STMicroelectronics STEVAL-ISA034V1

Overview

STEVAL-ISA034V1 from STMicroelectronics is an industrial 3-phase auxiliary power supply evaluation board implementing a quasi-resonant flyback topology with L6565 controller and STW3N150 1500 V MOSFET, delivering 12 V @ 0.6 A and 5 V @ 0.55 A (10 W total) across two isolated outputs, certified to EN60950 safety and EN55014 EMI standards for factory automation power subsystems.

For engineers reviewing the STEVAL-ISA034V1 datasheet, STEVAL-ISA034V1 pinout, STEVAL-ISA034V1 application, or STEVAL-ISA034V1 equivalent, this board supports rapid validation of high-voltage 3-phase AC-fed auxiliary supplies in PLC backplanes, motor drive control modules, and industrial I/O interface designs requiring dual-rail isolation and <10 W output.

Technical Context

The board implements a primary-side regulated quasi-resonant flyback converter operating from 185–460 V_AC 3-phase input, using the L6565 zero-current-detection (ZCD) controller to enable soft-switching at variable frequency up to ~100 kHz. The STW3N150 1500 V MOSFET-fabricated with ST's MESH OVERLAY™ technology-provides low R_DS(on) and gate charge for high efficiency under wide-input conditions.

Two independent secondary windings feed synchronous rectification (via STPS3L40S/STPS3L25S Schottky diodes) and TL431-based shunt regulation on the 5 V rail, while the 12 V rail uses passive rectification and filtering. Transformer T1 features E20/E25 core with N1/N5V = 87, N1/N12V = 38, and N1/Naux = 30 turns ratios.

Key Specifications

Availability

STEVAL-ISA034V1 is available at Aetrix Electronics and suitable for industrial programmable logic controllers, motor drive control units, and factory I/O module development requiring stable component supply, reference design traceability, and regulatory-compliant auxiliary power validation.

Supply support for STEVAL-ISA034V1 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 microcontrollers, power devices, analog ICs, and silicon solutions for industrial, automotive, and consumer markets.

This evaluation board belongs to ST's STEVAL (ST Evaluation) series, developed specifically to accelerate prototyping and compliance testing of high-voltage AC/DC power architectures for industrial automation and energy infrastructure applications.

FAQ

Is STEVAL-ISA034V1 still in active production?

No - STEVAL-ISA034V1 is marked "Obsolete Product(s)" in the official ST document revision history (Rev 1, Feb 2008). It remains available through authorized legacy distributors and Aetrix Electronics' extended-life inventory program with full documentation and test reports for legacy system maintenance and redesign projects.

Can STEVAL-ISA034V1 operate from single-phase AC input?

Yes - though designed for 3-phase operation, the board accepts 185–460 V_AC input regardless of phase count. When fed from single-phase, it draws current from one line-to-line pair; derating is not required, but input fuse and EMI filter components must be verified per local installation standards.

What is the role of the STW3N150 MOSFET on this board?

The STW3N150 serves as the primary-side switching element in the quasi-resonant flyback converter. Its 1500 V rating ensures robustness against 3-phase line transients, while its low R_DS(on) and gate charge - enabled by ST's MESH OVERLAY™ process - reduce conduction and switching losses at high input voltages.

Does STEVAL-ISA034V1 support remote ON/OFF control?

No - the board lacks dedicated enable/disable logic or control pins. Power sequencing is fully autonomous: startup occurs when input voltage exceeds the L6565's V_CC UVLO threshold (~12.5 V), and shutdown follows input dropout. External control requires modification to the V_CC bias network or GD driver path.