LINEAR TECHNOLOGY LTC2941, LTC2942 Technical data
I2C Battery Gas Gauges
LOAD
+
–
CHARGER
REGISTER
HOST
LTC2942-1
I2C
Measure Charge, Voltage and Temperature
For applications requiring accurate battery gas gauging, the LTC®2941 and LTC2942 coulomb counters provide tiny and
easy-to-use solutions. The LTC2941/LTC2942 use a continuous-time analog integrator, resulting in minimal offset and gain error
and better overall charge accuracy. The bidirectional analog integrator accommodates both battery charge and discharge, and
a programmable prescaler allows for a wide range of battery capacities. The LTC2942 incorporates a 14-bit ∆∑ ADC to measure
battery voltage and die temperature. The LTC2941-1 and LTC2942-1 also integrate a 50mΩ sense resistor to provide up to ±1A
measurement range. Charge, voltage* and temperature* are all communicated to the host system over an I2C/SMBus
compatible interface.
Features
n
Indicates Accumulated Battery Charge and Discharge
n
SMBus/I2C Interface
n
14-Bit ADC Measures Battery Voltage and Temperature
(*LTC2942)
n
High Side Current Sense with ±50mV Sense Range
n
Integrated 50mΩ High Side Sense Resistor with ±1A
Range (LTC2941-1/LTC2942-1)
n
1% Voltage and Charge Accuracy
n
±50mV Sense Voltage Range
n
Programmable High/Low Thresholds for All Measured
Parameters
n
Configurable Alert Output/Charge Complete Input
n
Quiescent Current <100µA
Linear Technology I2C Battery Gas Gauges
LTC2941/
LTC2941-1
Operating Voltage Range 2.7V to 5.5V 2.7V to 5.5V
Voltage and Temperature
Measurement
Integrated Sense Resistor No/Yes No/Yes
Package 2mm × 3mm
No Yes
DFN-6
LTC2942/
LTC2942-1
2mm × 3mm
DFN-6
Total Charge Error (TCE) Over Temperature
Part Sense Resistor TCE
LTC2942-1 N/A 2.8%
LTC2942 ±1%, 100ppm/°C ($0.10) 5.1%
±0.1%, 50ppm/°C ($0.30) 3.9%
±0.1%, 15ppm/°C ($3.75) 3.6%
L, LT, LTC, LTM, Linear Technology and the Linear logo
are registered trademarks and PowerPath and Bat-Track
are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
Power Manager Products for Li-Ion Batteries
0.1µF
1 CELL
Li-Ion
LOAD
3.3V
3.3µH
2k2k
22µF
2k
3.01k
USB
10µF
0.1µF
µP
V
DD
SW
IDGATE
NTCGNDPROG
V
DV
OUT
BAT
IRQ
SDA
SCL
CC
+
SENSE
SENSE
LTC2942-1
AL/CC
SDA
SCL
GND
V
BUS
LTC4099
CLPROG
USB Power Managers for 1-Cell Li-Ion/Polymer Batteries
The LTC2941/LTC2942 battery gas gauges
are ideal companions to Linear Technology’s
extensive family of single-cell Li-Ion battery
chargers and USB power managers. Pairing
with the LTC4099 I2C controlled USB power
manager/charger provides a powerful
combination that enables I2C programmability of
charge functions and complete I2C monitoring of
–
battery state-of-charge information.
The LTC4099’s switchmode topology features
PowerPath™ control, which seamlessly manages
power flow between a wall adapter or USB port
and the device’s Li-Ion/Polymer battery, while
preferentially providing power to the system
load. This revolutionary input current-limited
switching regulator design allows higher charge
current than conventional linear approaches,
while meeting USB specifications.
Part
Number
LTC4055/
Charge
Current (A)
1 Linear 4.3 to 5.5 No 4mm × 4mm
LTC4055-1
Maximum
LTC4160/
1.2 Switching 4.35 to 5.5 Yes 3mm × 4mm
LTC4160-1
LTC4089 1.2 Linear 4.35 to 5.5 USB,
LTC4089-1/
1.2 Linear 4.35 to 5.5 USB,
LTC4089-5
Power
Manager
Topology Input Voltage (V)
6 to 36 Wall (40V Max)
6 to 36 Wall (40V Max)
Optional
External Ideal
Diode Controller Package Comments and Features
QFN-16
QFN-20
Yes 3mm × 6mm
DFN-22
Yes 3mm × 6mm
DFN-22
LTC4067 1.25 Linear 4.35 to 5.5 Yes 3mm × 4mm
DFN-14
LTC4088/
LTC4088-1/
1.5 Switching 4.25 to 5.5 Yes, 30mΩ 3mm × 4mm
DFN-14
LTC4088-2
LTC4098/
LTC4098-1
LTC4099 1.5 Switching 4.35 to 5.5 USB, Up to
LTC4090/
LTC4090-5
LTC4066/
LTC4066-1
LTC4085/
LTC4085-1/
1.5 Switching 4.35 to 5.5 USB, Up to
38V Wall (60V Abs Max)
Yes, 30mΩ 3mm × 4mm
QFN-20
Yes, 30mΩ 3mm × 4mm
38V Wall (60V Abs Max)
1.5 Linear 4.35 to 5.5 USB,
6 to 36 Wall (60V Max)
Yes 3mm × 6mm
QFN-20
DFN-22
1.5 Linear 4.3 to 5.5 No 4mm × 4mm
QFN-24
1.5 Linear 4.35 to 5.5 Yes, 50mΩ 3mm × 4mm
DFN-14
LTC4085-3
LTC4155 3.5 Switching 4.35 to 5.5 USB,
LTC4156 ˆ
†
3.5 Switching 4.35 to 5.5 USB,
77V OVP
77V OVP
ˆ Future product, contact factory for details.
†
LiFePO4 compatible.
‡
Required external PFET serves as ideal diode.
Yes
Yes
‡
4mm × 5mm
QFN-28
‡
4mm × 5mm
QFN-28
Bat-Track™, LTC4055-1 Has 4.1V V
FLOAT
Bidirectional Switcher Generates 5V at 0.5A for USB
On-the-Go Applications, 6.1V OVP, Bat-Track, Instant-On
Operation, LTC4160-1 Has 4.1V V
FLOAT
Bat-Track, Instant-On Operation
Instant-On Operation, LTC4089-1 Has Bat-Track and for
4.1V Li-Ion, LTC4089-5 Has 5V Output and for 4.2V Li-Ion
13V OVP
Bat-Track, charge current reduces to maintain 3.6V
output at load. LTC4088 has 3.3V LDO while LTC4088-1
and LTC4088-2 do not. Power-up charger state is off for
LTC4088-1 and on for LTC4088-2.
66V OVP, Bat-Track, Instant-On Operation,
LTC4098-1 Has 4.1V V
FLOAT
I2C Control, Overtemperature Battery Conditioning Circuit,
66V OVP, Bat-Track, Instant-On Operation
Bat-Track, Instant-On Operation,
LTC4090-5 Has 5V Output and No Bat-Track
LTC4066-1 Has 4.1V V
LTC4085-1 Has 4.1V V
I2C Control, USB OTG, V
I2C Control, USB OTG, V
for Lithium Iron Phosphate
FLOAT
, LTC4085-3 Has 3.95V V
FLOAT
= 4.05V/4.1V/4.15V/4.2V
FLOAT
= 3.45V/3.55V/3.6V/3.8V
FLOAT
FLOAT
www.linear.com/2942 n 1-800-4-LINEAR
1111B
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