DS2786

Stand-Alone OCV-Based Fuel Gauge

2-Wire Stand-Alone Fuel Gauge Requires No Learn Cycle to Provide Initial Capacity Estimate or Maintain Accuracy During Use

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Status Explanations for product status codes

Part Number Status
DS2786 Active: In Production. See Ordering Information for details.

Description

The DS2786 estimates available capacity for rechargeable Li-Ion and Li-Ion Polymer batteries based on the cell voltage in the open-circuit state following a relaxation period. The open-circuit voltage (OCV) is used to determine relative cell capacity based on a lookup table stored in the IC. This capability makes accurate capacity information available immediately after a battery pack is inserted. During periods of moderate to high rate discharging, which preclude OCV measurements, the DS2786 uses coulomb counting as a secondary means of estimating relative capacity.

Remaining capacity is reported in percent, along with cell voltage, current and temperature information. Cell characteristics and application parameters used in the calculations are stored in on-chip EEPROM.

The DS2786 is intended for use on the host side of portable devices, though it can also be mounted within a battery pack. Measurement and estimated capacity data are accessed through an I²C interface. Temperature data is available from an on-die sensor. Resistance measurements of a pack identification resistor and pack thermistor are supported by ratiometric measurements on two auxiliary inputs.
 

Data Sheet

Download this datasheet in PDF formatDownload Rev 8 (PDF, 316kB)
Send this datasheet to any email addressE-Mail
An evaluation kit is available: DS2786EVKIT

NOTE: This product uses the following:
DS2786K_EVKit_Installation_v1_91_092811.zip

Key Features

  • Relative Capacity Calculated from Combination Coulomb Counter and Open-Circuit Cell Voltage (OCV) Battery Model
  • Accurate Warning of Low Battery Conditions Even On First Cycle (No Learn Cycle Needed)
  • 12-Bit Battery Voltage Measurement:
    • ±10mV Accuracy
    • 1.22mV LSB, 0V to 5V Input Range
  • 11-Bit Bidirectional Current Measurement:
    • 25µV LSB, ±51.2mV Dynamic Range
    • 1.67mA LSB, ±3.4A (RSNS = 15mΩ)
  • Current Accumulation Measurement Resolution:
    • ±204.8mVh Range
    • ±13.65Ah (RSNS = 15mΩ)
  • Internal Temperature Measurement:
    • 0.125°C LSB, ±3°C Accuracy
  • Two 11-Bit Aux Input Voltage Measurements:
    • ±8 LSB Accuracy, Ratiometric Inputs Eliminate Supply Accuracy Issues
  • VOUT Pin Drives Resistive Dividers, Reduces Current Consumption
  • 2-Wire Interface
  • Low Power Consumption:
    • Active Current: 50µA typ, 80µA max
    • Sleep Current: 1µA typ, 3µA max
 

Applications/Uses

  • 3G Multimedia Wireless Handsets
  • Digital Audio (MP3) Players
  • Digital Still Cameras
   

Key Specifications:

Battery Protectors, Selectors and Monitors
Part Number Functions Battery Type Interface User Data Storage
(Bytes)
Parameters Measured VSUPPLY
(V)
VSUPPLY
(V)
Package/Pins Smallest Available Pckg.
(mm2)
Oper. Temp.
(°C)
Budgetary Price
min max max w/pins See Notes
DS2786  Fuel Gauge
1 Cell Li-Ion
3-Cell NiMH
2-Wire 32 EEPROM
Current
Temperature
Voltage
2.5 5.5
TDFN-EP/10
TDFN/10
9.6 -40 to +85 $1.53 @1k
See All Battery Protectors, Selectors and Monitors (29)
Pricing 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.


Diagram

DS2786: Typical Operating Circuit
Typical Operating Circuit

Application Notes

Application Note 3978   Getting Started with the DS2786K
Application Note 3992   Interpreting the Open-Circuit-Voltage (OCV) Fuel Gauge of the DS2786
Application Note 4106   Using the DS2786 Battery Fuel Gauge in a 2-Cell Battery Pack
Application Note 4141   Programming and Testing a DS2786-Based Circuit
Application Note 4189   Characterizing a Lithium-Ion (Li+) Cell for Use with an Open-Circuit-Voltage (OCV) Based Fuel Gauge
Application Note 4224   Using the DS2786 Battery Fuel Gauge in the Host Side of a 2-Cell Battery Application
Application Note 4427   Demonstrating Green Technology with Apples, Oranges, Lemons, and Limes

Reliability Reports

Reliability Report: DS2786.pdf

Software/Models

DS2786K_EVKit_Installation_v1_91_092811.zip

Ordering Information

Filters: Part Number: Package: Temperature: Tape and Reel Sample
Part Number Free
Sample
Buy Status Explanations for product status codes Recommended Replacement Package:
TYPE PINS FOOTPRINT
DRAWING  CODE/VAR *
Temp RoHS/Lead-Free?
Materials Analysis
DS2786G+  
Active   TDFN-EP;10 pin;9.6 mm²
Outline Drawing:21-0137 (PDF)
Land Pattern: 90-0003 (PDF)
Use pkgcode/variation: T1033+1*
-40°C to +85°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS2786G+T&R    
Active   TDFN-EP;10 pin;9.6 mm²
Outline Drawing:21-0137 (PDF)
Land Pattern: 90-0003 (PDF)
Use pkgcode/variation: T1033+1*
-40°C to +85°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS2786G-5+T&R    
Active   TDFN;10 pin;11.3 mm²
Outline Drawing:21-0268 (PDF)
Land Pattern: 90-0247 (PDF)
Use pkgcode/variation: T1034N+1*
-40°C to +85°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS2786G-C03+T&R    
Active   TDFN-EP;10 pin;9.6 mm²
Outline Drawing:21-0137 (PDF)
Land Pattern: 90-0003 (PDF)
Use pkgcode/variation: T1033+1*
-40°C to +85°C RoHS/Lead-Free: Lead Free
Materials Analysis
DS2786K-SMP     N/A No Longer Available DS2786EVKIT+

 
TDFN;

Land Pattern: Not Available

0°C to +70°C See data sheet

Notes:
  1. Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
  2. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
  3. Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product Naming Conventions.
  4. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

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More Information

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Information Index

Document Ref.: 19-4637 Rev 8; 2009-06-22
This page last modified: 2009-09-01


 


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