Renesas ISL85003ADEMO1Z

Overview

ISL85003ADEMO1Z from Renesas Electronics is a demonstration board for the ISL85003A 3A synchronous buck regulator, designed to evaluate point-of-load DC/DC conversion from 4.5V–18V input to adjustable 5V output. It features programmable soft-start, current-mode control, and supports external synchronization up to 2MHz.

For engineers reviewing the ISL85003ADEMO1Z datasheet, ISL85003ADEMO1Z pinout, ISL85003ADEMO1Z application, or ISL85003ADEMO1Z equivalent, this board enables rapid validation of efficiency, transient response, and layout-sensitive performance in industrial and embedded power designs.

Technical Context

The ISL85003ADEMO1Z implements the ISL85003A IC in a fixed 5V output configuration using an external resistor divider on the FB pin, with VREF = 0.6V. The board uses internal compensation and defaults to PWM mode via R6 = 200kΩ tied to VCC.

Soft-start is enabled via the SS pin, where a 4μA internal current source charges C10 (default open) to control ramp rate; removing R7 disables the regulator by pulling EN low. Input filtering includes 10μF ×2 (C1, C2) and optional C10 for high-parasitic-inductance sources.

Key Specifications

Availability

ISL85003ADEMO1Z is available at Aetrix Electronics and suitable for industrial automation, embedded computing, and telecom power subsystem evaluation requiring stable component supply and fast prototyping turnaround.

Supply support for ISL85003ADEMO1Z 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 enterprise applications.

The ISL85003ADEMO1Z belongs to Renesas' high-efficiency DC/DC evaluation platform family, engineered specifically to accelerate design-in of compact, high-current buck regulators in space-constrained point-of-load applications.

FAQ

What is the primary function of the ISL85003ADEMO1Z?

The ISL85003ADEMO1Z is a fully assembled demonstration board built around the ISL85003A 3A synchronous buck regulator. Its purpose is to provide engineers with a ready-to-test platform for evaluating efficiency, thermal behavior, transient response, and layout implementation of the ISL85003A in real-world 4.5V–18V input applications. The ISL85003ADEMO1Z includes all necessary passives, feedback network, and test points per the ISL85003A datasheet recommendations.

How do I change the output voltage on the ISL85003ADEMO1Z?

The ISL85003ADEMO1Z is preset to 5V using R1 (301kΩ) and R2 (57.6kΩ) as the feedback divider. To adjust the output voltage, replace either resistor according to the formula VOUT = 0.6V × (1 + R1/R2). The board provides solder pads and footprint space for alternate resistors, and AN1930 and the ISL85003A datasheet specify exact divider calculation and stability guidelines for new VOUT settings.

Does the ISL85003ADEMO1Z support external synchronization?

Yes - the ISL85003ADEMO1Z supports external clock synchronization up to 2MHz via the SYNC pin on the ISL85003A IC. Although the default configuration ties MODE/SS to VCC, the schematic shows accessible SYNC and PHASE test points. External synchronization allows timing alignment with other switching regulators to reduce beat frequencies and system-level EMI in multi-rail power architectures using the ISL85003ADEMO1Z.

How is soft-start configured on the ISL85003ADEMO1Z?

Soft-start on the ISL85003ADEMO1Z is implemented via the SS pin of the ISL85003A, which sources a regulated 4μA current to charge an external capacitor (C10, default DNP). By populating C10 (e.g., 100nF), users set the soft-start time as tSS ≈ (VREF / 4μA) × C10 ≈ 15ms per 100nF. This controlled ramp prevents input inrush and downstream supply sequencing issues during power-up of the ISL85003ADEMO1Z.

Can the ISL85003ADEMO1Z be used to evaluate both ISL85003 and ISL85003A?

No - the ISL85003ADEMO1Z is specifically populated with the ISL85003AFRZ IC and configured for ISL85003A functionality, including dedicated SS pin routing and default soft-start enablement. While electrically similar, the ISL85003 lacks the SS pin and uses MODE instead; thus, ISL85003ADEMO1Z cannot substitute for ISL85003DEMO1Z without hardware modification. Each demo board matches its designated IC variant.