AAT3683IOQ-4.2-3-T1

AAT3683 1A Linear Li-Ion Battery Charger General Description The AAT3683 BatteryManager is a highly integrated single-cell lithium-ion / polymer (Li-Ion) battery charger that operates from a USB port or an AC adapter input up to an input voltage of 6.5V. The AAT3683 precisely regulates battery charge voltage and current for 4.2V Li-Ion battery cells. The battery charging current can be set by an external resistor up to 1A. Digital Thermal Loop Control maintains the maximum possible battery charging current for the given set of input to output power dissipation and ambient temperature conditions. Battery charge state is continuously monitored for fault conditions. In the event of an over-current, over-voltage, short-circuit, or over-temperature condition, the device will shut down automatically, thus protecting the charging device, control system, and the battery under charge. A status monitor output pin is provided to indicate the battery charge status by directly driving an external LED. An open-drain power source detection output is provided to report the power supply status. The AAT3683 is available in the Pb-free, thermallyenhanced, space-saving 2.2x2.2mm 10-pin STDFN (AAT3683-2 and -3) and 16-pin QFN33 (AAT3683-4) packages and is specified for operation over the -40°C to +85°C temperature range. Features • • • • BatteryManager™ • • • • • • • • • • • • • • USB or AC Adapter Input Programmable from 100mA to 1A 4.0V to 6.5V Input Voltage Range High Level of Integration with Internal: — Charging Device — Reverse Blocking Diode — Current Sensing Digital Thermal Regulation Charge Current Programming (ISET) Charge Termination Current Programming (TERM) Charge Timer (CT) Battery Temperature Sensing (TS) TS Pin Open Detection Automatic Recharge Sequencing Automatic Trickle Charge for Battery PreConditioning (no trickle charge option available) Full Battery Charge Auto Turn-Off / Sleep Mode / Charge Termination 1µA Max. Shutdown Current Over-Voltage and Over-Current Protection Emergency Thermal Protection Power On Reset and Soft Start 2.2x2.2mm STDFN-10 (AAT3863-2 and -3) and QFN33-16 (AAT3683-4) Packages Applications • • • • • Bluetooth Headsets, Headphones, Accessories Cellular Phones Digital Still Cameras MP3, Portable Music, and Portable Media Players Personal Data Assistants (PDAs) and Handheld Computers Other Li-Ion Battery-Powered Devices Typical Application • ENABLE EN ENABLE BATT+ BAT CBAT TERM EN BATT+ BAT CBAT RT TERM VIN C IN IN VIN C IN IN BATT BATTR TERM BATT - AAT3683-2 STAT ADPP# CT CT GND TS ISET AAT3683-4 STAT1 R TERM TEMP TS ISET GND R SET TEMP STAT2 CT R SET Battery Pack CT Battery Pack 3683.2007.06.1.0 1 AAT3683 1A Linear Li-Ion Battery Charger Pin Descriptions Pin AAT3683-2, AAT3683-3 AAT3683-4 Name STAT STAT1 TERM GND CT ADPP# STAT2 TS BAT IN ISET EN N/C Type O O I Function Charge status pin, open drain. Charge status pin, open drain. Charge termination current programming input pin (internal default 10% termination current if TERM is open). Ground. 1 n/a 2 3 4 5 n/a 6 7 8 9 10 n/a EP n/a 16 2 3 4 n/a 5 7 6 15 11 12 1, 8, 9, 10, 13, 14 EP I O O I/O O I I I Charge timer programming input pin (no timer if grounded). Input supply power-good status pin, open drain. Charge status pin, open drain. Battery temperature sense pin. (Leave this TS pin open to disable this function in AAT3683-2). Connect to Li-Ion battery. Input from USB port/AC adapter connector. Charge current programming input pin. Active high enable pin (with internal pull-down). Not connected. Exposed paddle (bottom); connect to ground as closely as possible to the device. Pin Configuration AAT3683-2, AAT3683-3 STDFN2.2x2.2-10 (Top View) AAT3683-4 QFN33-16 (Top View) N/C N/C IN STAT1 16 15 14 13 STAT TERM GND CT ADPP# 1 2 3 4 5 10 8 8 7 6 EN ISET IN BAT TS N/C TERM GND CT 1 2 3 4 5 6 7 8 12 11 10 9 EN ISET N/C N/C N/C TS BAT STAT2 3683.2007.06.1.0 2 AAT3683 1A Linear Li-Ion Battery Charger AAT3683 Feature Options Product AAT3683-2 AAT3683-3 AAT3683-4 Battery Temperature Sense For Use With 10kΩ NTC Thermistor For Use With Any Thermistor For Use With Any Thermistor Status Indicator Display 1 LED 1 LED 2 LEDs Absolute Maximum Ratings1 Symbol VIN VN TJ TLEAD Description IN Continuous BAT, STAT, ADPP#, EN, ISET, TS, STAT1, STAT2 Operating Junction Temperature Range Maximum Soldering Temperature (at Leads) Value -0.3 to 7.5 -0.3 to VIN + 0.3 -40 to 150 300 Units V V °C °C Thermal Information2 Symbol θJA PD Description Thermal Resistance Maximum Power Dissipation (TA = 25°C) STDFN2.2x2.2-10 QFN33-16 STDFN2.2x2.2-10 QFN33-16 Value 50 50 2 2 Units °C/W W 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on an FR4 board. 