1. Products
  2. Power Management
  3. Inductorless (Charge Pump) DC/DC Converters
  4. Regulated Inverting Charge Pumps
  5. MAX840


Features and Benefits

  • Fixed -2V or Adjustable -0.5V to -9.4V Output at 4mA (MAX840)
  • 2.5V to 10V Input Voltage Range
  • Operate with Small Capacitors (as low as 0.22µF)
  • 1mVp-p Output Voltage Ripple
  • Charge-Pump Switching Frequency:
    • 100kHz in Normal Operation
    • 20kHz in Shutdown Mode (MAX844)
  • 1µA Max Logic-Level Shutdown Over Temp. (MAX840/MAX843)
  • Small 8-Pin SO Package

Product Details

The MAX840/MAX843/MAX844 low-noise, inverting charge-pump power supplies are ideal for biasing GaAsFETs in cellular telephone transmitter amplifiers. They operate with inputs down to 2.5V.

The MAX840 offers both a -2V preset output and a -0.5V to -9.4V adjustable output. The MAX843/MAX844 use an external positive control voltage to set the negative output voltage. Input voltage range for all the devices is 2.5V to 10V, and output current is 4mA with VIN > 2.7V. These circuits can operate with small capacitors, as low as 0.22µF.

An internal linear regulator reduces the MAX840's output voltage ripple to 1mVp-p. With a well-filtered control voltage (VCTRL), the MAX843/MAX844 also achieve less than 1mVp-p typical output ripple. Supply current is 750µA, and reduces to less than 1µA in shutdown (MAX840/MAX843). The MAX844's unregulated output is active in shutdown, with the charge pump switching at 20kHz. It provides a low-power LCD supply.


  • Cell Phones
  • Continuously Adjustable GaAsFET Bias
  • GaAsFET Power Amplifier Modules
  • LCD-Bias Contrast Control
  • Personal Communicators, PDAs
  • Regulated Negative Power Supplies
  • Wireless Data Loggers

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (3)

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
MAX840ESA+ Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
MAX840ESA+T Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
MAX840ISA+ Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
MAX840ISA+T Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
Wafer Fabrication Data MAX840 Reliability Data

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