概述
The MAX31913 industrial interface serializer translates， conditions， and serializes the 24V digital output of sensors and switches used in industrial， process， and building automation to 5V CMOS-compatible signals required by microcontrollers. It provides the front-end interface circuit of a programmable logic controller （PLC） digital input module. The device features integrated current limiting， lowpass filtering， and channel serialization. Input current limiting allows a significant reduction in power consumed from the field voltage supply as compared to traditional discrete resistor-divider implementations. Selectable on-chip lowpass filters allow flexible debouncing and filtering of sensor outputs based on the application. On-chip serialization allows a drastic reduction in the number of optocouplers used for isolation. The device serializer is stackable so that any number of input channels can be serialized and output through only one SPI-compatible port. This reduces the number of optocouplers needed to only three， regardless of the number of input channels. For enhanced robustness with respect to high-frequency noise and fast electrical transients， a multibit CRC code is generated and transmitted through the SPI port for each 8 bits of data. The on-chip 5V voltage regulator can be used to power external optocouplers， digital isolators， or other external 5V circuitry. Field-side LED drivers recycle the current from the eight inputs to provide visual input status indication without any additional current or power consumption.
For ultra-low-power applications， and for the lowest possible heat dissipation. Maxim Integrated plans to offer a pin-compatible version of this device， the MAX31912. The MAX31912 uses patent-pending circuit techniques to achieve further reduction of power beyond what is possible by input current limiting alone. Contact the factory for availability
關鍵特性
Eight High-Voltage Input Channels （36V max）
Configurable for IEC 61131-2 Input Types 1， 2， 3
Wide Operating Supply Range of 7V to 36V
Optional Configuration Allows 5V Supply
Selectable Input Filtering and Debouncing from 0ms to 3ms
Configurable Input Current Limiting from 0.5mA to 6mA
High HBM ESD Immunity on All Field Input Pins
On-Chip 8-to-1 Serialization with SPI Interface
On-Chip 5V Regulator
Overtemperature Indicator
On-Chip 24V Field Supply Voltage Monitor
Very Low Quiescent Current and Power/Heat Dissipation
Multibit CRC Code Generation and Transmission for Error Detection and More Reliable Data Transmission to an External Micro
Field-Side Energyless LED Drivers
圖表
Typical Application Circuit
詳細PDF資料請下載：MAX31913數據規格書