Renesas ISL85418EVAL1Z

Overview

ISL85418EVAL1Z from Renesas Electronics is an evaluation board designed to characterize the ISL85418 synchronous buck regulator in point-of-load applications. It supports 3V–40V input, delivers up to 800mA at 3.3V (adjustable 0.6V–15V), operates at 500kHz default switching frequency, and achieves >84% peak efficiency at 50% load with <3mV output ripple.

For engineers reviewing the ISL85418EVAL1Z datasheet, ISL85418EVAL1Z pinout, ISL85418EVAL1Z application, or ISL85418EVAL1Z equivalent, this board enables rapid validation of wide-VIN DC/DC performance under real-world transient, thermal, and layout-sensitive conditions - especially for industrial power rails, embedded controllers, and space-constrained IoT nodes requiring low quiescent current and PFM/PWM mode flexibility.

Technical Context

The ISL85418EVAL1Z implements a fixed 3.3V output configuration using R1 = 90.9kΩ and R2 = 20kΩ feedback network, optimized for 22µH inductor (L1) and 69µF total output capacitance (C5 + C6). It integrates the ISL85418FRZ DFN-12 IC with internal high-side/low-side NMOS switches, BOOT capacitor (C9), soft-start capacitor (CSS = 33nF), and SYNC/FS/EN/PG signal access via test points and jumpers.

Board-level features include selectable PFM or forced PWM operation via S2 switch, enable/disable control via S1, external synchronization capability, internal/external soft-start selection (R15), and adjustable switching frequency (300kHz–2MHz) via resistor R12 - all configurable without soldering changes per AN1905 Rev.4.00.

Key Specifications

Availability

ISL85418EVAL1Z is available at Aetrix Electronics and suitable for industrial power validation, embedded system prototyping, and IoT node power architecture development requiring stable component supply and fast time-to-test.

Supply support for ISL85418EVAL1Z 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, infrastructure, and IoT applications.

The ISL85418EVAL1Z belongs to Renesas' ISL854xx family of wide-VIN synchronous buck regulators, engineered for high-efficiency, low-quiescent-current point-of-load conversion in space- and thermally constrained environments.

FAQ

What is the primary function of the ISL85418EVAL1Z?

The ISL85418EVAL1Z is an evaluation board purpose-built to validate the electrical performance, thermal behavior, and layout sensitivity of the ISL85418 synchronous buck regulator. It provides immediate access to VIN, VOUT, EN, PG, SYNC, FS, SS, and COMP signals, enabling engineers to measure efficiency, ripple, transient response, and mode-switching behavior without custom PCB design. The ISL85418EVAL1Z supports full characterization of the ISL85418 across its 3V–40V input range and 0.6V–15V output range.

Can the output voltage of the ISL85418EVAL1Z be adjusted?

Yes, the ISL85418EVAL1Z output voltage is preset to 3.3V but fully adjustable from 0.6V to 15V by modifying the R1/R2 feedback divider per Equation 1 in AN1905. For outputs below 1.8V, switching frequency must be reduced to 300kHz to accommodate minimum on-time limitations - a change implemented by adjusting R12 as documented in the ISL85418 datasheet. The ISL85418EVAL1Z schematic and Bill of Materials confirm R1 = 90.9kΩ and R2 = 20kΩ for the default 3.3V setting.

Does the ISL85418EVAL1Z support external clock synchronization?

Yes, the ISL85418EVAL1Z includes a dedicated SYNC pin (accessible at test point P2) that accepts an external clock signal to synchronize the ISL85418's switching frequency. By default, R6 = 200kΩ pulls SYNC to VCC, enabling PWM mode and locking frequency to the FS pin setting. Tying SYNC to GND forces PFM mode. This functionality is verified in the ISL85418EVAL1Z schematic (Figure 10) and confirmed in Section "SYNC Control" of AN1905 Rev.4.00.

What are the key test points and controls on the ISL85418EVAL1Z?

The ISL85418EVAL1Z provides labeled test points for VIN (P4), VOUT (P7), PGND (P3, P5, P9), EN (P6), PG (P1), SS (P10), VCC (P8), SYNC (P2), and SW (P11). It includes two SPDT toggle switches: S1 for enable/disable control and S2 for forced PFM/PWM mode selection. All critical signals are routed to 0.1"-spaced headers or mini test points (Keystone 5002) for oscilloscope probing and load connection - as detailed in the Bill of Materials and Figures 6–7 of AN1905.

Is thermal performance data available for the ISL85418EVAL1Z?

AN1905 Rev.4.00 specifies board temperature at +25°C during characterization and notes that the ISL85418FRZ IC must be connected to the GND plane with eight vias for thermal integrity. While no full thermal imaging or junction temperature curves are published for the ISL85418EVAL1Z specifically, Figure 21–22 show efficiency vs. load across multiple input voltages, indirectly reflecting thermal behavior. The board's 1.516cm² converter area and use of 22µH DR73-220-R inductor and 150µF/50V aluminum electrolytic (C10) support sustained 800mA operation within standard lab ambient conditions when properly heatsinked.