FIRST ±0.5% ACCURATE LITHIUM-ION CELL PROTECTOR INCREASES BATTERY PACK CAPACITY
SUNNYVALE, CA-June 7, 1999-Maxim Integrated Products introduces the MAX1666, the first lithium-ion cell protector to offer cell overvoltage threshold accuracy of ±0.5%. This accuracy allows charge voltages to be much closer to the cell's design limits, increasing the amount of stored charge in a typical four-cell battery pack by as much as 2% when compared to other protectors. The MAX1666 is also an industry first in that it closely monitors the cell-to-cell voltage mismatch and automatically shuts down the pack when the mismatch exceeds the user-adjusted limit.
The MAX1666 provides accurate user-adjustable threshold limits for cell overvoltage (+4.0V to +4.4V at ±0.5%), cell undervoltage (+2.0V to +3.0V at ±2.5%), cell-to-cell mismatch (0 to 500mV at ±10%), and charge/discharge current (any current, set by the sense resistor at ±10%). On-chip power MOSFET drivers control external P-channel MOSFETs to reliably disconnect the cells from the pack terminals when a fault condition occurs. The MAX1666 can operate as a stand-alone protection device or in conjunction with a pack microcontroller using its digital interface and status signals.
The MAX1666 alleviates the need for an external voltage regulator by integrating an on-board 3.3V low-dropout (LDO) linear regulator that can accept a +4V to +28V input and supply up to 5mA to power other circuitry. It is a true "micropower" device, consuming only 30µA while operating and <1µA in shutdown.
The MAX1666 is available in three versions: The "S" version monitors two-cell packs, the "V" version monitors three-cell packs, and the "X" version monitors four-cell packs. The MAX1666S comes in a 16-pin QSOP package, whereas the MAX1666V/MAX1666X come in 20-pin QSOP packages. All parts are specified for the extended-industrial temperature range (-40°C to +85°C). Prices for the four-cell protector start from $2.75 (1000-up, FOB USA). | 
