L6981NDR

Voltage Regulators - DC DC Switching Regulators Overview

The L6981NDR is a synchronous monolithic step-down switching regulator from STMicroelectronics, designed for high-efficiency power conversion. It delivers up to 1.5 A DC output current with an operating input voltage range of 3.5 V to 38 V. The device features a peak current mode architecture with internal compensation, housed in an SO-8 package. As the Low Noise Mode (LNM) variant, it maintains a constant switching frequency and minimizes output voltage ripple, making it suitable for noise-sensitive applications. Key electrical parameters include a typical shutdown current of 2 µA, an operating quiescent current of 17 µA for fixed output versions, and an internal soft-start time of 1.3 ms.

Voltage Regulators - DC DC Switching Regulators Feature Summary

• Low Noise Mode (LNM) operation ensures constant switching frequency and minimized output voltage ripple for noise-sensitive environments
• Peak current mode architecture with integrated internal compensation reduces external component count and design complexity
• Wide input voltage range supports diverse industrial and battery-powered system requirements
• Integrated protection mechanisms include pulse-by-pulse current sensing, thermal shutdown, and overvoltage protection

Voltage Regulators - DC DC Switching Regulators Applications

• HVAC power supplies
• Battery-powered equipment
• Decentralized intelligent nodes
• Smart sensors

Voltage Regulators - DC DC Switching Regulators Procurement Notes

Verify the specific suffix 'NDR' confirms the Low Noise Mode (LNM) variant, as opposed to the Low Consumption Mode (LCM). Confirm the package type is SO-8 and check RoHS compliance status. Ensure the order quantity matches the manufacturer's reel or cut tape specifications. Validate that the intended application aligns with the low-noise performance characteristics rather than light-load efficiency optimization.

Voltage Regulators - DC DC Switching Regulators Selection Notes

Select the L6981NDR when system noise immunity is critical, as its constant frequency operation prevents audible noise and EMI fluctuations common in skip-cycle modes. Choose this part over the LCM version if output ripple specifications are strict. Consider the 1.5 A current limit for loads requiring stable power delivery without excessive thermal management. Verify that the 38 V maximum input voltage covers the system's transient conditions.

Voltage Regulators - DC DC Switching Regulators Part Context

The L6981 series expands STMicroelectronics' portfolio of high-efficiency buck converters. It complements other regulators like the L6982 (2 A) and L7983 by offering a specialized low-noise solution. The device is part of a broader ecosystem supported by evaluation boards such as the STEVAL-L6981NDR, facilitating rapid prototyping for industrial and consumer electronics designs requiring precise power regulation.

Voltage Regulators - DC DC Switching Regulators Replacement Considerations

Public confirmed substitute part numbers: L6981CDR.