STMicroelectronics STEVAL-ISA119V1

Overview

STEVAL-ISA119V1 from STMicroelectronics is an evaluation board for the VIPER16 high-voltage off-line PWM converter IC, designed to demonstrate a 5 W non-isolated buck-boost auxiliary power supply operating directly from 85–265 VAC mains without auxiliary winding. It integrates an 800 V avalanche-rugged MOSFET, 115 kHz fixed-frequency jittered oscillator, adjustable current limit, and <30 mW standby consumption.

For engineers reviewing the STEVAL-ISA119V1 datasheet, STEVAL-ISA119V1 pinout, STEVAL-ISA119V1 application, or STEVAL-ISA119V1 equivalent, this board enables rapid validation of VIPER16-based low-power offline converters in metering, appliance auxiliary rails, and LED driver bias supplies - with emphasis on EMI reduction, thermal safety, and energy-compliant burst-mode operation.

Technical Context

The board implements a flyback-derived non-isolated buck-boost topology using the VIPER16HD (SO16N package), leveraging its integrated 800 V power MOSFET, self-biasing high-voltage startup circuit, and internal transconductance error amplifier. Feedback is configured via resistor divider to FB pin, with COMP pin hosting RC compensation network for loop stability.

It operates in burst mode below light load (VCOMP < 1.1 V), reducing average switching frequency to ~200 Hz and total system consumption to <30 mW at 230 VAC. Thermal protection engages at 150 °C junction temperature with 30 °C hysteresis, and fault recovery uses safe auto-restart after 1 s.

Key Specifications

Availability

STEVAL-ISA119V1 is available at Aetrix Electronics and suitable for appliance auxiliary power, smart metering subsystems, and industrial LED driver bias rails requiring stable component supply, reference design traceability, and production-ready layout validation.

Supply support for STEVAL-ISA119V1 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 devices for industrial, automotive, and consumer applications.

The VIPER™ plus family - including VIPER16 - was engineered specifically for cost-sensitive, low-to-mid power offline SMPS designs where integration, ruggedness, and regulatory compliance (e.g., <30 mW standby) are critical.

FAQ

What topologies does STEVAL-ISA119V1 support out-of-the-box?

The board ships configured as a non-isolated buck-boost converter delivering 12 V/420 mA from 85–265 VAC input. Its PCB layout and component footprints also support isolated flyback operation using optional optocoupler feedback and transformer replacement - verified in ST Application Note AN4170.

Can STEVAL-ISA119V1 be used with VIPER16L variants?

No - the board is hardware-optimized for VIPER16HD (115 kHz version), with compensation network values, transformer turns ratio, and snubber components tuned for 115 kHz operation and SO16N package thermal dissipation. Using VIPER16LN (60 kHz) would require redesign of timing, compensation, and EMI filtering.

How is thermal performance validated on this evaluation board?

ST measured junction temperature rise using IR thermography during 5 W continuous load at 50 °C ambient, confirming ≤110 °C max TJ under standard FR4 board conditions (100 mm² copper pour). The DRAIN pins are soldered to large copper areas per layout guideline Section 16 of DocID15232 Rev 7.

Does STEVAL-ISA119V1 include EMI filter components?

Yes - it integrates a two-stage common-mode choke (CMC), X-capacitor (0.1 µF), and Y-capacitors (2 × 2.2 nF) meeting EN 55032 Class B conducted EMI limits up to 30 MHz when tested per CISPR 22 layout rules. Filter component values are listed in BOM Table 1 of UM1591 reference manual.