Battery Manager

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The MAX1259 battery manager provides backup-battery switching for CMOS RAM, microprocessors, or other low-power logic ICs. It automatically switches to the backup battery when the primary power supply is interrupted. Low-loss switches guarantee an input-to-output differential of only 200mV while supplying 250mA from the primary power supply or 15mA from the battery.

Battery discharge during shipping does not occur in the MAX1259, since the backup battery can be disconnected by strobing the RST input.

A battery-fail output signal indicates when the backup battery is below +2V, and a power-fail output signal indicates when the primary power supply is low. The MAX1259 monitors the backup battery, warns of impending power failures, and switches the memory to the battery when failures occur. The MAX1259 is pin-compatible with the DS1259, but consumes three times less supply current. Commercial, extended, and military temperature range devices are available.
MAX1259: Typical Application Circuit MAX1259: Typical Application Circuit Enlarge+

Key Features

  • Switches to Backup Battery if Power Fails
  • Consumes Less than 100nA of Battery Current
  • Power-Fail Output Signals Primary Power-Supply Loss
  • Battery Monitor Indicates Low Battery
  • Battery Can Be Disconnected to Prevent Discharge During Shipping
  • Battery Automatically Reconnected when VCC is Applied
  • Pin-Compatible with the DS1259
  • Supply Current Three Times Lower than DS1259
  • Available in Extended-Industrial and Military Temperature Ranges


  • Battery Backup for CMOS RAM
  • Computers
  • Controllers
  • Uninterruptible Power Supplies

See parametric specs for Battery Backup Circuits (80)

Part NumberICC
Oper. Temp.
maxSee Notes
MAX1259 3330
-55 to +125
-40 to +85
0 to +70
SOIC (W)/16
$4.03 @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.
Request Reliability Report for: MAX1259 
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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