3683.2007.06.1.0 3 AAT3683 1A Linear Li-Ion Battery Charger Electrical Characteristics VIN = 5V, TA = -25°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Symbol Description Conditions Min 4.0 3 150 VIN > VUVLO Charge Current = 100mA VBAT = 4.25V, EN = GND VBAT = 4V, IN Pin Open 4.158 60 0.3 0.4 0.4 4.20 0.5 (Option available for no trickle charge) 2.5 2.6 VBAT_EOC - 0.1 100 -12.5 2 Constant Current Mode, VBAT = 3.6V RTERM = 13.3KΩ TERM Pin Open RTERM = 13.3KΩ, ICH_CC ≥ 800mA 5 5 8 800 0.2 10 10 10 V % ICH_CC % ICH_CC % 1000 12.5 2.7 110 1 1 2 4.242 Typ Max 6.5 4 Units V V mV mV mA µA µA V % V V Operation VIN Input Voltage Range Under-Voltage Lockout Threshold VUVLO UVLO Hysteresis VADPP_TH Adapter Present Indicator Threshold Voltage, VIN - VBAT IOP Operating Current ISHUTDOWN Shutdown Current IBAT Leakage Current from BAT Pin Voltage Regulation VBAT_EOC End of Charge Accuracy ΔVBAT_EOC/ End of Charge Tolerance VBAT_EOC VMIN VRCH Preconditioning Voltage Threshold Battery Recharge Voltage Threshold Rising Edge Current Regulation ICC_RANGE Charge Current Programmable Range ICH_CC Constant Current Mode Charge Current VISET ISET Pin Voltage KISET VTERM ICH_TRK ICH_TERM Charge Current Set Factor: ICH_CC/IISET TERM Pin Voltage Trickle-Charge Current Charge Termination Threshold Current VBAT = 3.6V mA % V 15 15 12 4 3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Electrical Characteristics VIN = 5V, TA = -25°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Symbol Description Conditions VIN = 5V 1.6 STAT Pin Sinks 4mA ADPP# Pin Sinks 4mA 4.4 105 25 3 3 75 331 25 2.39 25 30 60 115 85 100 140 15 0.4 0.2 8 0.2 8 Min Typ 0.5 Max 0.7 Units Ω V V V mA V mA V %ICH_CC Minute Hour Hour µA mV V mV %VIN %VIN ºC ºC ºC ºC Charging Devices RDS(ON) Charging Transistor On Resistance Logic Control / Protection VEN(H) Input High Threshold VEN(L) Input Low Threshold VSTAT Output Low Voltage ISTAT STAT Pin Current Sink Capability VADDP# Output Low Voltage IADPP# ADDP# Pin Current Sink Capability VOVP Over-Voltage Protection Threshold IOCP Over-Current Protection Threshold TK Trickle Timeout Trickle and Constant Current Mode TC Timeout TV Constant Voltage Mode Timeout ITS Current Source from TS Pin TS1 TS2 VTS1 VTS2 TLOOP_IN TLOOP_OUT TREG TSHDN TS Hot Temperature Fault TS Cold Temperature Fault High Temperature Threshold Low Temperature Threshold Thermal Loop Entering Threshold Thermal Loop Exiting Threshold Thermal Loop Regulation Over-Temperature Shutdown CT = 0.1µF, VIN = 5V CT = 0.1µF, VIN = 5V CT = 0.1µF, VIN = 5V AAT3683-2 Only Threshold, AAT3683-2 Only Hysteresis, AAT3683-2 Only Threshold, AAT3683-2 Only Hysteresis, AAT3683-2 Only AAT3683-3, AAT3683-4 Only AAT3683-3, AAT3683-4 Only 69 316 2.30 29.1 58.2 81 346 2.48 30.9 61.8 Threshold Hysteresis 3683.2007.06.1.0 5 AAT3683 1A Linear Li-Ion Battery Charger Typical Characteristics Constant Charging Current vs. Set Resistor Values CC Mode Charge Current (mA) 10000 1200 1000 1000 800 600 400 Charging Current vs. Battery Voltage RSET = 1.58k RSET = 2k RSET = 3.24k RSET = 8.06k 200 10 1 10 100 0 2.5 100 ICH (mA) 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4. 3 RSET (kΩ) VBAT (V) End of Charge Regulation Tolerance vs. Supply Voltage (VBAT_EOC = 4.2V) ΔVBAT_EOC/VBAT_EOC (%) 0.10 0.08 0.05 0.03 0.00 -0.03 -0.05 -0.08 -0.10 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 End of Charge Voltage vs. Temperature 4.220 4.210 VEOC (V) 4.200 4.190 4.180 -50 -25 0 25 50 75 100 Supply Voltage (V) Temperature (°C) Preconditioning Charge Current vs. Supply Voltage 120 100 2.7 Preconditioning Voltage Threshold vs. Temperature 2.65 2.6 RSET = 1.58k RSET = 2k VMIN (V) 5 5.5 6 6.5 ICH_TRK (mA) 80 60 40 20 0 4 RSET = 3.24k RSET = 8.06k 2.55 2.5 2.45 2.4 -40 4.5 -15 10 35 60 85 Output Current (mA) Temperature (°C) 6 3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Typical Characteristics Preconditioning Charge Current vs. Temperature (RSET = 8.06k; ICH_CC = 200mA) 23 4.14 4.12 Battery Recharge Voltage Threshold vs. Temperature Preconditioning Charge Current (mA) 22 21 20 19 18 17 -40 VRCH (V) 4.10 4.08 4.06 4.04 -15 10 35 60 85 -40 -15 10 35 60 85 Temperature (°C) Temperature (°C) Constant Charging Current vs. Supply Voltage (RSET = 1.58KΩ) Constant Charging Current (mA) Temperature Sense Output Current vs. Temperature (AAT3683-2 Only) 78.0 1100 VBAT = 3.3V 1000 76.0 ITS (µA) 6.0 6.5 74.0 72.0 70.0 68.0 -40 900 VBAT = 3.5V VBAT = 3.9V 800 700 4.0 4.5 5.0 5.5 -15 10 35 60 85 VIN (V) Temperature (°C) Temperature Sense Too Hot Threshold vs. Temperature (AAT3683-2 