Isolated 24-V to 60-V Digital Input Receivers for Digital Input Modules

Isolated 24-V to 60-V Digital Input Receivers for Digital Input Modules - ISO1212


The ISO1211 and ISO1212 devices are isolated 24-V to 60-V digital input receivers, compliant to IEC 61131-2 Type 1, 2, and 3 characteristics, suitable for programmable logic controllers (PLCs) and motor-control digital input modules. Unlike traditional optocoupler solutions with discrete, imprecise current limiting circuitry, the ISO121x devices provide a simple, low-power solution with an accurate current limit to enable the design of compact and high-density I/O modules. These devices do not require field-side power supply and are configurable as sourcing or sinking inputs.

The ISO121x devices operate over the supply range of 2.25 V to 5.5 V, supporting 2.5-V, 3.3-V, and 5-V controllers. A ±60-V input tolerance with reverse polarity protection helps ensure the input pins are protected in case of faults with negligible reverse current. These devices support up to 4-Mbps data rates passing a minimum pulse width of 150 ns for high-speed operation. The ISO1211 device is ideal for designs that require channel-to-channel isolation and the ISO1212 device is ideal for multichannel space-constrained designs.

The ISO121x devices reduce component count, simplify system design, improve performance, and reduce board temperatures compared to traditional solutions. For details, refer to the How To Simplify Isolated 24-V PLC Digital Input Module Designs TI TechNote and How To Improve Speed and Reliability of Isolated Digital Inputs in Motor Drives TI TechNote.


  • Compliant to IEC 61131-2; Type 1, 2, 3 Characteristics
  • Accurate Current Limit for Low-Power Dissipation:
    • 2.2 mA to 2.47 mA for Type 3
    • Adjustable up to 6.5 mA
  • Eliminates the Need for Field-Side Power Supply
  • High Input-Voltage Range With Reverse Polarity Protection: ±60 V
  • Wire-Break Detection (Refer to TIDA-01509)
  • Configurable as Sourcing or Sinking Input
  • High Data Rates: Up to 4 Mbps
  • Enable Pin to Multiplex Output Signals
  • High Transient Immunity: ±70-kV/µs CMTI
  • Wide Supply Range (VCC1): 2.25 V to 5.5 V
  • Ambient Temperature Range: –40°C to +125°C
  • Compact Package Options:
    • Single-Channel ISO1211, SOIC-8
    • Dual-Channel ISO1212, SSOP-16
  • Safety-Related Certifications:
    • Basic Insulation per DIN V VDE V 0884-10
    • UL 1577 Recognition, 2500-VRMS Insulation
    • CSA, CQC, TUV Certificates Available

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Parametrics Compare all products in Digital Isolators

Integrated Isolated Power
Number of Channels (#)
Forward/Reverse Channels
Isolation Rating (Vrms)
Surge Voltage Rating (Vpk)
Data Rate (Max) (Mbps)
Propagation Delay (Typ) (ns)
Default Output
VCC (Min) (V)
VCC (Max) (V)
Operating Temperature Range (C)
ISO1212 ISO1211
No    No   
2    1   
2/0    1/0   
2500    2500   
5200    5200   
4    4   
140    140   
N/A    N/A   
2.25    2.25   
5.5    5.5   
Catalog    Catalog   
-55 to 125    -55 to 125