Regulated, Adjustable -2x Inverting Charge Pump

Inductorless Regulated LCD Bias Generator

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The MAX868 inverting charge pump provides a low-cost and compact means of generating a regulated negative voltage up to -2 x VIN from a positive input voltage between 1.8V and 5.5V. It uses a pulse-frequency-modulation (PFM) control scheme to generate the regulated negative output voltage. PFM operation is obtained by gating the internal 450kHz oscillator on and off as needed to maintain output voltage regulation. This unique on-demand switching scheme gives the MAX868 excellent light-load efficiency without degrading its full-load operation (up to 30mA), permitting smaller capacitors to take advantage of the oscillator's high switching frequency.

The MAX868 requires no inductors; only four capacitors are required to build a complete DC-DC converter. Output voltage regulation is achieved by adding just two resistors. The MAX868 comes in a 10-pin µMAX® package, which is only 1.11mm high and occupies just half the board area of a standard 8-pin SO.
MAX868: Typical Operating Circuit MAX868: Typical Operating Circuit Enlarge+

Key Features

  • Regulated Negative Output Voltage (up to -2 x VIN)
  • Ultra-Small, 10-Pin µMAX Package
  • On-Demand Switching at up to 450kHz
  • 30µA Quiescent Supply Current
  • Requires Only Four Small External Capacitors
  • 1.8V to 5.5V Input Voltage Range
  • 0.1µA Logic-Controlled Shutdown
  • Up to 30mA Output Current
  • Adjustable output voltage


  • Battery-Powered Applications
  • Camcorders
  • Cell Phones
  • Cordless Phones
  • Handy-Terminals, PDAs
  • Medical Instruments
  • Small LCD Panels

See parametric specs for Charge Pumps (45)

Part NumberTopologyVIN
Unadj. VOUT
Oper. Freq.
Oper. Temp.
minmaxmaxminmaxtypSee Notes
Regulated to +85
$1.54 @1k

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.
Product Reliability Reports: MAX868.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

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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