STMicroelectronics STEVAL-ISA133V1

Overview

STEVAL-ISA133V1 from STMicroelectronics is a double-output AC-DC demonstration board implementing a 7.5 W quasi-resonant flyback SMPS for power line communication systems, featuring 13 V @ 0.55 A and 3.3 V @ 100 mA peak outputs, optoless primary-sensing CV/CC regulation, and ALTAIR04-900 integrated QR controller + 900 V MOSFET.

For engineers reviewing the STEVAL-ISA133V1 datasheet, STEVAL-ISA133V1 schematic, STEVAL-ISA133V1 application, or STEVAL-ISA133V1 equivalent, this board serves as a validated reference design for PLM power supplies requiring high reliability, EMI compliance (EN55022 Class-B), and dual-rail isolated output without optocouplers.

Technical Context

The board implements a quasi-resonant ZVS flyback topology using the ALTAIR04-900 IC, which integrates a current-mode PWM controller and a 900 V, 16 Ω R_DS(on) avalanche-rugged MOSFET in one package. It delivers primary-side constant-voltage and constant-current regulation without secondary feedback components.

Protection features include auxiliary winding disconnection detection, shorted secondary rectifier detection, and transformer saturation protection - all implemented in auto-restart mode. The design meets ST7580-based PLC system requirements with universal 90–264 V_AC, 45–65 Hz input.

Key Specifications

Availability

STEVAL-ISA133V1 is available at Aetrix Electronics and suitable for power line communication modems, smart metering front-ends, and PLC-based industrial IoT gateways requiring stable component supply and pre-validated safety-compliant AC-DC conversion.

Supply support for STEVAL-ISA133V1 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 applications.

This board belongs to ST's STEVAL evaluation platform series, developed specifically to accelerate adoption of ST's proprietary power control ICs - like ALTAIR04-900 - in energy-efficient, compact, and regulatory-compliant AC-DC adapter designs.

FAQ

What is the primary target application for STEVAL-ISA133V1?

The board is designed explicitly for power line communication (PLC) systems based on the ST7580 transceiver. It supplies both the 13 V analog front-end (PLM) and 3.3 V digital domain (MCU, logic) in a single, compact, EMI-compliant solution - eliminating need for external post-regulators or optocoupled feedback.

Does STEVAL-ISA133V1 require an optocoupler for regulation?

No. It uses primary-sensing constant-voltage and constant-current loops implemented by the ALTAIR04-900 IC. This architecture removes the optocoupler, secondary shunt reference (e.g., TL431), and associated compensation network - reducing BOM cost, size, and long-term drift risk while maintaining ±5% output accuracy.

Can the 3.3 V output be used to power an external microcontroller?

Yes. The 3.3 V rail is post-regulated and rated for 100 mA peak current, making it suitable for low-power MCUs such as STM32L0/L1 series or other 3.3 V logic devices. Load transient response and ripple are optimized per ST7580 system timing requirements, as confirmed in Figures 2 and 3 of DocID024356 Rev 1.

What protection mechanisms are implemented on this board?

The board includes auxiliary winding disconnection (brownout) detection, shorted secondary rectifier detection, and transformer saturation protection - all configured to trigger auto-restart recovery. These protections are embedded in the ALTAIR04-900 IC and do not require external circuitry, enhancing robustness in unattended PLC deployments.