STMicroelectronics STEVAL-ISA016V1

Overview

STEVAL-ISA016V1 from STMicroelectronics is a reference design evaluation board for a 17W quasi-resonant flyback AC/DC power supply targeting Set-Top Box (STB) applications in European mains (185–265 Vac). It integrates the L6565 controller, STD3NK80Z MOSFET, and multiple ST rectifiers and regulators to deliver six regulated DC outputs: 12V@500mA, 8V@40mA, 5V@1A, 3.3V@450mA, 2.5V@700mA, and 1.23V@1A.

For engineers reviewing the STEVAL-ISA016V1 datasheet, STEVAL-ISA016V1 pinout, STEVAL-ISA016V1 application, or STEVAL-ISA016V1 equivalent, this board serves as a validated hardware platform for evaluating quasi-resonant SMPS topology, multi-rail DC-DC conversion, EMI-compliant layout, and ST's high-voltage power component ecosystem in consumer STB power designs.

Technical Context

The board implements a variable-frequency quasi-resonant flyback converter using the L6565 controller, enabling zero-voltage switching (ZVS) at light loads to improve efficiency and reduce EMI. Primary-side regulation eliminates optocoupler dependency, while ZCD (Zero Current Detection) pin sensing ensures precise valley switching timing.

Secondary-side regulation employs ST's L5973D step-down regulator for the 5V rail and LD29080DT25 low-dropout linear regulator for the 3.3V output, complemented by Schottky rectifiers (STPS5L40, STPS5L25B, STPS340U) on all secondary windings to minimize conduction losses and thermal stress.

Key Specifications

Availability

STEVAL-ISA016V1 is available at Aetrix Electronics and suitable for Set-Top Box development, digital TV power architecture validation, and multi-output AC/DC reference design prototyping requiring stable component supply and documented ST ecosystem integration.

Supply support for STEVAL-ISA016V1 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 silicon solutions for automotive, industrial, power, and consumer markets.

This board belongs to ST's STEVAL (ST Evaluation) series-reference designs intended to accelerate time-to-market for power conversion, motor control, and sensor interface applications using ST's proprietary ICs and discrete components.

FAQ

What input voltage range does STEVAL-ISA016V1 support?

STEVAL-ISA016V1 is configured for European mains operation: 185–265 Vac at 50/60 Hz. It is not rated for universal input (90–265 Vac) out-of-box; the schematic and transformer (MAR5146) are optimized for high-line operation only, with no auto-sensing or dual-range circuitry included.

Which ST ICs are used for primary and secondary regulation?

The L6565 quasi-resonant controller handles primary-side regulation and ZVS timing. Secondary-side regulation uses the L5973D synchronous buck regulator for the 5V rail and the LD29080DT25 low-dropout linear regulator for the 3.3V rail; other outputs rely on diode rectification and RC filtering without active regulation.

Can STEVAL-ISA016V1 be modified for 110V input?

No - the board's transformer turns ratio, bulk capacitor rating (C1/C2: 400V), and startup resistor network (R2/R3: 1.5MΩ) are designed exclusively for 220V nominal input. Modifying for 110V would require redesigning the transformer, adjusting snubber components, re-rating bulk capacitors, and recalculating feedback dividers - not supported by the reference design.

Does STEVAL-ISA016V1 include safety certifications?

No - STEVAL-ISA016V1 is an evaluation board, not a certified end-product. It lacks UL/EN62368-1 certification, reinforced insulation documentation, or creepage/clearance validation for production use. Engineers must perform full safety compliance testing when integrating its topology into certified systems.