Isolated digital inputs

Replace your optocoupler and simplify your PLC, grid or motor drive design

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Isolated digital inputs provide galvanic isolation between a sensor input, or other input type, and a logic output for a host controller interface. Compared to traditional optocoupler solutions, our isolated digital input devices provide a simple low-power alternative with an accurate current limit. With solutions providing up to 8-channels, TI's isolated digital inputs provide substantial space savings and lower complexity integrated into one device. This alternative to optocouplers enables the design of compact and high-density I/O modules for PLC, AC and servo drives, and protection relay or substation automation grid applications.

Digital input and output solutions

Discover how our digital input/output portfolio enhances protection, minimizes power consumption, and enables reliable communication in factory and industrial control systems.

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Featured isolated digital inputs

Technical Resources

Application brief

How To Simplify Isolated 24V PLC Digital Input Module Designs (Rev. D)

Are you designing a PLC digital input module? Learn how isolated digital inputs can simplify your design for IEC61131-2 Type 1, Type 2 and Type 3 standards.

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Technical article

What are isolated digital inputs?

Find out how isolated digital inputs differ from digital isolators and why they are designed specifically for programmable logic control (PLC), motor control and grid applications.

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Application brief

How to Improve Speed and Reliability of Isolated Digital Inputs in Motor Drives

Learn how to improve the speed, noise immunity and reliability of isolated digital inputs in motor drive applications.

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Design & development resources

Reference design

Broken Wire Detection Using An Optical Switch Reference Design

This reference design shows a compact implementation of 16 isolated digital input channels using TI's ISO121x devices. The design is split into two groups of eight channels each. A broken wire detection can be executed using only one additional optical switch for each channel or two optical (...)

Reference design

Sub 1-W, 16-Channel, Isolated Digital Input Module Reference Design

This reference design shows a compact implementation of 16 isolated digital input channels using TI's ISO121x devices. The design works without an isolated supply and supports up to 100-kHz input signals (200-kbit) per channel. All 16 channels consume less than 1-W input power combined, which (...)

Reference design

96-Channel Bidirectional Digital Input Module Reference Design for PLC

This reference design is a compact implementation of 96 isolated digital input channels using the ISO1212, an isolated digital input receiver. This design shows the current limit feature of the ISO1212 device which has better thermal performance than traditional optocoupler solutions. This design (...)