Li-Ion/Polymer Shunt Battery Charger System with Low Battery Disconnect Ultracompact, 550nA Shunt Battery Charger & Protection Solution Features Charger Plus Pack Protection in One IC Low Operating Current (550nA) Near Zero Current (<0.1nA) Low Battery Disconnect Function to Protect Batteries from Overdischarge Pin Selectable Low Battery Disconnect Level: 2.7V or 3.2V 1% Float Voltage Accuracy Over Temperature 50mA Maximum Shunt Current Pin Selectable Float Voltage Options: 4.0V, 4.1V, 4.2V Ultralow Power Pulsed NTC Float Conditioning for Li-Ion/Polymer Protection Suitable for Intermittent, Continuous and Very Low Power Charging Sources High Battery Status Output Thermally Enhanced, Low Profile 8-Lead 2mm × 3mm × 0.75mm DFN and MSOP Packages n n n n n n n n n The LTC®4071 is an easy-to-use, tiny shunt battery system for Li-Ion/Polymer batteries, which integrates a charger and battery pack protection in one IC. The LTC4071, with its 550nA operating current, charges and protects batteries at up to 50mA from previously unusable very low current, intermittent or continuous charging sources. A near zero current (<0.1nA) low battery latching disconnect function protects even low capacity batteries from deep discharge and potentially irreparable damage. Housed in a low profile (0.75mm) 8-lead 2mm × 3mm DFN package, the LTC4071 provides the only complete and ultracompact battery charger and protection solution operating with low level power sources such as energy scavenging/ harvesting, resistive isolation or solar-powered systems. It can charge Li-Ion/Polymer, coin cell and thin film batteries. VF vs NTC Temperature n n 4.25 ADJ = VCC 4.20 4.15 ADJ = FLOAT 4.10 VF (V) 4.05 ADJ = GND 4.00 3.95 3.90 3.85 3.80 3.75 LBSEL = VCC 0 20 40 60 NTC TEMPERATURE (°C) 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. 80 100 LTC4071 Features and Benefits SHUNT ARCHITECTURE ALLOWS FOR UNLIMITED INPUT VOLTAGE VIN RIN PIN-STRAPPABLE VFLOAT SETTINGS 4.0V, 4.1V, 4.2V TO SYSTEM LOAD: VCC ADJ INTEGRATED PACK PROTECTION: LOW BATTERY DISCONNECT (UNDERVOLTAGE) AND ZENER (OVERVOLTAGE) VCC NTC NTC REDUCES FLOAT VOLTAGE TO PROTECT BATTERY CELLS AT ELEVATED TEMPERATURES BAT LTC4071 1µF LBSEL + GND CHARGE CURRENT UP TO 50mA Li-Ion Application Circuit – Energy Harvesting MMSD4148T1 15k VCC 22µF BAT 1µF LTC4071 + Li-Ion BATTERY GND LBSEL PFCB-W14 VCC 10µH 3.3V SYSTEM LOAD VOUT VIN2 PZ2 + Li-Ion 1µF CAP LTC3588-1 SW BAT LTC4071 BATTERY GND VIN PZ1 VIN2 D0 LBSEL 100µF D1 4.7µF GND Piezoelectric Energy Harvester with Battery Backup Reference Design - Energy Harvesting http://www.silabs.com/Support%20Documents/TechnicalDocs/AN588.pdf The energy management circuitry used for harvesting energy consists of a solar cell, which provides DC energy, a rectifier that can be used to convert AC vibration energy into DC energy, and the LTC4071 which takes in DC energy and regulates it to a constant 4.1V. The LTC4071 protects the battery from overdischarge (by disconnecting it from the circuit if its voltage gets too low) and provides a “ship mode” that disconnects the battery during shipping and ensures its energy is held until the end user starts up the system. Family of Shunt Battery Charger ICs Low Battery Disconnect Package (mm × mm) Shunt No 2 × 3 DFN-8, MSOP-8E Shunt Yes 2 × 3 DFN-8, MSOP-8E Part Number Number of Battery Cells (Series) Maximum Charge Current (A) Input Voltage (V) Battery Charger Type LTC4070 1 0.05 Unlimited LTC4071 1 0.05 Unlimited www.linear.com/4071 n 1-800-4-LINEAR 0911