LTC4054ES5-4.2: Standalone Linear Li-Ion Battery Charger

The LTC4054ES5-4.2 is a compact, high-efficiency, single-cell lithium-ion battery charger manufactured by Linear Technology, now part of Analog Devices. This device is designed to simplify the charging process for portable electronic devices by integrating most of the charging functions within a tiny SOT-23 package. The LTC4054ES5-4.2 is specifically engineered to work with a 4.2V lithium-ion battery, the most common voltage for single-cell Li-Ion batteries.

Key Features

• Adjustable Charge Current: The charger allows for programmable charging current up to 800mA through an external resistor, making it versatile for various battery capacities.
• High Accuracy: It offers precise end-of-charge control with ±1% accuracy at the final float voltage, ensuring the battery is charged safely and efficiently.
• Thermal Regulation: To protect against overheating, the LTC4054ES5-4.2 includes an internal thermal feedback loop that regulates the charge current to maintain a safe junction temperature.
• No External MOSFET, Sense Resistor, or Blocking Diode Required: This feature simplifies the design and reduces the external component count, which is ideal for space-constrained applications.
• Automatic Recharge: The device automatically initiates a new charging cycle if the battery voltage falls below an internal threshold, keeping the battery topped up.
• Charge Status Output: An open-drain status output pin indicates the charging progress, which can be used to drive an LED or interface with a microcontroller.
• Undervoltage Lockout: It automatically shuts down the charger if the input voltage falls too low, preventing the charger from draining the battery.

Applications

The LTC4054ES5-4.2 is ideal for a wide range of portable electronic applications, such as:

• Cellular Telephones
• Digital Cameras
• MP3 Players
• USB-Powered Devices
• Handheld Instruments

Its small footprint, coupled with the ease of integration into existing designs, makes the LTC4054ES5-4.2 a preferred choice for designers looking to implement a reliable and efficient charging solution for Li-Ion batteries without the need for complex circuitry.