LTC3639EMSE#PBF

PMIC - Voltage Regulators - DC DC Switching Regulators

The LTC3639EMSE#PBF is a high frequency, non-synchronous buck and boost DC/DC regulator controllers that offers high efficiency, high current and low input/output voltage capability. In addition, this device features integrated 8-bit PWM dimming, load disconnect/sense, adjustable PWM frequency and various fault protection features in a small, low cost 2mm × 3mm DFN-10 package.

Applications

The LTC3639EMSE#PBF is used in many applications, including cellular phones, PDAs, other handheld devices, various portable systems, and battery-powered equipment. Examples of REG0 applications where the LTC3639EMSE#PBF can be used include: USB charger, Infrared remote control, USB hub, Wireless (802.11) receiver, GSM phones, etc.

Working Principle

The LTC3639EMSE#PBF integrates non-synchronous buck and boost DC/DC regulators with a PWM dimming feature. It is capable of providing either a fixed or variable output voltage up to 4V. Whenever the input voltage is below 4V, the boost regulator supplies the output voltage. When the input voltage exceeds 4V, the buck regulator takes over and reduces the voltage to the specified output voltage.

The LTC3639EMSE#PBF operates with an integrated 8-bit PWM dimming. This feature allows a gradual dimming of the output voltage within a given voltage range while maintaining standard voltage regulation at each step. The PWM dimming frequency is adjustable from 250kHz to 3.2MHz. In addition, the LTC3639EMSE#PBF has a feature that allows for the automatic load disconnect and reconnect when operating with low input voltage.

The LTC3639EMSE#PBF provides protection features which include overtemperature protection, overvoltage protection, undervoltage protection, short-circuit protection, and open load protection. Moreover, the LTC3639EMSE#PBF features an adjustable soft-start which configures the transient response of a system.