Renesas ISL85413DEMO3Z

Overview

The ISL85413DEMO3Z from Renesas Electronics is a demonstration board built around the ISL85413 synchronous buck regulator, configured in an isolated buck topology using a coupled inductor to generate ±5V outputs - a +5V primary and a -5V secondary - with up to 150mA per rail at VIN = 24V. It supports input voltages from 9V to 40V and features PWM/PSM mode selection via JP1 and enable control via SW1.

For engineers reviewing the ISL85413DEMO3Z datasheet, ISL85413DEMO3Z pinout, ISL85413DEMO3Z application, or ISL85413DEMO3Z equivalent, this board enables rapid evaluation of isolated dual-rail power delivery for industrial analog systems, low-noise instrumentation, and bipolar supply requirements in compact space-constrained designs.

Technical Context

The ISL85413DEMO3Z implements an isolated buck converter using the ISL85413 IC, which integrates high-side and low-side NMOS FETs and operates at a fixed 700kHz switching frequency. Its core function is to derive a regulated negative output (VOUT_SC) referenced to ISOGND while maintaining a positive primary output (VOUT_PR) referenced to PGND - enabled by transformer-coupled energy transfer and internal soft-start.

Board-level design includes jumper-selectable PWM/PSM operation (JP1), switch-controlled enable (SW1), and configurable feedback resistors (R1/R2) to adjust VOUT_PR from 0.6V to 15V. Secondary isolation between PGND and ISOGND is achieved by replacing R10 with a 2200pF capacitor, supporting true galvanic separation for noise-sensitive applications.

Key Specifications

Availability

ISL85413DEMO3Z is available at Aetrix Electronics and suitable for industrial analog systems, precision instrumentation, and isolated dual-rail power validation requiring stable component supply and fast time-to-test capability.

Supply support for ISL85413DEMO3Z 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 industrial, automotive, and infrastructure markets, with strong heritage in high-performance analog and power management ICs.

The ISL85413DEMO3Z belongs to Renesas' Industrial Analog and Power demonstration platform family, designed specifically to accelerate evaluation of isolated DC-DC topologies for noise-critical analog subsystems and compact bipolar supply generation.

FAQ

What is the primary purpose of the ISL85413DEMO3Z?

The ISL85413DEMO3Z is a demonstration board that showcases the ISL85413 synchronous buck regulator in an isolated buck configuration, generating both +5V and -5V outputs using a coupled inductor. It enables engineers to validate performance, layout practices, and system integration of dual-rail isolated power supplies before committing to custom design - especially for analog signal chains requiring clean, separated voltage domains.

Can the ISL85413DEMO3Z generate output voltages other than ±5V?

Yes - the ISL85413DEMO3Z is preset to ±5V, but VOUT_PR can be adjusted from 0.6V to 15V by modifying the feedback resistor divider (R1 and R2). Table 3 in the UG132 manual provides exact resistor values for ±3.3V, ±5V, and ±12V configurations. The secondary output (VOUT_SC) tracks inversely with VOUT_PR when using the same coupled inductor.

How is isolation achieved on the ISL85413DEMO3Z?

Isolation on the ISL85413DEMO3Z is implemented via a coupled inductor (MSD7342-473ML), separating PGND (primary ground) from ISOGND (secondary ground). R10 (0Ω) normally shorts these grounds; replacing it with a 2200pF ceramic capacitor achieves capacitive isolation between the two domains, enabling noise rejection and ground-loop elimination in sensitive analog circuits.

What are the key user controls on the ISL85413DEMO3Z board?

The ISL85413DEMO3Z features SW1 (ON/OFF toggle switch) to enable or disable the converter, and JP1 (2-pin jumper) to select between PWM (pins 1–2 shorted, default) and PFM operation. PWM ensures tighter regulation and better coupling between primary and secondary outputs, while PFM improves light-load efficiency at the cost of variable frequency behavior.

What test equipment is recommended for evaluating the ISL85413DEMO3Z?

Renesas recommends a 0–50V/1A DC power supply, resistive loads capable of sinking up to 1A, digital multimeters for DC accuracy, and a 100MHz quad-trace oscilloscope to capture transient response (e.g., Figures 16–19 in UG132), output regulation vs. load/VIN, and startup/shutdown behavior - all critical for validating stability and dynamic performance in real-world analog applications.