The MAX77301 is a JEITA-compliant* lithium-ion linear battery charger that operates from a USB port, a dedicated charger, or universal adapter. The IC provides automatic adapter-type detection and enumeration with a USB host or hub. The IC integrates independent battery charge switch, current sense circuit, MOSFET pass elements, thermal regulation circuitry, and eliminates the external reverse-blocking Schottky diode to create the simplest and smallest USB-compliant charging solution.The IC includes automated detection of charge adapter type, making it possible to distinguish USB 2.0 device, USB charger, dedicated charger devices as well as standard input adapters. See Table 2 in the full data sheet. When enumeration is enabled, the IC automatically negotiates with a USB host, making it possible to achieve the highest-charging current available from a USB 2.0 device or USB charger without processor intervention. The adapter type detection is compliant with USB 2.0 as well as battery charging Specification Revision 1.1.The IC controls the charging sequence for single-cell Li+ batteries from battery detection, prequalification, fast charge, top-off, and charge termination. Charging is controlled using constant current, constant voltage and constant die-temperature (CCCVCTj) regulation for safe operation under all conditions. The IC is also compliant with JEITA battery charging requirements.The Smart Power Selector™ feature makes the best use of limited USB or adapter power. Battery charge current is set independent of the input current limit. Power not used by the system charges the battery. The battery assists the input source when needed. System voltage is maintained by allowing the application to operate without a battery, a discharged battery, or a dead battery. Automatic input selection switches the system from battery to external power.The I²C interface provides full programmability of battery charge characteristics, input current limit, and protection features. This provides flexibility for use with a wide range of adapter and battery sizes.Other features include undervoltage lockout (UVLO), overvoltage protection (OVP), charge status flag, charge fault flag, input power-OK monitor, battery detection, JEITA-compliant charging, charge timer, 3.3V/10mA auxiliary output, and an external power-on switch.ApplicationsBluetooth Headsets, PDAs, and MP3 PlayersOther Portable Devices

The MAX1720x/MAX1721x are ultra-low power stand-alone fuel gauge ICs that implement the Maxim ModelGauge™ m5 algorithm without requiring host interaction for configuration. This feature makes the MAX1720x/MAX1721x excellent pack-side fuel gauges. The MAX17201/MAX17211 monitor a single cell pack. The MAX17205/MAX17215 monitor and balance a 2S or 3S pack or monitor a multiple-series cell pack.To prevent battery pack cloning, the ICs integrate SHA-256 authentication with a 160-bit secret key. Each IC incorporates a unique 64-bit ID.The ModelGauge™ m5 algorithm combines the short-term accuracy and linearity of a coulomb counter with the long-term stability of a voltage-based fuel gauge, along with temperature compensation to provide industry-leading fuel gauge accuracy. The IC automatically compensates for cell aging, temperature, and discharge rate, and provides accurate state of charge (SOC) in milliampere-hours (mAh) or percentage (%) over a wide range of operating conditions. As the battery approaches the critical region near empty, the ModelGauge m5 algorithm invokes a special error correction mechanism that eliminates any error. The ICs provide accurate estimation of time-to-empty and time-to-full, Cycle+™ age forecast, and three methods for reporting the age of the battery: reduction in capacity, increase in battery resistance, and cycle odometer.The ICs provide precision measurements of current, voltage, and temperature. Temperature of the battery pack is measured using an internal temperature measurement and up to two external thermistors supported by ratiometric measurements on auxiliary inputs. A Maxim 1-Wire® (MAX17211/MAX17215) or 2-wire I2C (MAX17201/MAX17205) interface provides access to data and control registers. The ICs are available in lead-free, 3mm × 3mm, 14-pin TDFN and 1.6mm × 2.4mm 15-bump WLP packages.Design Solution: Advanced Battery Management for the Rest of Us ›How to Prevent Battery Cloning Using the MAX17211EVKITApplicationsDigital Still and Video Camerase-ReadersHandheld Computers and TerminalsHandheld RadiosPortable Game PlayersPortable Medical EquipmentSmartphones and Tablets

The MAX20094/MAX20095 ICs combine a configurable constant-current/constant-voltage (CC/CV) battery charger with a high-efficiency synchronous boost controller to supply critical systems in the event the primary power source is lost. In addition, diagnostic features are available to check battery state-of-health (SOH) and IC functionality. Charging thresholds and the boost output voltage are configurable to support popular battery chemistries and a wide range of cell counts. To support system integration, the ICs have an I2C target port through which configuration and status bits can be accessed.Switching frequency of 2.2MHz also helps to reduce system cost by minimizing inductor size. The ICs also include a precision battery SOH check and have built-in functionality to minimize leakage current out of the backup battery (BUB).The MAX20094/MAX20095 are available in a 28-pin (5mm x 5mm) side-wettable TQFN package and are AECQ-100 qualified.ApplicationsAutomotive Telematics Battery BackupSingle or Multicell Battery-Backup Systems

