Renesas ISL85402EVAL1Z

Overview

ISL85402EVAL1Z from Renesas Electronics is an evaluation board designed to demonstrate the synchronous buck, asynchronous buck, and boost-buck operation of the ISL85402 synchronous step-down/step-up controller IC. It supports 3V–36V input, delivers 5V/2A output by default, features programmable 500kHz switching frequency and 3.6A overcurrent threshold, and enables topology reconfiguration via jumper settings for power architecture validation.

For engineers reviewing the ISL85402EVAL1Z datasheet, ISL85402EVAL1Z pinout, ISL85402EVAL1Z application, or ISL85402EVAL1Z equivalent, this board provides hands-on verification of multi-topology DC-DC control, external synchronization capability, PFM/PWM mode selection, and real-time phase-node waveform monitoring across buck and boost-buck configurations.

Technical Context

The ISL85402EVAL1Z implements the ISL85402 controller in a fully assembled, test-ready layout with dual-path power stages: a primary buck section (J1/J2 inputs → J3/J4 outputs) and a boost-buck section (J5/J6 inputs → J7 output → connected to buck input via J26/J27). It uses two BSZ100N06LS3G MOSFETs and Cooper DR125-series inductors (10µH and 6.8µH) to support both topologies under shared control logic.

Configuration is managed through 28 discrete jumpers and test points-including J17 (MODE), J16 (ILIMIT), J12 (FS), J22 (SYNC), and J21/J28 (boost enable)-enabling hardware-selectable operating modes, protection thresholds, frequency tuning, and inter-board synchronization without firmware changes or soldering.

Key Specifications

Availability

ISL85402EVAL1Z is available at Aetrix Electronics and suitable for industrial power supply development, automotive subsystem prototyping, and telecom DC-DC architecture validation requiring stable component supply and rapid topology iteration.

Supply support for ISL85402EVAL1Z 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 high-performance analog, power, and embedded processing solutions for industrial, automotive, and infrastructure applications.

The ISL85402EVAL1Z belongs to Renesas' power management evaluation platform family, engineered to accelerate adoption of flexible multi-topology DC-DC controllers in next-generation power system designs.

FAQ

What topologies does the ISL85402EVAL1Z support out of the box?

The ISL85402EVAL1Z supports three distinct topologies without hardware modification: synchronous buck (default configuration), asynchronous buck (by removing R19 and setting R20 to 0Ω), and boost-buck (by configuring J21/J28, J26/J27, and auxiliary resistors). Each mode is verified in AN1763 with explicit setup sequences and operational boundaries defined for ISL85402EVAL1Z.

How is output voltage adjusted on the ISL85402EVAL1Z?

The ISL85402EVAL1Z defaults to 5V output using fixed feedback resistors (R2 = 220kΩ, R3 = 232kΩ). To change output voltage, replace R2 and R3 per the ISL85402's VOUT = 0.6V × (1 + R2/R3) formula. The manual cautions that raising output above 5V requires verifying output capacitor voltage ratings-C57/C59 are rated for 80V, supporting up to ~25V safely when reconfigured.

Can multiple ISL85402EVAL1Z boards be synchronized, and how?

Yes-ISL85402EVAL1Z boards can be synchronized by connecting their SYNC pins (J22) together, as confirmed in AN1763 Section 1. This enables deterministic interleaving or phase-shifted operation across multiple rails. External clock injection is also supported via J22, allowing alignment to system master clocks or noise-sensitive timing domains without modifying ISL85402EVAL1Z hardware.

What is the role of the AUXVCC function on the ISL85402EVAL1Z?

AUXVCC on ISL85402EVAL1Z provides auxiliary bias for the ISL85402 controller during startup and fault conditions. When J9 is shorted, VOUT+ powers AUXVCC after regulation is established; when J8 is shorted in boost-buck mode, AUXVCC monitors boost output voltage (via R24/R25) for overvoltage protection. This dual-path AUXVCC routing ensures reliable IC operation across all topologies supported by ISL85402EVAL1Z.

Does the ISL85402EVAL1Z include protection features beyond overcurrent?

Yes-the ISL85402EVAL1Z implements multiple hardware-configurable protections: boost output overvoltage protection (22V–25V window set by R24/R25), boost input undervoltage lockout (7V–10V hysteresis via R17/R18), and IC enable/disable control via J11. These are implemented using discrete resistive dividers and jumpers per AN1763, ensuring robust fault response without software intervention on ISL85402EVAL1Z.