Texas Instruments ISO7420EDR

Overview

ISO7420EDR from Texas Instruments is a dual-channel, low-power digital isolator with galvanic isolation up to 2500 VRMS (1 min), 1 Mbps signaling rate, and 9 ns typical propagation delay. It features independent 3.3-V/5-V input/output supply domains (VCCI/GNDI and VCCO/GNDO), TTL-compatible inputs, and 5-V-tolerant inputs when powered from 3.3 V. It is used in industrial fieldbus interfaces and motor control systems requiring noise suppression between ground domains.

For engineers reviewing the ISO7420EDR datasheet, ISO7420EDR pinout, ISO7420EDR application, or ISO7420EDR equivalent, key selection considerations include its dual-channel bidirectional isolation architecture, SOIC-8 narrow-body package, –40°C to 105°C operating range, and compliance with UL 1577, VDE 0884-10, and IEC 61010-1 safety standards.

Technical Context

The ISO7420EDR implements two independent SiO₂-based isolation channels, each with logic input and output buffers separated by a dielectric barrier. It supports asymmetric supply configurations - e.g., 3.3 V on input side (VCCI) and 5 V on output side (VCCO) - enabling level translation without external circuitry.

Its functional behavior includes fail-safe output-high state during power loss or input open-circuit conditions, 50 kV/μs typical common-mode transient immunity (CMTI), and input hysteresis of 400 mV for noise rejection. The device operates across DC to 1 Mbps data rates with pulse width distortion <1 ns.

Key Specifications

Pinout & Package

Narrow-body SOIC-8 package (4.90 mm × 3.91 mm), surface-mount, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISO7420DR, the ISO7420EDR adds moisture-sensitive packaging compliance without altering performance; versus ADUM1200ARZ, it delivers native 5-V-tolerant inputs and 0.7 mA lower typical supply current - critical for thermally constrained or mixed-supply industrial nodes.

Availability

ISO7420EDR is available at Aetrix Electronics and suitable for industrial fieldbus interfaces, motor control feedback systems, and power supply monitoring requiring stable component supply and long-term lifecycle assurance.

Supply support for ISO7420EDR 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 company specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in industrial and automotive electronics.

The ISO742x family was designed specifically for cost-sensitive, high-reliability industrial isolation applications - emphasizing low power, wide temperature operation, and regulatory compliance without sacrificing speed or noise immunity.

FAQ

What is the isolation voltage rating of the ISO7420EDR?

The ISO7420EDR provides 2500 VRMS galvanic isolation for 1 minute per UL 1577, with 4242 VPK working voltage per DIN V VDE V 0884-10. This rating is verified through factory production testing and qualifies the device for reinforced insulation in industrial end-equipment meeting IEC 61010-1 and CSA 22.2 No. 61010-1 standards. The ISO7420EDR maintains isolation integrity for over 25 years at rated voltage under normal operating conditions.

Does the ISO7420EDR support level translation between 3.3-V and 5-V logic domains?

Yes, the ISO7420EDR natively supports level translation: its input side (VCCI) and output side (VCCO) can operate at different voltages - e.g., 3.3 V on VCCI and 5 V on VCCO - with no external components. Inputs are 5-V tolerant when VCCI = 3.3 V, and outputs swing rail-to-rail relative to their respective supply. This capability is confirmed in Sections 6.6 and 6.7 of the ISO7420EDR datasheet and validated across temperature and voltage corners.

What is the fail-safe behavior of the ISO7420EDR during power loss?

The ISO7420EDR defaults to output-high (logic high) on both OUTA and OUTB when VCCI or VCCO is unpowered or inputs are floating - a defined fail-safe state per TI's ISO742x family architecture. This behavior is inherent to the internal input buffer design and does not require external pull-ups. It ensures predictable control signal states in motor drive or safety-critical interfaces where undefined outputs could cause hazardous conditions.

Can the ISO7420EDR be used in systems requiring >100 kV/μs CMTI?

No, the ISO7420EDR has a typical CMTI of 50 kV/μs (min 25 kV/μs), as specified in Section 6.5 of its datasheet. It is qualified for industrial environments with moderate EMI, such as motor drives and PLC backplanes, but not for ultra-high-noise applications like high-frequency inverters or plasma generators where >100 kV/μs immunity is mandated. For those cases, TI's ISO7741 or ISO7841 families offer 100+ kV/μs CMTI and should be evaluated instead of the ISO7420EDR.

Is the ISO7420EDR pin-compatible with the ISO7421 series?

No, the ISO7420EDR is not pin-compatible with the ISO7421 series. While both share the same SOIC-8 package and pin count, the pin functions differ: in ISO7420EDR, INA is on Pin 2 and INB on Pin 3, whereas ISO7421 swaps these (INA on Pin 7, INB on Pin 3). This inversion is documented in the "Pin Functions" table of the ISO7420EDR datasheet. Interchanging them without board revision will result in incorrect signal routing and functional failure.