Renesas ISL8105AEVAL1Z

Overview

The ISL8105AEVAL1Z from Renesas Electronics is an evaluation board designed to demonstrate the operation of the ISL8105A synchronous buck controller in a high-current DC/DC converter application, configured for 1.8V output at up to 15A load, with fixed 600kHz switching frequency and input voltage support across 4.5–5.5V or 6.5–14.4V ranges.

For engineers reviewing the ISL8105AEVAL1Z datasheet, ISL8105AEVAL1Z pinout, ISL8105AEVAL1Z application, or ISL8105AEVAL1Z equivalent, this board enables rapid validation of soft-start behavior, overcurrent hiccup protection, pre-biased output startup, transient response under 7.5A–15A load steps, and efficiency measurement with 5V/12V inputs.

Technical Context

The ISL8105AEVAL1Z implements a single-phase synchronous buck topology using the ISL8105A PWM controller (U1, SOIC-8) paired with discrete N-channel MOSFETs (RJK0305 and RJK0301), a 1.0µH power inductor (L1), and multi-capacitor output filtering including 100µF ceramic and 2200µF aluminum electrolytic banks.

It supports dual-input voltage ranges via jumper-selectable bias routing (R10 = 0Ω), delivers regulated 1.8V output with ±1% FB reference accuracy, and integrates current-limiting via bottom-FET r_DS(ON) sensing (R8 = 1.33kΩ sets ~19A trip at 5VBIAS), triggering hiccup-mode recovery on overcurrent fault.

Key Specifications

Availability

The ISL8105AEVAL1Z is available at Aetrix Electronics and suitable for power supply design validation, DC/DC controller qualification, and high-current buck converter prototyping requiring stable component supply and documented reference performance.

Supply support for ISL8105AEVAL1Z 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 manufacturer delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, and enterprise applications.

The ISL8105AEVAL1Z belongs to Renesas' legacy Intersil power management evaluation platform line, developed specifically to accelerate adoption of the ISL8105A synchronous buck controller in high-efficiency, medium-power point-of-load designs.

FAQ

What is the primary function of the ISL8105AEVAL1Z?

The ISL8105AEVAL1Z is an evaluation board that demonstrates the ISL8105A synchronous buck controller in a complete 1.8V/15A DC/DC converter. It provides accessible test points (J4/VOUT, J5/GND, TPVO1), configurable input ranges, and validated performance metrics-including efficiency curves, transient response, and hiccup-mode overcurrent protection-enabling engineers to verify design assumptions before custom PCB development. The ISL8105AEVAL1Z does not contain the ISL8105A as a standalone IC but hosts it as the core control element.

Does the ISL8105AEVAL1Z support adjustable output voltage?

No-the ISL8105AEVAL1Z is factory-configured for a fixed 1.8V output using a precision resistor divider (R1 = 10.5kΩ, R2 = 9.53kΩ) tied to the ISL8105A's FB pin. While the underlying ISL8105A supports adjustable outputs via external resistors, this evaluation board lacks onboard voltage adjustment components or jumpers; modifying output requires hardware changes to the feedback network. The ISL8105AEVAL1Z documentation confirms its purpose is to validate 1.8V operation only.

What input voltage options does the ISL8105AEVAL1Z support?

The ISL8105AEVAL1Z supports two distinct input voltage ranges: 4.5–5.5V and 6.5–14.4V. This is achieved by configuring the bias supply path-specifically through zero-ohm resistor R10-which ties the IC bias rail to the main input. The board's schematic and user manual (AN1258) confirm no single universal range; selection depends on how VIN is applied and whether VCC is derived internally. The ISL8105AEVAL1Z is not rated for continuous operation outside these specified bands.

How does overcurrent protection operate on the ISL8105AEVAL1Z?

Overcurrent protection on the ISL8105AEVAL1Z uses the bottom-side MOSFET's r_DS(ON) for lossless current sensing, with trip level set by R8 (1.33kΩ). When triggered, the ISL8105A disables switching and enters hiccup mode: two dummy soft-start timeouts followed by one full 6.8ms soft-start cycle. Recovery repeats until fault clearance. The ISL8105AEVAL1Z user manual documents this behavior in Figure 9 and Equation 1, confirming ~19A trip at 5VBIAS and ~24A at 12VBIAS.

Can the ISL8105AEVAL1Z be used with the ISL8105A DFN variant?

The ISL8105AEVAL1Z board includes footprint space and silkscreen for both SOIC-8 (U1, populated) and 10LD DFN (U2, DNP) versions of the ISL8105A, but only U1 (ISL8105AIBZ, SOIC-8) is installed. The DFN variant (ISL8105AIRZ) is listed in the BOM as "DNP" (Do Not Populate), and no design validation or performance data is provided for it on this board. Using the DFN version would require rework, thermal validation, and signal integrity verification-so the ISL8105AEVAL1Z is functionally and officially qualified only with the SOIC-8 ISL8105A.