Renesas ISL85415EVAL2Z

Overview

ISL85415EVAL2Z from Renesas Electronics is an evaluation board designed to demonstrate the ISL85415 synchronous buck-boost regulator in a negative-output configuration, supporting 3V–31V input and delivering up to 500mA at –5V with >85.6% peak efficiency at 12V_IN/250mA. It enables rapid validation of point-of-load power delivery in industrial and embedded systems requiring wide-VIN, low-quiescent-current DC/DC conversion.

For engineers reviewing the ISL85415EVAL2Z datasheet, ISL85415EVAL2Z pinout, ISL85415EVAL2Z application, or ISL85415EVAL2Z equivalent, this board provides pre-validated layout, jumper-selectable PFM/PWM mode, on-board EN control, SYNC capability, and configurable soft-start-key for evaluating negative V_OUT buck-boost performance under real-world thermal and transient conditions.

Technical Context

The ISL85415EVAL2Z implements the ISL85415 IC in a fixed –5V output configuration using a 22µH inductor (L1), dual 22µF output capacitors (C5/C6), and a 90.9kΩ/12.4kΩ feedback divider. It supports programmable switching frequency (300kHz–2MHz) via R12 and offers selectable operation modes (PFM or forced PWM) through JP1.

Thermal and EMI optimization is achieved via an 8-via GND pad connection from U1's exposed thermal pad to the internal ground plane, high-frequency MLCCs placed adjacent to VIN/PHASE/VCC pins, and strict separation between power paths (L1, C1–C3, C5–C6) and small-signal nodes (FB, COMP, SS).

Key Specifications

Availability

ISL85415EVAL2Z is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded sensor node development requiring stable component supply, fast prototyping cycles, and validated thermal/mechanical reference design.

Supply support for ISL85415EVAL2Z 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 IoT applications with emphasis on reliability and system integration.

The ISL85415EVAL2Z belongs to Renesas' high-efficiency DC/DC evaluation platform family, engineered specifically to accelerate adoption of wide-VIN buck-boost regulators in negative-output point-of-load applications where layout sensitivity and thermal performance are critical.

FAQ

What is the primary function of the ISL85415EVAL2Z evaluation board?

The ISL85415EVAL2Z evaluation board demonstrates the ISL85415 synchronous buck-boost regulator operating in negative-output mode. It delivers up to 500mA at –5V from a 3V–31V input, featuring on-board jumpers for PFM/PWM selection, an enable switch (SW1), SYNC input, and test points for soft-start and compensation. The ISL85415EVAL2Z is not a standalone power module but a fully assembled, layout-optimized reference design for rapid validation.

Can the ISL85415EVAL2Z be used to generate output voltages other than –5V?

Yes - the ISL85415EVAL2Z supports adjustable negative output voltages from –3.3V to –12V by modifying the R1/R2 feedback resistor network per Equation 1 in the AN1934 manual. Table 1 specifies exact component values (e.g., R2 = 4.75kΩ for –12V) and corresponding inductor/capacitor selections. The ISL85415EVAL2Z's preset –5V configuration serves as the baseline, but reconfiguration is straightforward using standard 0603 SMD parts.

How does the ISL85415EVAL2Z handle thermal management during continuous 500mA operation?

The ISL85415EVAL2Z uses an 8-via thermal connection from the ISL85415FRZ IC's exposed GND pad to the internal ground plane, ensuring low-impedance current return and efficient heat dissipation. Layout Figures 3–6 confirm placement of high-frequency capacitors (C1, C2, C3, C5, C6) directly adjacent to their respective pins with dedicated vias to the GND plane - reducing thermal resistance and maintaining <40°C temperature rise at full load under +25°C ambient conditions.

Does the ISL85415EVAL2Z support external clock synchronization?

Yes - the ISL85415EVAL2Z includes a dedicated SYNC input (P2) that accepts an external clock signal to synchronize the ISL85415's switching frequency. By default, R6 (200kΩ) pulls SYNC to VCC for internal PWM operation; tying SYNC to GND forces PFM mode. JP1 allows manual selection between PFM and forced PWM, making the ISL85415EVAL2Z suitable for EMI-sensitive environments or multi-rail systems requiring deterministic switching alignment.

What test equipment is required to evaluate the ISL85415EVAL2Z?

A 0–50V/2A power supply, electronic load capable of sinking up to 1.5A, two digital multimeters (for VIN/VOUT monitoring), and a 100MHz quad-trace oscilloscope are recommended. Test points P1–P10 provide direct access to PG, EN, SS, VCC, SYNC, VIN, VNEG, and PHASE signals. The ISL85415EVAL2Z's compact layout and clearly labeled connectors (e.g., P4/P5 for input, P7 for –5V output) simplify setup and measurement accuracy.