STMicroelectronics STEVAL-ISA154V1

Overview

STEVAL-ISA154V1 from STMicroelectronics is an evaluation board for the L5980 0.7 A step-down switching regulator IC, configured with fixed 3.3 V output, 500 kHz switching frequency, 2.9–18 V input range, and VFQFPN8 (3 × 3 mm) package integration. It includes all external components-inductor (15 µH), Schottky diode (STPS2L25U), input/output capacitors, and resistor divider-for immediate functional validation in power supply design.

For engineers reviewing the STEVAL-ISA154V1 datasheet, STEVAL-ISA154V1 schematic, STEVAL-ISA154V1 layout, or STEVAL-ISA154V1 BOM, this board enables rapid prototyping of compact DC-DC converters targeting industrial sensors, portable instrumentation, and low-power embedded systems requiring stable 3.3 V rail generation from wide-input sources.

Technical Context

The board implements a non-synchronous buck topology using the L5980 controller IC, which integrates internal soft-start, enable/inhibit logic, and thermal/overcurrent protection. Input voltage is conditioned by a 10 µF/25 V ceramic capacitor; output filtering uses a 22 µF/16 V MLCC stabilized via a Type II compensation network (R3/C3/C5).

Switching frequency is set to 500 kHz via R5 (100 kΩ) connected to the FSW pin; feedback is provided through a precision resistor divider (R1 = 4.99 kΩ, R2 = 1.1 kΩ) yielding 3.3 V output. The Schottky rectifier (STPS2L25U) supports 2.5 A forward current and 25 V reverse voltage rating, matching the board's full input range capability.

Key Specifications

Availability

STEVAL-ISA154V1 is available at Aetrix Electronics and suitable for industrial sensor nodes, portable test equipment, and low-power IoT edge devices requiring stable component supply and fast evaluation-to-design transition.

Supply support for STEVAL-ISA154V1 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, delivering silicon solutions across automotive, industrial, power management, and microcontrollers.

The STEVAL-ISA154V1 belongs to ST's ST EVAL series of application-specific evaluation boards, designed to accelerate development of efficient, compact DC-DC power stages using their proprietary switching regulators.

FAQ

Can the output voltage be adjusted on the STEVAL-ISA154V1?

Yes. The board ships with R1 (4.99 kΩ) and R2 (1.1 kΩ) configured for 3.3 V, but the feedback divider is accessible via solder pads. Replacing R1/R2 allows adjustment from 0.6 V to 16 V, constrained only by the 16 V output capacitor rating and L5980's FB reference (0.6 V).

What is the maximum achievable switching frequency on this board?

The L5980 supports up to 1 MHz, and the board's R5 (100 kΩ) sets it to 500 kHz. To reach 1 MHz, replace R5 with a 51 kΩ resistor per the L5980 datasheet's FSW vs. resistor curve - no other component changes are required.

Does the board support synchronous rectification?

No. The STEVAL-ISA154V1 uses the non-synchronous L5980 with an external Schottky diode (STPS2L25U). The IC does not drive a low-side MOSFET; synchronous operation requires a different controller such as the L5981 or L6926.

Is thermal performance characterized on this evaluation board?

Yes. The board includes thermal protection circuitry tied to the L5980's internal sensor. At ambient 25°C and 0.7 A load, measured junction temperature rise is ≤35°C. Full derating curves and PCB copper area recommendations are provided in the L5980 datasheet (Section 7.2).