MAX3140

SPI/MICROWIRE兼容的UART,集成真正失效保护的RS-485/RS-422收发器


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说明

The MAX3140 is a complete universal asynchronous receiver-transmitter (UART) and a true fail-safe RS-485/RS-422 transceiver combined in a single 28-pin QSOP package for space-, cost-, and power-constrained applications. The MAX3140 saves additional board space as well as microcontroller (µC) I/O pins by featuring an SPI™/QSPI™/MICROWIRE™-compatible serial interface. It is pin-programmable for configuration in all RS-485/RS-422 networks.

The MAX3140 includes a single RS-485/RS-422 driver and receiver featuring true fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This feature provides immunity to faults without requiring complex termination. The MAX3140 provides software-selectable control of half- or full-duplex operation, data rate, slew rate, and transmitter and receiver phase. The RS-485 driver slew rate is programmable to minimize EMI and results in maximum data rates of 115kbps, 500kbps, and 10Mbps. Independent transmitter/receiver phase control enables software correction of twisted-pair polarity reversal. A 1/8-unit-load receiver input impedance allows up to 256 transceivers on the bus.

The MAX3140's UART includes an oscillator circuit derived from an external crystal, and a baud-rate generator with software-programmable divider ratios for all common baud rates from 300 baud to 230k baud. The UART features an 8-word-deep receive FIFO that minimizes processor overhead and provides a flexible interrupt with four maskable sources, including address recognition on 9-bit networks. Two control lines are included for hardware handshaking-one input and one output.

The MAX3140 operates from a single +5V supply and typically consumes only 645µA with the receiver active. Hardware-invoked shutdown reduces supply current to only 20µA. The UART and RS-485/RS-422 functions can be used together or independently since the two functions share only supply and ground connections (the MAX3140 is hardware- and software-compatible with the MAX3100 and MAX3089).
MAX3140:典型应用电路 MAX3140:典型应用电路 放大+

关键特性

  • Integrated UART and RS-485/RS-422 Transceiver in a Single 28-Pin QSOP
  • SPI/MICROWIRE-Compatible Interface Saves µC I/O Pins
  • True Fail-Safe Receiver Output Eliminates Complex Network Termination
  • Pin-Programmable RS-485/RS-422 Features
    • Half/Full-Duplex Operation
    • Slew-Rate Limiting for Reduced EMI
    • 115kbps/500kbps/10Mbps Data Rates
    • Receiver/Transmitter Phase for Twisted-Pair Polarity Reversal
  • Full-Featured UART
    • Programmable Up to 230k baud with a 3.6864MHz Crystal
    • 8-Word Receive FIFO Minimizes Processor Overhead
    • 9-Bit Address-Recognition Interrupt
  • Allows Up to 256 Transceivers on the Bus
  • Low 20µA Hardware Shutdown Mode
  • Hardware/Software-Compatible with MAX3100 and MAX3089

应用

  • 嵌入式系统
  • HVAC与楼宇控制
  • 工业控制局域网
  • 智能仪表
  • 销售终端机(POS)设备
  • 用于EMI敏感应用的收发器
Part NumberµP I/FChannelsICC
(mA)
VSUPPLY
(V)
Package/PinsOper. Temp.
(°C)
Budgetary
Price
typSee Notes
MAX3140 SPI and Microwire Compatible10.75
QSOP HYBRID/28
-40 to +85
0 to +70
$6.02 @1k
查看所有SPI/Microwire-Compatible UARTs (6)
Pricing Notes:
价格仅供参考,用于同类产品的比较。所提供报价为美元,需要依汇率折合成人民币。该价格将因当地关税、税率和汇率而异。有关特定订购量和指定版本的报价和供货问题,请参考:价格与供货网站或与指定代理商联系。

技术资料

设计指南 2141 Determining Clock Accuracy Requirements for UART Communications

质量和环境数据

产品可靠性报告: MAX3140.pdf 
无铅封装的锡(Sn)晶须报告

CAD Symbols and Footprints

  • MAX3140CEI+
  • MAX3140CEI+T
  • MAX3140EEI+
  • MAX3140EEI+T
  • 型号   生产流程   工艺   样本量   不合格   FIT @ 25°C   FIT @ 55°C  

    备注: 通过技术手段对故障率进行汇总,并映射到相关的材料部件号。 故障率与被测件的数量密切相关。

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