LT3641HFE#PBF

PMIC - Voltage Regulators - DC DC Switching Regulators

The LT3641HFE#PBF (LT3641) is a synchronous DC-DC buck converter with a wide range of switch current limit and fixed frequency operation, making it suitable for a wide variety of applications. The LT3641 features a constant frequency current mode control scheme with a programmable switch current limit, allowing optimized efficiency and superior line and load regulation. The LT3641 has a wide input voltage range with a high efficiency synchronous buck topology. The adjustable operating frequency is between 200kHz and 2.2MHz and includes an Auto PFM/PWM modes for lighter loads.

Applications

• Automotive battery-powered systems
• Point-of-load (POL) DC-DC converters
• Portable end equipment supplies
• UL Class 2 and 4 applications
• Medical and professional device supplies
• Lighting and LED drivers
• Ecologies battery charger

Working Principle

The LT3641 is a simple, synchronous buck-boost regulator. It has an internal buck-boost transistor connected between the input voltage and the output. A control signal adjusts the duty cycle of the switch network, to control the output voltage. At higher input voltages, the device operates as a buck regulator, stepping the input voltage down to the desired level. At lower input voltages, it operates as a boost regulator, stepping the voltage up. The buck-boost control signal adjusts the duty cycle of the switch network, to control the output voltage. The LT3641 features adjustable switching frequency between 200kHz and 2.2MHz and includes synchronizable and adjustable auto-PWM modes.

The LT3641 has a low quiescent current, low noise, internal compensation, programmable soft-start, output current limit and over voltage protection, making it ideal for use in power management and POL convertor applications. The minimum on time of the LT3641 allows the converter to support output voltages as low as 0.6V.

To maximize efficiency, the LT3641 uses an adjustable constant frequency control architecture that can be synchronized with an external clock for increased output power capability and improved EMI performance. Additionally, the device integrates an under-voltage lock out to prevent the circuit from operating at input voltages below 1V, providing improved system reliability and protection.

Conclusion

The LT3641HFE#PBF is a highly efficient synchronous buck converter with a wide range of switch current limit and fixed frequency operation, making it suitable for a wide variety of applications. It features an adjustable operating frequency between 200kHz and 2.2MHz, an adjustable soft start and current limit, over voltage protection, and an internal compensation network. The LT3641 offers high efficiency, low noise and excellent line and load regulation.