General Description

The MAX8680 highly efficient complete power-supply solution is designed for digital still cameras (DSCs) and digital video cameras (DVCs). The device integrates seven on-chip power MOSFET DC-DC converters with up to 95% efficiency to power all critical power supplies in DSC systems. Each converter also features True Shutdown™, as well as internal compensation to minimize external component count. The seven DC-DC converter outputs are:
• Step-up synchronous-rectified DC-DC converter (SU). The MAX8680 is bootstrapped from VSU.
• MAIN synchronous-rectified step-down DC-DC converter (M) for DSP I/O supply voltage.
• DDRZ synchronous-rectified step-down DC-DC converter (Z) for DSP DDR supply voltage.
• Low-voltage (down to 1V) synchronous-rectified step-down DC-DC converter (SD) for DSP core supply voltage.
• High-voltage, step-up DC-DC converter with current regulation and PWM dimming control (LEDBST) for white LEDs (WLED).
• High-voltage step-up DC-DC converter (CCDBST) for CCD imagers or positive LCD bias supplies.
• Transformerless inverting DC-DC converter (CCDINV) for CCD imagers or negative LCD bias supplies.

Features

♦ 95% Efficient Synchronous-Rectified DC-DC Converters
♦ 90% Efficient Boost-Buck Operation
♦ 85% Efficient DC-DC Converters for CCD, LCD, WLED, and/or OLED
♦ Internal Compensation on All Channels
♦ True Shutdown on All Step-Up Converters
♦ Overload Protection
♦ Soft-Start for Controlled Startup Current
♦ Dropout Operation (100% Duty Cycle) on StepDown Converters
♦ Regulated Current Output for Up to 6 White LEDs
♦ PWM Dimming of WLED Current
♦ Adjustable LED Overvoltage Protection Up to 27V
♦ Transformerless Inverting Converter for CCD
♦ 2MHz Switching Frequency for Low-Voltage Channels
♦ ±2.5% Switching Frequency Accuracy
♦ 1µA Shutdown Supply Current
♦ Power-On Voltage Tracking for Core and Main Outputs
♦ All Internal Power MOSFETs
♦ SDOK Power-OK Indicator

Applications

DSCs and DVCs
PDAs and Portable Media Players
GPS Navigation Systems