STMicroelectronics STEVAL-ISA006V1

Overview

STEVAL-ISA006V1 from STMicroelectronics is a 6W non-isolated flyback reference design board based on the VIPer12AS monolithic SMPS controller, delivering regulated 5V/500mA and auxiliary 15V/200mA outputs from 90–264Vac input. It implements discontinuous conduction mode (DCM) operation without input-output isolation, targeting cost-sensitive auxiliary power supplies in industrial and consumer electronics.

For engineers reviewing the STEVAL-ISA006V1 datasheet, STEVAL-ISA006V1 schematic, STEVAL-ISA006V1 application notes, or STEVAL-ISA006V1 bill of materials, this board provides validated implementation guidance for VIPer12AS-based offline flyback converters with dual-output regulation, EMI filtering, and snubber-protected transformer drive.

Technical Context

The board implements a DCM flyback topology using the VIPer12AS SO-8 IC, which integrates a 60kHz oscillator, PWM controller, and vertical Power MOSFET. Input rectification uses two series-connected fast-recovery diodes (STPR120A) for 2kV burst immunity, while EMI filtering combines C1, C2, and L1.

Regulation is achieved via optocoupler-free feedback: the 5V output is sensed by an R5/R7 divider and compared to the TS2431ILT's 2.5V reference; the resulting error signal modulates the VIPer12AS FB pin current to adjust peak primary current and maintain output stability.

Key Specifications

Availability

STEVAL-ISA006V1 is available at Aetrix Electronics and suitable for industrial control panels, smart meter auxiliary supplies, appliance sub-power rails, and consumer electronics standby power requiring stable component supply and reference design validation.

Supply support for STEVAL-ISA006V1 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 family, developed to accelerate prototyping and qualification of VIPer-series AC-DC converters in cost-constrained, non-isolated auxiliary power applications.

FAQ

Is STEVAL-ISA006V1 certified for safety standards such as UL or EN62368?

No. STEVAL-ISA006V1 is a reference design board intended for engineering evaluation only and lacks safety certification, isolation barriers, or enclosure compliance required for end-product certification. It must be redesigned and validated per applicable safety standards before integration into certified equipment.

Can the 15V output be regulated using the existing feedback circuit?

No. The feedback loop exclusively monitors the 5V output via R5/R7 and TS2431ILT. The 15V output is unregulated and varies with load and line conditions; adding regulation would require a separate feedback path, optocoupler, or secondary-side controller not present on this board.

What is the role of the two-series diodes (D1/D2) in the input stage?

D1 and D2 are STPR120A fast-recovery diodes placed in series to withstand 2kV burst pulses per IEC 61000-4-5. Their combined voltage rating and low trr (25ns) suppress EMI while maintaining reliable rectification under transient overvoltage events on the AC line.

Does STEVAL-ISA006V1 support adjustable output voltage?

No. Output voltages are fixed by hardware: 5V is set by R5/R7 values (10kΩ/4.7kΩ) referencing TS2431ILT's 2.5V, and 15V is determined by transformer turns ratio. Adjusting either requires physical component changes and revalidation of regulation stability and transformer stress.