Analog Devices Inc./Maxim Integrated ADUM1252ASA+T

Overview

ADUM1252ASA+T from Analog Devices is a bidirectional I²C isolator with two open-drain isolated channels, ultra-low standby current (21 µA per side), 1.71 V to 5.5 V dual-supply operation, and 2 MHz SCL support. It enables robust hot-swap on Side 2 via idle-bus detection and precharge, and delivers low VOL (0.69 V on Side 1, 0.4 V on Side 2) for compatibility with legacy I²C devices in battery management and PoE systems.

For engineers reviewing the ADUM1252ASA+T datasheet, ADUM1252ASA+T pinout, ADUM1252ASA+T application, or ADUM1252ASA+T equivalent, key selection criteria include bidirectional I²C timing integrity across isolation, side-specific logic-low regulation, hot-swap bus state monitoring, and reinforced isolation ratings up to 848 VRMS (wide SOIC).

Technical Context

The ADUM1252ASA+T implements galvanically isolated bidirectional I²C communication using iCoupler® technology. Side 1 uses regulated buffers to fix VOL at 0.64 V and maintain ΔVO/IT ≥ 45 mV, preventing latch-up; Side 2 uses conventional buffers with 50 mA sink capability and voltage-dependent VIH/VIL thresholds.

Its idle-bus hot-swap logic monitors SDA2/SCL2 for STOP or sustained high states before enabling cross-side connection, while internal precharge (VPRECHG = 0.3 × VDD2, RPRECHG = 140 kΩ) prevents glitches during plug-in. Propagation delays range from 35.9 ns to 133.3 ns depending on supply and load conditions.

Key Specifications

Pinout & Package

ADUM1252ASA+T is packaged in an 8-pin narrow-body SOIC (SOIC_N-8) with creepage/clearance of 4 mm and reinforced isolation rating. Pin functions are validated per Analog Devices' official pinout diagram and datasheet Rev 1 (2024).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI8602ED-B-IS and ISO1540DR, ADUM1252ASA+T uniquely combines Side 1 VOL regulation, Side 2 hot-swap readiness, and 2 MHz timing-making it the only option qualified for battery pack telemetry and PoE PD enumeration where bus reliability during dynamic insertion is mandatory.

Availability

ADUM1252ASA+T is available at Aetrix Electronics and suitable for battery management systems, Power over Ethernet infrastructure, and industrial motor control applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for ADUM1252ASA+T 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The ADuM1252 belongs to Analog Devices' iCoupler® digital isolator product line, engineered specifically for reliable, low-power, bidirectional I²C/SMBus isolation in safety-critical and energy-constrained systems.

FAQ

What is the maximum ambient operating temperature for ADUM1252ASA+T?

The ADUM1252ASA+T is rated for operation from −40°C to +125°C ambient temperature. Its thermal design supports junction temperatures up to +150°C, and the narrow SOIC package has θJA = 182°C/W. Derating begins above +70°C, with power dissipation limited to 440 mW at +25°C ambient.

Does ADUM1252ASA+T support clock stretching across the isolation barrier?

Yes, ADUM1252ASA+T fully supports clock stretching in both directions. Its bidirectional architecture preserves SCL arbitration and allows slaves on either side to hold SCL low-enabling standard I²C protocol compliance for devices like EEPROMs or ADCs that require extended response time.

How does the hot-swap feature of ADUM1252ASA+T prevent I²C bus corruption?

ADUM1252ASA+T prevents bus corruption by precharging SDA2/SCL2 to 0.3 × VDD2 and waiting ≥75 µs for an idle bus (both lines high) or STOP condition before enabling cross-side conduction. This eliminates false START/STOP generation during mechanical insertion, ensuring protocol integrity in live systems.

What is the minimum pull-up resistor value recommended for SDA2/SCL2 when using ADUM1252ASA+T?

With 50 mA sink capability on Side 2, ADUM1252ASA+T supports pull-up resistors as low as 1 kΩ for 3.3 V buses (yielding ~300 ns rise time into 400 pF). For 400 kHz operation, 2.2 kΩ is typical; for 2 MHz, ≤1.5 kΩ is recommended-always verifying against actual bus capacitance and VOL limits.

Is ADUM1252ASA+T certified for reinforced isolation per IEC 60747-17?

Yes, ADUM1252ASA+T in the narrow SOIC package is pending certification per IEC 60747-17 with VIORM = 630 VPEAK and VIOWM = 445 VRMS. It also meets pending UL 1577 (3000 VRMS/1 min) and CSA C22.2 No. 14-18 requirements for reinforced insulation in industrial equipment.