LT3651EUHE-4.1

Overview

Product Category

LT3651EUHE-4.1 belongs to the category of integrated circuits (ICs) and specifically falls under the battery charger ICs.

Use

The LT3651EUHE-4.1 is primarily used for charging single-cell lithium-ion/polymer batteries in various portable electronic devices such as smartphones, tablets, digital cameras, and portable media players.

Characteristics

• Input Voltage Range: 4V to 32V
• Charge Current: Up to 2A
• Programmable Charge Current Limit
• Maximum Float Voltage: 4.2V
• Automatic Recharge
• Thermal Regulation and Protection
• Reverse Battery Protection
• Low Quiescent Current: 85µA
• Package Type: 16-Lead 3mm × 3mm QFN

Packaging/Quantity

The LT3651EUHE-4.1 is available in a 16-Lead 3mm × 3mm QFN package. It is typically sold in reels or tubes containing a specific quantity of units, depending on the manufacturer's packaging standards.

Specifications

• Input Voltage Range: 4V to 32V
• Charge Current: Up to 2A
• Float Voltage: 4.2V
• Quiescent Current: 85µA
• Operating Temperature Range: -40°C to 125°C
• Package Type: 16-Lead 3mm × 3mm QFN

Pin Configuration

The LT3651EUHE-4.1 has a 16-pin configuration with the following pin assignments:

1. VIN: Input voltage pin
2. GND: Ground pin
3. PROG: Charge current programming pin
4. ISET: Charge current setting pin
5. STAT: Status indicator pin
6. FLT: Fault indicator pin
7. TS: Thermal shutdown pin
8. BAT: Battery voltage sense pin
9. VCC: Internal regulator output pin
10. PGND: Power ground pin
11. ILIM: Current limit programming pin
12. SS: Soft-start capacitor pin
13. FB: Feedback pin
14. EN: Enable pin
15. SCL: I2C serial clock pin
16. SDA: I2C serial data pin

Functional Features

1. Wide Input Voltage Range: The LT3651EUHE-4.1 can accept input voltages ranging from 4V to 32V, making it suitable for a wide range of power sources.
2. Programmable Charge Current Limit: The charge current can be programmed using the PROG and ISET pins, allowing flexibility in charging different battery capacities.
3. Automatic Recharge: The IC automatically restarts the charging process if the battery voltage drops below a certain threshold after completion.
4. Thermal Regulation and Protection: The LT3651EUHE-4.1 incorporates thermal regulation to prevent overheating during charging. It also provides protection against over-temperature conditions.
5. Reverse Battery Protection: The IC includes reverse battery protection to prevent damage in case of accidental battery polarity reversal.

Advantages and Disadvantages

Advantages

• Wide input voltage range allows compatibility with various power sources.
• Programmable charge current limit enables charging flexibility.
• Automatic recharge feature ensures continuous charging even after battery voltage drops.
• Thermal regulation and protection prevent overheating and ensure safe operation.
• Reverse battery protection safeguards against accidental polarity reversal.

Disadvantages

• Limited to single-cell lithium-ion/polymer battery charging applications.
• Requires additional external components for complete charging circuit implementation.

Working Principles

The LT3651EUHE-4.1 operates as a constant-current/constant-voltage (CC/CV) charger for single-cell lithium-ion/polymer batteries. It utilizes a switching regulator architecture to efficiently convert the input voltage to the required charging voltage.

The charge current is programmable using external resistors connected to the PROG and ISET pins. The IC monitors the battery voltage and adjusts the charging current accordingly to maintain a constant current during the initial charging phase. Once the battery voltage reaches the programmed float voltage, the IC switches to constant voltage mode to prevent overcharging.

Thermal regulation ensures that the IC operates within safe temperature limits. In case of excessive heat, the IC reduces the charging current to protect itself and the battery from damage. Reverse battery protection prevents any harm caused by accidental battery polarity reversal.

Detailed Application Field Plans

The LT3651EUHE-4.1 is widely used in various portable electronic devices that require single-cell lithium-ion/polymer battery charging. Some common application fields include:

1. Smartphones and Tablets: The IC is commonly found in smartphones and tablets to provide efficient and safe charging for their built-in batteries.
2. Digital Cameras: Many digital cameras