Analog Devices Inc. ADUM7240CRZ

Overview

ADUM7240CRZ from Analog Devices is a dual-channel, 1 kV functional digital isolator in narrow-body 8-lead SOIC, supporting bidirectional communication up to 25 Mbps with 3.0–5.5 V supply on both sides, <5 ns pulse width distortion (C grade), and 15 kV/µs common-mode transient immunity - used for isolated data converter interfaces in industrial PLC I/O modules.

For engineers reviewing the ADUM7240CRZ datasheet, ADUM7240CRZ pinout, ADUM7240CRZ application, or ADUM7240CRZ equivalent, key selection criteria include channel directionality (A/B inputs → A/B outputs), mixed-voltage level translation (3.3 V ↔ 5 V), thermal derating above 70°C, and absence of default-low output behavior.

Technical Context

The ADUM7240CRZ implements two independent iCoupler® air-core transformer channels with integrated CMOS encoder/decoder circuitry, enabling galvanic isolation without optocoupler aging or LED drive complexity. Its architecture supports simultaneous high-speed NRZ signaling and DC-correct logic state retention via periodic refresh pulses.

Each channel features input glitch filtering, programmable default-high output during input-side power loss, and propagation delay matching within ±10 ns (C grade) between channels. It operates across −40°C to +105°C with no external components required beyond local 0.01–0.1 µF VDD bypass capacitors.

Key Specifications

Pinout & Package

Narrow-body 8-lead SOIC package (SOIC_N), 5.3 mm width, 1.27 mm pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI8620ED-B-IS and ISO7220CDR, the ADUM7240CRZ offers optimal cost-performance balance for functional isolation at 1 kV, with guaranteed default-high outputs and proven robustness in industrial temperature cycling - making it ideal for cost-sensitive, high-volume PLC and sensor interface designs.

Availability

ADUM7240CRZ is available at Aetrix Electronics and suitable for industrial fieldbus isolation, data converter interface, and PLC digital I/O modules requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for ADUM7240CRZ 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, with design centers worldwide.

The ADUM7240CRZ belongs to the iCoupler® digital isolator product line, engineered specifically for replacing optocouplers in industrial automation, energy metering, and motor control systems where reliability, low power, and precise timing are critical.

FAQ

What is the maximum data rate supported by the ADUM7240CRZ?

The ADUM7240CRZ supports up to 25 Mbps NRZ data rate in C grade configuration. This performance is validated under load conditions of CL = 15 pF and applies across the full operating temperature range (−40°C to +105°C). At lower speeds (≤1 Mbps), the device achieves reduced power consumption while maintaining <5 ns pulse width distortion - critical for timing-sensitive applications like encoder signal isolation. The ADUM7240CRZ does not support 50 Mbps or higher rates.

Does the ADUM7240CRZ support level translation between different supply voltages?

Yes, the ADUM7240CRZ supports true bidirectional level translation: VDD1 may operate from 3.0 V to 5.5 V independently of VDD2, which also ranges from 3.0 V to 5.5 V. This enables use cases such as interfacing a 3.3 V microcontroller (VDD1) with a 5 V ADC or transceiver (VDD2). Logic thresholds scale with respective VDDx (VIH = 0.7×VDDx), and output drive strength remains consistent across the voltage range - verified in mixed-supply test tables (e.g., Table 7 and Table 10).

What happens to the outputs of the ADUM7240CRZ when VDD1 is unpowered?

When VDD1 is unpowered while VDD2 remains active, the ADUM7240CRZ outputs (VOA and VOB) default to a high logic state within 1 µs, as confirmed in Table 19 (ADUM7240 Truth Table). This behavior is implemented via an internal watchdog timer and is independent of input pin states (VIA/VIB). It provides fail-safe operation in systems where loss of controller power must not result in undefined or low-level outputs - such as enabling safety relays or disabling gate drivers.

How does the ADUM7240CRZ ensure DC correctness during static input conditions?

The ADUM7240CRZ maintains DC correctness by transmitting periodic refresh pulses (~550–600 kHz) across the isolation barrier when no input transitions occur for >1 µs. These pulses update the output latch to reflect the current input logic state, preventing drift or metastability. This mechanism is intrinsic to the iCoupler® architecture and requires no external components or host intervention - unlike optocouplers, which cannot guarantee static-state retention without continuous toggling.

Is the ADUM7240CRZ pin-compatible with the ADUM7241 series?

No, the ADUM7240CRZ is not pin-compatible with the ADUM7241 series. As shown in Figures 4 and 5 of the datasheet, ADUM7240 has VIA/VIB on pins 2/3 and VOA/VOB on pins 7/6, whereas ADUM7241 swaps output positions (VOA on pin 2, VIA on pin 7). This difference affects PCB layout and firmware mapping - using ADUM7241 in place of ADUM7240CRZ would require board revision and signal reassignment. Both share the same SOIC package footprint but differ in internal channel routing.