Renesas ISL8105BEVAL1Z

Overview

ISL8105BEVAL1Z from Renesas Electronics is an evaluation board for the ISL8105B single-phase synchronous buck PWM controller, configured with 8-lead SOIC-packaged ISL8105BIBZ IC, 1.8V/15A output, and optimized for DC/DC converter development using Infineon BSC080N03LS (high-side) and BSC030N03LS (low-side) MOSFETs.

For engineers reviewing the ISL8105BEVAL1Z datasheet, ISL8105BEVAL1Z pinout, ISL8105BEVAL1Z application, or ISL8105BEVAL1Z equivalent, this board enables rapid validation of voltage-mode buck regulator designs targeting 1.8V core supplies in FPGA, ASIC, and DSP power systems with ≤30mV_P-P ripple and ≥90% efficiency at 12V input.

Technical Context

The ISL8105BEVAL1Z implements a fixed-frequency (300kHz) voltage-mode synchronous buck topology using the ISL8105BIBZ controller, which integrates boot diode, linear bias regulator, and dual N-channel gate drivers. It supports single-rail (12V) or split-rail (5V/12V) bias operation via jumper J7.

Board-level design includes Type-III compensation (R1=11.8kΩ, R2=12kΩ, C1=10nF, C2=390pF, R3=301Ω, C3=3.3nF), 1µH output inductor (Cooper Bussmann HC9-1R0-R), and 1560µF total output capacitance (four 470µF Sanyo 2R5TPF470ML) to meet 80mV transient response and 30mV_P-P ripple requirements.

Key Specifications

Availability

ISL8105BEVAL1Z is available at Aetrix Electronics and suitable for FPGA power delivery, ASIC core voltage regulation, and DSP processor supply applications requiring stable component supply, reference design validation, and production-ready buck converter characterization.

Supply support for ISL8105BEVAL1Z 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 computing markets.

The ISL8105BEVAL1Z belongs to Renesas' legacy analog power evaluation platform, designed specifically to accelerate development of efficient, high-current synchronous buck converters for digital logic core supplies.

FAQ

What is the primary function of the ISL8105BEVAL1Z evaluation board?

The ISL8105BEVAL1Z evaluation board is a fully assembled, tested reference design for the ISL8105B synchronous buck PWM controller. It provides a working 1.8V/15A DC/DC converter to validate performance metrics-including efficiency, transient response, and loop stability-before custom board design. The board uses the ISL8105BIBZ IC in SOIC-8 packaging and supports both single- and dual-rail bias configurations via jumper J7.

Which controller IC is mounted on the ISL8105BEVAL1Z board?

The ISL8105BEVAL1Z board mounts the ISL8105BIBZ, an 8-lead SOIC-packaged version of the ISL8105B single-phase synchronous buck PWM controller. This variant integrates gate drivers, boot diode, and internal linear regulator, and is explicitly listed in the bill of materials (BOM) on page 7 of AN1288. It differs from the ISL8105BEVAL2Z, which uses the 10-lead DFN-packaged ISL8105BIRZ.

What are the key power stage components used on the ISL8105BEVAL1Z?

The ISL8105BEVAL1Z uses Infineon BSC080N03LS as the high-side MOSFET (7.3mΩ r_DS(ON)) and BSC030N03LS as the low-side MOSFET (5mΩ r_DS(ON)), paired with a Cooper Bussmann HC9-1R0-R 1µH output inductor (1.87mΩ DCR). Input bulk capacitance consists of three 330µF/35V aluminum electrolytics (Sanyo 35ME330AX), while output capacitance totals 1560µF using four 470µF/2.5V organic polymer capacitors (Sanyo 2R5TPF470ML).

How does the ISL8105BEVAL1Z implement overcurrent protection?

The ISL8105BEVAL1Z implements cycle-by-cycle overcurrent protection using the low-side MOSFET's r_DS(ON) as a current-sense element. A 1.74kΩ resistor (R5) sets the trip threshold to 21A at 12V bias (17A at 5V bias), per Equation 14 in AN1288. Upon detection, the controller shuts down output and enters hiccup mode-executing two dummy soft-start timeouts followed by one real soft-start attempt-until fault clearance.

Can the ISL8105BEVAL1Z be used with a 5V bias supply instead of 12V?

Yes, the ISL8105BEVAL1Z supports 5V bias operation. Section "Power and Load Connections" on page 3 of AN1288 specifies that separate supplies can be used by connecting pins 1 and 2 of jumper J7 to route 5V to terminal J2 (VBIAS), while applying input voltage to J1 (VIN). The overcurrent trip point adjusts to 17A under 5V bias, and startup timing remains valid per the 23.8ms total sequence described on page 4.