Renesas ISL91108IIA-EVZ

Overview

ISL91108IIA-EVZ from Intersil is an evaluation board for the ISL91108IIAZ adjustable-output buck-boost regulator IC, supporting 1.0V–5.2V output programming via external resistor divider, delivering up to 1.6A DC output current (PVIN = 2.8V, VOUT = 3.3V), and featuring 2.6MHz switching frequency with 27.5µA quiescent current for portable power applications including smartphones and wireless communication devices.

For engineers reviewing the ISL91108IIA-EVZ datasheet, ISL91108IIA-EVZ pinout, ISL91108IIA-EVZ application, or ISL91108IIA-EVZ equivalent, this page provides verified technical context, key specifications, supply availability, manufacturer background, and targeted FAQs specific to the ISL91108IIA-EVZ evaluation platform - not the underlying ISL91108IIAZ IC.

Technical Context

The ISL91108IIA-EVZ implements a complete reference design for the ISL91108IIAZ adjustable-output buck-boost regulator, configured with 1µH inductor, dual 10µF input capacitors, dual 22µF output capacitors, and R1/R2 feedback network (187kΩ/60kΩ) to demonstrate 3.3V output. It supports all operating modes - PFM, forced PWM, and external clock synchronization - and includes thermal shutdown, short-circuit protection, and soft-start/soft-discharge functionality.

This board enables validation of input voltage range (1.8V–5.5V), burst current capability (2.7A, t<600µs), efficiency up to 95%, and seamless buck-to-boost transitions without output disturbance. The layout follows Intersil's recommended PCB guidelines, including minimized high-current loop area, dedicated PGND/GND separation, and guard banding around the FB network.

Key Specifications

Availability

ISL91108IIA-EVZ is available at Aetrix Electronics and suitable for smartphone power validation, wireless PA biasing, and portable embedded system development requiring stable component supply, rapid prototyping support, and documented reference performance under real-world load transients and input voltage variation.

Supply support for ISL91108IIA-EVZ 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 Corporation (now part of Renesas Electronics) is a leading provider of precision analog and power management ICs, with deep expertise in high-efficiency DC/DC conversion for mobile and infrastructure applications.

The ISL91108 product line was designed specifically for space-constrained, battery-powered systems requiring wide-input buck-boost regulation - such as 4G/LTE power amplifiers and multi-rail portable SoC platforms - where seamless mode transition and ultra-low quiescent current are critical.

FAQ

What is the primary purpose of the ISL91108IIA-EVZ?

The ISL91108IIA-EVZ is an evaluation board intended solely for hardware validation and performance characterization of the ISL91108IIAZ adjustable-output buck-boost regulator IC. It is not a production-ready power module but a fully assembled, tested reference design that demonstrates proper layout, component selection, and functional behavior - including PFM/PWM mode transitions, soft-start, and thermal response - under real operating conditions.

Does the ISL91108IIA-EVZ support variable output voltage?

Yes - the ISL91108IIA-EVZ is configured for the ISL91108IIAZ IC, which supports adjustable output voltages from 1.0V to 5.2V using an external resistor divider. The board ships with R1 = 187kΩ and R2 = 60kΩ to set VOUT = 3.3V, but users may replace these resistors to program other output voltages per Equation 1 in the FN8448 datasheet. No firmware or configuration tool is required.

Can the ISL91108IIA-EVZ be synchronized to an external clock?

Yes - the ISL91108IIA-EVZ exposes the MODE/SYNC pin (D3) of the ISL91108IIAZ IC, allowing connection to an external 2.75MHz–3.25MHz clock source. When driven with a valid sync signal, the ISL91108IIA-EVZ forces the underlying ISL91108IIAZ into synchronous operation, eliminating beat frequencies and reducing EMI in noise-sensitive RF subsystems such as cellular front-ends.

What protection features are implemented on the ISL91108IIA-EVZ?

The ISL91108IIA-EVZ inherits all protection features of the ISL91108IIAZ IC: undervoltage lockout (UVLO) with 1.775V rising threshold, thermal shutdown at 150°C (with 35°C hysteresis), short-circuit detection via FB monitoring, and soft-discharge (110Ω internal pull-down on VOUT when EN is low). These are fully operational on the evaluation board without modification.

Is the ISL91108IIA-EVZ compatible with the ISL91108IIN-EVZ?

Yes - the ISL91108IIA-EVZ and ISL91108IIN-EVZ share identical mechanical layout, component placement, and test points; they differ only in the fitted ISL91108 variant (adjustable vs. fixed 3.3V output). Both boards use the same WLCSP package footprint, pinout, and support circuitry, enabling direct comparison of fixed versus programmable output configurations using identical test setups and measurement fixtures.