STMicroelectronics STEVAL-L6982NDR

Overview

STEVAL-L6982NDR from STMicroelectronics is an evaluation board built around the L6982NDR synchronous step-down DC-DC converter, configured in Low Noise Mode (LNM) with adjustable output voltage (0.85 V to VIN), 38 V max input, 2 A DC output capability, and SO 8L package. It supports external clock synchronization, output voltage sequencing, and thermal/overvoltage protection for industrial power tool and noise-sensitive embedded power supply applications.

For engineers reviewing the STEVAL-L6982NDR datasheet, STEVAL-L6982NDR pinout, STEVAL-L6982NDR application, or STEVAL-L6982NDR equivalent, this board enables rapid validation of L6982NDR's constant-frequency operation, low-output-ripple performance, EN-controlled startup, and EMI-filtered layout under real load conditions up to 2 A.

Technical Context

The STEVAL-L6982NDR implements peak current mode control using the L6982NDR IC, which operates in fixed-frequency Low Noise Mode (LNM) across its full load range to minimize output voltage ripple and meet stringent EMI requirements. It features internal compensation, pulse-by-pulse current sensing on both high- and low-side MOSFETs, and thermal shutdown.

Board-level design includes a 33 µH main inductor (L1), 4.7 µH auxiliary inductor (L4), 10 µF input capacitor (C1), 4.7 µF × 3 output capacitors (C5/C11/C12), MPZ2012S221A EMI filter (L3), and 10 pF clock input filter (C8). The EN/SYNC pin (Pin 4) accepts external clock signals for frequency synchronization.

Key Specifications

Availability

STEVAL-L6982NDR is available at Aetrix Electronics and suitable for industrial power tools, battery-powered test instrumentation, noise-sensitive analog front-ends, and automotive body electronics requiring stable component supply and fast evaluation turnaround.

Supply support for STEVAL-L6982NDR 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, sensors, and analog devices for industrial, automotive, and consumer markets.

The STEVAL-L6982NDR belongs to ST's STEVAL evaluation board portfolio, engineered to accelerate design-in of L6982 series regulators-specifically targeting low-noise, wide-input industrial and portable power applications.

FAQ

What is the purpose of the CLK_IN connector (J2) on the STEVAL-L6982NDR?

The CLK_IN connector accepts an external clock signal (applied to Pin 4/EN-SYNC of U1) to synchronize the L6982NDR's switching frequency. This ensures deterministic timing in multi-rail systems, reduces beat frequencies, and improves EMI profile-critical for mixed-signal or RF-sensitive designs.

Can the STEVAL-L6982NDR be used to evaluate both LCM and LNM versions of the L6982?

No-the STEVAL-L6982NDR is specifically configured for the L6982NDR (LNM version). The LCM variant (L6982LCR) uses different internal control logic and cannot be evaluated on this board without hardware modification, as component values and feedback behavior are optimized for constant-frequency operation.

How is output voltage sequencing implemented on this board?

Sequencing is enabled via the EN pin (U1 Pin 4), which controls startup timing relative to other rails. When driven by a sequenced enable signal (e.g., from a supervisor IC), the internal 1.3 ms soft-start ramps VOUT monotonically, ensuring controlled ramp-up before downstream logic or analog circuits power up.

Does the board include EMI filtering components, and where are they located?

Yes-EMI filtering is implemented with ferrite bead L3 (MPZ2012S221A) between VIN and C1, plus optional RC network (R4/C9) on the EN line and 10 pF capacitor C8 on CLK_IN. These suppress high-frequency noise at source and prevent coupling into sensitive clock or enable paths.