DESCRIPTION
The SC1408 is a low voltage boost controller that operates from a 1.8V to 16.5V input range. A shutdown pin allows the user to turn the controller off reducing supply current to less than 2µA typical. Output voltage can be preset to 5V or is adjustable from 3V to 16.5V with a resistor divider. The controller changes frequency in low load conditions to improve efficiency.
The SC1408 was designed for two cell Alkaline or single cell Lithium Ion battery applications. With the proper external components it can be used as a boost converter or a buck/boost converter.
A current sense is implemented with an external resistor that is not in the load current path.
The SC1408 operates in “bootstrapped” mode. When the input voltage to the device is less than 2.5V during startup, a low voltage 50% fixed duty cycle oscillator is switched in to initiate boost action.

FEATURES
• 1.8V to 16.5V input range
• Up to 10W output power
• Preset 5V or adjustable output
• Up to 300kHz switching frequency
• 10µA max shutdown current
• Industrial temperature range
• SO-8 or MSOP-8 package

APPLICATIONS
• PDA Power supplies
• Battery powered applications
• Positive LCD Bias generator
• Portable communications (cellular phones)
• Peripheral card supplies
• Industrial power supplies