QuickView - DS2775, DS2776, DS2777, DS2778 2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with Protector and Optional SHA-1 Authentication

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Description

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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 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.

Key Features

Applications/Uses

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

	Commercial and Military Radios
	DSLR Cameras
	Low-Cost Notebooks
	Portable Medical Equipment
	UMPCs
	Video Cameras

Key Specifications: Battery Protectors, Selectors and Monitors

Part Number

Functions

Battery Type

Interface

User Data Storage (bytes)

Parameters Measured

Battery Protection

Supply Voltage (min) (V)

Supply Voltage (max) (V)

Package

Smallest Available Package (max w/pins) (mm²)

Operating Temp. Range (°C)

Price^**

DS2775

•	Fuel Gauge

•

Protector

•	Status Monitor

1-2 Cell Li-Ion
2-4 Cell Li-Ion
2-6 Cell Li-Ion

1-Wire

16 EEPROM

Current
Temperature
Time
Voltage

Over Voltage
Over-Current
Over/Under Voltage

9.2

TDFN/14

-20 to +70

$2.73 @ 1k

DS2776

1-Wire

$2.93 @ 1k

DS2777

2-Wire

$3.18 @ 1k

DS2778

2-Wire

$2.93 @ 1k

See All Battery Protectors, Selectors and Monitors (26)

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 prices and delivery, please see the price and availability page or contact an authorized distributor.