STMicroelectronics STEVAL-ISA017V1

Overview

STEVAL-ISA017V1 from STMicroelectronics is a reference design evaluation board for a 17 W quasi-resonant flyback AC/DC power supply targeting Set-Top Box (STB) applications with US-input voltage range (88–138 V_AC). It integrates six regulated DC outputs: 12 V/500 mA, 8 V/40 mA, 5 V/1 A, 3.3 V/450 mA, 2.5 V/700 mA, and 1.23 V/1 A, all derived using the L6565 QR controller and supporting ST power semiconductors including STD5NK50Z MOSFET and STPS-series Schottky rectifiers.

For engineers reviewing the STEVAL-ISA017V1 datasheet, STEVAL-ISA017V1 pinout, STEVAL-ISA017V1 application, or STEVAL-ISA017V1 equivalent, this board serves as a validated hardware platform to evaluate multi-rail SMPS architecture, quasi-resonant control loop stability, output cross-regulation behavior, and component-level thermal performance under real-world STB load profiles.

Technical Context

The board implements a variable-frequency quasi-resonant flyback topology driven by the L6565 controller, enabling zero-voltage switching (ZVS) at light-to-moderate loads to improve efficiency and reduce EMI. Primary-side regulation is achieved via optocoupler feedback with TS2431ILT shunt regulator, while secondary-side post-regulation uses L5973D buck converter and LD29080DT25 LDOs for tight tolerance on 3.3 V, 2.5 V, and 1.23 V rails.

Input stage includes bridge rectification (S1ZB80), bulk filtering (C1–C4), and EMI suppression (I1A/I1B common-mode chokes). Output rectification employs STPS5L40 (5 V), STPS5L25B (1.23 V), STPS340U (2.5 V), and SMBYW02-200 (8 V), with STTH108 used in auxiliary bias winding.

Key Specifications

Availability

STEVAL-ISA017V1 is available at Aetrix Electronics and suitable for Set-Top Box power design validation, multi-output SMPS reference implementation, and quasi-resonant flyback topology evaluation requiring stable component supply and documented ST reference schematics.

Supply support for STEVAL-ISA017V1 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, Switzerland, designing and manufacturing microcontrollers, power ICs, analog devices, and reference evaluation platforms for industrial, consumer, and automotive markets.

This board belongs to ST's STEVAL (ST Evaluation) series-engineered to accelerate power supply design adoption by providing fully tested, documented, and application-specific hardware based on ST's proprietary controllers and power discretes.

FAQ

What is the primary function of STEVAL-ISA017V1?

STEVAL-ISA017V1 is a complete, assembled reference design board-not a component-for evaluating a 17 W, six-output quasi-resonant flyback AC/DC power supply optimized for Set-Top Box applications. It demonstrates system-level integration of ST's L6565 controller, power MOSFETs, rectifiers, and post-regulators, with full schematic, layout, and test data provided in its official documentation.

Does STEVAL-ISA017V1 support universal AC input?

No. STEVAL-ISA017V1 is specifically configured for US-line input: 88–138 V_AC (nominal 110 V). Its transformer turns ratio, bulk capacitor rating (200 V), and controller startup circuitry are optimized for this range. Universal input (90–265 V_AC) requires redesign of the transformer, snubber, and input filter components per ST's application notes.

Can the 1.23 V output be used as an adjustable reference?

Yes. The 1.23 V rail is generated by the LD29080DT25 low-dropout regulator, which features an adjustable output mode using external resistive feedback. The board implements it as fixed 1.23 V, but the IC's ADJ pin is accessible, allowing reconfiguration to any output between 1.23 V and 20 V via resistor divider per the LD29080 datasheet.

Are Gerber files and bill of materials publicly available?

Yes. STMicroelectronics provides the full design package-including schematic (PDF), PCB layout (Gerber RS-274X), BOM (Excel), and test report-for STEVAL-ISA017V1 free of charge on its official website under document number CD00171535. No NDA or registration is required to download these resources.