The MAX8570 family of LCD step-up converters uses an internal n-channel switch and an internal p-channel output isolation switch. These converters operate from a 2.7V to 5.5V supply voltage and deliver up to 28V at the output.

A unique control scheme provides the highest efficiency over a wide range of load conditions. The internal MOSFET switch reduces external component count and a high switching frequency (up to 800kHz) allows for tiny surface-mount components. Three current-limit options are available. The MAX8570 and MAX8572 use a 110mA current limit to reduce ripple and component size in low-current applications. For high-power requirements, the MAX8574 and MAX8575 use a 500mA current limit and supply up to 20mA at 20V. The MAX8571 and MAX8573 use a 250mA current limit for a compromise between ripple and power. Built-in safety features protect the internal switch and down-stream components from fault conditions.

Additional features include a low quiescent current and a True Shutdown™ mode to save power. The MAX8570/MAX8571/MAX8574 allow the user to set the output voltage between 3V and 28V, and the MAX8572/MAX8573/MAX8575 have a preset 15V output. These step-up converters are ideal for small LCD panels with low current requirements, but can also be used in other applications. The MAX8571 evaluation kit is available to help reduce design time.

Applications

• Cell Phones/Cordless Phones
• Handy Terminals
• LCD Bias Generators
• Organizers
• Palmtop Computers
• PDAs and Other Handheld Devices
• Polymer LEDs (OLED)