STMicroelectronics STEVAL-ISA111V1

Overview

STEVAL-ISA111V1 from STMicroelectronics is a wide-range 12 V, 1 A non-isolated flyback demonstration board built around the VIPER26HN offline high-voltage PWM converter IC. It operates from 90–264 VAC input, delivers >80% average efficiency, maintains ±5% output regulation, consumes <30 mW standby power at 230 VAC, and includes thermal shutdown, overload, and open-loop protection for industrial AC/DC adapter development.

For engineers reviewing the STEVAL-ISA111V1 datasheet, STEVAL-ISA111V1 application schematic, STEVAL-ISA111V1 bill of materials, or STEVAL-ISA111V1 evaluation board layout, this page provides verified electrical specifications, topology context, design-level performance metrics, and supply-chain support details for rapid prototyping of compact offline SMPS designs.

Technical Context

The board implements a non-isolated flyback topology using the VIPER26HN IC, which integrates an 800 V avalanche-rugged power section and operates at 115 kHz with frequency jittering to reduce EMI. Control is achieved via primary-side regulation using feedback through the COMP and FB pins, eliminating optocoupler dependency.

Protections include delayed overload response, thermal shutdown with hysteresis, and auto-restart after fault clearance. Input filtering uses a 1 mH inductor (L2), while output filtering employs ultra-low-ESR Rubycon ZL-series capacitors (C10, C11) to maintain 50 mV peak-to-peak ripple under full load.

Key Specifications

Availability

STEVAL-ISA111V1 is available at Aetrix Electronics and suitable for industrial AC/DC adapter development, smart meter auxiliary power supplies, and IoT gateway power subsystem validation requiring stable component supply and documented reference design fidelity.

Supply support for STEVAL-ISA111V1 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 silicon solutions for industrial, automotive, and consumer applications.

This board belongs to ST's STEVAL (ST Evaluation) series - purpose-built demonstration platforms that validate application-specific IC functionality, accelerate customer design-in, and provide production-ready schematics, layout, and test data for offline SMPS implementations.

FAQ

Is STEVAL-ISA111V1 isolated or non-isolated?

STEVAL-ISA111V1 implements a non-isolated flyback topology. Though flyback is typically isolated, this board omits transformer secondary-side isolation by referencing output ground to input neutral, confirmed by its single-ground-plane PCB layout and absence of safety-rated transformer insulation in the BOM. It is intended for low-risk, internally powered applications where galvanic isolation is not required.

What is the role of the VIPER26HN on this board?

The VIPER26HN serves as the integrated high-voltage PWM controller and power switch, combining an 800 V avalanche-rugged MOSFET, oscillator, current-sense comparator, and protection circuitry. It enables primary-side regulation via feedback pin (FB) and compensation pin (COMP), eliminating need for optocouplers or TL431-based secondary-side control.

Can STEVAL-ISA111V1 be modified for 5 V or 24 V output?

Yes - output voltage is set by resistor divider R4a/R4b on the FB pin. Scaling R4a to 7.5 kΩ yields ~5 V; scaling to 47 kΩ yields ~24 V. However, diode D3 (STPS3150) and capacitor C10 (1000 µF/16 V) must be reselected for voltage rating and ripple current handling per IEC 61000-3-2 and thermal derating guidelines.

Does this board meet RoHS and REACH requirements?

Yes - the STEVAL-ISA111V1 is explicitly declared RoHS compliant in its data brief (Doc ID 023970 Rev 1, p.1). All listed BOM components - including Panasonic NHG/SMG capacitors, Vishay DF06M bridge, STTH1L06 diode, and STPS3150 Schottky - carry RoHS-compliant part numbers and are supplied with full material declarations traceable to ST's component sourcing policy.