Smallest, All-Internal MOSFET, 7-Channel 2 AA DSC PMIC

The MAX8857A PMIC provides a complete power-supply solution for digital still cameras (DSCs) and digital video cameras (DVCs). The MAX8857A improves performance, component count, and board space utilization compared to currently available solutions for 2 AA cell and dual-battery designs. On-chip power MOSFETs provide up to 95% efficiency for critical power supplies. The CCD inverter can operate directly from 2 AA/NiMH batteries without the use of any additional external components.

* Step-up synchronous-rectified DC-DC converter (SU). The MAX8857A is bootstrapped from VSU.

* MAIN synchronous-rectified step-up DC-DC converter (M) with active discharge for DSP I/O supply voltage.

* SDZ 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.

* Step-up DC-DC converter with current regulation and PWM dimming control (LEDBST) for up to 6 series 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. This converter can connect directly to 2 AA batteries.

The MAX8857A has an independent/simultaneous power-on sequence of the CCDBST and CCDINV converters. For a preset power-on sequence of CCDBST before CCDINV, contact the factory.

The MAX8857A is available in a 5mm x 5mm, 40-pin thin QFN package and operates over the -40°C to +85°C extended temperature range.

Applications

* DSCs and DVCs * PDAs and Portable Media Players

* 95% Efficient Synchronous-Rectified DC-DC Converters

* 90% Efficient Boost-Buck Operation

* Up to 85% Efficient, High-Voltage DC-DC Converters

* Inverter Operates Directly from 2 AA Batteries

* Internal Compensation on All Channels

* True Shutdown™ on All Step-Up Converters

* Overload Protection

* Startup into Short Protection

* Soft-Start for Controlled Startup Current

* 100% Duty Cycle on Step-Down 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 ±2.5% Switching Frequency

* 1µA Shutdown Supply Current

* CCD Voltage Sequencing

* All Internal Power MOSFETs

* SDOK Power-OK Indicator