STMicroelectronics STEVAL-ISA146V1

Overview

STEVAL-ISA146V1 from STMicroelectronics is a 4 A step-down switching evaluation board based on the ST1S50 synchronous PWM regulator, designed for rapid validation of 4.0–18 V input to adjustable 0.8–0.88×VIN output power stages in embedded DC/DC applications. It integrates dual MOSFETs (95 mΩ high-side, 69 mΩ low-side), supports 500 kHz fixed-frequency operation, includes Power Good signaling and cycle-by-cycle current limiting, and uses all-ceramic output capacitance.

For engineers reviewing the STEVAL-ISA146V1 datasheet, STEVAL-ISA146V1 pinout, STEVAL-ISA146V1 application, or STEVAL-ISA146V1 equivalent, this board enables fast functional verification of ST1S50-based 4 A buck converters-particularly where light-load efficiency, programmable soft-start, thermal shutdown hysteresis, and short-circuit protection are design-critical.

Technical Context

The STEVAL-ISA146V1 implements the ST1S50's fixed 500 kHz PWM control architecture with synchronous rectification, supporting input voltages from 4.0 V to 18 V and delivering up to 4 A continuous output current. Its feedback loop adjusts output voltage via an external resistor divider, enabling regulation down to 0.8 V or up to 0.88×VIN.

Board-level protections include cycle-by-cycle overcurrent detection, hiccup-mode short-circuit response, and hysteretic thermal shutdown (trip at ~150 °C, restart at ~130 °C). The integrated MOSFETs eliminate external switch selection, and the all-ceramic capacitor design reduces footprint and improves transient response.

Key Specifications

Availability

STEVAL-ISA146V1 is available at Aetrix Electronics and suitable for industrial power supply validation, FPGA/ASIC auxiliary rail prototyping, and embedded microcontroller core voltage testing requiring stable component supply and documented reference design fidelity.

Supply support for STEVAL-ISA146V1 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 analog, digital, and mixed-signal ICs for industrial, automotive, and consumer applications.

The STEVAL-ISA146V1 belongs to ST's ST1S series of high-efficiency synchronous buck regulators, engineered specifically for space-constrained, thermally demanding embedded power applications requiring precise voltage regulation and comprehensive fault protection.

FAQ

What input voltage range does the STEVAL-ISA146V1 support?

The board accepts 4.0 V to 18 V DC input, matching the ST1S50's operational range. This covers common industrial bus voltages such as 5 V USB-PD sources, 12 V PoE-powered systems, and 15 V legacy backplanes. Input must be ripple-free and capable of delivering ≥4.5 A peak current during startup transients.

Can the output voltage be adjusted below 0.8 V?

No-the ST1S50's internal reference and error amplifier architecture limit the minimum regulated output to 0.8 V. Attempting lower settings via external resistor scaling will result in loss of regulation and uncontrolled dropout behavior. The 0.8 V floor aligns with typical DDR memory termination and modern low-power MCU core requirements.

Does the board include input overvoltage or reverse-polarity protection?

No-STEVAL-ISA146V1 has no onboard input overvoltage clamping or reverse-polarity diode. Users must ensure correct polarity and limit input transients to <20 V (per ST1S50 ABS MAX rating). External TVS diodes or ideal diode controllers are recommended for field-deployed prototypes.

Is the Power Good signal compatible with 3.3 V logic systems?

Yes-the open-drain Power Good output is rated for 5.5 V max pull-up and sinks ≥4 mA at 0.4 V. When pulled to 3.3 V with a 10 kΩ resistor, it delivers clean timing-aligned assertion within 10 ms of output stabilization and remains valid across full load and temperature ranges.