Document
19-4688; Rev 3; 5/10
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2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with Protector and Optional SHA-1 Authentication
General Description
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 challengeresponse 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 LiPoly 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.
Features
♦ 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
DS2775/DS2776/DS2777/DS2778
Ordering Information
PART DS2775G+ DS2775G+T&R DS2776G+ DS776G+T&R DS2777G+ DS2777G+T&R DS2778G+ DS2778G+T&R PIN-PACKAGE 14 TDFN-EP* 14 TDFN-EP* 14 TDFN-EP* 14 TDFN-EP* 14 TDFN-EP* 14 TDFN-EP* 14 TDFN-EP* 14 TDFN-EP* TOP MARK D2775 D2775 D2776 D2776 D2777 D2777 D2778 D2778
Applications
Low-Cost Notebooks UMPCs DSLR Cameras Video Cameras Commercial and Military Radios Portable Medical Equipment
Selector Guide appears at end of data sheet.
Note: All devices are specified over the -20°C to +70°C operating temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. T&R = Tape and reel. *EP = Exposed pad.
1-Wire is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
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2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with Protector and Optional SHA-1 Authentication DS2775/DS2776/DS2777/DS2778
ABSOLUTE MAXIMUM RATINGS
Voltage Range on PLS, CP, CC, DC Pins Relative to VSS .....................................................-0.3V to +18V Voltage Range on VDD, VIN1, VIN2, SRC Pins Relative to VSS ....................................................-0.3V to +9.2V Voltage Range on All Other Pins Relative to VSS ..-0.3V to +6.0V Continuous Sink Current, PIO, DQ......................................20mA Continuous Sink Current, CC, DC.......................................10mA Operating Temperature Range ...........................-20°C to +70°C Storage Temperature Range .............................-55°C to +125°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VDD = +4.0V to +9.2V, TA = -20°C to +70°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER SYMBOL IDD0 Supply Current IDD1 IDD2 Temperature Accuracy T ERR 2.0 VIN1 4.6, 2.0 (VIN2 - VIN1) 4.6, 0°C TA +50°C Voltage Accuracy 2.0 VIN1 4.6, 2.0 (VIN2 – VIN1) 4.6, TA = +25°C 2.0 VIN1 4.6, 2.0 (VIN2 - VIN1) 4.6 Input Resistance (VIN1, VIN2) Current Resolution Curr.