LTC6802IG-1#PBF Linear Technology, LTC6802IG-1#PBF Datasheet - Page 14

• Manufacturer Part Number: LTC6802IG-1#PBF
• Description: IC MONITOR BATT STACK MC 44-SSOP
• Manufacturer: Linear Technology

Specifications of LTC6802IG-1#PBF

• Function: Battery Monitor
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4 V ~ 50 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-SOP (0.200", 5.30mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LTC6802-1
OPERATION
through C11 by looking at the measurements of cells B2
through B12. Therefore the algorithm cannot be used to
determine if the topmost C pin is open. Fortunately, an open
wire from the battery to the top C pin usually means the V
pin is also floating. When this happens, the readings for
the top battery cell will always be 0V, indicating a failure.
If the top C pin is open yet V
best way to detect an open connection to the top C pin
is by comparing the sum of all cell measurements using
the STCVAD command to an auxiliary measurement of the
sum of all the cells, using a method similar to that shown
in Figure 18. A significantly lower result for the calculated
sum of all 12 cells suggests an open connection to the top
C pin, provided it was already determined that no other
C pin is open.
DISCHARGING DURING CELL MEASUREMENTS
The primary cell voltage A/D measurement commands
(STCVAD and STOWAD) automatically turn off a cell’s
discharge switch while its voltage is being measured. The
discharge switches for the cell above and the cell below will
also be turned off during the measurement. For example,
discharge switches S4, S5, and S6 will be disabled while
cell 5 is being measured.
In some systems it may be desirable to allow discharging
to continue during cell voltage measurements. The cell
voltage A/D conversion commands STCVDC and STOWDC
allow any enabled discharge switches to remain on during
cell voltage measurements. This feature allows the system
to perform a self-test to verify the discharge functionality
and multiplexer operation.
All discharge switches are automatically disabled during
OV and UV comparison measurements.
14
+
is still connected, then the
+
A/D CONVERTER DIGITAL SELF TEST
Two self test commands can be used to verify the func-
tionality of the digital portions of the ADC. The self tests
also verify the cell voltage registers and temperature
monitoring registers. During these self tests a test signal
is applied to the ADC. If the circuitry is working properly
all cell voltage and temperature registers will contain
identical codes. For Self Test 1 the registers will contain
0x555. For Self Test 2, the registers will contain 0xAAA.
The time required for the self test function is the same as
required to measure all cell voltages or all temperature
sensors. Perform the self test function with CDC[2:0] set
to 1 in the configuration register.
USING THE S PINS AS DIGITAL OUTPUTS OR
GATE DRIVERS
The S outputs include an internal 10k pull-up resistor.
Therefore the S pins will behave as a digital output when
loaded with a high impedance, e.g. the gate of an external
MOSFET. For applications requiring high battery discharge
currents, connect a discrete PMOS switch device and suit-
able discharge resistor to the cell, and the gate terminal
to the S output pin, as illustrated in Figure 4.
Figure 4. External Discharge FET Connection (One Cell Shown)
15Ω
1W
VISHAY CRCW2512 SERIES
SI2351DS
3.3k
68021 F04
C(n)
S(n)
C(n – 1)
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