STMicroelectronics STEVAL-L7983V50

Overview

STEVAL-L7983V50 from STMicroelectronics is an evaluation board for the L7983PU50R 5 V/300 mA synchronous step-down DC/DC converter, operating from 5–60 V input, featuring 1 MHz switching frequency, internal soft-start, and dynamic Low Consumption Mode (LCM)/Low Noise Mode (LNM) selection for industrial power rails. It supports output voltage sequencing via RST open-collector output and delivers regulated 5 V to MCU/FPGA loads.

For engineers reviewing the STEVAL-L7983V50 datasheet, STEVAL-L7983V50 pinout, STEVAL-L7983V50 application, or STEVAL-L7983V50 equivalent, this board enables rapid validation of L7983PU50R performance in 12 V/24 V/48 V bus systems, light-load efficiency optimization, and noise-sensitive power-up sequencing with reset supervision.

Technical Context

The board implements a peak-current-mode-controlled synchronous buck regulator using the L7983PU50R IC in DFN10 (3×3 mm) package, with fixed 5 V output set by internal feedback. Switching frequency is factory-set to 1 MHz but adjustable via external clock injection on LNM/LCM pin or resistor programming.

It integrates pulse-by-pulse current sensing on both high- and low-side MOSFETs, auto-recovery overcurrent/overvoltage/thermal protection, and an internal compensation network eliminating external loop components. The RST output provides open-drain reset signaling synchronized to output voltage ramp-up.

Key Specifications

Availability

STEVAL-L7983V50 is available at Aetrix Electronics and suitable for industrial sensor nodes, PLC I/O modules, smart meter auxiliary supplies, and 24 V fieldbus-powered edge controllers requiring stable component supply and fast design validation.

Supply support for STEVAL-L7983V50 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 management ICs, analog devices, and MEMS sensors for industrial, automotive, and consumer applications.

The STEVAL-L7983V50 belongs to ST's high-voltage DC/DC evaluation platform family, engineered to accelerate adoption of ultra-low-quiescent-current buck regulators in harsh industrial environments with wide input ranges and stringent EMC requirements.

FAQ

What is the purpose of the LNM/LCM pin on STEVAL-L7983V50?

The LNM/LCM pin selects between Low Noise Mode (constant 1 MHz frequency, low output ripple) and Low Consumption Mode (variable frequency, <10 µA IQ). It enables dynamic trade-off between EMI compliance and standby power in battery-backed or energy-harvested systems, with transition controlled by external logic or resistor divider.

Can STEVAL-L7983V50 be used to evaluate different output voltages?

No - the board is configured exclusively for 5 V output using the L7983PU50R variant with internal feedback. To evaluate other voltages (e.g., 3.3 V), users must replace the IC with corresponding variants (e.g., L7983PU33R) and modify feedback routing per datasheet guidelines; the PCB layout does not support external resistor-based adjustment.

How is output voltage sequencing implemented on this board?

Sequencing is achieved via the open-collector RST pin, which asserts low until VOUT reaches 90% of nominal 5 V and remains asserted for ≥20 ms after regulation. This signal can drive enable inputs of downstream regulators or reset lines of MCUs/FPGAs, ensuring deterministic power-up order without external timing circuitry.

Does STEVAL-L7983V50 support synchronization to an external clock?

Yes - the LNM/LCM pin doubles as a synchronization input. Applying a clean 1 MHz square wave (or frequency-divided/multiplied version) forces the L7983PU50R to lock its switching frequency to the external source, enabling EMI reduction through frequency dithering or system-level clock alignment in multi-rail power architectures.