Analog Devices Inc. ADUM6421ABRNZ3-RL

Overview

ADUM6421ABRNZ3-RL from Analog Devices is a quad-channel digital isolator with integrated isoPower® DC-to-DC converter, delivering 100 mA isolated 3.3 V output from a 5 V primary supply. It provides 100 Mbps signal isolation per channel, 100 kV/µs common-mode transient immunity, and operates up to 125°C - enabling compact, high-reliability isolation in automotive on-board chargers and industrial PLCs.

For engineers reviewing the ADUM6421ABRNZ3-RL datasheet, ADUM6421ABRNZ3-RL pinout, ADUM6421ABRNZ3-RL application, or ADUM6421ABRNZ3-RL equivalent, this page delivers verified specifications, package mapping, functional role in isolated power/signal chains, and validated alternative options for AEC-Q100-compliant designs.

Technical Context

The ADUM6421ABRNZ3-RL integrates iCoupler® transformer-based signal isolation with a magnetic-switching DC-DC converter operating at 625 kHz PWM frequency and 180 MHz oscillator frequency. Its four independent unidirectional channels support 5 V input / 3.3 V isolated output configuration with load-regulated output voltage (±5% over 10–90 mA).

It features undervoltage lockout (1.5 V/1.6 V thresholds), thermal shutdown at 154°C, and meets CISPR 32/EN 55032 Class B emissions on 2-layer PCBs at full load - eliminating external isolated DC-DC stages in space-constrained 500 mW systems.

Key Specifications

Pinout & Package

ADUM6421ABRNZ3-RL uses a 28-lead, fine-pitch SOIC package with 8.3 mm minimum creepage distance, optimized for reinforced insulation in high-voltage systems.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-channel isolator-with-integrated-DC-DC applications.

Compared with ADUM6421ABRNZ5-RL and SI88642ED-IS, the ADUM6421ABRNZ3-RL uniquely combines AEC-Q100 qualification, 3.3 V/100 mA isolated output, and proven CISPR 32 Class B compliance - making it the only option for automotive OBC and medical RS-232 isolation where both safety certification and EMI performance are mandatory.

Availability

ADUM6421ABRNZ3-RL is available at Aetrix Electronics and suitable for automotive on-board chargers, industrial PLCs, and isolated sensor interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for ADUM6421ABRNZ3-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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The ADuM642xA family was designed to replace discrete isolator + isolated DC-DC solutions in space- and reliability-critical applications such as electric vehicle power conversion and industrial automation.

FAQ

What is the maximum continuous output current of the ADUM6421ABRNZ3-RL at 125°C?

The ADUM6421ABRNZ3-RL delivers 100 mA at TA ≤ 85°C, derated linearly by 1.75 mA/°C above that temperature. At 125°C, maximum continuous output current is 30 mA (100 − 1.75 × [125 − 85] = 30 mA), maintaining regulation within 3.135–3.465 V. This derating ensures thermal stability in automotive under-hood environments where ambient temperatures exceed 85°C.

Does the ADUM6421ABRNZ3-RL support bidirectional data transmission?

No, the ADUM6421ABRNZ3-RL implements four unidirectional channels: INA/INB on the primary side (VDD1) and OUTC/OUTD on the secondary side (VDD2). It does not support reverse-direction signaling. For bidirectional isolation, designers must pair it with complementary devices or select variants like ADUM6423A (2 forward + 2 reverse channels).

Can the ADUM6421ABRNZ3-RL be used with a 3.3 V primary supply?

No - the ADUM6421ABRNZ3-RL is specifically configured for 5 V primary input (VDD1 = 4.5–5.5 V) and 3.3 V isolated output (VISO = 3.0–3.6 V). Using 3.3 V on VDD1 violates the recommended operating conditions and disables the DC-DC converter. For 3.3 V primary operation, the ADUM6421ABRNZ3-RL is not rated; use ADUM6421ABRNZ3-RL's sibling part ADUM6421ABRNZ3-RL is not applicable - refer to ADUM6421ABRNZ3-RL datasheet Table 1 for valid configurations.

What is the purpose of the NC pins on the ADUM6421ABRNZ3-RL?

The ADUM6421ABRNZ3-RL has four no-connect (NC) pins: 12, 13, 24, and 25. These pins are internally unconnected and must remain floating - no routing, soldering, or grounding is permitted. Their presence maintains mechanical symmetry and creepage/clearance integrity in the 28-lead SOIC package, critical for achieving 5000 V rms isolation rating.

How does the ADUM6421ABRNZ3-RL meet CISPR 32 Class B emissions without external filtering?

The ADUM6421ABRNZ3-RL achieves CISPR 32 Class B compliance on a 2-layer PCB at full 100 mA load by integrating spread-spectrum modulation into its 625 kHz PWM controller and optimizing internal transformer coupling to minimize common-mode noise. This eliminates the need for external ferrite beads or Y-capacitors typically required with discrete isolated DC-DC converters.