The MAX14920/MAX14921 battery measurement analog front-end devices accurately sample cell voltages and provide level shifting for primary/secondary battery packs up to 16 cells/+65V (max). The MAX14920 monitors up to 12 cells, while the MAX14921 monitors up to 16 cells. Both devices simultaneously sample all cell voltages, allowing accurate state-of-charge and source-resistance determination. All cell voltages are level shifted to ground reference with unity gain, simplifying external ADC data conversion.The devices have a low-noise, low-offset amplifier that buffers differential voltages of up to +5V, allowing monitoring of all common lithium-ion (Li+) cell technologies. The resulting cell voltage error is ±0.5mV.The devices’ high accuracy make them ideal for monitoring cell chemistries with very flat discharge curves, such as lithium-metal phosphate.Passive-cell balancing is supported by external FET drivers. Integrated diagnostics in the devices allow open-wire detection and undervoltage/overvoltage alarms. The devices are controlled by a daisy-chainable SPI interface.The MAX14920 is available in a 64-pin (10mm x 10mm) TQFP package with an exposed pad. The MAX14921 is available in an 80-pin (12mm x 12mm) TQFP package. Both devices are specified over the -40°C to +85°C extended temperature range.Applicationse-Transportation Energy PacksEnergy Storage PacksIndustrial Battery Backup SystemsTelecom Battery Backup Systems

The MAX17048/MAX17049 ICs are tiny, micropower current fuel gauges for lithium-ion (Li+) batteries in handheld and portable equipment. The MAX17048 operates with a single lithium cell and the MAX17049 with two lithium cells in series.The ICs use the sophisticated Li+ battery-modeling algorithm ModelGauge™ to track the battery relative state-of-charge (SOC) continuously over widely varying charge and discharge conditions. The ModelGauge algorithm eliminates current-sense resistor and battery-learn cycles required in traditional fuel gauges. Temperature compensation is implemented using the system microcontroller.The ICs automatically detect when the battery enters a low-current state and switches into a low-power 3µA hibernate mode, while still providing accurate fuel gauging. The ICs automatically exit hibernate mode when the system returns to active state.On battery insertion, the ICs debounce initial voltage measurements to improve the initial SOC estimate, thus allowing them to be located on system side. SOC, voltage, and rate information is accessed using the I2C interface. The ICs are available in a tiny 0.9mm × 1.7mm, 8-bump wafer-level package (WLP), or a 2mm × 2mm, 8-pin TDFN package.ApplicationsBluetooth HeadsetsDigital Still, Video, and Action CamerasHandheld Computers and TerminalsHealth and Fitness MonitorsHome and Building Automation, SensorsMedical DevicesSmartphones, TabletsSmartwatches, WearablesWireless Speakers

The DS2438 remains in production, however, for new projects, we recommend ModelGauge m5 MAX17215 fuel gauge.The DS2438 smart battery monitor provides several functions that are desirable to carry in a battery pack: a means of tagging a battery pack with a unique serial number, a direct-to-digital temperature sensor which eliminates the need for thermistors in the battery pack, an A/D converter which measures the battery voltage and current, an integrated current accumulator which keeps a running total of all current going into and out of the battery, an elapsed time meter, and 40 bytes of nonvolatile EEPROM memory for storage of important parameters such as battery chemistry, battery capacity, charging methodology and assembly date. Information is sent to/from the DS2438 over a 1-Wire® interface, so that only one wire (and ground) needs to be connected from a central microprocessor to a DS2438. This means that battery packs need only have three output connectors: battery power, ground, and the 1-Wire interface.Because each DS2438 contains a unique silicon serial number, multiple DS2438s can exist on the same 1-Wire bus. This allows multiple battery packs to be charged or used in the system simultaneously.Applications for the smart battery monitor include portable computers, portable/cellular telephones, and handheld instrumentation battery packs in which it is critical to monitor real-time battery performance. Used in conjunction with a microcontroller in the host system, the DS2438 provides a complete smart battery pack solution that is fully chemistry-independent. The customization for a particular battery chemistry and capacity is realized in the code programmed into the microcontroller and DS2438 EEPROM, and only a software revision is necessary should a designer wish to change battery pack chemistry.ApplicationsCell PhonesDigital Still CamerasDigital Video CamerasPalmtops, Handy Terminals (incl. barcode)Pen Entry Palmtops, PDAs and OrganizersSmart Battery Packs/Chargers

