STMicroelectronics STEVAL-ISA202V1

Overview

STEVAL-ISA202V1 from STMicroelectronics is an evaluation board for the L4971 1.5 A asynchronous step-down switching regulator, operating from 8 V to 55 V input and delivering a regulated 5.1 V ±3% output at up to 1.5 A. It features 200 kHz fixed-frequency operation, <51 mV output ripple, and 2.5 A typical current limit, validated for industrial power supply design and automotive subsystem testing.

For engineers reviewing the STEVAL-ISA202V1 datasheet, STEVAL-ISA202V1 pinout, STEVAL-ISA202V1 application, or STEVAL-ISA202V1 equivalent, this board enables rapid validation of L4971-based buck converter performance under line/load/thermal variation, RMS current handling in input/output capacitors, and zero-load quiescent behavior in wide-input industrial systems.

Technical Context

The board implements the L4971 in a non-synchronous buck topology with external MOSFET drive via BOOT and OUT pins, using a DIP-8 packaged IC and discrete diode (STPS3L60) for freewheeling. Feedback is configured via R2/R3 voltage divider for 5.1 V output, and soft-start/inhibit control is accessible via SS/INH pin.

Input filtering uses 180 µF/63 V and 220 nF/63 V capacitors; output employs 150 µF/35 V and dual 100 nF ceramic caps. The 120 µH toroidal inductor (MSS1260-124KLD) supports peak currents up to 2.5 A with ≤30% ripple current.

Key Specifications

Availability

STEVAL-ISA202V1 is available at Aetrix Electronics and suitable for industrial power supply validation, automotive subsystem prototyping, and embedded system DC-DC stage development requiring stable component supply and documented reference design implementation.

Supply support for STEVAL-ISA202V1 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 STEVAL evaluation board series targets rapid validation of ST's power management ICs-specifically enabling engineers to verify thermal behavior, loop stability, and transient response of buck regulators like the L4971 before full-system integration.

FAQ

What is the primary function of the STEVAL-ISA202V1 evaluation board?

This board demonstrates and validates the L4971 1.5 A asynchronous step-down regulator. It delivers a fixed 5.1 V output from 8–55 V input, supporting design verification of efficiency, thermal performance, load regulation, and startup behavior under real-world conditions including zero-load operation.

Can the output voltage be adjusted, and if so, how?

Yes-the output voltage is set by the R2/R3 voltage divider network (2.7 kΩ / 4.99 kΩ), yielding 5.1 V. To adjust, replace R2 and/or R3 per the L4971 feedback equation: VOUT = 2.5 V × (1 + R2/R3). Output range is limited by capacitor voltage ratings (3.3 V to 30 V).

Does the board support soft-start and enable/inhibit functionality?

Yes-pin 2 (SS/INH) of the L4971 is brought out to JP1. Applying a logic high enables operation with internal soft-start; pulling low disables the regulator. This allows controlled power sequencing and integration into larger system power management schemes.

What type of inductor and diode are used on the board?

The board uses a 120 µH toroidal inductor (MSS1260-124KLD) rated for ≥2.5 A saturation current and a STPS3L60 3 A Schottky diode in DO-201AD package. These components ensure low conduction loss, minimal reverse recovery, and reliable operation across the full input voltage and load range.