Only) Temperature Sense Threshold Voltage - TS1 (V) Temperature Sense Too Cold Threshold vs. Temperature (AAT3683-2 Only) Temperature Sense Threshold Voltage- TS2 (V) 2.42 2.41 2.40 2.39 2.38 2.37 -40 -15 10 35 60 85 0.345 0.340 0.335 0.330 0.325 0.320 -40 -15 10 35 60 85 Temperature (°C) Temperature (°C) 3683.2007.06.1.0 7 AAT3683 1A Linear Li-Ion Battery Charger Typical Characteristics Operating Current vs. ISET Resistor 1.6 1.4 1 0.9 0.8 Shutdown Current vs. Supply Voltage ISHUTDOWN (µA) 1.2 Constant Current Mode 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 IOP (mA) 1.0 0.8 0.6 0.4 0.2 0.0 1 10 100 1000 Preconditioning Mode 85°C 25°C -40°C 4 4.5 5 5.5 6 6.5 RSET (kΩ) VIN (V) Counter Timeout vs. Temperature (CT = 0.1µF) CT Pin Capacitance vs. Counter Timeout 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Preconditioning + Constant Current Timeout or Constant Voltage Timeout Preconditioning Timeout Counter Timeout (%) 0.10 0.05 0.00 -0.05 -0.10 -40 Capacitance (µF) -15 10 35 60 85 0 1 2 3 4 5 Temperature (°C) Time (hours) Termination Current to Constant Current Ratio (%) vs. Termination Resistance 50% 40% 700 800 750 Charging Transistor On Resistance vs. Supply Voltage 85°C ICH_TERM/ICH_CC (%) RDS(ON) (mΩ) 30% 20% 10% 0% 0 10 20 30 40 50 60 650 600 550 500 450 400 3.6 3.9 4.2 4.5 4.8 5.1 25°C ITERM Resistance (kΩ) VIN (V) 8 3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Typical Characteristics Input High Threshold vs. Supply Voltage 1.1 1.0 1.1 Input Low Threshold vs. Supply Voltage -40°C VEN(L) (V) 1.0 VEN(H) (V) -40°C 0.9 0.9 0.8 0.7 0.6 4.0 25°C 85°C 25°C 85°C 0.8 0.7 0.6 4.5 5.0 5.5 6.0 6.5 4.0 4.5 5.0 5.5 6.0 6.5 Supply Voltage (V) Supply Voltage (V) 3683.2007.06.1.0 9 AAT3683 1A Linear Li-Ion Battery Charger Functional Block Diagram Reverse Blocking IN Current Compare CV/ Precharge BAT ISET Constant Current Charge Control UVLO ADPP# (3683-2/-3 only) Power Detection OverTemp. Protect Thermal Loop Battery OV Protection 75μA (3683-2 only) TS IC Enable Window Comparator Charge Status Watchdog Timer STAT (3683-2/-3 only) STAT1 (3683-4 only) STAT2 (3683-4 only) EN CT GND Functional Description The AAT3683 is a high performance battery charger designed to charge single-cell lithium-ion or lithium-polymer batteries with up to 1A of current from an external power source. It is a stand-alone charging solution, with just one external component required for complete functionality. The AAT3683 precisely regulates battery charge voltage and current for 4.2V lithium-ion/polymer battery cells with constant current level being programmed up to 1A for rapid charging applications. The charge termination current can be programmed by an external resistor. The AAT3683 is rated for operation from -40°C to +85°C. In the event of operating ambient temperatures exceeding the power dissipation abilities of the device package for a given constant current charge level, the charge control will enter into thermal limit. 10 AAT3683-2 and -3 provide one status monitor output pin (STAT) by directly driving one external LED to indicate the battery charging state. AAT3683-4 provides two status pins to indicate the battery charging state. Device junction temperature and charge state are fully monitored for fault conditions. In the event of an over-voltage or over-temperature failure, the device will automatically shut down, protecting the charging device, control system, and the battery under charge. During battery charging, the device temperature will rise. In some cases with adapter (ADP) charging, the power dissipation in the device may causethe junction temperature to rise to close to its thermal shutdown threshold. In the event of an internal over-temperature condition caused by excessive ambient operating temperature or excessive power dissipation condition, the AAT3683 enables a digi3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger tally controlled thermal loop system that will reduce the charging current to prevent the device from thermal shutdown. The digital thermal loop will maintain the maximum possible battery charging current for the given set of input to output power dissipation and ambient temperature conditions. The digital thermal loop control is dynamic in the sense that it will continue to adjust the battery charging current as operating conditions change. The digital thermal loop will reset and resume normal operation when the power dissipation or overtemperature conditions are removed. battery voltage is below the preconditioning voltage threshold, VMIN, then the AAT3683 begins preconditioning the battery cell (trickle