LNK304

Updated: 2026-09-16

Overview

The LNK304 is a power management integrated circuit (IC) developed for offline switch-mode power supplies (SMPS). It is part of the LinkSwitch-TN family from Power Integrations, designed to provide efficient power conversion in a compact form factor. The IC is widely used in low-power applications such as LED drivers, consumer electronics, and industrial controls. Its design simplifies the power supply circuitry by integrating a high-voltage power MOSFET, oscillator, and control circuitry into a single package. This integration reduces component count and board space, making it a cost-effective solution for manufacturers.

Structure and Working Principle

The LNK304 operates as a buck converter, stepping down high-voltage AC or DC input to a lower, regulated DC output. It uses a proprietary control method called ON/OFF modulation, which adjusts the duty cycle to maintain output regulation. The IC includes built-in protection features such as over-temperature shutdown and output over-voltage protection. The device requires minimal external components, typically just a diode, inductor, and capacitor to form a complete power supply. Its self-biasing design eliminates the need for a separate bias winding, further simplifying the circuit layout.

Key Features

One of the standout features of the LNK304 is its high efficiency, which can exceed 85% in typical applications. It also boasts low standby power consumption, often below 100 mW, making it suitable for energy-conscious designs. The IC supports a wide input voltage range, typically from 85 VAC to 265 VAC, accommodating global power standards. Other notable features include cycle-by-cycle current limiting for overload protection and built-in auto-restart for fault recovery. These features enhance reliability and reduce the need for additional protective components.

Application Areas

The LNK304 is commonly found in LED lighting applications, where its efficiency and compact size are particularly advantageous. It is also used in power adapters for small appliances, consumer electronics, and industrial control systems. Its ability to operate in harsh environments makes it suitable for automotive and outdoor applications. In addition to its primary uses, the IC is often employed in auxiliary power supplies for larger systems, such as those in white goods and HVAC equipment. Its versatility and reliability have made it a popular choice across multiple industries.

Maintenance and Precautions

Proper thermal management is critical when using the LNK304, as excessive heat can degrade performance and lifespan. Designers should ensure adequate PCB copper area for heat dissipation and consider using thermal vias if necessary. The IC should be operated within its specified temperature range, typically -40°C to 150°C. Attention to PCB layout is also important to minimize electromagnetic interference (EMI). Keeping high-current traces short and using proper grounding techniques can help maintain signal integrity and compliance with regulatory standards.

B2B Procurement Guide

When procuring the LNK304 in bulk, buyers should verify the authenticity of the product to avoid counterfeit components. Working with authorized distributors or directly with the manufacturer is recommended. Lead times can vary, so planning ahead is advisable, especially for large orders. Pricing is typically volume-dependent, with discounts available for larger quantities. Buyers should also consider the total cost of ownership, including shipping, handling, and potential tariffs, when comparing suppliers.