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