BQ2085 Datasheet, PDF (2/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085
SLUS541 – OCTOBER 2002
DESCRIPTION (CONTINUED)
The bq2085 uses an integrating converter with
continuous sampling for the measurement of battery
charge and discharge currents. Optimized for coulomb
counting in portable applications, the self-calibrating
integrating converter has a resolution better than 3-nVh
and an offset measurement error of less than 1-µV
(typical). For voltage and temperature reporting, the
bq2085 uses a 16-bit A-to-D converter. In conjunction
with the bq29311, the onboard ADC also monitors
individual cell voltages in a battery pack and allows the
bq2085 to generate the control signals necessary to
implement the cell balancing and the required safety
protection for Li-ion and Li-polymer battery chemistries.
The bq2085 supports the Smart Battery Data (SBData)
commands and charge-control functions. It
communicates data using the System Management
Bus (SMBus) 2-wire protocol. The data available
include the battery’s remaining capacity, temperature,
voltage, current, and remaining run-time predictions.
The bq2085 provides LED drivers and a push-button
input to depict remaining battery capacity from full to
empty in 20%, 25%, or 33% increments with a 3-, 4-, or
5-segment display.
The bq2085 contains 512 bytes of internal data flash
memory, which store configuration information. The
information includes nominal capacity and voltage,
self-discharge rate, rate compensation factors, and
other programmable cell-modeling factors used to
accurately adjust remaining capacity for use-conditions
based on time, rate, and temperature. The bq2085 also
automatically calibrates or learns the true battery
capacity in the course of a discharge cycle from
programmable near full to near empty levels.
The bq29311 AFE protection IC provides power to the
bq2085 from a 3 or 4 series Li-ion cell stack, eliminating
the need for an external regulator circuit.
TSSOP PACKAGE
(TOP VIEW)
VIN ₁
TS ₂
OC ₃
N/C ₄
N/C ₅
SCLK ₆
N/C ₇
VDDD 8
RBI 9
SDATA 10
VSSD 11
SAFE 12
N/C 13
N/C 14
SMBC 15
SMBD 16
DISP 17
EVENT 18
VSSD 19
38 ^VSSD
37 ^N/C
36 ^N/C
35 ^CLKOUT
34 ^VSSA
33 ^ROSC
32 ^FILT
31 ^VDDA
30 ^VSSA
29 ^VSSP
28 ^SR1
27 ^SR2
26 ^MRST
25 ^N/C
24 LED1
23 LED2
22 LED3
21 LED4
20 LED5
NC – No internal connection
AVAILABLE OPTIONS
PACKAGE
TA
38-PIN TSSOP
(DBT)
–20°C to 85°C
bq2085DBT^{
† _{The bq2085 is available taped and reeled. Add an R suffix to the}
device type (e.g., bq2085DBTR) to order tape and reel version.
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