Data Sheet
ADBMS1818
18-Cell Battery Monitor with Daisy Chain Interface
► 9 general-purpose digital I/O or analog inputs
► Temperature or other sensor inputs
► Configurable as an I2C or SPI master
► 6 µA sleep mode supply current
► 64-lead eLQFP package
FEATURES
► Measures up to 18 battery cells in series
► 3 mV maximum total measurement error
► Stackable architecture for high voltage systems
► Built-in isoSPI interface
► 1 Mb isolated serial communications
APPLICATIONS
► Uses a single twisted pair, up to 100 meters
► Low EMI susceptibility and emissions
► Bidirectional for broken wire protection
► 290 µs to measure all cells in a system
► Synchronized voltage and current measurement
► 16-bit Δ-Σ ADC with programmable third-order noise filter
► Backup battery systems
► Grid energy storage
► Residential energy storage
► UPS
► High power portable equipment
► Passive cell balancing up to 200 mA (maximum) with program-
mable pulse‑width modulation
GENERAL DESCRIPTION
The ADBMS1818 is a multicell battery stack monitor that measures
up to 18 series connected battery cells with a total measurement
error (TME) of less than 3.0 mV. The cell measurement range
of 0 V to 5 V makes the ADBMS1818 suitable for most battery
chemistries. All 18 cells can be measured in 290 µs, and lower data
acquisition rates can be selected for high noise reduction.
TYPICAL APPLICATION CIRCUIT
Multiple ADBMS1818 devices can be connected in series, permit-
ting simultaneous cell monitoring of long, high voltage battery
™
strings. Each ADBMS1818 has an isoSPI interface for high
Figure 1. Typical Application Circuit
speed, RF immune, long distance communications. Multiple devi-
ces are connected in a daisy chain with one host processor connec-
tion for all devices. This daisy chain can be operated bidirectionally,
ensuring communication integrity, even in the event of a fault along
the communication path.
The ADBMS1818 can be powered directly from the battery stack or
from an isolated supply. The ADBMS1818 includes passive balanc-
ing for each cell, with individual pulse-width modulation (PWM) duty
cycle control for each cell. Other features include an on-board 5 V
regulator, nine general-purpose I/O lines, and a sleep mode, where
current consumption is reduced to 6 µA.
Figure 2. Cell 18 Measurement Error vs. Temperature
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