Skyworks Solutions Inc. SI88440EC-ASR

Overview

SI88440EC-ASR from Skyworks Solutions is a quad-channel digital isolator with integrated isolated DC-DC converter, delivering up to 5 W peak output power at 3.3 V or 5.0 V secondary-side regulation. It provides four unidirectional isolation channels with ≤23 ns max propagation delay and supports data rates up to 100 Mbps. Designed for high-voltage input (up to 24 V) to low- or high-voltage output conversion, it is used in traction inverters and battery management systems requiring reinforced insulation.

For engineers reviewing the SI88440EC-ASR datasheet, SI88440EC-ASR pinout, SI88440EC-ASR application, or SI88440EC-ASR equivalent, key selection criteria include its external switch driver (ESW), current sense input (RSN), 5000 VRMS isolation rating, AEC-Q100 qualification, and SOIC-20 wide-body RoHS-compliant package - all critical for automotive and industrial isolated power + signal integrity designs.

Technical Context

The SI88440EC-ASR implements a modified flyback DC-DC topology with external primary-side NMOS switch control via ESW and current sensing via RSN, enabling operation with input voltages up to 24 V. Its digital isolation uses RF on/off keying across a silicon dioxide capacitive barrier, delivering robust noise immunity and 100 kV/µs transient immunity.

It features secondary-side voltage feedback via VSNS, type-I loop compensation at COMP (RCOMP = 100 kΩ), and supports programmable switching frequency (default 250 kHz). Unlike Si882xx/3xx, it lacks SH/SS pins - shutdown and soft-start are not implemented on this variant.

Key Specifications

Pinout & Package

SI88440EC-ASR is housed in a RoHS-compliant SOIC-20 wide-body package (10.3 mm × 7.5 mm, 1.27 mm pitch) with creepage/clearance ≥8.3 mm, rated for 5000 VRMS isolation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI88440EC-ASR, SI88441EC-ASR offers identical power and isolation specs but inverted failsafe behavior - critical for functional safety validation - while ADUM6420ARWZ trades 10× less power and no external switch support for smaller footprint and lower cost in non-automotive contexts.

Availability

SI88440EC-ASR is available at Aetrix Electronics and suitable for traction inverters, battery management systems, and industrial PLCs requiring stable component supply with automotive-grade reliability and 5000 VRMS isolation.

Supply support for SI88440EC-ASR 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

Skyworks Solutions is a global semiconductor company specializing in analog and mixed-signal connectivity solutions, with leadership in RF, timing, and isolation technologies.

The Si88x4x family was designed specifically for automotive and industrial applications demanding integrated signal isolation and high-power isolated DC-DC conversion - eliminating external power supplies while meeting stringent safety and reliability standards.

FAQ

What is the maximum isolated DC-DC output power supported by SI88440EC-ASR?

The SI88440EC-ASR supports up to 5 W peak isolated output power when used with an appropriately rated external NMOS FET, transformer, and rectifier. This is achieved using its ESW driver and RSN current sense interface in a flyback configuration - significantly higher than typical integrated-isolator DC-DC solutions limited to <1 W. The actual continuous output depends on thermal design and transformer selection.

Does SI88440EC-ASR include shutdown or soft-start functionality?

No, SI88440EC-ASR does not implement shutdown (SH) or soft-start (SS) functionality - these pins are omitted per the Si884xx product definition. Unlike Si882xx/3xx, the Si884xx family relies on external control of the external FET for sequencing. Designers must manage inrush and fault response externally via gate driver logic or controller firmware.

What transformer specifications are validated for use with SI88440EC-ASR?

Skyworks validates transformers for Si884xx with 24 V input, including UMEC UTB02250s (7–24 V in, 3.3–5.5 V out, 3:1 turns ratio, 5 kVRMS), Coilcraft TA7788-AL (12 V in, 5/15 V out), and Mentech TTER09-0458S1 (8–24 V in/out, 1:1 ratio, 5 kVRMS). All meet leakage inductance, primary inductance, and isolation rating requirements per AN901.

How is feedback implemented in the SI88440EC-ASR DC-DC converter?

Feedback is implemented via secondary-side sensing: the VSNS pin receives a resistor-divider voltage from the isolated output, which is encoded and transmitted across the isolation barrier to the primary-side controller. This eliminates optocouplers and their associated drift, enabling ±0.5% output regulation accuracy over temperature and lifetime - a key advantage over traditional isolated DC-DC architectures.

Is SI88440EC-ASR pin-compatible with other Si88x4x variants?

Yes, SI88440EC-ASR shares identical SOIC-20 pinout and package with all Si884xx variants (e.g., SI88441EC-ASR, SI88442EC-ASR), differing only in failsafe default states and ordering options. This allows drop-in replacement within the Si884xx family for design flexibility, provided the application's default logic state aligns with the selected variant's failsafe configuration.