STMicroelectronics STEVAL-ISA010V1

Overview

STEVAL-ISA010V1 from STMicroelectronics is a demonstration board implementing a non-isolated dual-output buck converter using the VIPER16 high-voltage PWM controller IC, delivering 12 V ±10% and 5 V ±4% outputs with up to 150 mA total load across 85–500 VAC input, targeting auxiliary power in home appliances and energy metering systems.

For engineers reviewing the STEVAL-ISA010V1 datasheet, STEVAL-ISA010V1 pinout, STEVAL-ISA010V1 application, or STEVAL-ISA010V1 equivalent, this board provides validated reference design for ultra-wide-input AC/DC conversion without auxiliary winding, featuring EN55022 Class B EMI compliance, IEC 61000-4-5 surge immunity (2 kV), and RoHS-compliant FR4 PCB layout (27 × 45 mm).

Technical Context

The board implements a single-switch buck topology powered directly from rectified high-voltage DC bus, eliminating need for auxiliary supply - enabled by VIPER16's internal self-supply circuit and 800 V rugged power switch. It operates in burst mode at light load to achieve 96 mW standby consumption at 230 VAC.

Input stage uses X2-class capacitors (C1, C2) and bridge rectifier D2/D3; output regulation relies on feedback via U1's FB pin and LDO U2 (L78L05) for clean 5 V rail. Isolation is non-existent: N-line connects directly to output GND, confirming auxiliary-only use case.

Key Specifications

Availability

STEVAL-ISA010V1 is available at Aetrix Electronics and suitable for home appliance control boards, smart energy meters, industrial auxiliary supplies, and HVAC system logic power rails requiring stable component supply under wide-input AC conditions.

Supply support for STEVAL-ISA010V1 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 devices, and silicon solutions for industrial, automotive, and consumer applications.

This board belongs to ST's STEVAL evaluation platform series, engineered to accelerate development of certified, cost-optimized AC/DC auxiliary supplies for metering and white goods where ultra-wide input range and no-aux-winding operation are critical.

FAQ

Is STEVAL-ISA010V1 isolated or non-isolated?

STEVAL-ISA010V1 is explicitly non-isolated: the neutral (N) line connects directly to output ground, as confirmed in the data brief. This architecture eliminates transformer complexity and cost but restricts use to applications where primary-side grounding is acceptable - such as auxiliary rails inside sealed metering enclosures or appliance control units with reinforced insulation.

Can this board replace a flyback-based auxiliary supply?

No - STEVAL-ISA010V1 implements a buck topology, not flyback. It requires continuous input DC after rectification and cannot regulate during zero-crossings like flyback. Its design assumes stable HV DC bus; it lacks transformer isolation and zero-voltage switching features essential for true flyback replacement in safety-critical primary-side applications.

What is the role of VIPER16's LIM pin on this board?

The LIM pin (Pin 3) configures overcurrent protection threshold via external resistor R7 (marked "N.A." in schematic, indicating factory-trimmed internal setting). On STEVAL-ISA010V1, current limiting is fixed internally - no external component populates R7 - enabling robust short-circuit protection without calibration, consistent with VIPER16's integrated fault-handling architecture.

Does this board support 500 VAC continuously, or only transiently?

It supports 500 VAC continuously: the 85–500 VAC rating is specified for full operational range, including thermal stability and regulation accuracy. Input capacitor C4 (10 µF / 450 V) and C3 (10 µF / 450 V) are rated for ≥450 VDC, and the VIPER16's 800 V switch ensures safe conduction margin at peak 500 VAC × √2 ≈ 707 V, validated per IEC 61000-4-5 surge testing.