外文翻譯--- max232-5v的供電多通道rs-232接口驅(qū)動器接收器-預(yù)覽頁
【正文】 MAX245–MAX247, where these pins are not available. V+ and V are not regulated, so the output voltage drops with increasing load current. Do not load V+ and V to a point that violates the minimum 177。30V inputs. Each driver converts TTL/CMOS input levels into TIA/EIA232F levels. The driver, receiver, and voltagegenerator functions are available as cells in the Texas Instruments LinASIC MAX220–MAX249 contain four sections: dual chargepump DCDC voltage converters, RS232 drivers,RS232 receivers, and receiver and transmitter enable control inputs.Dual ChargePump Voltage ConverterThe MAX220–MAX249 have two internal chargepumps that convert +5V to 177。5V minimum driver output levels under worstcase conditions. These include a minimum 3kΩ load, VCC = +, and maximum operating temperature. Unloaded driver output voltage ranges from (V+ ) to (V +).Input thresholds are both TTL and CMOS inputs of unused drivers can be left unconnected since 400kΩ input pullup resistors to VCC are built in (except for the MAX220). The pullup resistors force theoutputs of unused drivers low because all drivers internal input pullup resistors typically source 12μA, except in shutdown mode where the pullups are outputs turn off and enter a highimpedance state—where leakage current is typically microamperes (maximum 25μA)—when in shutdown mode, in threestate mode, or when device power is removed. Outputs can be driven to 177。并且可以接受177。 該MAX220MAX249包含四個(gè)部分：雙電荷泵型DCDC電壓轉(zhuǎn)換器，RS232接口的驅(qū)動程序，RS232接口接收器和能控制輸入的發(fā)射器。少量的功率可能來自電源外部電路10V(V+）和10V（V）的輸出（見典型工作特性部分），除非MAX225和MAX245MAX247，這些引腳不可用。 當(dāng)在MAX222，MAX225，MAX230，MAX235，MAX236，MAX240，MAX241和MAX245，MAX249中使用停機(jī)功能，應(yīng)避免在電源外部電路使用V+和V。8V。 TTL和CMOS的輸入閥值是相互兼容的。驅(qū)動器輸出端關(guān)閉了并且進(jìn)入了高阻抗?fàn)顟B(tài)下—泄漏電流通常是微安（最大25μA），在停機(jī)模式，三態(tài)模式，或者設(shè)備電源被移除時(shí)。該MAX220沒有上拉電阻使未使用的驅(qū)動器輸出電壓降低。無論三態(tài)門使能端是不是接高電平，TTL/CMOS接收器輸出端都處于高阻抗，三態(tài)模式（為MAX225/MAX235/MAX236/MAX239MAX241），并且關(guān)斷控制端是否高電平也同樣處于高阻抗模式。發(fā)射極與1kΩ的電阻串聯(lián)之后接到6V的外部電壓上。所以TTL接收器和EIA/。接收器傳輸延遲通常是600ns和具有獨(dú)立的輸入擺動方向。此作業(yè)可節(jié)省系統(tǒng)功耗。發(fā)射器有兩種操作模式：全速傳輸（正常激活）和三態(tài)門（禁用端）。關(guān)斷MAX222MAX242 關(guān)于MAX222，MAX235，MAX236，MAX240和MAX241，在關(guān)斷過程中，所有的接收器都被禁用。在MAX223和MAX242也有接收器輸出使能輸入（MAX242和MAX223的使能端），使接收器輸出控制端具有獨(dú)立的SHDN（MAX241為關(guān)斷）。當(dāng)輸入端ENT為邏輯高電平時(shí)，該電荷泵和設(shè)備關(guān)閉。當(dāng)ENR處于邏輯高電平時(shí)，RA1RA4和RB1RB4處于三態(tài)模式狀態(tài)下。第九個(gè)接收器（RB5）始終都是活動的。ENTA和ENTB發(fā)射器每個(gè)輸入端都能控制四個(gè)
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