STMicroelectronics STEVAL-ISA023V2

Overview

STEVAL-ISA023V2 from STMicroelectronics is an evaluation board for a flyback AC-DC converter based on the VIPer53-E controller/MOSFET hybrid IC, delivering dual negative outputs (–5 V and –12 V) at up to 24 W total power from universal 90–265 V_AC input, with standby consumption <1 W and EN55022 Class B EMI compliance - designed for industrial and white-goods SMPS applications.

For engineers reviewing the STEVAL-ISA023V2 datasheet, STEVAL-ISA023V2 schematic, STEVAL-ISA023V2 application, or STEVAL-ISA023V2 equivalent, this board enables rapid validation of VIPer53-E-based negative-output flyback topologies under real-world line-voltage and load-transient conditions while meeting global safety (EN 60950) and EMI requirements.

Technical Context

The board implements a primary-side regulated, discontinuous conduction mode (DCM) flyback converter using the VIPer53-E - an integrated high-voltage (800 V) MDmesh™ MOSFET and current-mode PWM controller in DIP-8 package. Feedback is via optocoupler (PC817) and TL431 shunt regulator, enabling precise regulation of both negative outputs without secondary-side controllers.

Input rectification uses bridge diodes (D1–D4), bulk storage employs two 1000 µF/25 V electrolytics (C10, C11), and output filtering includes dedicated low-ESR capacitors (C9, C13, C14). EMI suppression incorporates X2-class input capacitors (C1, C2), Y1-class capacitor (C16), and common-mode choke (L3).

Key Specifications

Availability

STEVAL-ISA023V2 is available at Aetrix Electronics and suitable for industrial motor drives, appliance control units, and white-goods auxiliary power supplies requiring stable component supply, reference design validation, and regulatory-compliant AC-DC conversion.

Supply support for STEVAL-ISA023V2 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/mixed-signal devices for industrial, automotive, and consumer markets.

This board belongs to ST's STEVAL (ST Evaluation) series - purpose-built reference designs that demonstrate application-specific implementations of ST's power, interface, and control ICs, accelerating customer prototyping and certification.

FAQ

What is the primary topology implemented on STEVAL-ISA023V2?

The board implements a primary-side regulated, discontinuous conduction mode (DCM) flyback converter using the VIPer53-E IC. It features transformer-coupled dual negative outputs, optocoupler-based feedback via PC817 and TL431, and passive input rectification with bulk DC filtering - optimized for cost-sensitive, low-noise industrial auxiliary supplies.

Can STEVAL-ISA023V2 be modified to deliver positive outputs?

No - the board is specifically laid out for negative-output operation: secondary windings are grounded at the cathode side of output rectifiers (D6, D7), and regulation circuitry references ground to the negative rail. Reconfiguring for positive outputs would require transformer rewinding, PCB trace modification, and feedback network redesign - not supported by the original design.

Does STEVAL-ISA023V2 include protection features beyond basic overvoltage?

Yes - it integrates overtemperature shutdown via the VIPer53-E's internal thermal foldback, overcurrent limiting through primary peak-current sensing, and overvoltage protection triggered by TOVL pin monitoring. Input surge protection is provided by MOV D5 (1.5KE150A) and fuse F1 (2 A), meeting IEC 61000-4-5 Level 3 immunity.

Is the VIPer53-E on this board socketed or soldered?

The VIPer53-E (U1) is permanently soldered in a DIP-8 footprint on the board. It is not socketed - replacement requires desoldering and rework. The DIP-8 layout allows manual replacement with compatible VIPer53 variants (e.g., VIPer53ED, VIPer53HS) if needed for testing, but no socket or adapter is included.