Click here for production status of specific part numbers. MAX8971 Industry s Smallest 1.55A 1-Cell Li+ DC-DC Charger General Description Benefits and Features The MAX8971 is a compact, high-frequency, high-effi- Switch-Mode Charger ciency switch-mode charger for a one-cell lithium-ion (Li+) High-Efficiency battery. It delivers up to 1.55A of current to the battery Low Heat Fast Charge Time from inputs up to 7.5V and withstands transient inputs up to 22V. The 4MHz switch-mode charger is ideally suited Small and Simple for small portable devices, such as Bluetooth headsets, Precise AR/VR glasses, and other lithium-ion powered accesso- Up to 5% Current Regulation and 0.5% Voltage ries. It minimizes component size and heat. Regulation Battery-protection features include: low-voltage prequalifi- Safe cation, charge fault timer, die temperature monitoring, and JEITA Battery Temperature Monitor battery temperature monitoring. The battery temperature Over/Undervoltage Protection, Safety Timers, monitoring adjusts the charge current and termination Temperature Regulation voltage for safe use of secondary lithium-ion batteries. USB Friendly The IC accepts either a general DC input or USB. It has Flexible programmable automatic input-current limiting to protect Programmable Voltage/Current upstream charging sources such as USB. 2 Status/Interrupts Through I C 2 Charge parameters are easily adjustable through an I C Automatic Input Current Limit interface. Charge is terminated based on user-selectable 2 I C Interface minimum current level. Charge status is provided to the Input Current Limit (100mA to 1500mA) application processor through an interrupt pin. Fast-Charge/Termination Current (250mA to The IC is available in a space-saving, 20-bump, 2.18mm 1550mA) x 1.62mm WLP package. Charge Voltage (4.1V, 4.15V, 4.2V, 4.35V) Termination Enable Applications +22V Absolute Maximum Input Voltage Rating USB Charging Up to 7.5V Maximum Operating Input Voltage Smartphones 5V USB/Safeout LDO for USB PHY Bluetooth Headsets 2.3A GSM RF Test Mode (Factory Testing) AR/VR Glasses Charge Current to Voltage Conversion (V ) for ICHG Hearables Baseband ADC Wearables Reverse Battery Leakage Protection Portable Devices Input/Output Overvoltage Protection Interrupt Status Output Ordering Information and Simplified Applications Circuit appear at end of data sheet. The Bluetooth word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of such marks by Maxim is under license. 19-6110 Rev 2 8/18MAX8971 Industry s Smallest 1.55A 1-Cell Li+ DC-DC Charger TABLE OF CONTENTS General Description ............................................................................ 1 Applications .................................................................................. 1 Benefits and Features .......................................................................... 1 Absolute Maximum Ratings ...................................................................... 5 Package Thermal Characteristics ................................................................. 5 Electrical Characteristics ........................................................................ 5 Typical Operating Characteristics ................................................................ 10 Bump Configuration ........................................................................... 15 Bump Description............................................................................. 15 Detailed Description........................................................................... 17 DC InputFast-Hysteretic Step-Down Regulator 17 Soft-Start 17 PVL and AVL . 17 Thermistor Input (THM) . 17 Thermal Foldback . 18 Charger States . 18 Charger-Disabled State 21 Dead-Battery State . 21 Dead-Battery + Prequalification State . 21 Prequalification State 21 Fast-Charge Constant-Current State 21 Fast-Charge Constant Voltage State 21 Top-Off State 21 Done State 21 Timer Fault State . 22 Overvoltage and Protection . 22 Automatic Input Current Limit Protection . 22 V Charging Current Monitor . 23 ICHG SAFEOUT . 23 JEITA Description . 23 Maxim Model Gauge M3 Support . 23 Factory-Mode GSM Test Mode Support 23 Maxim Integrated 2 www.maximintegrated.com