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Product Spec Banner
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RT9721A/RT9721B 是一系列低电压单 N-MOSFET 高侧电源开关（High-Side Power Switch），专为自供电（Self-Powered）及汇流排供电（Bus-Powered）的 USB（Universal Serial Bus）应用最佳化设计。RT9721A/RT9721B 内建电荷帮浦（Charge Pump）驱动电路，用于驱动内部 MOSFET 开关；其低导通电阻（RDS(ON)）仅 80mΩ，可满足 USB 规范对电压降的要求。此外，产品提供故障旗标（Flag）输出，可向本地 USB 控制器回报异常状态。 本产品还具备多项保护功能，包括软启动（Soft-Start）功能，可限制插入设备时的涌入电流；过温保护（Thermal Shutdown）功能，可避免高电流负载造成开关元件损坏；以及欠压锁定保护（UVLO），确保只有在有效输入电压存在时元件才会启动。 依据 USB 电源规范要求，双埠应用时最大输出电流限制通常为 750mA。此外，其静态电流低至 50μA，使其非常适合可携式电池供电设备。 RT9721A 不具备输出自动放电（Auto-Discharge）功能，而 RT9721B 则内建输出自动放电功能，可在关闭时快速释放输出端残留电荷。 RT9721A/RT9721B 采用 SOT-23-5 封装，可有效节省电路板空间并降低系统尺寸。
RT9721A/RT9721B 电路图
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<div class="spec-list"><ul class="lv1"><li>Compliant to USB Specifications </li><li>Built-In N-MOSFET <ul class="lv2"> <li></li><li>Typical R<sub>DS(ON)</sub> : 80mΩ </li></ul> </li><li>Output Can Be Forced to Higher Than Input (Off-State) </li><li>Low Supply Current : <ul class="lv2"> <li></li><li>50μA Typical at Switch On State </li><li>0.1μA Typical at Switch Off State </li></ul> </li><li>Guaranteed 500mA Continuous Load Current </li><li>Wide Input Voltage Ranges : 2.5V to 5.5V </li><li>Open-Drain Fault Flag Output </li><li>Hot Plug-In Application (Soft-Start) </li><li>2.15V Typical Under-Voltage Lockout (UVLO) </li><li>Current Limiting Protection </li><li>Thermal Shutdown Protection </li><li>Reverse Current Flow Blocking (no body diode) </li><li>UL Approved-E219878 <img width="42" height="38" alt="" align="middle" style="width: 31px; height: 23px; vertical-align: middle;" src="/assets/2011/08/03/99769apajs.GIF"> </li><li>RoHS Compliant and Halogen Free </li></ul></div>
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RT9721A/RT9721B 订购信息
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<div class="spec-list"><ul class="lv1"><li>USB Bus/Self Powered Hubs </li><li>USB Peripherals </li><li>Notebook, Motherboard PCs </li></ul></div>
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