STMicroelectronics STEVAL-ISA081V1

Overview

STEVAL-ISA081V1 from STMicroelectronics is an isolated 12 W switched-mode power supply (SMPS) demonstration board based on the VIPER26 monolithic high-voltage converter IC, delivering 12 V/1 A and 3.3 V/100 mA outputs across 85–305 V_AC input, with <120 mW standby power at 230 V_AC, 4 kV isolation, and EN55022 Class B EMI compliance.

For engineers reviewing the STEVAL-ISA081V1 datasheet, STEVAL-ISA081V1 schematic, STEVAL-ISA081V1 application, or STEVAL-ISA081V1 equivalent, this board serves as a validated reference design for cost-optimized, compact AC-DC offline SMPS in industrial control interfaces, smart metering front-ends, and low-power IoT gateway power stages.

Technical Context

The board implements primary-side regulation using the VIPER26's integrated 800 V avalanche-rated MOSFET and current-mode PWM controller, eliminating optocoupler feedback. Input rectification and filtering are implemented with discrete diodes and bulk electrolytic capacitors, while output rectification uses Schottky diodes on both rails.

Transformer design enables reinforced isolation (4 kV/8 mm creepage), and the layout complies with EN55022 Class B conducted/radiated emission limits without external shielding. Standby consumption is minimized via burst-mode operation below light load thresholds.

Key Specifications

Availability

STEVAL-ISA081V1 is available at Aetrix Electronics and suitable for industrial HMI power supplies, smart energy meter auxiliary rails, and isolated sensor node DC-DC conversion requiring stable component supply and pre-validated safety-compliant design.

Supply support for STEVAL-ISA081V1 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 ICs, analog chips, and MEMS sensors for industrial, automotive, and consumer applications.

This board belongs to ST's STEVAL evaluation platform series, developed to accelerate prototyping of certified AC-DC and DC-DC power architectures using ST's proprietary VIPer and HVLED driver families.

FAQ

What is the maximum total output power supported by STEVAL-ISA081V1?

The board delivers up to 12 W total output power: 12 V × 1 A = 12 W on the main rail, with the 3.3 V rail limited to 100 mA (0.33 W). Total combined load must not exceed 1 A peak output current, as specified in the data brief. Thermal derating applies above 50 °C ambient.

Does STEVAL-ISA081V1 require external feedback components for voltage regulation?

No. It uses primary-side regulation via the VIPER26's internal sensing circuitry and transformer auxiliary winding feedback-no optocoupler, TL431, or secondary-side compensation network is needed. Regulation accuracy depends on transformer turns ratio and winding resistance matching.

Can STEVAL-ISA081V1 be used in medical or safety-critical applications?

No. ST explicitly states in the document that its products-including this board-are not authorized for life-sustaining, life-saving, or safety-critical applications unless expressly approved in writing by ST. It lacks medical-grade certification (e.g., IEC 60601-1) and redundant fault protection.

What PCB material and construction does STEVAL-ISA081V1 use?

The board uses FR4 substrate with single-sided 35 µm copper, measuring 32 × 90 mm. Creepage and clearance distances meet reinforced insulation requirements for 4 kV isolation, and layout follows ST's recommended practices for EMI suppression and thermal management.