Synchronous, Fixed Frequency Step-Up DC/DC Converter

The LT1306 is a fully integrated, fixed frequency synchronous boost converter capable of generating 5V at 1A from a Li-Ion cell. The device contains both the main power switch and synchronous rectifier on chip and automatically disconnects the output from the input in shutdown, eliminating the need for external load disconnect circuitry. Additionally, the output remains regulated when VIN exceeds VOUT, allowing difficult step-up/step-down converter functions to be easily realized using a single inductor.

The internal 300kHz oscillator of the LT1306 can be easily synchronized to an external clock from 425kHz to 500kHz. This allows switching harmonics to be tightly controlled and eliminates any beat frequencies that may result from a multifrequency system. The LT1306 automatically shifts into power saving Burst Mode™ operation at light loads. At heavy loads the LT1306 operates in fixed frequency current mode. No-load quiescent current is 160µA and reduces to 9µA in shutdown mode.

The LT1306 is available in an SO-8 package.

Applications

* Satellite Phones

* Portable Instruments

* Personal Digital Assistants

* Palmtop Computers

* Output Disconnected from Input During Shutdown

* Output Voltage Remains Regulated When VIN > VOUT

* Controlled Input Current During Start-Up

* 300kHz Current Mode PWM Operation

* Can Be Externally Synchronized

* Internal 2A Switches

* Operates with VIN as Low as 1.8V

* Automatic Burst Mode Operation at Light Loads

* Quiescent Current: 160µA

* Shutdown Current: 9µA Typ