The DS2438 remains in production, however, for new projects, we recommend ModelGauge m5 MAX17215 fuel gauge.The DS2438 smart battery monitor provides several functions that are desirable to carry in a battery pack: a means of tagging a battery pack with a unique serial number, a direct-to-digital temperature sensor which eliminates the need for thermistors in the battery pack, an A/D converter which measures the battery voltage and current, an integrated current accumulator which keeps a running total of all current going into and out of the battery, an elapsed time meter, and 40 bytes of nonvolatile EEPROM memory for storage of important parameters such as battery chemistry, battery capacity, charging methodology and assembly date. Information is sent to/from the DS2438 over a 1-Wire® interface, so that only one wire (and ground) needs to be connected from a central microprocessor to a DS2438. This means that battery packs need only have three output connectors: battery power, ground, and the 1-Wire interface.Because each DS2438 contains a unique silicon serial number, multiple DS2438s can exist on the same 1-Wire bus. This allows multiple battery packs to be charged or used in the system simultaneously.Applications for the smart battery monitor include portable computers, portable/cellular telephones, and handheld instrumentation battery packs in which it is critical to monitor real-time battery performance. Used in conjunction with a microcontroller in the host system, the DS2438 provides a complete smart battery pack solution that is fully chemistry-independent. The customization for a particular battery chemistry and capacity is realized in the code programmed into the microcontroller and DS2438 EEPROM, and only a software revision is necessary should a designer wish to change battery pack chemistry.ApplicationsCell PhonesDigital Still CamerasDigital Video CamerasPalmtops, Handy Terminals (incl. barcode)Pen Entry Palmtops, PDAs and OrganizersSmart Battery Packs/Chargers

The MAX1925/MAX1926 single-cell lithium-ion (Li+) switch-mode battery chargers use an external PMOS pass element step-down configuration. Charge current is programmable, and an external capacitor sets the maximum charge time.Additional features include automatic input power detection (active-low ACON output), logic-controlled enable, and temperature monitoring with an external thermistor. The MAX1925 disables charging for inputs greater than 6.1V, while the MAX1926 charges for inputs between 4.25V and 12V.The MAX1925/MAX1926 feature two precondition levels to restore near-dead cells. The devices source 4mA to a cell that is below 2V while sourcing C/10 to a cell between 2V and 3V. Full charge current is then applied above 3V. A active-low CHG output drives an LED to indicate charging (LED on) and fault conditions (LED blinking).The MAX1925/MAX1926 are available in a 12-pin 4mm x 4mm thin QFN package and are specified over the extended temperature range (-40°C to +85°C). An evaluation kit is available to speed design.ApplicationsCradle ChargersDigital Still CamerasPDAsSelf-Charging Battery Packs

The MAX1925/MAX1926 single-cell lithium-ion (Li+) switch-mode battery chargers use an external PMOS pass element step-down configuration. Charge current is programmable, and an external capacitor sets the maximum charge time.Additional features include automatic input power detection (active-low ACON output), logic-controlled enable, and temperature monitoring with an external thermistor. The MAX1925 disables charging for inputs greater than 6.1V, while the MAX1926 charges for inputs between 4.25V and 12V.The MAX1925/MAX1926 feature two precondition levels to restore near-dead cells. The devices source 4mA to a cell that is below 2V while sourcing C/10 to a cell between 2V and 3V. Full charge current is then applied above 3V. A active-low CHG output drives an LED to indicate charging (LED on) and fault conditions (LED blinking).The MAX1925/MAX1926 are available in a 12-pin 4mm x 4mm thin QFN package and are specified over the extended temperature range (-40°C to +85°C). An evaluation kit is available to speed design.ApplicationsCradle ChargersDigital Still CamerasPDAsSelf-Charging Battery Packs

The MAX20335 is a battery-charge-management solution ideal for low-power wearable applications. The device includes a linear battery charger with a smart power selector and several power-optimized peripherals. The MAX20335 features two ultra-low quiescent current buck regulators and three ultra-low quiescent current low-dropout (LDO) linear regulators, providing up to five regulated voltages, each with an ultra-low quiescent current, allows designers to minimize power consumption and extend battery life in 24/7 operation devices, such as those in the wearable market.The battery charger features a smart power selector that allows operation on a dead battery when connected to a power source. To avoid overloading a power adapter, the input current to the smart power selector is limited based on an I2C register setting. If the charger power source is unable to supply the entire system load, the smart power control circuit supplements the system load with current from the battery. The charger also supports temperature dependent charge currents.The two synchronous, high-efficiency step-down buck regulators feature a variable frequency mode for increased efficiency during light-load operation. The output voltage of these regulators can be programmed through I2C with the default preconfigured. The buck regulators cansupport dynamic voltage scaling to further improve system power consumption.The three configurable LDOs each have a dedicated input pin. Each LDO regulator output voltage can be programmed through I2C with the default preconfigured. The linear regulators can also be configured to operate as power switches that may be used to disconnect the quiescent load of the system peripherals.The MAX20335 features a programmable power controller that allows the device to be configured for applications that require the device be in a true-off, or always-on, state. The controller also provides a delayed reset signal and voltage sequencing.The MAX20335 is available in a 36-bump, 0.4mm pitch, 2.72mm x 2.47mm wafer-level package (WLP).ApplicationsFitness MonitorsRechargeable IoT devicesWearable Electronics