Octal Industrial Digital Input with Diagnostics

Industry's Smallest, Robust, Octal Digital Input

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The MAX22190 is an IEC 61131-2 compliant industrial digital input device. The MAX22190 translates eight, 24V current-sinking, industrial inputs to a serialized SPI-compatible output that interfaces with 3V to 5.5V logic. A current setting resistor allows the MAX22190 to be configured for Type 1, Type 2, or Type 3 inputs. Field wiring is verified for proximity switches, by a second threshold detector on each input. When wire-break is enabled, the active-low FAULT output is asserted and a register flag is set if the input current drops below the wire-break threshold for more than 20ms. Additional diagnostics that assert the active-ow FAULT pin include: overtemperature, low 24V field supply, 24V field supply missing, CRC communication error, etc.

For robust operation in industrial environments, each input includes a programmable glitch filter. The filter delay on each channel can be independently programmed to one of eight values between 50μs and 20ms, or filter bypass.

The MAX22190 has a 4-pin SPI interface and in addition uses the active-low LATCH input for synchronizing input data across multiple devices in parallel.

MAX22190 field-side accepts a single 7V to 65V supply to VDD24 pin. When powered by the field supply, MAX22190 generates a 3.3V output from an integrated LDO regulator, which can provide up to 25mA of current for external loads in addition to powering the MAX22190. Alternatively, MAX22190 can be powered from a 3.0V to 5.5V logic side supply connected to VDD pin. For flexibility, the SPI interface operates at 3.3V or 5V logic levels as controlled by the VL pin.

Design Solution: Industrial Digital Inputs: They’re Not Quite as Simple as Counting from 0 to 1 ›

MAX22190: Functional/Block Diagram MAX22190: Functional/Block Diagram Enlarge+

Key Features

  • High Integration Reduces BOM Count and Board Space
    • Eight Input Channels with Serializer
    • Operates Directly from Field Supply (7V to 65V)
    • Compatible with 3.3V or 5V Logic
    • 5mm x 5mm TQFN Package
  • Reduced Power and Heat Dissipation
    • Accurate Input-Current Limiters
    • Energyless Field-Side LED Drivers
  • Fault Tolerant with Built-In Diagnostics
    • Input Protection to ±40V with Low-Input Leakage Current
    • Wire Break Detection
    • Integrated Field-Supply Voltage Monitors
    • Integrated Overtemperature Monitors
    • 5-Bit CRC Code Generation and Transmission for Error Detection
  • Configurability Enables Wide Range of Applications
    • Configurable IEC 61131-2 Type 1, 2, 3 Inputs
    • Configurable Input Current-Limiting from 0.5mA to 3.4mA
    • Selectable Input Debounce Filtering
  • Robust Design
    • ±8kV Contact ESD and ±15kV Air Gap ESD Using Minimum 1kΩ Resistor
    • ±1kV Surge Tolerant Using Minimum 1kΩ Resistor
    • -40°C to +125°C Ambient Operating Temperature


  • Building Automation
  • Industrial Automation
  • Process Automation
  • Programmable Logic Controllers
Part NumberDigital Input/OutputµC Interface TypeChannelsVSUPPLY
Digital Input TypeCurrent Limit
Current Limit
Min. Detectable Field Input Pulse Width
FeaturesOper. Temp.
MAX22190 Digital InputSPI87650.6
Type 1
Type 2
Type 3
2.12.63Wire-Break Detection-40 to +125
See All Digital I/O (13)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX22190EVKIT: Evaluation Kit for the MAX22190
MAX22190EVSYS: Evaluation Kit for the MAX22190
MAX22190PMB: Evaluation Kit for the MAX22190
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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