STMicroelectronics EVAL5980

Overview

EVAL5980 from STMicroelectronics is a demonstration board for the L5980 step-down switching regulator IC, delivering up to 0.7 A DC output current with input voltage range 2.9 V–18 V, adjustable output voltage (0.6 V–16 V), 500 kHz default switching frequency, and integrated soft-start/inhibit control. It implements a complete buck converter with MLCC-compatible compensation, Schottky rectification (STPS2L25V), and 15 µH power inductor.

For engineers reviewing the EVAL5980 datasheet, EVAL5980 pinout, EVAL5980 application, or EVAL5980 equivalent, this board enables rapid validation of L5980-based 3.3 V/0.7 A power supplies, evaluation of loop stability with ceramic output capacitors, thermal performance under load, and programmable frequency tuning via external resistor on FSW pin.

Technical Context

The EVAL5980 implements a synchronous buck topology using the L5980 controller IC, which integrates gate drivers, PWM logic, and protection circuitry. It supports zero-load operation and 100% duty-cycle low-dropout mode for near-input-output voltage regulation.

Switching frequency is set to 500 kHz by a 100 kΩ resistor on the FSW pin and is programmable up to 1 MHz. The board uses a fixed 3.3 V output configuration via R1 (4.99 kΩ) and R2 (1.1 kΩ), but allows reconfiguration across 0.6 V–16 V using the FB pin and external divider.

Key Specifications

Availability

EVAL5980 is available at Aetrix Electronics and suitable for power supply validation, embedded system prototyping, and DC-DC converter design verification requiring stable component supply, repeatable test conditions, and production-ready reference schematics.

Supply support for EVAL5980 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The EVAL5980 belongs to ST's evaluation board product line, developed specifically to accelerate adoption of its L5980 buck regulator by providing a fully assembled, tested, and characterized reference design with documented layout and bill-of-materials.

FAQ

What is the default output voltage and how is it set?

The EVAL5980 is configured for 3.3 V output using a precision resistor divider: R1 = 4.99 kΩ and R2 = 1.1 kΩ connected to the FB pin of the L5980 IC. This ratio sets the feedback voltage to 0.6 V, resulting in VOUT = 0.6 V × (1 + R1/R2) ≈ 3.3 V. Output voltage can be adjusted by changing R1 and R2 values.

Can the switching frequency be changed, and how?

Yes, the switching frequency is programmable from 250 kHz up to 1 MHz using an external resistor connected between the FSW pin and ground. On this board, a 100 kΩ resistor sets the default frequency to 500 kHz. Frequency scaling follows the L5980 datasheet's FSW vs. RFSW curve and requires no hardware modification beyond resistor replacement.

Does EVAL5980 support ceramic output capacitors?

Yes, the compensation network is designed for stability with multilayer ceramic capacitors (MLCCs) as the output filter. The board includes C2 (22 µF, 25 V X5R MLCC) and supports additional MLCCs per layout guidelines. No electrolytic capacitor is required, enabling smaller footprint and longer lifetime.

What protection features are implemented on the board?

The EVAL5980 inherits all protections of the L5980 IC: cycle-by-cycle over-current detection, thermal shutdown, internal soft-start, and inhibit functionality. These are active without external components. The board also uses a 25 V-rated input capacitor and 25 V Schottky diode (STPS2L25V), ensuring margin across the full 2.9–18 V input range.