STMicroelectronics STEVAL-ISA012V1

Overview

STEVAL-ISA012V1 from STMicroelectronics is a 3-phase industrial reference design board implementing an ultra-wide-input (90–450 VAC) flyback power supply using VIPer12AS and STD3NK50Z MOSFET, delivering regulated 5 V/10 mA and 3.3 V/100 mA outputs for metering and auxiliary bias applications.

For engineers reviewing the STEVAL-ISA012V1 datasheet, STEVAL-ISA012V1 pinout, STEVAL-ISA012V1 application, or STEVAL-ISA012V1 equivalent, this board provides verified layout, component selection, and performance validation for high-voltage AC input SMPS in three-phase utility metering and street lighting auxiliary supplies.

Technical Context

The design employs a patented series-switch topology where Q1 (STD3NK50Z) limits DC bulk voltage before the VIPer12AS primary stage, enabling use of standard 500 V-rated components instead of 1000 V parts. This reduces cost and footprint while maintaining compliance with IEC62053-21.

Feedback is implemented via TS2431 shunt regulator and PC817 optocoupler for isolated 3.3 V regulation; 5 V output is derived from the same secondary winding with passive post-regulation. Line and load regulation are both ±1%, and hold-up time exceeds 50 ms at full load.

Key Specifications

Availability

STEVAL-ISA012V1 is available at Aetrix Electronics and suitable for smart electricity metering, industrial auxiliary power supplies, and high-voltage street lighting control systems requiring stable component supply and validated reference design reuse.

Supply support for STEVAL-ISA012V1 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, sensors, and analog products for industrial, automotive, and consumer markets.

This board belongs to ST's STEVAL evaluation platform family, developed to accelerate adoption of ST's high-voltage power solutions in utility infrastructure and industrial control applications.

FAQ

What is the primary function of STEVAL-ISA012V1?

STEVAL-ISA012V1 is a reference design board for a 3-phase, ultra-wide-input (90–450 VAC) flyback power supply. It delivers two isolated, regulated DC outputs (5 V/10 mA and 3.3 V/100 mA) using VIPer12AS and STD3NK50Z, targeting auxiliary power in revenue-grade electricity meters and industrial control systems.

Does STEVAL-ISA012V1 support three-phase input directly?

Yes - the board accepts 3-phase input with neutral, as well as 1-phase with neutral or 2-phase without neutral. Its input bridge rectifier and patented series-switch topology enable seamless operation across all three configurations without hardware modification.

What regulatory standards does this design meet?

The design complies with IEC62053-21 for energy meter auxiliary supplies: it achieves <6 W no-load power consumption, >50 ms hold-up time, and ±3% output accuracy. It is not certified for safety standards (e.g., UL/EN62368), and users must validate final system-level compliance.

Can the 3.3 V output be used to power a microcontroller?

Yes - the 3.3 V output delivers up to 100 mA with ±1% line/load regulation and <50 mV ripple, making it suitable for powering low-power MCUs (e.g., STM32L0/L1) and metrology ASICs in smart meters. The TS2431 + PC817 feedback loop ensures tight regulation under dynamic load changes.