Analog Devices Inc. ADUM1240ARSZ

Overview

ADUM1240ARSZ from Analog Devices is a micropower, dual-channel digital isolator based on iCoupler® transformer technology, providing reinforced 3750 V_rms isolation in a 20-lead SSOP package. It supports bidirectional communication up to 2 Mbps, operates from 2.25 V to 3.6 V supplies, and delivers ultralow quiescent current (5.6 μA/channel with refresh enabled, 0.3 μA/channel with refresh disabled at 3.3 V), enabling use in isolated SPI interfaces and 4 mA–20 mA loop controllers.

For engineers reviewing the ADUM1240ARSZ datasheet, ADUM1240ARSZ pinout, ADUM1240ARSZ application, or ADUM1240ARSZ equivalent, key selection criteria include its 20-lead SSOP package with EN1/EN2 control pins for refresh disable, <8 ns pulse width distortion, 25 kV/μs common-mode transient immunity, and compliance with UL 1577 (3750 V_rms) and VDE V 0884-10 (VIORM = 849 V_peak).

Technical Context

The ADUM1240ARSZ implements two independent, bidirectional CMOS-isolated channels using monolithic air-core transformers and integrated refresh/wdog logic controlled by EN1 and EN2 pins. Its architecture enables deterministic low-power operation: when both ENx pins are tied high, internal refresh is disabled, reducing total supply current to <1 μA per channel at 3.3 V.

It supports asymmetric supply configurations (e.g., VDD1 = 3.3 V / VDD2 = 2.5 V), maintains DC correctness across temperature (−40°C to +125°C), and includes input glitch filtering and undervoltage lockout (UVLO = 1.5 V) on both sides. Propagation delay skew is ≤10 ns (codirectional), and pulse width distortion remains ≤8 ns at 3.3 V operation.

Key Specifications

Pinout & Package

ADUM1240ARSZ is packaged in a 20-lead SSOP (RS-20) with 0.65 mm lead pitch and 5.1 mm minimum PCB clearance. The package supports reinforced isolation and thermal derating up to 150°C case temperature per DIN V VDE V 0884-10.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADUM1240ARSZ, ADUM1241ARSZ offers identical performance with reversed channel mapping-requiring layout verification-while SI8620ED-IS trades off micropower capability for higher isolation voltage and capacitive architecture, making it unsuitable for applications dependent on sub-1 μA/channel operation.

Availability

ADUM1240ARSZ is available at Aetrix Electronics and suitable for industrial automation, energy metering, and motor control applications requiring stable component supply, long-lifecycle assurance, and regulatory-compliant reinforced isolation.

Supply support for ADUM1240ARSZ 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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The ADUM1240ARSZ belongs to the iCoupler® digital isolator product line, engineered specifically for low-power, high-reliability galvanic isolation in industrial, instrumentation, and energy infrastructure systems where safety certification and timing precision are critical.

FAQ

What is the isolation voltage rating of the ADUM1240ARSZ?

The ADUM1240ARSZ is rated for 3750 V_rms for 1 minute per UL 1577 and has a maximum working insulation voltage (VIORM) of 849 V_peak per VDE V 0884-10. These ratings apply specifically to the 20-lead SSOP package variant and confirm reinforced insulation suitability for industrial safety standards including IEC 61800 and IEC 61000-4-5.

Does the ADUM1240ARSZ support bidirectional communication on both channels?

Yes, the ADUM1240ARSZ supports true bidirectional communication on both channels (VIA/VOA and VIB/VOB) without external direction control. Each channel automatically adapts input/output roles based on signal source and load configuration, enabling seamless integration into SPI, I²C, and custom serial protocols without added logic or routing complexity.

How does the EN1 and EN2 pin functionality affect power consumption in the ADUM1240ARSZ?

In the ADUM1240ARSZ, tying EN1 and EN2 to VDD1/VDD2 disables internal refresh circuitry, reducing quiescent current to 0.3 μA per channel at 3.3 V. When tied to GND1/GND2, refresh is enabled, increasing current to 5.6 μA per channel. Both EN pins must share the same logic state to ensure synchronized operation and DC correctness across the isolation barrier.

Can the ADUM1240ARSZ operate with different supply voltages on each side?

Yes, the ADUM1240ARSZ supports asymmetric supply operation: VDD1 and VDD2 may be independently set between 2.25 V and 3.6 V. Verified configurations include VDD1 = 3.3 V / VDD2 = 2.5 V and VDD1 = 2.5 V / VDD2 = 3.3 V, enabling direct interfacing between 3.3 V microcontrollers and 2.5 V ADCs or DACs without level shifters.

What is the maximum data rate supported by the ADUM1240ARSZ?

The ADUM1240ARSZ supports a maximum data rate of 2 Mbps in nonreturn-to-zero (NRZ) format, verified across the full operating temperature range (−40°C to +125°C) and supply range (2.25 V to 3.6 V). This rate is sustained while maintaining pulse width distortion ≤8 ns and propagation delay skew ≤10 ns, ensuring robust timing margins in high-speed isolated interfaces.