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

Highly Efficient 2 AA DSC PMIC

Product Details

Key Features

Simplified Block Diagram

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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

Applications/Uses

  • DSCs and DVCs
  • PDAs and Portable Media Players

Description

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.

Simplified Block Diagram

MAX8857A: Typical Operating Circuit MAX8857A: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .