STMicroelectronics STEVAL-ISA054V1

Overview

STEVAL-ISA054V1 from STMicroelectronics is a 100 W, 3-phase auxiliary power supply demonstration board built around the STW9N150 1500 V Power MOSFET and UC3844B primary-side controller, delivering dual regulated outputs (24 V @ 4 A and selectable 5 V or 3.3 V @ 1 A) for industrial medium-power applications.

For engineers reviewing the STEVAL-ISA054V1 datasheet, STEVAL-ISA054V1 schematic, STEVAL-ISA054V1 application, or STEVAL-ISA054V1 equivalent, this board provides a validated flyback + secondary DC-DC architecture with EN60950 safety certification, EN55014 EMI compliance, and RoHS-conformant construction-ideal for evaluating high-voltage AC/DC conversion in factory automation and control systems.

Technical Context

The board implements a two-stage architecture: a primary-side flyback converter using UC3844B PWM control and STW9N150 (1500 V, 9 A) MOSFET, followed by a secondary-side L5970D synchronous buck regulator deriving 5 V or 3.3 V from the 24 V rail. Input accepts dual AC sources: 400 V_RMS ±20% (3-phase line-to-line) or 180–265 V_RMS (single-phase).

Key design elements include X2/Y1 EMI filtering (C12, C15), NTC inrush limiting, transformer-isolated feedback via PC817 optocoupler and TL1431 shunt regulator, and output regulation stability verified across 50 Hz input frequency. Total output power exceeds 100 W with thermal derating per EN60950.

Key Specifications

Availability

STEVAL-ISA054V1 is available at Aetrix Electronics and suitable for industrial control panels, programmable logic controller (PLC) auxiliary supplies, factory automation sensor hubs, and 3-phase motor drive auxiliary power generation requiring stable component supply and pre-validated safety compliance.

Supply support for STEVAL-ISA054V1 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 board belongs to ST's STEVAL evaluation platform family, engineered to accelerate prototyping and validation of high-reliability AC/DC power architectures for industrial equipment manufacturers and power supply designers.

FAQ

What input configurations does STEVAL-ISA054V1 support?

The board supports two independent AC inputs: Connector J1 accepts 400 V_RMS ±20% three-phase line-to-line voltage, while J2 accepts 180–265 V_RMS single-phase mains. Both are rated for 50 Hz operation and include fuse, NTC, and X/Y-capacitor filtering per EN60950.

How is output voltage selection implemented for the 5 V / 3.3 V rail?

Output voltage is selected by configuring the external resistor divider on the L5970D FB pin: R14 = 10 kΩ and R15 = 3.3 kΩ yield 3.3 V; replacing R15 with 5.6 kΩ yields 5 V. The L5970D operates as a synchronous buck converter powered from the 24 V rail.

Is isolation provided between input and outputs?

Yes-galvanic isolation is achieved via the custom flyback transformer (T5) and reinforced insulation between primary and secondary windings. Feedback uses PC817 optocoupler + TL1431, meeting EN60950 creepage/clearance requirements for 300 V_DC working voltage.

Can STEVAL-ISA054V1 be used in safety-critical applications?

No-ST explicitly states in the document that its products are not recommended, authorized, or warranted for life-saving, life-sustaining, or safety-critical applications unless expressly approved in writing by an authorized ST representative. This board is intended for industrial evaluation only.