LTC2942-1C View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC2942-1C
Linear Technology
'LTC2942-1C' PDF : 16 Pages View PDF
LTC2942-1
Pin Functions
SENSE+ (Pin 1): Positive Current Sense Input and Power
Supply. Connect to the load and battery charger output.
VSENSE+ operating range is 2.7V to 5.5V.
GND (Pin 2): Device Ground. Connect directly to the nega-
tive battery terminal.
SCL (Pin 3): Serial Bus Clock Input.
SDA (Pin 4): Serial Bus Data Input and Output.
AL/CC (Pin 5): Alert Output or Charge Complete Input.
Configured either as an SMBus alert output or charge
complete input by control register bits B[2:1]. At power-up,
the pin defaults to alert mode conforming to the SMBus
alert response protocol. It behaves as an open-drain logic
output that pulls to GND when any threshold register value
is exceeded. When configured as a charge complete input,
a high level at CC sets the value of the accumulated charge
(registers C, D) to FFFFh. Columb counting starts when
the input returns to low level.
SENSE– (Pin 6): Negative Current Sense Input. Connect
SENSE– to the positive battery terminal. Current from/into
this pin must not exceed 1A in normal operation.
Exposed Pad (Pin 7): Do Not Connect. Soldering the
exposed pad to adequate electrically isolated copper area
is recommended for best thermal performance, and best
accuracy of the integrated temperature sensor.
Block Diagram
RBOND
SENSE+ 12mΩ
1
VSUPPLY
RSENSE
50mΩ
TEMPERATURE
SENSOR
RBOND
SENSE– 12mΩ
6
GND
2
MUX
COULOMB COUNTER
REF
CLK
REFERENCE
GENERATOR
OSCILLATOR
REF+
CLK
IN
ADC
REF–
CC
ACCUMULATED
CHARGE
REGISTER
DATA AND
CONTROL
REGISTERS
AL AL/CC
5
I2C/
SMBus
SCL
3
SDA
4
29421 BD
Operation
Overview
The LTC2942-1 is a battery gas gauge device designed
for use with single Li-Ion cells and other battery types
with terminal voltages from 2.7V to 5.5V. It measures
battery charge and discharge, battery voltage and chip
temperature. A precision coulomb counter integrates
current through an internal sense resistor between the
battery’s positive terminal and the load or charger. Battery
voltage and on-chip temperature are measured with an
internal 14-bit/10-bit ADC. The integrated, temperature-
compensated sense resistor offers board space savings
and superior charge measurement accuracy in applications
with currents up to 1A.
29421f
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