Analog Devices Inc. ADUM1285BRZ

Overview

ADUM1285BRZ from Analog Devices is a 3 kV_RMS dual-channel digital isolator with default-low output logic, 100 Mbps data rate, 23 ns typical propagation delay, and 3.135 V to 5.5 V dual-supply operation. It enables bidirectional signal isolation in high-noise industrial interfaces such as isolated SPI buses and motor drive control loops.

For engineers reviewing the ADUM1285BRZ datasheet, ADUM1285BRZ pinout, ADUM1285BRZ application, or ADUM1285BRZ equivalent, key selection criteria include its reinforced insulation rating (VIORM = 565 V_PEAK), high common-mode transient immunity (>25 kV/μs), automotive-grade AEC-Q100 qualification, and default-low output behavior distinguishing it from ADUM1280/ADUM1281.

Technical Context

The ADUM1285BRZ implements iCoupler® monolithic air-core transformer technology for galvanic isolation, eliminating LED aging and timing drift inherent in optocouplers. Its two independent channels support asymmetric voltage translation (e.g., 3.3 V side 1 to 5 V side 2) while maintaining dc-correct output states via patented refresh circuitry.

Unlike optocoupler alternatives, the ADUM1285BRZ guarantees output state retention during input-side power loss due to its default-low configuration - critical for fail-safe operation in battery monitor and motor gate driver enable paths. Channel-to-channel matching is specified at ≤5 ns (codirectional) and ≤10 ns (opposing-direction) across −40°C to +125°C.

Key Specifications

Pinout & Package

Narrow-body 8-lead SOIC package (SOIC_N), RoHS-compliant, with creepage and clearance ≥4.0 mm per IEC 62368-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADUM1280BRZ, ADUM1285BRZ provides inverted default logic essential for fail-closed systems; compared with SI8621ED-B-IS, it delivers higher safety certification, superior CMTI, and automotive-grade reliability - making it the sole choice for ISO 26262-relevant battery monitoring and motor control functions.

Availability

ADUM1285BRZ is available at Aetrix Electronics and suitable for industrial motor drives, automotive battery monitors, isolated SPI interfaces, and programmable logic controller I/O modules requiring stable component supply across extended temperature and safety-critical operating conditions.

Supply support for ADUM1285BRZ 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 technologies, serving industrial, automotive, communications, and healthcare markets.

The ADUM1285BRZ belongs to the iCoupler® digital isolator product line, engineered specifically for robust galvanic isolation in high-noise, high-reliability applications including EV powertrain systems and industrial automation.

FAQ

What is the default output state of ADUM1285BRZ during power-up?

The ADUM1285BRZ features a default-low output configuration: both VOA and VOB pins assert logic low when VDD1 or VDD2 is unpowered or during initial power application. This behavior is confirmed in Table 24 of the Rev. E datasheet and ensures fail-safe operation in gate driver and enable-line applications. The ADUM1285BRZ maintains this state until valid input transitions occur and supplies stabilize.

Does ADUM1285BRZ support mixed-voltage operation between 3.3 V and 5 V domains?

Yes, ADUM1285BRZ supports mixed-voltage operation: VDD1 may be 3.3 V while VDD2 is 5 V (or vice versa), enabling direct level translation across the isolation barrier. Electrical characteristics for 3.3 V/5 V and 5 V/3.3 V configurations are fully specified in Tables 7 and 10 of the datasheet, with propagation delay remaining ≤31 ns and data rate sustaining 100 Mbps.

What safety certifications does ADUM1285BRZ hold?

ADUM1285BRZ is certified to UL 1577 (3000 V_RMS, 1 min), IEC/EN/CSA 62368-1, IEC/CSA 61010-1, and DIN EN IEC 60747-17 (VDE 0884-17) with VIORM = 565 V_PEAK. These approvals confirm reinforced insulation suitability for functional safety applications in industrial and automotive systems, as documented in Tables 14 and 16 of the Rev. E datasheet.

How does ADUM1285BRZ maintain dc correctness without input toggling?

ADUM1285BRZ uses Analog Devices' patented refresh circuitry to periodically sample and retransmit the last valid input state, ensuring correct dc output levels even with static inputs. The refresh period is fixed at 1.6 µs (Table 3, 6, 9, 12), eliminating the need for external clocks or pulse injection - a key advantage over optocouplers and competing capacitive isolators.

Is ADUM1285BRZ pin-compatible with other members of the ADUM128x family?

ADUM1285BRZ shares identical pinout and package (8-lead narrow SOIC) with ADUM1280BRZ, ADUM1281BRZ, and ADUM1286BRZ, as shown in Figures 4 and 5 of the datasheet. However, output default states differ: ADUM1285BRZ and ADUM1286BRZ are default-low, while ADUM1280BRZ and ADUM1281BRZ are default-high - requiring firmware or logic-level verification before substitution.