1229 ǖ ǖ V IR 1.4 0.5 1201 1A2.5 IC PCB 20 SIMPLE SWITCHER V L*dI/dt 1A dI/dt1a 1b 1c dI/dt ǖ 1.2 0.8 FET, LM267x 30 ns, LM259x 75 ns 30 ns1 1A0.7V2.5mV 2 3A 4V1c , Np/ NsRCD , ǖEMI IC IC V*……