charging) by charging at 10% of the programmed constant current. For example, if the programmed current is 500mA, then the preconditioning mode (trickle charge) current is 50mA. Battery cell preconditioning (trickle charging) is a safety precaution for deeply discharged cells and will also reduce the power dissipation in the internal series pass MOSFET when the input-output voltage differential is at the greatest potential. Constant Current Charging Battery cell preconditioning continues until the battery voltage reaches the preconditioning voltage threshold, VMIN. At this point, the AAT3683 begins constant current charging. The current level for this mode is programmed using a single resistor from the ISET pin to ground. Programmed current can be set at a minimum 100mA up to a maximum of 1A. Constant Voltage Charging Constant current charging will continue until such time that the battery voltage reaches the voltage regulation point, VBAT_EOC. When the battery voltage reaches VBAT_EOC, the AAT3683 will transition to constant voltage mode. The regulation voltage is factory programmed to a nominal 4.2V and will continue charging until the charge termination current is reached. Battery Charging Operation Figure 1 illustrates the entire battery charging profile or operation, which consists of three phases: 1. Preconditioning (Trickle) Charge 2. Constant Current Charge 3. Constant Voltage Charge Battery Preconditioning Battery charging commences only after the AAT3683 checks several conditions in order to maintain a safe charging environment. The input supply must be above the minimum operating voltage (VUVLO) and the enable pin must be high. When the battery is connected to the BAT pin, the AAT3683 checks the condition of the battery and determines which charging mode to apply. If the Preconditioning Trickle Charge Phase Charge Complete Voltage Regulated Current I = Max CC Constant Current Charge Phase Constant Voltage Charge Phase Constant Current Mode Voltage Threshold Trickle Charge and Termination Threshold I = CC / 10 Figure 1: Current vs. Voltage Profile During Charging Phases. 3683.2007.06.1.0 11 AAT3683 1A Linear Li-Ion Battery Charger System Operation Flow Chart Enable Power On Reset No Yes Power Input Voltage VIN > VUVLO Enable Yes Shut Down Yes Fault Conditions Monitoring OV, OT, VTS1 < TS < V TS2 Expired Charge Timer Control No Thermal Loop Thermal Loop Current Current Reduction in Reduction in ADP C.C. Mode Charging Mode Preconditioning Test VMIN > VBAT Yes Preconditioning (Trickle Charge) Yes No No No Recharge Test VRCH > VBAT Yes Current Phase Test VIN > VBAT_EOC Yes Constant Current Charge Mode Device Thermal Loop Monitor TJ > 115° C No Voltage Phase Test IBAT > ITERM Yes Constant Voltage Charge Mode No Charge Completed 12 3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Application Information Adapter or USB Power Input Constant current charge levels up to 1A may be programmed by the user when powered from a sufficient input power source. The AAT3683 will operate from the adapter input over a 4.0V to 6.5V range. The constant current mode fast charge current for the adapter input is set by the RSET resistor connected between ISET and ground. Refer to Table 4 for recommended RSET values for a desired constant current charge level. Adapter Input Charge Inhibit and Resume The AAT3683 has a UVLO and power on reset feature so that if the input supply to the ADP pin drops below the UVLO threshold, the charger will suspend charging and shut down. When power is reapplied to the IN pin or the UVLO condition recovers, the system charge control will assess the state of charge on the battery cell and will automatically resume charging in the appropriate mode for the condition of the battery. controls the system charge level; therefore, the AAT3683 will always provide the highest level of constant current in the fast charge mode possible for any given ambient temperature condition. Enable / Disable The AAT3683 provides an enable function to control the charger IC on and off. The enable (EN) pin is internally pulled down. When pulled to a logic high level, AAT3683 is enabled. When left open or pulled to a logic low level, the AAT3683 will be shut down. Charging will be halted regardless of the battery voltage or charging state. When the device is re-enabled, the charge control circuit will automatically reset and resume charging functions with the appropriate charging mode based on the battery charge state and measured cell voltage on the BAT pin. Programming Charge Current The constant current mode charge level is user programmed with a set resistor