STMicroelectronics STEVAL-L7983V33

Overview

STEVAL-L7983V33 from STMicroelectronics is an evaluation board for the L7983PU33R 3.3 V/300 mA synchronous step-down DC/DC converter, operating from 3.5 V to 60 V input, featuring 1 MHz switching frequency, internal soft-start, and dynamic Low Consumption Mode (LCM) / Low Noise Mode (LNM) selection. It supports synchronization, internal compensation, and auto-recovery protection for industrial power rails.

For engineers reviewing the STEVAL-L7983V33 datasheet, STEVAL-L7983V33 pinout, STEVAL-L7983V33 application, or STEVAL-L7983V33 equivalent, this board enables rapid validation of L7983PU33R performance in 12 V/24 V/48 V bus systems, low-noise digital supply sequencing, and ultra-low-quiescent-current operation under light load.

Technical Context

The board implements the L7983PU33R - a peak-current-mode monolithic buck regulator with integrated high- and low-side MOSFETs, fixed 3.3 V output, and programmable UVLO threshold. Its 10 µA quiescent current in LCM mode enables battery-backed or always-on industrial sensors.

LNM mode fixes switching frequency across load range for EMI-sensitive applications, while LNM/LCM pin control allows real-time noise-efficiency trade-off. The RST open-collector output provides reset signaling for microcontrollers and FPGAs during power-up sequencing.

Key Specifications

Availability

STEVAL-L7983V33 is available at Aetrix Electronics and suitable for industrial sensor nodes, PLC I/O modules, smart meter auxiliary supplies, and 48 V telecom subsystems requiring stable component supply and fast design validation cycles.

Supply support for STEVAL-L7983V33 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, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The STEVAL-L7983V33 belongs to ST's high-voltage DC/DC evaluation platform family, engineered to accelerate adoption of ultra-low-I_Q buck regulators in harsh industrial environments with wide input voltage tolerance.

FAQ

What is the primary function of the STEVAL-L7983V33 evaluation board?

This board demonstrates the L7983PU33R 3.3 V/300 mA synchronous buck regulator in a DFN10 3×3 mm package. It provides a fully assembled, tested reference design for validating input range (3.5–60 V), LCM/LNM mode switching, reset sequencing, and EMI-controlled operation in industrial power applications.

How does the LNM/LCM pin affect system behavior?

The LNM/LCM pin selects between two operating modes: LCM enables variable-frequency pulse-skipping for <10 µA quiescent current and high light-load efficiency; LNM forces constant 1 MHz switching for predictable EMI and low output ripple across all loads. Mode selection is active-high and requires no external components.

Can the STEVAL-L7983V33 be used for output voltage sequencing with MCUs?

Yes. The open-drain RST pin asserts low during startup until VOUT reaches 90% of 3.3 V, then releases after a fixed delay (~10 ms). This provides a hardware reset signal compatible with most microcontrollers and FPGAs, enabling reliable power-up sequencing without external supervisors.

What inductor and output capacitor values are implemented on the board?

The board uses a 47 µH shielded power inductor (L1) and a 2.2 µF ceramic output capacitor (C2), plus a 470 nF ceramic (C3) and 100 nF ceramic (C6) for high-frequency filtering. These values are optimized for 1 MHz operation, minimal footprint, and stability with the L7983PU33R's internal compensation network.