DS2784 1-Cell Stand-Alone Fuel Gauge IC with Li+ Protector and SHA-1 Authentication

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The DS2784 operates from 2.5V to 4.6V for integration in battery packs using a single lithium-ion (Li+) or Li+ polymer cell. Available capacity is reported in mAh and as a percentage. Safe operation is ensured with the included Li+ protection function and SHA-1-based challenge-response authentication.

Precision measurements of voltage, temperature, and current, along with cell characteristics and application parameters are used to estimate capacity. The available capacity registers report a conservative estimate of the amount of charge that can be removed given the current temperature and discharge rate.

In addition to the nonvolatile (NV) storage for cell compensation and application parameters, 16 bytes of EEPROM memory is made available for the exclusive use of the host system and/or pack manufacturer. This facilitates battery lot and date tracking or NV storage of system or battery usage statistics.

A 1-Wire® interface provides serial communication at 16kbps or 143kbps to access data registers, control registers, and user memory. Additionally, 1-Wire communication enables challenge-response pack authentication using SHA-1 as the hash algorithm in a hash-based message authentication code (HMAC) authentication protocol.

Key Features

Applications/Uses

Precision Voltage, Temperature, and Current Measurement System
Available Capacity Estimated from Coulomb Count, Discharge Rate, Temperature, and Cell Characteristics
Estimates Cell Aging Using Learn Cycles
Uses Low-Cost Sense Resistor
Allows for Calibration of Gain and Temperature Coefficient
Li+ Safety Circuitry—Overvoltage, Undervoltage, Overcurrent, Short-Circuit Protection
Programmable Safety Thresholds for Overvoltage and Overcurrent
Authentication Using SHA-1 Algorithm and 64-Bit Secret
32-Byte Parameter EEPROM
16-Byte User EEPROM
Dallas 1-Wire Interface with 64-Bit Unique ID
Tiny, Pb-Free, 14-Pin TDFN Package Embeds Easily in Battery Packs Using Thin Prismatic Cells

	Cordless VoIP Phones
	Digital Still and Video Cameras
	Portable GPS Navigation
	Smartphones/PDAs

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)

Features

Package

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

RoHS Available

Operating Temp. Range (°C)

Price^*

DS2784

•	Fuel Gauge

•

Protector

1 Cell Li-Ion

1-Wire

16 EEPROM

Current
Temperature
Time
Voltage

Over Voltage
Over-Current
Over-Temperature
Over/Under Voltage

2.5

4.6

•	Digital Current Accumulation

•	Internal MOSFET Drivers

•	On-chip Remaining Capacity Algorithms

•

Unique ID

TDFN/14

Yes

-40 to +85

$2.94 @ 1k

See All Battery Protectors, Selectors and Monitors (23)

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.