Renesas ISL78235EVAL1Z

Overview

ISL78235EVAL1Z from Renesas Electronics is an evaluation board for the ISL78235 5A automotive synchronous buck regulator, configured with a 3mm×3mm TQFN package, 2.7V–5.5V input, adjustable output voltage, and 2MHz default switching frequency. It supports forced PWM or PFM light-load operation and integrates hiccup-mode OCP, OVP, OTP, and soft-stop discharge for automotive infotainment and SoC power applications.

For engineers reviewing the ISL78235EVAL1Z datasheet, ISL78235EVAL1Z pinout, ISL78235EVAL1Z application, or ISL78235EVAL1Z equivalent, this page delivers verified board-level specifications, thermal performance data, supported IC configuration modes (SYNC, FS, EN), layout guidance per Renesas FN8713 Rev 8.01, and direct links to reference schematics and BOM components used on the board.

Technical Context

The ISL78235EVAL1Z implements peak current mode control with internal 35mΩ/11mΩ HS/LS FETs, enabling 100% duty cycle operation and <250mV dropout at 5A. It supports external synchronization (1–4MHz), adjustable soft-start (1ms fixed or capacitor-programmable), and seamless transition between internal oscillator and external clock without shutdown.

Board-level design includes dual 22µF input capacitors, 0.68µH inductor, feedback divider (R2/R3), COMP compensation network options (internal or external), and PG monitoring with 1ms delay. Thermal management leverages the exposed pad connected to SGND via multiple vias, optimized for -40°C to +105°C ambient operation.

Key Specifications

Availability

ISL78235EVAL1Z is available at Aetrix Electronics and suitable for automotive infotainment development, SoC/FPGA power validation, and DC/DC POL module prototyping requiring stable component supply and full AEC-Q100-compliant reference designs.

Supply support for ISL78235EVAL1Z 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 high-reliability analog, power, and embedded processing solutions for automotive, industrial, and enterprise systems.

The ISL78235 product line targets automotive power management with AEC-Q100 qualification, integrated MOSFETs, and pin-compatible scalability (3A/4A/5A) for scalable SoC and microcontroller core voltage rails.

FAQ

What is the primary function of the ISL78235EVAL1Z evaluation board?

The ISL78235EVAL1Z evaluation board demonstrates and validates the ISL78235 5A synchronous buck regulator in its 3mm×3mm TQFN package. It provides a fully assembled, tested platform with reference component values (0.68µH inductor, dual 22µF input/output caps, feedback resistors), enabling rapid evaluation of efficiency, transient response, thermal behavior, and protection features under real automotive operating conditions.

Does the ISL78235EVAL1Z support both PWM and PFM modes?

Yes, the ISL78235EVAL1Z supports both forced PWM and discontinuous conduction mode (PFM) via the SYNC pin. When SYNC is pulled high (to VIN), the board operates in forced PWM mode for low-noise, constant-frequency operation. When SYNC is grounded, it enters PFM mode to maximize light-load efficiency - a configuration verified in Figure 6 and Figure 8 of the ISL78235 datasheet (FN8713 Rev 8.01).

What input and output capacitor values are used on the ISL78235EVAL1Z board?

The ISL78235EVAL1Z uses two 22µF low-ESR ceramic capacitors (C1) at the VIN input and two 22µF ceramic capacitors (C2) at the VOUT output, as specified in the Typical Application Diagram (Figure 4) and Component Selection Table (Table 2) of the ISL78235 datasheet. An optional 22pF capacitor (C3) is included for loop stability tuning.

How is thermal performance managed on the ISL78235EVAL1Z?

Thermal performance on the ISL78235EVAL1Z is managed through the ISL78235's exposed thermal pad (EPAD), which is soldered directly to a dedicated SGND plane on the PCB. The board layout follows Renesas' recommendation to place multiple vias under the EPAD to connect it to an internal ground plane, achieving a θJA of 43°C/W - matching the 3mm×3mm TQFN package specification in FN8713 Rev 8.01.

Can the ISL78235EVAL1Z be synchronized to an external clock source?

Yes, the ISL78235EVAL1Z supports external clock synchronization from 1MHz to 4MHz via the SYNC pin. As documented in the Pin Descriptions (Page 4) and Theory of Operation (Page 17), connecting an external function generator to SYNC enables seamless, glitch-free transition between internal oscillator and external clock without disabling the ISL78235 - a feature validated in the board's schematic and layout.