Renesas IW3658-31F

Overview

The IW3658-31F from Renesas Electronics is a single-stage, phase-cut dimmable SSL LED driver IC with integrated 650V/2A high-voltage MOSFET in SO-7 package, supporting 230VAC input and delivering up to 15W output power with buck-boost topology, primary-side constant-current regulation, and flicker-free dimming across leading- and trailing-edge wall dimmers.

For engineers reviewing the IW3658-31F datasheet, IW3658-31F pinout, IW3658-31F application, or IW3658-31F equivalent, key selection criteria include its 650V HV drain rating, filament-load optimization, -40°C to +150°C operating junction temperature, boundary conduction mode operation, and integrated VCC regulation for stable low-end dimming performance.

Technical Context

The IW3658-31F implements PrimAccurate™ primary-side sensing to eliminate optocoupler-based feedback while maintaining ±3% LED current regulation accuracy. It operates in boundary conduction mode (BCM) with resonant control to achieve >85% typical efficiency and low EMI.

This variant is specifically optimized for 230VAC filament-load applications, featuring a 650V-rated internal MOSFET and dedicated CFG pin configuration for overvoltage protection tuning - distinct from 120VAC or high-power-factor variants in the iW3658 family.

Key Specifications

Pinout & Package

Package: 7-lead SO (SO-7) with enhanced creepage spacing between HV drain and low-voltage pins to support reinforced insulation in retrofit lamp designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED driver applications.

Compared with MP4008GQ-Z and NCP1075P, the IW3658-31F delivers higher integration (650V MOSFET + sensing + VCC regulation), filament-specific dimming behavior, and reduced system-level validation effort - making it optimal for compact, certified 230VAC retrofit lamps.

Availability

IW3658-31F is available at Aetrix Electronics and suitable for dimmable LED retrofit lamps, GU10 spotlights, and outdoor PAR38 floodlights requiring stable component supply, long-lifecycle support, and compliance with IEC 61000-3-2 Class C harmonic limits.

Supply support for IW3658-31F 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 leader delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, and IoT markets.

The iW3658 product line was developed by Dialog Semiconductor (acquired by Renesas in 2021) specifically for high-efficiency, single-stage, dimmable LED drivers targeting retrofit lamp replacement in residential and commercial lighting.

FAQ

What input voltage range does the IW3658-31F support?

The IW3658-31F is specified for 230VAC nominal input with 45–66Hz line frequency support. Its 650V HV drain rating provides margin for 230VAC surge transients per IEC 61000-4-5. It is not rated for 120VAC operation - other iW3658 variants (e.g., -00F, -06F) are designated for 120VAC systems. The IW3658-31F must be used with appropriate bridge rectification and EMI filtering for 230VAC mains.

Does the IW3658-31F require an optocoupler for feedback?

No, the IW3658-31F uses Dialog's PrimAccurate™ primary-side sensing technology to regulate LED current without an optocoupler or secondary-side feedback components. This is achieved via the ISENSE pin monitoring primary winding current and the COMP pin configuring the regulation loop. The IW3658-31F maintains ±3% current accuracy across line, load, and temperature - eliminating isolation barriers and reducing BOM cost and board space.

How is filament-load optimization implemented in the IW3658-31F?

Filament-load optimization in the IW3658-31F includes tailored startup timing, dynamic OVP response via the CFG pin, and thermal derating behavior calibrated for low-thermal-mass LED filaments. Unlike generic LED drivers, the IW3658-31F avoids false OVP trips during cold-start inrush and sustains stable dimming down to 5% with minimal flicker. This behavior is factory-set and distinguishes the IW3658-31F from non-filament variants like IW3658-21F.

What protection features are integrated into the IW3658-31F?

The IW3658-31F integrates LED open-circuit and short-circuit protection, over-temperature shutdown with automatic recovery, and built-in thermal derating above 100°C junction temperature. It also includes VCC undervoltage lockout and gate-drive fault detection. These functions operate autonomously without external supervision - critical for self-contained retrofit lamps where service access is impractical. All protections are verified per JEDEC JESD78E latch-up and JS-001 ESD standards.

Can the IW3658-31F be used in isolated topologies?

Yes, the IW3658-31F supports both isolated and non-isolated off-line LED driver designs, as confirmed in its Product Summary. In isolated flyback configurations, it uses transformer-coupled primary sensing; in non-isolated buck-boost, it relies on direct primary winding sensing. The choice depends on safety certification requirements (e.g., SELV compliance) and physical constraints. The IW3658-31F's SO-7 package and internal 650V MOSFET simplify both implementations without requiring external HV switches.