MP2307 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED STEP-DOWN CONVERTER 5) Connect IN, SW, and especially GND External Bootstrap Diode respectively to a large copper area to cool An external bootstrap diode may enhance the the chip to improve thermal performance efficiency of the regulator, the applicable and long-term reliability. conditions of external BS diode are: z VOUT is 5V or 3.3V; and V z Duty cycle is high: D= OUT >65% IN V In these cases, an external BS diode is recommended from the output of the voltage regulator to BS pin, as shown in Figure3 External BST Diode IN4148 BS C MP2307 BST SW 5V or 3.3V L COUT Figure 3—Add Optional External BootstrapDiode to Enhance Efficiency The recommended external BS diode is IN4148, and the BS cap is 0.1~1µF. TOP Layer MP2393 O RECOMMENDED FOR NEW DESIGNS NOT