Renesas ISL91107IRTAZ

Overview

ISL91107IRTAZ from Intersil is an evaluation board designed specifically for the ISL91107IR adjustable-output buck-boost DC/DC regulator IC. It supports user-configurable output voltages from 1V to 5.2V via external resistor divider, delivers up to 2A output current at 3.3V with 1.8V–5.5V input, and features 2.5MHz switching frequency, 45µA quiescent current, and automatic seamless buck/boost mode transition - enabling compact, high-efficiency power solutions in space-constrained portable electronics.

For engineers reviewing the ISL91107IRTAZ datasheet, ISL91107IRTAZ pinout, ISL91107IRTAZ application, or ISL91107IRTAZ equivalent, this evaluation board provides validated reference design, layout guidance, component selection data (including 1µH inductor, 22µF input/44µF output ceramic capacitors), thermal pad grounding, SGND/PGND separation, and soft-start/soft-discharge behavior verification - critical for rapid prototyping of battery-powered systems requiring wide VIN/VOUT overlap.

Technical Context

The ISL91107IRTAZ evaluation board implements the ISL91107IR adjustable buck-boost regulator in a 3×4 mm 20-lead TQFN package with dedicated PVIN/VIN dual-input rails, LX1/LX2 inductor connections, MODE-selectable PFM/PWM operation, EN-controlled startup/shutdown, and FB-based voltage programming. Its layout strictly follows Intersil's recommended practices: short high-current PGND loops, isolated SGND guard band around feedback resistors, minimized FB trace length, and thermal pad soldered to PGND.

It validates key functional behaviors including 1ms soft-start delay before VOUT ramp, 2–3ms total soft-start time (buck vs. boost dependent), 35Ω internal VOUT soft-discharge path during disable, ±0.005mV/mA load regulation in PWM mode, and seamless mode transitions under dynamic load and line transients - all measured per FN8687 Rev 0.00 test conditions using 1µH inductor and 2×22µF X5R output capacitors.

Key Specifications

Availability

ISL91107IRTAZ is available at Aetrix Electronics and suitable for smartphone power rail validation, tablet PC PMIC subsystem testing, and optical module voltage margining requiring stable component supply, full documentation access, and repeatable lab characterization.

Supply support for ISL91107IRTAZ 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, specializing in high-efficiency DC/DC conversion, battery management, and thermal-aware power solutions for mobile and infrastructure markets.

The ISL91107IR product line was designed to address portable electronics requiring single-inductor buck-boost regulation across wide input/output voltage overlap - eliminating need for separate buck and boost stages in battery-powered systems with varying state-of-charge.

FAQ

What is the primary purpose of the ISL91107IRTAZ evaluation board?

The ISL91107IRTAZ evaluation board is a fully assembled, tested reference design intended to accelerate development and validation of the ISL91107IR adjustable-output buck-boost regulator IC. It enables engineers to verify performance metrics - including efficiency, transient response, soft-start behavior, and mode transition smoothness - under real-world conditions using recommended external components and PCB layout practices defined in FN8687.

Does the ISL91107IRTAZ board include the ISL91107IR IC pre-mounted?

Yes, the ISL91107IRTAZ evaluation board ships with the ISL91107IR IC (adjustable version, marked "107A") permanently mounted in its 3×4 mm 20-lead TQFN package. The board includes all required passive components - 1µH inductor, 22µF input capacitor, two 22µF output capacitors, feedback resistors, and soft-discharge capacitor - as specified in the ISL91107IR datasheet Figure 23.

Can the ISL91107IRTAZ be used to evaluate fixed-output configurations?

No - the ISL91107IRTAZ is explicitly designated for the adjustable-output variant (ISL91107IRTAZ ordering code) and includes R1/R2 feedback resistors to support user-defined VOUT from 1V to 5.2V. To evaluate the fixed 3.3V version, the ISL91107IRN-EVZ evaluation board must be used, as confirmed in the Ordering Information table on page 3 of FN8687 Rev 0.00.

What are the critical layout features validated by the ISL91107IRTAZ board?

The ISL91107IRTAZ board implements and validates five critical layout practices: (1) short, low-inductance PGND return paths between input/output capacitors and IC PGND pins; (2) isolated SGND plane with guard ring around FB resistor network; (3) minimal-length FB trace without vias; (4) direct thermal pad connection to PGND via multiple vias; and (5) co-planar LX1/LX2 routing adjacent to the IC to minimize switching loop area - all essential for stable, low-noise operation per datasheet Page 11 guidelines.

How does the ISL91107IRTAZ demonstrate soft-start and soft-discharge functionality?

The ISL91107IRTAZ board demonstrates soft-start via controlled VOUT ramp-up after EN assertion - with typical 1ms delay before ramp initiation and total times of ~2ms (buck) or ~3ms (boost) to reach 95% of target voltage. Soft-discharge is verified by measuring ~35Ω resistance between VOUT and SGND when EN is pulled low, causing controlled discharge of output capacitance without external circuitry - both behaviors directly traceable to ISL91107IR internal circuitry per Functional Description section (Page 9).