Analog Devices Inc. ADUM2251ARIZ-RL

Overview

ADUM2251ARIZ-RL from Analog Devices is a hot-swappable, dual-channel digital isolator with one bidirectional I²C channel (SDA1/SCL1) and one unidirectional clock channel (SCL2 output), rated for 5 kV rms isolation, 1000 kHz operation, and 3.0–5.5 V dual-supply operation across isolated domains. It enables isolated I²C communication in power supply monitoring and hot-swap server backplanes.

For engineers reviewing the ADUM2251ARIZ-RL datasheet, ADUM2251ARIZ-RL pinout, ADUM2251ARIZ-RL application, or ADUM2251ARIZ-RL equivalent, key selection factors include its reinforced 645 V_PEAK VIORM rating, side-specific logic thresholds (Side 1: fixed 500–700 mV low threshold; Side 2: I²C-compliant 0.3×VDD2), 30 mA SDA2/SCL2 sink capability, and RI-16-2 package with 8.7 mm creepage for medical/industrial safety compliance.

Technical Context

The ADUM2251ARIZ-RL implements iCoupler® chip-scale transformer isolation to split bidirectional I²C signals into dedicated unidirectional magnetic channels, eliminating external signal splitting. Its latch-up prevention relies on ≥50 mV margin between Side 1 output low voltage (600–900 mV) and input low threshold (500–700 mV).

Startup requires both VDD1 and VDD2 ≥2.5 V with ≥40 μs delay after crossing 2.0 V; outputs remain high until valid. Side 2 is fully I²C-compliant (0.3×VDD2 low threshold, 30 mA sink), while Side 1 is I²C-compatible only-requiring connection solely to I²C-compliant devices to avoid bus contention.

Key Specifications

Pinout & Package

ADUM2251ARIZ-RL uses the RI-16-2 package: 16-lead SOIC wide-body with enhanced creepage (8.7 mm) and clearance for reinforced insulation per IEC 62368-1 and IEC 60601-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C isolator applications.

Compared with ADUM2251ARWZ-RL, the ADUM2251ARIZ-RL provides critical 8.7 mm creepage and IEC 60601-1 2 MOPP certification for medical systems; versus SI8621ED-B-IS, it delivers superior 35 kV/μs CMTI and integrated hot-swap logic-reducing BOM count and improving reliability in dynamic power systems.

Availability

ADUM2251ARIZ-RL is available at Aetrix Electronics and suitable for server power management, medical isolated monitoring, industrial PLC backplanes, and Power over Ethernet (PoE) PSE controllers requiring stable component supply with long-term lifecycle assurance.

Supply support for ADUM2251ARIZ-RL 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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial automation, and communications infrastructure.

The ADUM2251ARIZ-RL belongs to Analog Devices' iCoupler® digital isolator product line, engineered specifically for robust, standards-compliant galvanic isolation of I²C, SMBus, and PMBus interfaces in safety-critical and noise-prone applications.

FAQ

What is the key functional difference between ADUM2251ARIZ-RL and ADUM2250ARIZ-RL?

The ADUM2251ARIZ-RL provides one bidirectional I²C channel (SDA1/SCL1) and one unidirectional clock output (SCL2), whereas the ADUM2250ARIZ-RL offers two full bidirectional channels (SDA1/SCL1 and SDA2/SCL2). This makes ADUM2251ARIZ-RL ideal for applications where only clock isolation is needed on one side-reducing pin count and simplifying routing. Both share identical isolation ratings, package, and safety certifications.

Does ADUM2251ARIZ-RL support hot-swap insertion on a live I²C bus?

Yes, ADUM2251ARIZ-RL incorporates dedicated hot-swap circuitry that holds all outputs high until both VDD1 and VDD2 exceed 2.5 V and stabilize for ≥40 μs. This prevents bus contention or false START/STOP conditions during live card insertion-critical for redundant server power supplies and modular industrial controllers where ADUM2251ARIZ-RL is deployed.

What safety certifications apply specifically to the ADUM2251ARIZ-RL variant?

The ADUM2251ARIZ-RL carries the RI-16-2 package, which is certified to DIN EN IEC 60747-17 (VDE 0884-17) for reinforced isolation, UL 1577 (5000 V_rms), IEC 60601-1 (2 MOPP, 250 V_rms), and IEC 61010-1 (reinforced, 300 V_rms, overvoltage category II). These certifications are validated for the RI-16-2 package only-not the RW-16 variant-making ADUM2251ARIZ-RL suitable for medical and test equipment.

Can ADUM2251ARIZ-RL be used with 3.3 V logic on Side 1 and 5 V logic on Side 2?

Yes, ADUM2251ARIZ-RL supports independent 3.0–5.5 V supplies on each side. Side 1 operates with 3.3 V logic (VDD1 = 3.3 V), maintaining fixed 500–700 mV input thresholds and 600–900 mV output low levels. Side 2 runs at 5 V (VDD2 = 5 V), delivering I²C-compliant 0.3×VDD2 = 1.5 V low threshold and 30 mA sink-enabling seamless interfacing between mixed-voltage domains in ADUM2251ARIZ-RL-based systems.

What is the maximum capacitive load supported on the SDA1/SCL1 pins of ADUM2251ARIZ-RL at 400 kHz?

At 400 kHz fast-mode operation with VDD1 = 3.3 V, ADUM2251ARIZ-RL supports up to 188 pF on SDA1/SCL1 when using the minimum recommended pull-up resistor (235 Ω). This value scales inversely with pull-up resistance-e.g., doubling R1 to 470 Ω reduces max CL to ~94 pF. The 40 pF limit cited in datasheets applies only to 1 Mbps operation; ADUM2251ARIZ-RL's design allows relaxed loading at lower speeds.