EVALUATION KIT AVAILABLE MAX31912 Ultra-Low Power Industrial, Octal, Digital Input Translator/Serializer General Description Benefits and Features The MAX31912 industrial interface serializer translates, Ultra-Low Power and Heat Dissipation conditions, and serializes the 24V digital output of sensors Low Quiescent Current (1.6mA, typ) and switches used in industrial, process, and building Highly Accurate and Stable Input Current Limiters, Adjustable from 0.5mA to 6mA automation to 5V CMOS-compatible signals required by microcontrollers. It provides the front-end interface Special (Patent-Pending) Ultra-Low-Power Mode with Switched Current Limiters circuit of a programmable logic controller (PLC) digital input module. Energy-Less Field-Side LED Drivers High Integration Reduces BOM Count, Board Size, The device features integrated current limiting, lowpass and System Cost filtering, and channel serialization. Input current limiting 8 High-Voltage Input Channels (36V max) allows a significant reduction in power consumed from On-Chip 8-1 Serialization with SPI Interface, the field voltage supply as compared to traditional dis- On-Chip 5V Regulator crete resistor-divider implementations. Selectable on-chip On-Chip Overtemperature Indicator lowpass filters allow flexible debouncing and filtering of Dual On-Chip Field Supply Voltage Monitors sensor outputs based on the application. Integrated Debounce Filters, Selectable from 0 to 3ms On-chip serialization allows a drastic reduction in the Robust Features and Performance for Industrial number of optocouplers used for isolation. The device Environments serializer is stackable so that any number of input channels Multibit CRC Code Generation and Transmission for can be serialized and output through only one SPI- Error Detection and More Reliable Data Transmission compatible port. This reduces the number of optocouplers High ESD Immunity on All Field Input Pins needed to only three, regardless of the number of input Accepts Industry Standard Input Types channels. Configurable for IEC 61131-2 Input Types 1, 2, and 3 Flexible Power Supply Capability Enables Usage in For enhanced robustness with respect to high-frequency 5V, 12V, 24V, and Higher Voltage Systems noise and fast electrical transients, a multibit CRC code Wide Operating Field Supply Range of 7V to 36V is generated and transmitted through the SPI port for Can Be Powered from the Logic-Side Using a 5V each 8 bits of data. The on-chip 5V voltage regulator can Supply be used to power external optocouplers, digital isolators, or other external 5V circuitry. Field-side LED drivers recycle Applications the current from the eight inputs to provide visual input Digital Input Modules for PLCs status indication without any additional current or power Industrial, Building, and Process Automation consumption. Motor Control The MAX31912 uses patent-pending circuit techniques to achieve further reduction of power beyond what is possible by input current limiting alone. For low-cost applications, Maxim Integrated offers a pin- Ordering Information appears at end of data sheet. compatible version of this device, the MAX31913, which does not include the patent-pending current-switching circuitry included in the MAX31912. 19-6925 Rev 3 4/15MAX31912 Ultra-Low Power Industrial, Octal, Digital Input Translator/Serializer Block Diagram 24V 5V 5VOUT V CC24V 5V REGULATOR MAX31912 VREF SUPPLY FAULTB MONITOR TEMP MONITOR DB0 DB1 RIREF SWITCHED CRC GEN. RT1 CURRENT LIMITER IN1 CONTROLLER LP SENSORS SIN OR FILTER ISOLATION MODESEL VOLTAGE COMPARATOR VREF CLK SERIALIZER CS INPUT CHANNEL 0 RT8 SOUT INPUT CHANNEL 7 IN8 GND