STMicroelectronics STEVAL-ISA093V1

Overview

STEVAL-ISA093V1 from STMicroelectronics is a 3 A step-down switching power supply demonstration board built around the L7981 QFN synchronous buck regulator. It accepts 4.5 V–28 V input, delivers adjustable 0.6 V–VIN output, operates at 250 kHz (programmable up to 1 MHz), and supports 100% duty cycle for low-dropout operation in industrial power rails.

For engineers reviewing the STEVAL-ISA093V1 datasheet, STEVAL-ISA093V1 pinout, STEVAL-ISA093V1 application, or STEVAL-ISA093V1 equivalent, this board enables rapid validation of L7981-based 3 A DC-DC designs requiring programmable frequency, zero-load operation, voltage feed-forward stability, and integrated thermal/overcurrent protection.

Technical Context

The board implements a non-isolated synchronous buck topology using the L7981 IC, which integrates a high-side MOSFET and current-mode PWM controller. Input-to-output regulation leverages voltage feed-forward compensation to improve transient response across wide VIN ranges.

Internal soft-start, enable control, and 100% duty-cycle capability allow seamless operation down to ultra-low output voltages while maintaining stability under no-load and light-load conditions typical in embedded power subsystems.

Key Specifications

Availability

STEVAL-ISA093V1 is available at Aetrix Electronics and suitable for industrial motor drives, programmable logic controllers, and IoT edge node power subsystems requiring stable component supply and fast design validation.

Supply support for STEVAL-ISA093V1 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The STEVAL evaluation board series targets rapid prototyping of ST's power management ICs-specifically enabling quick functional verification and layout reference for switching regulators like the L7981.

FAQ

What is the primary function of the STEVAL-ISA093V1 board?

The STEVAL-ISA093V1 is a fully assembled and tested demonstration board for the L7981 synchronous step-down regulator. Its purpose is to validate the electrical performance, thermal behavior, and PCB layout implementation of 3 A buck converter designs-providing immediate hardware reference for engineers developing industrial power supplies.

Does the board support adjustable output voltage, and how is it configured?

Yes-the output voltage is adjustable from 0.6 V to VIN using an external resistor divider on the FB pin. The board includes test points and footprint options for fine-tuning feedback resistors, allowing precise setting of regulated output for specific load requirements such as 3.3 V for microcontrollers or 1.2 V for FPGA cores.

Can the switching frequency be modified, and what is the method?

Yes-the default 250 kHz frequency is set by an internal oscillator but can be programmed up to 1 MHz using an external resistor connected between the RT pin and ground. This allows designers to optimize trade-offs between efficiency, EMI filtering size, and transient response for their target application.

Is the STEVAL-ISA093V1 RoHS compliant and suitable for production use?

Yes-the board is RoHS compliant per its documentation and uses only qualified industrial-grade components. While intended for evaluation, its validated layout, BOM, and thermal design serve as a production-ready reference for integrating the L7981 into volume-manufactured systems, subject to full system-level qualification.