MAX31914 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – Ultra-Low Power Industrial

MAX31914
EVALUATION KIT AVAILABLE
Ultra-Low Power Industrial, Octal,
Digital Input Translator
General Description
The MAX31914 translates and conditions the 24V digi-
tal 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 signal voltage translation is performed in conjunction
with input current limiting and lowpass filtering. Input
current limiting allows a significant reduction in power
consumed from the field-supply voltage, as compared
to traditional discrete resistor-divider implementations.
To achieve the lowest in-class power dissipation, the IC
uses patent-pending circuit techniques to achieve further
reduction of power dissipation beyond what is possible
by input current limiting alone. This special low-power
operating mode is automatically activated when on-chip
lowpass filtering is selected.
Selectable on-chip lowpass filters allow flexible debouncing
and filtering of sensor inputs based on the application.
When no filtering is selected, the IC is capable of detecting
pulses as short as 0.75µs at its field inputs.
All 8 input channels are translated to CMOS logic levels and
presented in parallel on the eight output pins for direct or
galvanically isolated interface with a controller ASIC or
micro.
The on-chip 5V voltage regulator can be used to power
external optocouplers, digital isolators, or other external
5V circuitry.
For low-cost applications, Maxim Integrated offers a pin
compatible version of this device, the MAX31915, which
does not include the current-switching circuitry included
in the MAX31914.
Applications
●● Digital Input Modules for Programmable
Logic Controllers (PLCs)
●● Industrial Automation, Building Automation
●● Process Automation
Benefits and Features
●● Flexible Supply Options Enables Usage in 24V, 12V,
and 5V Supplied Systems
• 7V to 36V Wide Operating Field-Supply Range
• Device Can Be Optionally Powered from the Logic-
Side Using a 5V Supply
●● Low Power and Low Heat Dissipation
• Very Low Quiescent Current
• Extremely Accurate and Stable Input Current Limiters
• Special Ultra-Low-Power Operating Mode with
Switched Current Limiters
●● Configurability Enables a Wide Range of Standard
and Custom Applications
• Configurable Inputs for IEC 61131-2 Input Types 1,
2, and 3 or for Standard CMOS Logic Levels
• 0.5mA to 6mA Configurable Input Current Limiting
• Selectable Input Filtering and Debounce: 0, 25µs,
0.75ms, and 3ms Settings
●● High Integration Reduces BOM Count and Board
Space
• 8 High-Voltage Input Channels (36V Max)
• 8 CMOS Logic Outputs for High-Speed Simultaneous
Transfer of All Input States to the Controller
• On-Chip 5V Regulator
• On-Chip Overtemperature Indicator
• On-Chip Field-Supply Voltage Monitor
• High HBM ESD Immunity on all Field Input Pins
(15kV HBM)
Ordering Information appears at end of data sheet.
19-7474; Rev 1; 4/15