MAX713 Datasheet

• Fast-Charge NiMH or NiCd Batteries
• Voltage Slope, Temperature, and Timer Fast-Charge Cutoff
• Charge 1 to 16 Series Cells
• Supply Battery's Load While Charging (Linear Mode)
• Fast Charge from C/4 to 4C Rate
• C/16 Trickle-Charge Rate
• Automatically Switch from Fast to Trickle Charge
• Linear Mode Power Control
• 5µA (max) Drain on Battery when Not Charging
• 5V Shunt Regulator Powers External Logic

• Cellular Phones
• Cordless Phones
• Handy-Terminals
• Laptop, Notebook, and Palmtop Computers
• Portable Stereos

The MAX713 fast-charge Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCd) batteries from a DC source at least 1.5V higher than the maximum battery voltage. 1 to 16 series cells can be charged at rates up to 4C. A voltage-slope detecting analog-to-digital converter, timer, and temperature window comparator determine charge completion. The MAX713 are powered by the DC source via an on-board +5V shunt regulator. They draw a maximum of 5µA from the battery when not charging. A low-side current-sense resistor allows the battery charge current to be regulated while still supplying power to the battery's load.

The MAX713 uses a negative voltage-slope detection scheme. The MAX713 parts come in 16-pin DIP and SO packages. An external power PNP transistor, blocking diode, three resistors, and three capacitors are the only required external components.