Neoway N21 Series Hardware User's Manual

Neoway N21 Series Hardware User's Manual Manual pdf 17 page image

N21Hardware User GuideCopyright © Neoway Technology Co., Ltd. All rights reserved. 8Figure 3-1 Recommended circuit design 1Power Supply N21 ModuleD1 C1 C2 C3 C4Close to the pin of the moduleVBATTest pointI_maxC5 The maximum input voltage is 4.3 V and the typical value is 3.6V. The protection voltage across D1 should not exceed the maximum input voltage the module canbear.Place TVS diode close to the input interface of the power supply to clamp the surge voltagebefore it enters back-end circuits. Therefore, the back-end components and the module areprotected. A large bypass tantalum capacitor (220 μF or 100 μF) or aluminum capacitor (470 μF or 1000 μF)is expected at C1 to reduce voltage drops during bursts. Its maximum safe operating voltageshould be higher than 1.5 times the voltage across the power supply. Place a bypass capacitor of low-ESR close to the module to filter out high-frequency noise fromthe power supply.A controllable power supply is preferable if the module is used in harsh conditions. Figure 3-2 showsthe recommended schematic design.