STMicroelectronics STEVAL-ISA055V2

Overview

STEVAL-ISA055V2 from STMicroelectronics is a demonstration board implementing the ST1S12XX synchronous buck converter, delivering 3.3 V at up to 0.7 A from 2.5–5.5 V input. It features 1.7 MHz fixed-frequency current-mode PWM control, ±3% output voltage tolerance, internal soft-start, and enable functionality-designed for HDD digital core power supply replacement of linear regulators.

For engineers reviewing the STEVAL-ISA055V2 datasheet, STEVAL-ISA055V2 pinout, STEVAL-ISA055V2 application, or STEVAL-ISA055V2 equivalent, this evaluation board enables rapid validation of high-efficiency, space-constrained DC-DC conversion in low-voltage embedded systems with thermal protection and synchronous rectification.

Technical Context

The board implements the ST1S12 IC in TSOT23-5L package, using current-mode PWM control with 1.7 MHz switching frequency to minimize external passive size. Output regulation relies on internal feedback reference and fixed 3.3 V configuration-no external resistor divider required.

Thermal shutdown and cycle-by-cycle current limiting are integrated to protect against short-circuit and overtemperature events. Non-switching quiescent current remains ≤600 µA across temperature, supporting low-power standby modes in portable HDD and embedded storage subsystems.

Key Specifications

Availability

STEVAL-ISA055V2 is available at Aetrix Electronics and suitable for hard disk drive controller power, portable storage subsystems, and low-voltage embedded microcontroller supply requiring stable component supply and fast design validation.

Supply support for STEVAL-ISA055V2 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 specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer applications.

The STEVAL-ISA055V2 belongs to ST's ST1S12 evaluation platform series, developed to accelerate adoption of high-frequency synchronous buck converters for low-noise, thermally efficient digital core power in storage and portable electronics.

FAQ

What input voltage range does the STEVAL-ISA055V2 support?

The board accepts 2.5 V to 5.5 V DC input, enabling direct operation from single-cell Li-ion batteries, USB ports, or regulated 3.3 V/5 V system rails. This range ensures compatibility with common portable and storage subsystem power sources without additional pre-regulation.

Is the output voltage adjustable or fixed on this board?

The STEVAL-ISA055V2 provides a fixed 3.3 V output. Unlike adjustable ST1S12 variants, it omits the external feedback resistor divider-simplifying design, reducing component count, and improving stability for dedicated 3.3 V digital core applications.

Does the board include thermal protection?

Yes-the underlying ST1S12 IC integrates thermal shutdown and cycle-by-cycle current limiting. These protections activate automatically during overload or elevated ambient temperature, preventing permanent damage and enabling safe operation in enclosed HDD enclosures.

What is the purpose of the EN (Enable) pin on the ST1S12 used in this board?

The EN pin allows external logic-level control of converter operation: applying ≥1.2 V enables regulation; pulling below 0.4 V disables switching and reduces quiescent current to ≤600 µA. This supports system-level power sequencing and deep-sleep mode integration.