The DS2775–DS2778 report available capacity for rechargeable lithium-ion (Li+) and Li+ polymer (Li-Poly) batteries in mAh and as a percentage of full. Safe operation is ensured by the integrated Li+ protector. The DS2776/DS2778 support SHA-1-based challenge-response authentication in addition to all other DS2775/DS2777G features. Precision measurements of voltage, temperature, and current, along with a cell characteristics table and application parameters, are used for capacity estimation calculations. The capacity registers report a conservative estimate of the amount of charge that can be removed given the current temperature, discharge rate, stored charge, and application parameters. The DS2775–DS2778 operate from +4.0V to +9.2V for direct integration into battery packs with two Li+ or Li- Poly cells. In addition to nonvolatile storage for cell compensation and application parameters, the DS2775–DS2778 offer 16 bytes of EEPROM for use by the host system and/or pack manufacturer to store battery lot and date tracking information. The EEPROM can also be used for nonvolatile storage of system and/or battery usage statistics. A Maxim 1-Wire (DS2775/DS2776) or 2-wire (DS2777/DS2778) interface provides serial communication to access measurement and capacity data registers, control registers, and user memory. The DS2776/DS2778 use the SHA-1 hash algorithm in a challenge-response pack authentication protocol for battery-pack verification.
Feature
- High-Side nFET Drivers and Protection Circuitry
- Precision Voltage, Temperature, and Current Measurement System
- Cell-Capacity Estimation from Coulomb Count, Discharge Rate, Temperature, and Cell Characteristics
- Estimates Cell Aging Between Learn Cycles
- Uses Low-Cost Sense Resistor
- Allows Calibration of Gain and Temperature Coefficient
- Programmable Thresholds for Overvoltage and Overcurrent
- Pack Authentication Using SHA-1 Algorithm (DS2776/DS2778)
- 32-Byte Parameter EEPROM
- 16-Byte User EEPROM
- Maxim 1-Wire Interface with 64-Bit Unique ID (DS2775/DS2776)
- 2-Wire Interface with 64-Bit Unique ID (DS2777/DS2778)
- 3mm x 5mm, 14-pin TDFN Lead-Free Package
Applications
- Digital Still, Video, and Action Cameras
- Handheld Computers and Terminals
- Handheld Radios
- Health and Fitness Monitors
- Home and Building Automation, Sensors
- Medical Devices
- Power Tools
- Smart Batteries