placed between the ISET pin and ground. The accuracy of the constant charge current, as well as the preconditioning trickle charge current, is dominated by the tolerance of the set resistor used. For this reason, a 1% tolerance metal film resistor is recommended for the set resistor function. The constant charge current levels from 100mA to 1A may be set by selecting the appropriate resistor value from Table 1. Constant Charging Current (mA) 100 200 300 400 500 600 700 800 900 1000 Set Resistor Value (kΩ) 16.2 8.06 5.36 4.02 3.24 2.67 2.26 2 1.78 1.58 Digital Thermal Loop Control Due to the integrated nature of the linear charging control pass device for the adapter mode, a special thermal loop control system has been employed to maximize charging current under all operation conditions. The thermal management system measures the internal circuit die temperature and reduces the fast charge current when the device exceeds a preset internal temperature control threshold. Once the thermal loop control becomes active, the fast charge current is initially reduced by a factor of 0.44. The initial thermal loop current can be estimated by the following equation: ITLOOP = ICH_CC · 0.44 The thermal loop control re-evaluates the circuit die temperature every three seconds and adjusts the fast charge current back up in small steps to the full fast charge current level or until an equilibrium current is discovered and maximized for the given ambient temperature condition. The thermal loop Table 1: RSET Values. 3683.2007.06.1.0 13 AAT3683 1A Linear Li-Ion Battery Charger 10000 Charge Status Output The AAT3683 provides battery charge status via a status pin (AAT3683-4 provides battery charge status via two status pins). This pin is internally connected to an N-channel open-drain MOSFET, which can be used drive an external LED. The status pin can indicate the following conditions (AAT3683-2, AAT3683-3): 1 10 100 ICH_CC (mA) 1000 100 10 RSET (kΩ) Event Description No battery charging activity Battery charging via adapter or USB port Charging completed STATUS OFF ON OFF Figure 2: Constant Charging Current vs. Set Resistor Values. Programmable Charge Termination Current The charge termination current ICH_TERM can be programmed by connecting a resistor from TERM to GND: Table 2: LED Status Indicator (AAT3683-2/AAT3683-3). The status pins can indicate the following conditions (AAT3683-4): Event Description STAT1 STAT2 ICH_TERM = 15µA · RTERM · ICH_CC 2V If the TERM pin is left open, the termination current will set to 10% of the constant charging current as the default value. When the charge current drops to the defaulted 10% of the programmed charge current level or programmed terminated current in the constant voltage mode, the device terminates charging and goes into a sleep state. The charger will remain in this sleep state until the battery voltage decreases to a level below the battery recharge voltage threshold (VRCH). Consuming very low current in sleep state, the AAT3683 minimizes battery drain when it is not charging. This feature is particularly useful in applications where the input supply level may fall below the battery charge or under-voltage lockout level. In such cases where the AAT3683 input voltage drops, the device will enter sleep state and automatically resume charging once the input supply has recovered from the fault condition. Charge enabled without battery FLASH1 FLASH1 Battery charging ON OFF Charge completed OFF ON Fault OFF OFF Table 3: LEDs Status Indicator. (AAT3683-4). The LED should be biased with as little current as necessary to create reasonable illumination; therefore, a ballast resistor should be placed between the LED cathode and the STAT pin. LED current consumption will add to the overall thermal power budget for the device package, hence it is good to keep the LED drive current to a minimum. 2mA should be sufficient to drive most low-cost green or red LEDs. It is not recommended to exceed 8mA for driving an individual status LED. 1. Flashing rate depends on output capacitance. 