Renesas IW1797-39

Overview

The iW1797-39 from Renesas Electronics is a primary-side AC/DC rapid charge controller supporting USB PD and QC2.0/3.0 protocols, delivering 10mV-step voltage resolution up to 21V, multi-level CV/CC regulation without secondary feedback, and <75mW no-load power at 230VAC/5VOUT. It integrates DLNK digital communication with compatible Dialog secondary controllers for dynamic output control in smartphone adapters.

For engineers reviewing the iW1797-39 datasheet, iW1797-39 pinout, iW1797-39 application, or iW1797-39 equivalent, key selection criteria include its SOT23-6 package, 3V CC shutdown voltage, 10mV/step DLNK resolution up to 21V, primary-side quasi-resonant operation, and built-in soft-short protection - all critical for compact, high-efficiency USB PD adapter design.

Technical Context

The iW1797-39 implements PrimAccurate™ primary-side regulation using VSENSE and CS/CDC inputs to achieve tight CV/CC without optocoupler or TL431. Its DLNK pin enables bidirectional digital communication with Dialog secondary controllers (e.g., iW657P) for real-time VBUS requests, current limits, undershoot detection, and OVP reporting via single optocoupler.

Operating in quasi-resonant mode with load-adaptive maximum constant frequency PWM, the iW1797-39 maintains stability across line/load/temperature while eliminating loop compensation components. Its GATE driver supports external MOSFET switching, and VCC pin tolerates up to 45V, removing need for external LDO.

Key Specifications

Pinout & Package

The iW1797-39 is housed in a 6-lead SOT23-6 package with exposed pad for thermal enhancement. Pin 1 (VCC) supplies IC power; Pin 2 (VSENSE) senses auxiliary winding voltage for primary-side regulation; Pin 3 (DLNK) carries bidirectional digital communication signals; Pin 4 (CS/CDC) senses primary current for cycle-by-cycle control and cable drop compensation configuration; Pin 5 (GND) is system ground; Pin 6 (GATE) drives external MOSFET switch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side rapid charge controller applications.

Compared with MP6908A and INN3379C, the iW1797-39 uniquely delivers 10mV-step programmability, DLNK-based bidirectional communication, and primary-side-only multi-level CV/CC - making it the only option for compact, high-resolution USB PD PPS and QC3.0 designs requiring no secondary feedback components.

Availability

iW1797-39 is available at Aetrix Electronics and suitable for smartphone adapters, tablet chargers, USB-C docking stations, and portable power banks requiring stable component supply, rapid charge protocol flexibility, and ultra-low standby power.

Supply support for iW1797-39 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 Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and SoC products for automotive, industrial, infrastructure, and IoT applications.

The iW1797-39 belongs to Renesas' Dialog-branded AC/DC rapid charge controller family, designed specifically for high-efficiency, compact USB PD and QC-compliant adapters with primary-side digital control and minimal external components.

FAQ

What is the DLNK communication protocol used by the iW1797-39?

The iW1797-39 uses Dialog's proprietary DLNK protocol to exchange rapid charge information-including output voltage requests, current limits, undershoot detection, and over-voltage status-with compatible secondary-side controllers like iW657P. This bidirectional digital communication occurs over a single analog pin (DLNK) and requires only one optocoupler, reducing component count and improving signal integrity compared to traditional analog feedback methods. The iW1797-39 relies on this interface to enable USB PD PPS and QC3.0 functionality without secondary-side regulation circuitry.

Does the iW1797-39 require an optocoupler for feedback?

No, the iW1797-39 does not require an optocoupler for primary-side voltage regulation, as it uses VSENSE-based auxiliary winding sensing to achieve tight CV/CC control. However, one optocoupler is required for DLNK communication with the secondary-side controller to transmit rapid charge commands. This architecture eliminates the optocoupler traditionally used for feedback isolation while retaining a single optocoupler solely for digital protocol signaling-reducing BOM cost and board space. The iW1797-39 achieves this through integrated PrimAccurate™ technology and DLNK interface design.

What is the significance of the "-39" suffix in iW1797-39?

The "-39" suffix in iW1797-39 denotes a specific factory-configured variant with 3V CC shutdown voltage, distinguishing it from other iW1797 variants like iW1797-02 (CC shutdown disabled) and iW1797-32 (CC shutdown disabled). This 3V threshold enables early detection and graceful power reduction during cable soft-short conditions, enhancing safety and reliability in high-current USB PD applications. All iW1797-39 units ship in SOT23-6 tape-and-reel packaging with 3,000 units per reel, and the part retains full 10mV/step DLNK resolution up to 21V VBUS.

Can the iW1797-39 operate without an external active startup circuit?

Yes, the iW1797-39 can operate without an external active startup circuit, achieving <75mW no-load power consumption at 230VAC/5VOUT using its internal RC charging VCC technology. An optional external DFET-based active startup circuit can further reduce no-load power to <20mW, but it is not required for basic operation or compliance with most energy standards. The iW1797-39's high VCC pin rating (up to 45V) and integrated start-up logic allow reliable initial power-up from bulk capacitor voltage, making it suitable for cost-sensitive and space-constrained adapter designs where simplicity is prioritized.

Which secondary-side controllers are compatible with the iW1797-39 for USB PD implementation?

The iW1797-39 is designed to work exclusively with Dialog Semiconductor's DLNK-compatible secondary-side controllers, including the iW657P (USB PD controller) and iW676 (synchronous rectifier controller). These devices form a chipset that enables full USB PD 3.0 Programmable Power Supply (PPS) functionality, including 10mV-step voltage control and dynamic current limiting. The iW1797-39 relies on DLNK protocol timing and command structure defined for these specific controllers; third-party or non-DLNB secondary controllers are not supported. Integration requires matching DLNK firmware versions and proper optocoupler bandwidth calibration as specified in Renesas' iW1797-39 application notes.