Features and Benefits

  • High Integration for Flexible Circuit Designs
    • Interfaces to Optocouplers or Digital Isolators
    • Capable of Driving an Optocoupler and Status LED
    • Operational as Sink or Source Digital Input
    • Ultra-High Speed: 250ns (max) Propagation Delay
    • Test Pulse Diagnostic
    • Allows for Small Footprint TVS Surge Protection
  • Reduced Power and Heat Dissipation
    • Parasitically Powered from the Field Input
    • Accurate ±15% Input-Current Limiting
    • 100µA (typ) Quiescent Current with Optocoupler
    • 96% (typ) Current-Transfer Efficiency to Optocoupler
  • Robust Design
    • Operates from -60V to +60V Input Voltage
    • -40°C to +125°C Ambient Operating Temperature

Product Details

The MAX22191 is an IEC 61131-2 compliant, industrial digital input (DI) device. The MAX22191 translates a 24V industrial switching signal to a 3.3V/5V CMOS-level output, or to a 2.3mA (typ) current output for driving an optocoupler and/or LED. Voltage thresholds and current levels in the MAX22191 are compliant with Type 1 and Type 3 inputs, while minimizing power dissipation. The MAX22191 is also compliant with 48V inputs, with the addition of external resistors.

Operating power is derived from the input signal, eliminating the need for an external field-side power supply. A 250ns (max) fast response time is ideal for high-speed inputs. Additionally, a CMOS-compatible test input is available for safety diagnostics.

The MAX22191 features robust functionality for harsh industrial systems and is capable of normal operation with input signals ranging from -60V to +60V. Integrated thermal shutdown further protects the device when VCC is present.

The MAX22191 is available in a small, 6-lead SOT23 package and operates over the -40°C to +125°C ambient temperature range.

Design Solution: Worried About Heat in Your I/O Module? No Need to Sweat ›


  • Current Sourcing Inputs
  • Individually Isolated Inputs
  • Industrial Automation
  • Motor Controls
  • Process Automation

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.