Texas Instruments ISO1211DR

Overview

ISO1211DR from Texas Instruments is a single-channel, capacitive-isolated 24V–60V digital input receiver compliant with IEC 61131-2 Type 1/2/3 characteristics. It provides field-side current limiting (2.2–2.47 mA for Type 3), ±60V reverse-polarity input protection, and 4 Mbps data rate - enabling compact, low-power PLC digital input modules without field-side power supply.

For engineers reviewing the ISO1211DR datasheet, ISO1211DR pinout, ISO1211DR application, or ISO1211DR equivalent, key selection criteria include its IEC 61131-2 compliance, accurate current-limiting architecture, high CMTI (±70 kV/µs), wide VCC1 range (2.25–5.5 V), and SOIC-8 package with channel-to-channel isolation.

Technical Context

The ISO1211DR implements capacitive isolation with dual-die architecture separating field-side (IN/SENSE/FGND) and controller-side (OUT/VCC1/GND1) domains. Its internal feedback loop regulates input current via external RSENSE, eliminating discrete current-limiting components and enabling precise Type 3 threshold behavior (VIH = 8.2–8.55 V, VIL = 6.5–7 V).

It supports sourcing or sinking configuration, features an EN pin for output multiplexing, and delivers fast switching (tPHL = 10–15 ns, tPLH = 110–140 ns) with 150 ns minimum pulse width - optimized for high-density industrial I/O where thermal performance (RθJA = 146.1 °C/W) and functional safety documentation support are critical.

Key Specifications

Pinout & Package

ISO1211DR is housed in an 8-pin SOIC (D) package (4.90 mm × 3.91 mm), with creepage/clearance ≥4 mm and 10.5 µm internal DTI. The package supports surface-mount assembly and thermal management via SUB pin connection to a 2 mm × 2 mm floating copper plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar isolated digital input receiver applications.

Compared with Si8920BD-IS and ADUM1250ARZ, the ISO1211DR uniquely integrates IEC 61131-2-compliant input conditioning, programmable current limiting, and output enable in a single SOIC-8 package - reducing bill-of-materials count by up to 7 components per channel and eliminating layout-sensitive analog design.

Availability

ISO1211DR is available at Aetrix Electronics and suitable for PLC digital input modules, motor drive I/O interfaces, and CNC machine control systems requiring stable component supply, long lifecycle support, and certified functional safety documentation.

Supply support for ISO1211DR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader focused on analog and embedded processing technologies, serving industrial, automotive, and communications markets with high-reliability, safety-certified solutions.

The ISO121x family was designed specifically for space-constrained, thermally demanding industrial I/O applications - delivering integrated isolation, precise current limiting, and IEC 61131-2 compliance in minimal footprint packages.

FAQ

What is the maximum input voltage the ISO1211DR can withstand?

The ISO1211DR supports a field-side input voltage range of ±60 V DC with built-in reverse polarity protection. This allows direct connection to 24 V, 48 V, or 60 V industrial field buses without external clamping diodes. Absolute maximum ratings specify –60 V to +60 V on IN and SENSE pins, and the device maintains functionality across this full range while delivering accurate current limiting and IEC 61131-2-compliant thresholds.

How does the ISO1211DR achieve IEC 61131-2 Type 3 compliance?

The ISO1211DR achieves IEC 61131-2 Type 3 compliance through its internally regulated current-limiting architecture. With RSENSE = 562 Ω and RTHR = 0 Ω, it delivers VIH = 8.2–8.55 V and VIL = 6.5–7 V at 24 V input, with 1.0–1.2 V hysteresis - matching Type 3 thresholds exactly. Temperature stability across –40°C to +125°C is ensured by on-chip feedback, eliminating drift seen in resistor-based optocoupler solutions.

Can the ISO1211DR be used in both sourcing and sinking input configurations?

Yes, the ISO1211DR supports both sourcing and sinking configurations via external circuit topology. When the field-side switch connects between power and IN, the device operates as a sinking input. When the switch connects between FGND and SENSE, it functions as a sourcing input. This flexibility enables compatibility with NPN and PNP sensors without changing the IC - only the external resistor network and connection scheme require adjustment.

What safety certifications apply to the ISO1211DR?

The ISO1211DR holds multiple safety certifications including DIN EN IEC 60747-17 (VDE 0884-17), UL 1577 (2500 VRMS), IEC 60950-1, IEC 62368-1, IEC 61010-1, and GB 4943.1-2011. It is rated for basic insulation with 400 VRMS working voltage and 4000 VPK surge isolation. Functional safety documentation - including FMEDA, safety manual, and certification reports - is provided to support IEC 61508 SIL2 and IEC 62061 SIL2 system-level certification.

Does the ISO1211DR require an external power supply on the field side?

No, the ISO1211DR does not require a field-side power supply. It derives operating power directly from the input signal via its regulated current path through IN and SENSE pins. This self-powered architecture eliminates the need for isolated DC-DC converters or auxiliary supplies on the field side - simplifying system design, reducing cost, and improving reliability in multi-channel PLC modules where field-side power distribution is challenging.