Renesas ISL6439EVAL1

Overview

ISL6439EVAL1 from Intersil is an evaluation board designed to demonstrate and validate the ISL6439 single synchronous buck PWM controller for broadband gateway power supplies. It supports 3.3V or 5V input, delivers adjustable output down to 0.8V with ±1.5% regulation accuracy, operates at 300kHz fixed frequency, and enables lossless overcurrent protection via upper MOSFET r_DS(ON) sensing.

For engineers reviewing the ISL6439EVAL1 datasheet, ISL6439EVAL1 pinout, ISL6439EVAL1 application, or ISL6439EVAL1 equivalent, this board provides a fully assembled, tested reference design for rapid prototyping of DC/DC step-down converters targeting cable modems, set-top boxes, DSP core supplies, and low-voltage distributed power rails.

Technical Context

The ISL6439EVAL1 implements a complete voltage-mode synchronous buck converter using the ISL6439 IC, which integrates gate drivers for N-channel MOSFETs, a 15MHz gain-bandwidth error amplifier, adaptive shoot-through protection, and internal soft-start. It leverages the ISL6439's charge-pump bias (CPVOUT), dual CT pins for oscillator timing, and OCSET-based programmable overcurrent trip.

This board validates key functional blocks: PHASE node switching with UGATE/LGATE drive, feedback loop stability via FB/COMP compensation network, CPVOUT POR-initiated startup, and hiccup-mode fault recovery triggered by ROCSET-sensed overcurrent events - all operating across –40°C to +85°C industrial temperature range.

Key Specifications

Availability

ISL6439EVAL1 is available at Aetrix Electronics and suitable for cable modem development, set-top box power validation, and DSP processor supply design requiring stable component supply and fast-turn reference implementation.

Supply support for ISL6439EVAL1 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

Intersil Americas LLC is a semiconductor company specializing in precision analog, power management, and interface ICs for communications, computing, and industrial applications.

The ISL6439EVAL1 belongs to Intersil's broadband gateway power management product line, engineered specifically to accelerate design of high-efficiency, compact DC/DC regulators for cable/DSL modems and multimedia consumer equipment.

FAQ

What is the primary function of the ISL6439EVAL1 evaluation board?

The ISL6439EVAL1 evaluation board is a fully assembled reference design that demonstrates the operation of the ISL6439 synchronous buck PWM controller. It enables engineers to validate converter performance-including output regulation, transient response, soft-start behavior, and overcurrent protection-using real-world components and layout. The ISL6439EVAL1 supports both 3.3V and 5V inputs and delivers precisely regulated outputs down to 0.8V.

Which IC does the ISL6439EVAL1 evaluate, and what package does it use?

The ISL6439EVAL1 evaluates the ISL6439 single synchronous buck PWM controller, specifically the 300kHz version (as opposed to the ISL6439A's 600kHz variant). It uses the ISL6439 in the 14-lead SOIC package (M14.15 footprint), matching the ISL6439IBZ ordering option. The board is not compatible with QFN variants like ISL6439IRZ.

Does the ISL6439EVAL1 support adjustable output voltage, and how is it configured?

Yes, the ISL6439EVAL1 supports adjustable output voltage from 0.8V up to the input rail. Output is set using an external resistor divider connected to the FB pin, referenced to the ISL6439's internal 0.8V precision reference. The board includes provision for R1 and R4 resistors per Equation 2 in the ISL6439 datasheet, enabling accurate scaling without populating additional compensation components unless required for stability.

How does overcurrent protection work on the ISL6439EVAL1, and can it be adjusted?

Overcurrent protection on the ISL6439EVAL1 is implemented losslessly using the upper MOSFET's r_DS(ON), eliminating the need for a sense resistor. The trip point is programmed via an external ROCSET resistor connected to the OCSET pin and VIN, leveraging the ISL6439's internal 20µA current source. The ISL6439EVAL1 includes pads for ROCSET, allowing designers to adjust the peak inductor current threshold per Equation 3 in the datasheet.

Is the ISL6439EVAL1 still supported, and are replacement parts available?

While the ISL6439EVAL1 itself remains available through Aetrix Electronics, its underlying ISL6439 IC has legacy status: the ISL6439CBZ is discontinued (replaced by ISL6439IBZ), and QFN variants (ISL6439IRZ/ISL6439AIRZ) are no longer supported. The ISL6439EVAL1 continues to serve as a functional validation platform for existing designs and legacy system upgrades where the ISL6439IBZ SOIC part is used.