L6981N33DR

Voltage Regulators - DC DC Switching Regulators Overview

The L6981N33DR is a synchronous step-down switching regulator manufactured by STMicroelectronics, designed for industrial power systems. It operates with an input voltage range of 3.5 V to 38 V and delivers a fixed output voltage of 3.3 V at up to 1.5 A DC. The device features a low quiescent current of 17 μA in fixed output versions and a shutdown current of 2 μA. It utilizes a peak current mode architecture within an SO-8L package, incorporating internal compensation to simplify design. The component supports operation temperatures from -40°C to +150°C and includes protection functions such as thermal shutdown and overcurrent limiting.

Voltage Regulators - DC DC Switching Regulators Feature Summary

• Synchronous buck topology with integrated high-side and low-side power switches
• Low quiescent current consumption for improved efficiency in battery-powered applications
• Internal compensation network reduces external component count and board size
• Peak current mode control with pulse-by-pulse current sensing for robust protection

Voltage Regulators - DC DC Switching Regulators Applications

• Industrial power supply systems
• Battery-powered equipment requiring high efficiency at light loads
• Point-of-load regulation in noisy environments
• General-purpose DC-DC conversion for embedded systems

Voltage Regulators - DC DC Switching Regulators Procurement Notes

Verify the specific suffix 'N' indicates the Low Noise Mode (LNM) variant when sourcing, as this affects switching frequency behavior and ripple characteristics compared to the standard Low Consumption Mode. Confirm package integrity for SO-8L and ensure compatibility with required thermal management solutions given the 150°C maximum junction temperature rating. Cross-reference datasheet revisions for any updates to electrical specifications or recommended external component values.

Voltage Regulators - DC DC Switching Regulators Selection Notes

Select this component when a wide input voltage range up to 38 V is required alongside moderate output current capabilities. The fixed 3.3 V output eliminates the need for external feedback resistors, simplifying the bill of materials. Consider the LNM version if electromagnetic interference (EMI) mitigation is critical, as it offers constant switching frequency and minimized output voltage ripple under overload conditions compared to variable frequency modes.

Voltage Regulators - DC DC Switching Regulators Part Context

This part belongs to the L6981 series of monolithic synchronous step-down regulators. It is distinct from higher-current variants like the L6982 or L6983, which offer 2 A and 3 A outputs respectively, often in different packages such as QFN-16. The L6981 series is characterized by its compact SO-8L packaging and internal compensation, targeting applications where space constraints and design simplicity are prioritized over maximum power delivery.

Voltage Regulators - DC DC Switching Regulators Replacement Considerations

Direct functional substitutes include other STMicroelectronics parts within the same family, such as the L6981C33DR, though pinout and feature sets must be verified against specific mode requirements. Alternative manufacturers offering similar 38 V input, 1.5 A synchronous buck converters in SO-8 packages should be evaluated for pin compatibility and electrical parameter alignment.