Dual-Output Step-Down and LCD Step-Up Power Supply for PDAs

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The MAX1878 dual power supply contains a step-down and step-up DC-DC converter in a small 12-pin TQFN package for use in PDAs. The step-down DC-DC converter delivers over 500mA to an output as low as 1.25V for logic power. The step-up DC-DC converter delivers over 15mA and an output as high as 28V for a liquid crystal display (LCD). With an input voltage from 2.0V to 5.5V the MAX1878 is intended for use in systems powered by a 2-cell alkaline or 1-cell lithium-ion (Li+) battery.

Fast switching frequency allows the use of small inductors and capacitors, and the low 19µA typical quiescent current allows high efficiency when the system is in standby mode. Each output can be independently enabled.

The MAX1878 is available in a small 0.75mm high 4mm x 4mm 12-pin TQFN package and requires no external FETs. The MAX1878 evaluation kit is available to speed designs.
MAX1878: Typical Operating Circuit MAX1878: Typical Operating Circuit Enlarge+

Key Features

  • Evaluation Kit Available to Speed Designs
  • Two Output Voltages
    • Main Output: 1.25V to VIN
    • LCD Output: Up to 28V
  • 2.0V to 5.5V Input Range
  • Low 19µA Quiescent Supply Current
  • 1µA Shutdown Supply Current
  • High Switching Frequency for Small External Components
  • Small 0.75mm High 4mm x 4mm 12-Pin TQFN Package


  • GPS Receivers
  • MP3 Players
  • Organizers/Translators
  • Personal Digital Assistants (PDAs)

See parametric specs for Multifunction PMICs (83)

Part NumberVIN
Number of Step-Down OutputsNumber of Step-Up Outputs
MAX1878 25.511

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
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Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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