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MAX8857A：Smallest, All-Internal MOSFET, 7-Channel 2 AA DSC PMIC

Highly Efficient 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.

Key Features 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

MAX8857A: Typical Operating Circuit Applications/Uses DSCs and DVCs PDAs and Portable Media Players

DataSheet

Parametrics

Design kits & evaluation modules

• MAX8857AEVKIT

Quality and Environmental Data

• MAX8857A.pdf

Related Products

• MAX8680：Smallest, All-Internal MOSFET, 7-Channel DSC PMIC in Tiny 5mm x 5mm Thin QFN
• MAX858：3.3V/5V or Adjustable Output, Step-Up DC-DC Converters

Ordering Information