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/ DS2777 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 non-volatile 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.
The DS2775‑DS2778 family are 2‑cell, stand‑alone Li+ fuel‑gauge ICs that measure voltage, temperature, and current while providing capacity estimation, over‑voltage/over‑current protection, and optional SHA‑1 challenge‑response authentication. They include 16 bytes of user EEPROM and a Maxim 1‑Wire or 2‑Wire interface for host communication.
The datasheet lists absolute maximum ratings, detailed electrical characteristics, pin configurations for the 3 mm × 5 mm 14‑pin TDFN package, and command sets for EEPROM operations, pack authentication, and protection features. Typical application circuits and timing diagrams are also provided.
| Operating Temperature Range | -20 °C to +70 °C |
|---|---|
| User EEPROM Size | 16 Byte |
| Package | 3 mm × 5 mm, 14‑Pin TDFN Lead‑Free |
| SHA‑1 Authentication | Supported (challenge‑response) |
| 1‑Wire Interface | 64‑bit unique ID |
| 2‑Wire Interface | Available on DS2777/DS2778 |
Each device provides a 16‑byte user EEPROM.
Yes, DS2776 and DS2778 support SHA‑1 challenge‑response authentication.
They are offered in a 3 mm × 5 mm, 14‑pin TDFN lead‑free package.