1 Features
1• Compliant to IEC 61131-2; Type 1, 2, 3
characteristics for 24-V isolated digital inputs
• Supports 9-V to 300-V DC and AC digital input
designs using external resistors
• 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 VDE V 0884-11
– UL 1577 recognition, 2500-VRMS insulation
– IEC 60950-1, IEC 62368-1, IEC 61010-1 and
GB 4943.1-2011 certifications

2 Applications
• Programmable Logic Controller (PLC)
– Digital Input Modules
– Mixed I/O Modules
• Motor Drive I/O and Position Feedback
• CNC Control
• Data Acquisition
• Binary Input Modules

3 Description
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. These
devices enable 9-V to 300-V DC and AC digital input
modules in programmable logic controllers (PLCs),
motor-control, grid infrastructure, and other industrial
applications. 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, How To Improve Speed and Reliability of
Isolated Digital Inputs in Motor Drives TI TechNote,
and How to Design Isolated Comparators for ±48V,
110V and 240V DC and AC Detection TI TechNote.