Rainbow Electronics DS2778 - Manual

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 oper-
ation 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 estima-
tion calculations. The capacity registers report a con-
servative 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 statis-
tics. A Maxim 1-Wire
® (DS2775/DS2776) or 2-wire
(DS2777/DS2778) interface provides serial communica-
tion to access measurement and capacity data regis-
ters, 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.
Applications
Low-Cost Notebooks
UMPCs
DSLR Cameras
Video Cameras
Commercial and Military Radios
Portable Medical Equipment
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
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
Rev 1; 3/09
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.
PART PIN-PACKAGE TOP MARK
DS2775G+ 14 TDFN-EP* D2775
DS2775G+T&R 14 TDFN-EP* D2775
DS2776G+ 14 TDFN-EP* D2776
DS776G+T&R 14 TDFN-EP* D2776
DS2777G+ 14 TDFN-EP* D2777
DS2777G+T&R 14 TDFN-EP* D2777
DS2778G+ 14 TDFN-EP* D2778
DS2778G+T&R 14 TDFN-EP* D2778
Note: All devices are specified over the -20°C to +70°C oper-
ating temperature range.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
*
EP = Exposed pad.
Selector Guide and Pin Configuration appear at end of data
sheet.
1-Wire is a registered trademark of Maxim Integrated Products, Inc.