Texas Instruments ISO7220AD

Overview

ISO7220AD from Texas Instruments is a dual-channel digital isolator with 1 Mbps signaling rate, 4000 V_PK isolation rating per VDE, and SOIC-8 package. It provides galvanic isolation between input and output domains using silicon-dioxide (SiO₂) barrier technology, supports 3.3 V or 5 V dual supplies, and features <1 ns channel-to-channel output skew and <1 ns pulse-width distortion for precise timing-critical industrial interfaces.

For engineers reviewing the ISO7220AD datasheet, ISO7220AD pinout, ISO7220AD application, or ISO7220AD equivalent, this device serves as a robust, safety-certified solution for Modbus/Profibus data bus isolation, servo control signal conditioning, and factory automation I/O modules requiring high CMTI (>25 kV/μs), wide temperature operation (–40°C to +125°C), and fail-safe logic-high output on input power loss.

Technical Context

The ISO7220AD uses TI's SiO₂ isolation barrier to separate two independent CMOS channels with bidirectional signal translation. Its architecture includes differential comparator-based output recovery, periodic DC-refresh pulses every 4 μs, and failsafe circuitry that drives outputs high if refresh pulses are missed - ensuring predictable behavior during input-side power failure.

It implements TTL-compatible input thresholds with integrated noise filtering, supports asymmetric supply configurations (e.g., 5 V input / 3.3 V output), and delivers 4 mA CMOS output drive capability. The device is characterized for operation across –40°C to +125°C ambient and meets VDE 0884-17, UL 1577, and IEC 62368-1 safety standards.

Key Specifications

Pinout & Package

ISO7220AD is housed in an 8-pin SOIC (D package) with 4.90 mm × 3.91 mm body size and 4.9 mm × 6 mm overall footprint. Pin numbering follows standard SOIC top-view orientation with isolation barrier separating input-side (pins 1, 4, 7, 8) and output-side (pins 2, 3, 5, 6) terminals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel digital isolator applications.

Compared with ISO7220CDR and ADUM1200ARZ, ISO7220AD offers the optimal balance of certified safety, predictable failsafe behavior, and sufficient speed for legacy industrial protocols - making it ideal for retrofitting existing Modbus/Profibus installations without redesigning layout or firmware.

Availability

ISO7220AD is available at Aetrix Electronics and suitable for factory automation, servo control interface, and data acquisition systems requiring stable component supply, long-lifecycle support, and compliance with international safety standards.

Supply support for ISO7220AD 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 specializing in analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The ISO722x family was designed specifically for high-reliability industrial isolation needs - delivering certified galvanic separation, fail-safe operation, and robust EMC performance in harsh electromagnetic environments.

FAQ

What is the maximum signaling rate supported by ISO7220AD?

The ISO7220AD supports a maximum signaling rate of 1 Mbps, as specified in its A-option variant designation. This rate is validated across the full operating temperature range (–40°C to +125°C) and under recommended supply conditions (3.3 V or 5 V). At this rate, the device maintains ≤18 ns pulse-width distortion and ≤600 ns propagation delay, making it suitable for Modbus RTU and Profibus DP implementations without timing margin violations. ISO7220AD does not support higher rates like the C- or M-options.

Does ISO7220AD require external components for basic operation?

No, ISO7220AD operates autonomously with only decoupling capacitors (0.1 μF ceramic per supply rail) recommended near VCC1 and VCC2 pins. It integrates input noise filtering, failsafe monitoring, and DC-refresh circuitry internally. No external resistors, capacitors, or level shifters are needed for standard 3.3 V/5 V dual-supply operation. The ISO7220AD pinout and internal architecture eliminate dependency on external timing or biasing networks.

How does the failsafe function behave in ISO7220AD?

In ISO7220AD, the failsafe circuit monitors periodic 4 μs DC-refresh pulses across the isolation barrier. If these pulses cease - indicating input-side power loss or signal inactivity - the output stage drives both OUTA and OUTB to logic high within 3 μs. This behavior is inherent to the ISO7220AD design and requires no configuration. It ensures defined output states during fault conditions, directly supporting SIL-2 functional safety requirements in industrial control systems.

Can ISO7220AD operate with mismatched supply voltages?

Yes, ISO7220AD supports asymmetric supply configurations such as 5 V on VCC1 (input side) and 3.3 V on VCC2 (output side), or vice versa. Input pins remain 5 V tolerant regardless of VCC1 voltage, and outputs deliver full CMOS swing referenced to VCC2. This flexibility allows ISO7220AD to bridge mixed-voltage domains - for example, isolating a 5 V microcontroller UART from a 3.3 V FPGA interface - without external level translators.

What safety certifications apply to ISO7220AD?

ISO7220AD is certified to DIN EN IEC 60747-17 (VDE 0884-17) for reinforced isolation, UL 1577 Component Recognition (2500 V_RMS withstand), and IEC 62368-1 for end-equipment safety. These certifications cover the full production lot and are verified through 100% routine testing per UL and VDE requirements. The ISO7220AD datasheet documents VIOTM = 4000 V_PK, VIORM = 560 V_PK, and creepage/clearance ≥4 mm - enabling direct use in safety-critical industrial designs without additional barrier validation.