14 \3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger The required ballast resistor values can be estimated using the following formula: The CT pin is driven by a constant current source and will provide a linear response to increases in the timing capacitor value. Thus, if the timing capacitor were to be doubled from the nominal 0.1µF value, the time-out periods would be doubled. If the programmable watchdog timer function is not needed, it can be disabled by terminating the CT pin to ground. The CT pin should not be left floating or un-terminated, as this will cause errors in the internal timing control circuit. The constant current provided to charge the timing capacitor is very small, and this pin is susceptible to noise and changes in capacitance value. Therefore, the timing capacitor should be physically located on the printed circuit board layout as close as possible to the CT pin. Since the accuracy of the internal timer is dominated by the capacitance value, a 10% tolerance or better ceramic capacitor is recommended. Ceramic capacitor materials, such as X7R and X5R types, are a good choice for this application. Over-Voltage Protection An over-voltage event is defined as a condition where the voltage on the BAT pin exceeds the maximum battery charge voltage and is set by the overvoltage protection threshold (VOVP). If an over-voltage condition occurs, the AAT3683 charge control will shut down the device until the voltage on the BAT pin drops below VOVP. The AAT3683 will resume normal charging operation after the overvoltage condition is removed. During an over-voltage event, the STAT LEDs (3683-4 only) will report a system fault. Over-Temperature Shutdown The AAT3683 has a thermal protection control circuit which will shut down charging functions should the internal die temperature exceed the preset thermal limit threshold. Once the internal die temperature falls below the thermal limit, normal operation will resume the previous charging state. Battery Temperature Fault Monitoring In the event of a battery over-temperature condition, the charge control will turn off the internal pass device and report a battery temperature fault on the DATA pin function. The STAT LEDs will also display a system fault. After the system recovers from a temperature fault, the device will resume charging operation. RBALLAST = (VIN - VF(LED)) ILED Example: RBALLAST = (5.0V - 2.0V) = 1.5kΩ 2mA Note: Red LED forward voltage (VF) is typically 2.0V @ 2mA. Protection Circuitry Programmable Watchdog Timer The AAT3683 contains a watchdog timing circuit to shut down charging functions in the event of a defective battery cell not accepting a charge over a preset period of time. Typically, a 0.1µF ceramic capacitor is connected between the CT pin and ground. When a 0.1µF ceramic capacitor is used, the device will time out a shutdown condition if the trickle charge mode exceeds 25 minutes and a combined trickle charge plus constant current mode of 3 hours. When the device transitions to the constant voltage mode, the timing counter is reset and will time out after an additional 3 hours if the charge current does not drop to the charge termination level. The 3683-4 has a battery fault detector, which, when used in conjunction with a 0.1µF capacitor on the CT pin, outputs a 1Hz signal with 50% duty cycle at the STAT1 pin in the event of a timeout while in the trickle charge mode. Mode Trickle Charge (TC) Time Out Trickle Charge (TC) + Constant Current (CC) Mode Time Out Constant Voltage (VC) Mode Time Out Time 25 minutes 3 hours 3 hours Table 4: Summary for a 0.1µF Ceramic Capacitor Used for the Timing Capacitor. 3683.2007.06.1.0 15 AAT3683 1A Linear Li-Ion Battery Charger The AAT3683-2 checks battery temperature before starting the charge cycle, as well as during all stages of charging. This is accomplished by monitoring the voltage at the TS pin. This system is intended for use with negative temperature coefficient thermistors (NTC) which are typically integrated into the battery package. Most of the commonly used NTC thermistors in battery packs are approximately 10kΩ at room temperature (25°C). The TS pin (3683-2 only) has been specifically designed to source 75µA of current to the thermistor. The voltage on the TS pin resulting from the resistive load should stay within a window of 331mV to 2.39V. If the battery becomes too hot during charging due to an internal fault or excessive constant charge current, the thermistor will heat up and reduce in value, pulling the TS pin voltage lower than the TS1 threshold, and the AAT3683-2 will stop charging until the condition is removed, when charging will be resumed. If the use of the TS pin function is not required by the system, it should be terminated to ground using a 10kΩ resistor. Alternatively, on the AAT3683-2, the TS pin may be left open. For AAT3683-3 and -4, the internal battery temperature sensing system is comprised of two comparators which establish a voltage window for safe operation. The thresholds for the TS operating window are bounded by the TS1 and TS2 specifications. Referring to the electrical characteristics table in this datasheet, the TS1 threshold = 0.30 · VIN and the TS2 threshold = 0.60 · VIN. VIN Thermal Considerations The AAT3683 is offered in two packages (STDFN2.2x2.2-10 and QFN33-16) both of which can provide up to 2W of power dissipation when properly bonded to a printed circuit board and have a maximum thermal resistance of 50°C/W. Many considerations should be taken into account when designing the printed circuit board layout, as well as the placement of the charger IC package in proximity to other heat generating devices in a given application design. The ambient temperature around the charger IC will also have an effect on the thermal limits of a battery charging application. The maximum limits that can be expected for a given ambient condition can be estimated by the following discussion. First, the maximum power dissipation for a given situation should be calculated: PD(MAX) = Where: (TJ - TA) θJA PD(MAX) = Maximum Power Dissipation (W) θJA TJ TA = Package Thermal Resistance (°C/W) = Thermal Loop Entering Threshold (ºC) [115ºC] = Ambient Temperature (°C) Figure 4 shows the relationship of maximum power dissipation and ambient temperature of AAT3683. IN AAT3683-3 and -4 0 .60x VIN 2.5 2 TS Battery Cold Fault PD(MAX) (W) 1.5 1 0.5 0 Battery Pack Battery Hot Fault x V IN 0 25 50 75 10 0 TA (°C) Figure 3: AAT3683-3 and -4 Battery Temperature Sense Circuit. Figure 4: Maximum Power Dissipation Before Entering Thermal Loop. 16 \3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Next, the power dissipation can be calculated by the following equation: Capacitor Selection Input Capacitor In general, it is good design practice to place a decoupling capacitor between the IN pin and GND. An input capacitor in the range of 1µF to 22µF is recommended. If the source supply is unregulated, it may be necessary to increase the capacitance to keep the input voltage above the under-voltage lockout threshold during device enable and when battery charging is initiated. If the AAT3683 adapter input is to be used in a system with an external power supply source, such as a typical AC-to-DC wall adapter, then a CIN capacitor in the range of 10µF should be used. A larger input capacitor in this application will minimize switching or power transient effects when the power supply is "hot plugged" in. Output Capacitor The AAT3683 only requires a 1µF ceramic capacitor on the BAT pin to maintain circuit stability. This value should be increased to 10µF or more if the battery connection is made any distance from the charger output. If the AAT3683 is to be used in applications where the battery can be removed from the charger, such as with desktop charging cradles, an output capacitor greater than 10µF may be required to prevent the device from cycling on and off when no battery is present. PD = [(VIN - VBAT) · ICH + (VIN · IOP)] Where: PD = Total Power Dissipation by the Device VIN = Input Voltage VBAT = Battery Voltage as Seen at the BAT Pin ICH IOP = Constant Charge Current Programmed for the Application = Quiescent Current Consumed by the Charger IC for Normal Operation [0.3mA] By substitution, we can derive the maximum charge current before reaching the thermal limit condition (thermal loop). The maximum charge current is the key factor when designing battery charger applications. ICH(MAX) = (PD(MAX) - VIN · IOP) VIN - VBAT (TJ - TA) - V · I IN OP θJA ICH(MAX) = VIN - VBAT In general, the worst condition is the greatest voltage drop across the charger IC, when battery voltage is charged up to the preconditioning voltage threshold and before entering thermal loop regulation. Figure 5 shows the maximum charge current in different ambient temperatures. 1000 800 Printed Circuit Board Layout Considerations For the best results, it is recommended to physically place the battery pack as close as possible to the AAT3683 BAT pin. To minimize voltage drops on the PCB, keep the high current carrying traces adequately wide. When designing with >500mA charging current system, a multilayer PCB design is highly recommended. Putting thermal vias on the thermal pad design will effectively transfer heat from the top metal layer of the PCB to the inner or bottom layers. The number of thermal vias will depend on the application and power dissipation. Refer to the AAT3683 evaluation board for a good layout example. TA = 45°C TA = 25°C ICC_MAX (mA) 600 400 200 0 4.25 TA = 85°C 4.5 4.75 TA = 60°C 5 5.25 5.5 5.75 6 6.25 6.5 6.75 VIN (V) Figure 5: Maximum Charging Current Before the Digital Thermal Loop Becomes Active. 