LTC6802-1_1 Datasheet, PDF (1/38 Pages) Linear Technology – Multicell Battery Stack Monitor

FEATURES
n _{Measures up to 12 Li-Ion Cells in Series (60V Max)}
n _{Stackable Architecture Enables >1000V Systems}
n _{0.25% Maximum Total Measurement Error}
n _{13ms to Measure All Cells in a System}
n _{Cell Balancing:}
On-Chip Passive Cell Balancing Switches
Provision for Off-Chip Passive Balancing
n _{Two Thermistor Inputs Plus On-Board}
Temperature Sensor
n _{1MHz Daisy-Chainable Serial Interface}
n _{High EMI Immunity}
n _{Delta Sigma Converter with Built-In Noise Filter}
n _{Open Wire Connection Fault Detection}
n _{Low Power Modes}
n _{44-Lead SSOP Package}
APPLICATIONS
n _{Electric and Hybrid Electric Vehicles}
n _{High Power Portable Equipment}
n _{Backup Battery Systems}
n _{High Voltage Data Acquisition Systems}
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
LTC6802-1
Multicell
Battery Stack Monitor
DESCRIPTION
The LTC^®6802-1 is a complete battery monitoring IC that
includes a 12-bit ADC, a precision voltage reference, a
high voltage input multiplexer and a serial interface. Each
LTC6802-1 can measure up to 12 series connected bat-
tery cells with an input common mode voltage up to 60V.
In addition, multiple LTC6802-1 devices can be placed in
series to monitor the voltage of each cell in a long battery
string. The unique level-shifting serial interface allows the
serial ports of these devices to be daisy-chained without
optocouplers or isolators.
When multiple LTC6802-1 devices are connected in series
they can operate simultaneously, permitting all cell voltages
in the stack to be measured within 13ms.
To minimize power, the LTC6802-1 offers a measure mode,
which simply monitors each cell for overvoltage and un-
dervoltage conditions. A standby mode is also provided.
Each cell input has an associated MOSFET switch for
discharging overcharged cells.
For large battery stack applications requiring individually
addressable serial communications, see the LTC6802-2.
TYPICAL APPLICATION
NEXT 12-CELL
PACK ABOVE
V⁺
12-CELL
BATTERY
MUX
STRING
LTC6802-1 ^{SERIAL DATA}
TO LTC6802-1
DIE TEMP
ABOVE
REGISTERS
AND
CONTROL
12-BIT
Δ∑ ADC
NEXT 12-CELL
PACK BELOW
V^–
100k NTC
EXTERNAL
TEMP
VOLTAGE
REFERENCE
SERIAL DATA
TO LTC6802-1
BELOW
68021 TA01a
100k
Measurement Error Over
Extended Temperature
0.30
0.25
0.20
0.15
0.10
0.05
0
–0.05
–0.10
–0.15
–0.20
–0.25
–0.30
–50 –25
7 REPRESENTATIVE
UNITS
0 25 50 75
TEMPERATURE (°C)
100 125
68021 TA01b
68021fa
1