Renesas EL7535EVAL1

Overview

EL7535EVAL1 from Intersil is a fully assembled, ready-to-use evaluation board for the EL7535 synchronous 350mA step-down DC/DC regulator IC. It implements the recommended 1.8V @ 350mA reference design with 1.8µH inductor, dual 10µF ceramic input/output capacitors, and precision 124kΩ/100kΩ feedback divider. The board supports input voltage range 2.5V–6V (e.g., Li-ion, 3.3V, or 5V rails) and delivers regulated output with <1µA shutdown current, 1.4MHz PWM switching, and integrated POR functionality.

For engineers reviewing the EL7535EVAL1 datasheet, EL7535EVAL1 pinout, EL7535EVAL1 application, or EL7535EVAL1 equivalent, this evaluation platform enables rapid validation of power sequencing, transient response, efficiency, and thermal behavior in portable and space-constrained systems - especially where compact footprint, low quiescent current, and reliable power-on reset signaling are critical.

Technical Context

The EL7535EVAL1 implements the EL7535's internally compensated voltage-mode PWM controller with fixed 1.4MHz switching frequency and synchronous N/P-MOSFET power stage. It validates the IC's ability to regulate from 0.8V to VIN using external resistive feedback while maintaining stability with minimal external components: one inductor, two 10µF X5R/X7R MLCCs, and phase-lead capacitor C4 (470pF).

Board-level features include dedicated SGND/PGND separation, optimized high-current LX trace routing, thermal vias under the MSOP-10 footprint, and accessible test points for VIN, VO, EN, RSI, POR, and FB. The layout adheres to Intersil's published guidelines to ensure accurate measurement of soft-start (650µs), POR delay (100ms), and over-temperature recovery (145°C trip / 130°C hysteresis).

Key Specifications

Availability

EL7535EVAL1 is available at Aetrix Electronics and suitable for portable medical devices, barcode scanners, SFP transceivers, and Li-ion powered instrumentation requiring stable component supply, fast design validation, and production-ready power architecture verification.

Supply support for EL7535EVAL1 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

Intersil Corporation is a recognized leader in precision analog and power management ICs, now part of Renesas Electronics, delivering high-efficiency, thermally robust solutions for mobile, industrial, and infrastructure applications.

The EL7535EVAL1 belongs to Intersil's evaluation platform family for DC/DC regulators and was designed specifically to accelerate prototyping and qualification of the EL7535 in space-constrained, battery-operated systems demanding high efficiency and reliable power sequencing.

FAQ

What is the primary purpose of the EL7535EVAL1 evaluation board?

The EL7535EVAL1 is a fully populated demonstration board built to validate the performance of the EL7535 synchronous step-down regulator under real-world conditions. It implements the exact component values and layout practices specified in the FN7003 datasheet, enabling engineers to measure efficiency, transient response, soft-start behavior, and POR timing without custom PCB development. The EL7535EVAL1 confirms correct operation across the full -40°C to +85°C temperature range and supports immediate bench testing with standard lab supplies.

Does the EL7535EVAL1 support adjustable output voltages, or is it fixed at 1.8V?

The EL7535EVAL1 is configured for a fixed 1.8V output using the 124kΩ/100kΩ resistor divider per the FN7003 datasheet's typical application diagram. However, the board includes solder pads and test points that allow replacement of R1/R2 to set other output voltages from 0.8V to VIN. This flexibility lets users verify the EL7535's full adjustable range while retaining all other validated layout and thermal characteristics of the EL7535EVAL1 design.

Can the EL7535EVAL1 be used to evaluate thermal performance of the EL7535 IC?

Yes - the EL7535EVAL1 incorporates thermal vias beneath the MSOP-10 footprint and follows Intersil's recommended copper pour and ground plane guidelines. Its layout enables direct junction temperature estimation using the published θJA of +100°C/W (4-layer board) and measured power dissipation. Engineers can monitor VO regulation, POR timing, and thermal shutdown behavior (145°C trip) under sustained 350mA load, confirming thermal integrity before integrating the EL7535 into final designs.

Is the EL7535EVAL1 RoHS compliant and compatible with lead-free reflow processes?

Yes - the EL7535EVAL1 uses RoHS-compliant components and PCB fabrication, consistent with the EL7535IYZ's Pb-free MSOP package (MDP0043). Its assembly meets IPC/JEDEC J-STD-020 requirements for peak reflow temperatures up to 260°C, supporting both SnPb and Pb-free soldering. The board's documentation and bill-of-materials reflect full compliance with EU RoHS Directive 2011/65/EU and related substance restrictions.

How does the RSI input function on the EL7535EVAL1, and what is its design impact?

On the EL7535EVAL1, the RSI pin is routed to a test point and can be driven externally to force an immediate POR reset pulse - independent of power-up conditions. When asserted high, RSI pulls POR low for ~100ms, then releases it after returning to logic low. This allows synchronized system resets during firmware updates or fault recovery. The EL7535EVAL1 includes optional pull-down resistor R6 to ensure proper RSI default state, preserving POR integrity during normal operation.