3683.2007.06.1.0 17 AAT3683 1A Linear Li-Ion Battery Charger Figure 6: AAT3683-2 Evaluation Board Top Side Layout. Figure 7: AAT3683-2 Evaluation Board Middle Layer. Figure 8: AAT3683-2 Evaluation Board Bottom Side Layout. JP2 D1 GRN LED R3 1.5k R2 13.3k VIN VBAT Enable D2 RED LED R4 1.5k STDFN2.2x2.2-10 1 2 3 4 5 JP1 STAT EN TERM ISET GND IN CT BAT ADPP# TS U1 AAT3683-2 10 9 8 7 6 C3 0.1μF R5 R1 10K 1.58k C2 10μF C1 10μF Figure 9: AAT3683-2 Evaluation Board Schematic. 18 3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Figure 10: AAT3683-3 Evaluation Board Top Side Layout. Figure 11: AAT3683-3 Evaluation Board Middle Layer. Figure 12: AAT3683-3 Evaluation Board Bottom Side Layout. JP2 D2 RED LED D1 GRN LED R3 1.5k R4 1.5k R2 13.3k 1 2 3 4 5 VIN R5 10K VBAT Enable STDFN2.2x2.2-10 JP1 10 9 8 7 6 STAT TERM GND CT ADPP# U1 EN ISET IN BAT TS AAT3683-3 C3 0.1μF R6 R1 10K 1.58k C2 10μF C1 10μF Figure 13: AAT3683-3 Evaluation Board Schematic. 3683.2007.06.1.0 19 AAT3683 1A Linear Li-Ion Battery Charger Figure 14: AAT3683-4 Evaluation Board Top Side Layout. Figure 15: AAT3683-4 Evaluation Board Middle Layer. Figure 16: AAT3683-4 Evaluation Board Bottom Side Layout. VIN JP2 D1 R3 1.5k GRN LED AAT3683-4 U1 16 15 14 13 QFN33-16 JP1 Enable STAT1 IN N/C N/C C3 0.1μF R4 1.5k 5678 D2 STAT2 BAT TS N/C R2 13.3k 1 2 3 4 N/C TERM GND CT EN ISET N/C N/C 12 11 10 9 R5 10K R1 1.58k VBAT RED LED R6 10K C2 10μF Figure 17: AAT3683-4 Evaluation Board Schematic. 20 3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Component U1 R1 R2 R3, R4 R5 C1, C2 C3 JP1 D1 D2 Part# AAT3683IOQ-4.2-2 Chip Resistor Chip Resistor Chip Resistor Chip Resistor ECJ-1VB0J106M GRM188R71C104KA01 PRPN401PAEN CMD15-21VGC/TR8 CMD15-21SRC/TR8 Description 1A Linear Li-Ion Battery Charger, 2.2x2.2mm STDFN-10 Package 1.58KΩ, 1%, 1/4W 0603 13.3KΩ, 1%, 1/4W 0603 1.5KΩ, 5%, 1/4W 0402 10KΩ, 1%, 1/4W 0603 CER 10μF 6.3V 10% X5R 0603 CER 0.1μF 6.3V 10% X7R 0603 Conn. Header, 2mm zip Green LED 1206 Red LED 1206 Manufacturer AnalogicTech Vishay Vishay Vishay Vishay Panansonic Murata Sullins Electronics Chicago Miniature Lamp Chicago Miniature Lamp Table 5: AAT3683-2 Evaluation Board Bill of Materials. Component U1 R1 R2 R3, R4 R5, R6 C1, C2 C3 JP1 D1 D2 Part# AAT3683IOQ-4.2-3 Chip Resistor Chip Resistor Chip Resistor Chip Resistor ECJ-1VB0J106M GRM188R71C104KA01 PRPN401PAEN CMD15-21VGC/TR8 CMD15-21SRC/TR8 Description 1A Linear Li-Ion Battery Charger; 2.2x2.2mm STDFN-10 Package 1.582KΩ, 1%, 1/4W; 0603 13.3KΩ, 1%, 1/4W; 0603 1.5KΩ, 5%, 1/4W; 0402 10KΩ, 1%, 1/4W; 0603 CER 10μF 6.3V 10% X5R 0603 CER 0.1μF 6.3V 10% X7R 0603 Conn. Header, 2mm zip Green LED; 1206 Red LED; 1206 Manufacturer AnalogicTech Vishay Vishay Vishay Vishay Panansonic Murata Sullins Electronics Chicago Miniature Lamp Chicago Miniature Lamp Table 6: AAT3683-3 Evaluation Board Bill of Materials. Component U1 R1 R2 R3, R4 R5, R6 C1, C2 C3 JP1 D1 D2 Part# AAT3683IVN-4.2-4 Chip Resistor Chip Resistor Chip Resistor Chip Resistor GRM21BR61A106KE19 GRM188R71C104KA01 PRPN401PAEN CMD15-21VGC/TR8 CMD15-21SRC/TR8 Description 1A Linear Li-Ion Battery Charger, QFN33-16 Package 1.58KΩ, 1%, 1/4W 0603 13.3KΩ, 1%, 1/4W 0603 1.5KΩ, 5%, 1/4W 0402 10KΩ, 1%, 1/4W 0603 CER 10μF 10V 10% X5R 0805 CER 0.1μF 6.3V 10% X7R 0603 Conn. Header, 2mm zip Green LED 1206 Red LED 1206 Manufacturer AnalogicTech Vishay Vishay Vishay Vishay Murata Murata Sullins Electronics Chicago Miniature Lamp Chicago Miniature Lamp Table 7: AAT3683-4 Evaluation Board Bill of Materials. 3683.2007.06.1.0 21 AAT3683 1A Linear Li-Ion Battery Charger Ordering Information Package STDFN-10 (2.2x2.2mm) STDFN-10 (2.2x2.2mm) QFN33-16 Marking1 WIXYY WJXYY WKXYY Part Number (Tape and Reel)2 AAT3683IOQ-4.2-2-T1 AAT3683IOQ-4.2-3-T1 AAT3683IVN-4.2-4-T1 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 22 3683.2007.06.1.0 AAT3683 1A Linear Li-Ion Battery Charger Package Information1 STDFN2.2x2.2-10 Index Area 2.200 ± 0.050 1.000 ± 0.050 Detail "A" Top View 2.200 ± 0.050 1.710 ± 0.050 Bottom View 0.350 ± 0.050 0.550 ± 0.050 0.025 ± 0.025 0.152 REF Side View Pin 1 Indicator (optional) R0.200 Detail "A" All dimensions in millimeters. 1. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection. 3683.2007.06.1.0 0.210 ± 0.050 0.400 BSC 23 AAT3683 1A Linear Li-Ion Battery Charger QFN33-16 Pin 1 Identification 1 0.230 ± 0.050 0.500 ± 0.050 5 3.000 ± 0.050 C0.3 0.400 ± 0.100 Pin 1 Dot By Marking 13 9 3.000 ± 0.050 1.250 ± 0.050 Top View Bottom View 1.250 ± 0.050 0.214 ± 0.036 0.025 ± 0.025 Side View All dimensions in millimeters. © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Except as provided in AnalogicTech’s terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737- 4600 Fax (408) 737- 4611 24 3683.2007.06.1.0 0.900 ± 0.100