Renesas IW3689-21

Overview

The iW3689-21 from Renesas Electronics is a digital AC/DC power controller IC designed for single-stage, high-power-factor, dimmable LED drivers operating from 230VAC input and optimized for external LED driver applications. It delivers ±5% LED current regulation, supports 1%–100% dimming range, and enables quasi-resonant flyback or buck-boost topologies without opto-coupler or auxiliary winding.

For engineers reviewing the iW3689-21 datasheet, iW3689-21 pinout, iW3689-21 application, or iW3689-21 equivalent, key selection considerations include dimmer type detection (leading-edge, trailing-edge, smart), PrimAccurate™ primary-side sensing, EZ-EMI® filter simplification, and thermal operation up to 120°C junction temperature in SOIC-8 packaging.

Technical Context

The iW3689-21 implements cycle-by-cycle waveform analysis for fast dimmer transient response and dynamically adjusts impedance to interface with diverse wall dimmers. Its digital control loop eliminates need for external compensation components while maintaining stability across line voltages (45–66 Hz), load variations, and temperature.

It integrates VCC charging, current sink, and MOSFET gate drive functions into a single SOIC-8 package. The PrimAccurate™ technology enables accurate LED current regulation using only primary-side voltage and current sensing-no secondary feedback required.

Key Specifications

Pinout & Package

Package: 8-Lead SOIC-8 (JEDEC MS12F compliant, RoHS/Halide-free, MSL-1).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar AC/DC digital LED driver controller applications.

Compared with UCC28810DR and NCP1083DR2G, the iW3689-21 provides integrated digital dimmer detection, single-stage high-PF operation, and primary-side regulation-reducing component count and enabling compact, standards-compliant 230VAC external LED driver designs without secondary feedback.

Availability

iW3689-21 is available at Aetrix Electronics and suitable for dimmable LED retrofit lamps, commercial luminaires, and smart home lighting systems requiring stable component supply, RoHS compliance, and JEDEC-standard SOIC-8 packaging.

Supply support for iW3689-21 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

Renesas Electronics is a global semiconductor manufacturer delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, and IoT applications.

The iW3689-21 belongs to Renesas' digital LED driver controller product line, engineered specifically for high-efficiency, single-stage, dimmable AC/DC LED drivers targeting 230VAC external driver applications with stringent PF and THD requirements.

FAQ

What is the primary function of the iW3689-21 in an LED driver design?

The iW3689-21 serves as a digital AC/DC power controller that manages LED current regulation, dimmer interface, and power factor correction in single-stage LED drivers. It replaces traditional analog controllers by integrating digital dimmer detection, PrimAccurate™ primary-side sensing, and quasi-resonant control-enabling the iW3689-21 to deliver ±5% current accuracy without opto-couplers or auxiliary windings in 230VAC external driver applications.

Does the iW3689-21 support both leading-edge and trailing-edge dimmers?

Yes, the iW3689-21 supports leading-edge (R-type/R-L type), trailing-edge (R-C type), and digital smart dimmers through its patented cycle-by-cycle waveform analysis engine. This capability is confirmed in the official Renesas Product Summary Rev. 1.2, which states the iW3689-21 achieves excellent dimmer compatibility across all three types-making the iW3689-21 suitable for global residential and commercial lighting installations with mixed dimmer infrastructure.

What package type and thermal specifications apply to the iW3689-21?

The iW3689-21 is housed in an 8-Lead SOIC-8 package compliant with JEDEC MS12F, RoHS, and Halide-free standards. Its absolute maximum junction temperature is 150°C, with recommended continuous operation below 120°C. Thermal resistance ψJB is 75°C/W to PCB ground leads, and it meets IPC/JEDEC J-STD-020D moisture sensitivity level 1-ensuring robust manufacturability and thermal performance for the iW3689-21 in compact external LED driver layouts.

How does the iW3689-21 achieve power factor correction without a dedicated PFC stage?

The iW3689-21 implements single-stage PFC by combining boost-derived current shaping with digital control of conduction angle and switching timing. It meets IEC61000-3-2 Class C with PF >0.92 and THD <20%, eliminating the need for a separate PFC controller or stage. This architecture is intrinsic to the iW3689-21's design and validated in its typical application circuits-reducing system cost and board space while maintaining compliance in 230VAC external LED driver implementations.

Can the iW3689-21 operate without a dimmer connected?

Yes, the iW3689-21 operates in no-dimmer mode by default, delivering regulated LED current in quasi-resonant mode with >85% efficiency and optimized power factor. In this mode, it minimizes AC line harmonic distortion and maintains tight current regulation. The iW3689-21 detects absence of dimmer activity during start-up and configures internal control loops accordingly-ensuring reliable, flicker-free operation for the iW3689-21 whether or not a dimmer is installed.