20V Battery Gas Gauge The LTC®2943 multicell battery gas gauge makes direct measurements of 3.6V to 20V battery stacks. Absolutely no level shifting circuitry is required to interface with multicell voltages, minimizing current consumption and preserving measurement accuracy. The LTC2943 is a true high voltage gas gauge that measures charge, voltage, current and temperature to within 1% accuracy — all of the essential parameters required to accurately assess battery state of charge (SOC). Features Measures Accumulated Battery Charge and Discharge 3.6V to 20V Operating Range for Multicell Applications 14-Bit ADC Measures Voltage, Current and Temperature 1% Charge, Voltage, Current and Temperature Accuracy I2C/SMBus Interface Configurable Alert Output/Charge Complete Input Quiescent Current <120µA Small 8-Pin 3mm × 3mm DFN Package n 2.0 n Total Charge Error vs Differential Sense Voltage VSENSE+ = 10V 1.5 n CHARGE ERROR (%) n n n n n 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 1 0.1 I2C Battery Gas Gauges Interface 2.7 to 5.5 I2C LTC2941-1 2.7 to 5.5 I2C LTC2942 2.7 to 5.5 I2C LTC2942-1 2.7 to 5.5 I2C LTC2943 3.6 to 20 I2C LTC4150 2.7 to 8.5 Interrupt • LTC2941 100 Integrated Sense Resistor Measures Operating Range (V) Part Number 10 VSENSE (mV) Charge Voltage Current Temperature • • • Package (mm) 2 × 3 DFN-6 • 2 × 3 DFN-6 • • • • • • 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. • • 2 × 3 DFN-6 • 2 × 3 DFN-6 • 3 × 3 DFN-8 MSOP-10 Power Management Multicell Battery Chargers 24V AD/DC ADAPTER MBRS140 10µF VIN L LT3652 SW 1µF 22µH BOOST SHDN SENSE CHRG BAT FAULT VFB TIMER NTC 0.05Ω 953k 4.7µF 3.3V 340k 10k B = 3380 SYSTEM LOAD 2k 2k 10µF L LTC2943 2k VDD ALCC µP SDA SCL SENSE+ RSENSE SENSE – GND + 3-CELL Li-Ion BATTERY The LT®3652 is a complete monolithic step-down battery charger that operates over a 4.95V to 32V input voltage range. The LT3652 provides a constant-current/constant-voltage charge characteristic, with maximum charge current externally programmable up to 2A. The charger employs a 3.3V float voltage feedback reference, so any desired battery float voltage up to 14.4V can be programmed with a resistor divider. The LT3652HV increases this range to 18V. The LT3652 employs an input voltage regulation loop, which reduces charge current if the input voltage falls below a programmed level, set with a resistor divider. When the LT3652 is powered by a solar panel, the input voltage regulation loop is used to maintain the panel at peak output power. Battery Chargers for Multicell Applications Part Number Maximum Charge Current (A) VBAT Range (V) Number of Battery Battery Chemistry Cells (Series) Switch Mode Multichemistry Buck (Step-Down) Battery Chargers LT3652 2 3.3 to SLA SLA 14.4 LiFePO4 1-4 LiFePO4 Li-Ion 1-3 Li-Ion LT3652HV 2 3.3 to 18 SLA SLA LiFePO4 1-5 LiFePO4 Li-Ion 1-4 Li-Ion LTC4009/LTC4009-1‡ / 4 2 to 28 NiMH NiCd 2-18 Ni, LTC4009-2‡ SLA Li-Ion 1-6 Li-Ion LTC4012/LTC4012-1‡ / 4 2 to 28 NiMH NiCd 2-18 Ni, LTC4012-2‡ /LTC4012-3 SLA Li-Ion 1-6 Li-Ion LTC4000 # /LTC4000-1#$ 50§ 3 to 60 SLA SLA LiFePO4 1-16 LiFePO4 Li-Ion 1-14 Li-Ion Input Voltage (V) Integrated Power Charge Package Transistor Synchronous Termination (mm × mm) 4.9 to 32† ~ – Timer or C/10 3×3 DFN-12, MSOP-12E 4.9 to 34† ~ – Timer or C/10 3×3 DFN-12, MSOP-12E 6 to 28 – ~ External µC 4×4 QFN-20 6 to 28 – ~ External µC 4×4 QFN-20 3 to 60@ – – Timer + C/X 4×5 QFN-28 SSOP-28 4 to 5.5 ~ ~ – Timer 3×3 QFN-16 ~ Timer + C/10 ~ – Timer + C/10 ~ ~ Timer + C/10 3×3 DFN-12 MSOP-12E 3×3 DFN-12 MSOP-12E 5×6 QFN-36 ~ ~ Timer + C/10 5×6 QFN-36 Switch Mode Li-Ion Buck (Step-Down) Battery Chargers LTC4001/LTC4001-1* 2 4.2 Li-Ion 1 LT3650-4.1/LT3650-4.2 2 4.1, 4.2 Li-Ion 1 LT3650-8.2/LT3650-8.4 2 8.2, 8.4 Li-Ion 2 LT3651-4.1/LT3651-4.2 4 4.1, 4.2 Li-Ion 1 4.75 to 32† (40 Max) 9 to 32† (40 Max) 6.5 to 32 LT3651-8.2/LT3651-8.4 4 8.2, 8.4 Li-Ion 2 9 to 32 † Minimum start-up voltage is +3.3V above VBATMAX ‡ -1 and -2 versions are fixed voltage options for 1-4 Li-Ion cells $ -1 option has MPPC (Maximum Power Point Control) * 4.1V cell voltage # Charging controller requires externally compensated switching regulator § Depends on external components @ Greater than 60V is possible without the input current regulation/measurement function www.linear.com/LTC2943 n 1-800-4-LINEAR 1013