Renesas ISL91127IIA-EVZ

Overview

ISL91127IIA-EVZ from Renesas Electronics is an evaluation board for the ISL91127IR adjustable-output buck-boost regulator IC, designed to validate 1.0V–5.2V output operation with up to 2A load current across 1.8V–5.5V input range. It implements Renesas' proprietary 4-switch synchronous architecture with 2.5MHz switching, 30µA quiescent current, and seamless buck/boost mode transitions - enabling brownout-free power for Li-ion battery systems in handheld medical and consumer devices.

For engineers reviewing the ISL91127IIA-EVZ datasheet, ISL91127IIA-EVZ pinout, ISL91127IIA-EVZ application, or ISL91127IIA-EVZ equivalent, this page delivers verified board-level specifications, supported test configurations (e.g., 1µH inductor, 2×22µF output capacitors), thermal pad grounding requirements, MODE pin clock sync capability, and design guidance for adjustable VOUT using external R1/R2 dividers per Equation 1.

Technical Context

The ISL91127IIA-EVZ provides a fully assembled, tested platform for the ISL91127IR buck-boost regulator IC, pre-configured for adjustable output voltage operation via FB pin and external resistor divider. It supports both PFM (auto) and forced PWM modes through the MODE pin, and includes integrated soft-start (1–3ms ramp), soft-discharge (120Ω internal pull-down), and comprehensive protection (short-circuit, over-temperature at 155°C, UVLO at 1.725V).

Board-level implementation follows Renesas' recommended layout: PVIN and VOUT ceramic capacitors placed adjacent to IC pins, low-ESR X5R dielectrics (2×10µF input, 2×22µF output), shielded 1µH inductor with ≥4A saturation rating, and dedicated SGND/PGND separation to minimize noise coupling into the feedback network.

Key Specifications

Availability

ISL91127IIA-EVZ is available at Aetrix Electronics and suitable for battery-powered medical instrumentation, smartphone power validation, RF amplifier bias testing, and portable diagnostic equipment requiring stable component supply and rapid prototyping support.

Supply support for ISL91127IIA-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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog power, and SoC solutions for automotive, industrial, and IoT applications, with headquarters in Tokyo and design centers worldwide.

The ISL91127IR product line targets high-efficiency, wide-input-range DC/DC conversion in space-constrained battery-powered systems - specifically engineered to maximize usable energy from advanced Li-ion chemistries operating below traditional system voltages.

FAQ

What is the primary function of the ISL91127IIA-EVZ evaluation board?

The ISL91127IIA-EVZ is a Renesas-provided evaluation board for the ISL91127IR adjustable-output buck-boost regulator IC. It enables hardware validation of 1.0V–5.2V output regulation, 2A load capability, and seamless buck/boost transitions across 1.8V–5.5V input. The board includes all required passive components (1µH inductor, 2×10µF input caps, 2×22µF output caps), MODE pin access for PWM/PSM control, and FB resistor pads for custom VOUT programming - allowing immediate bench testing without additional component selection.

Does the ISL91127IIA-EVZ support fixed-output voltage configurations?

No - the ISL91127IIA-EVZ is specifically configured for the adjustable-output ISL91127IRAZ variant and requires external R1/R2 resistors on the FB pin to set VOUT per Equation 1 (VOUT = 0.8V × (1 + R1/R2)). Fixed-output versions like ISL91127IRNZ-T use internal feedback and are evaluated on the ISL91127IRN-EVZ board. Attempting fixed-output operation on ISL91127IIA-EVZ would require hardware modification and is not supported per Renesas documentation.

How is the MODE pin used on the ISL91127IIA-EVZ board?

On the ISL91127IIA-EVZ, the MODE pin (Pin 12 of ISL91127IR) is brought out to a test point and supports two functions: logic-level selection between auto PFM (MODE = HIGH) and forced PWM (MODE = LOW), and optional external clock synchronization within 2.75–3.25MHz range. This allows users to evaluate light-load efficiency trade-offs, EMI-sensitive timing constraints, or system-level clock domain alignment - all without soldering changes, as confirmed in FN8859 Pin Descriptions and Figure 12 transient waveforms.

What thermal management features does the ISL91127IIA-EVZ implement?

The ISL91127IIA-EVZ implements Renesas' recommended thermal design: the ISL91127IR's exposed thermal pad (EPAD) is soldered directly to a large PGND copper area on the PCB, with multiple thermal vias connecting to inner and bottom ground planes. This achieves θJA ≈ 40°C/W and θJC ≈ 5°C/W per FN8859 Table "Thermal Resistance (Typical)", enabling sustained 2A operation at +85°C ambient. Thermal shutdown triggers at 155°C junction temperature, with 30°C hysteresis ensuring reliable recovery after cooling.

Can the ISL91127IIA-EVZ be used to validate short-circuit protection behavior?

Yes - the ISL91127IIA-EVZ fully supports short-circuit testing per FN8859 Figure 16. When VOUT is shorted to GND, the ISL91127IR reduces switching frequency and activates peak current limiting (3.7–5A P-channel limit) to clamp fault current while maintaining safe junction temperature. The board's layout preserves signal integrity for observing LX1/LX2 waveforms during fault events, and its 120Ω soft-discharge resistor ensures controlled VOUT collapse when EN is deasserted - critical for validating system-level fault response in battery-powered designs.