AAT3684IOQ-4.2-1-T1

PRODUCT DATASHEET AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger Features • USB or AC Adapter System Power Charger ▪ Programmable from 15mA to 500mA • 4.0V ~ 6.5V Input Voltage Range • High Level of Integration with Internal: ▪ Charging Device ▪ Reverse Blocking Diode General Description The AAT3684 BatteryManager is an integrated single cell lithium-ion/polymer battery charger IC, designed to operate from a DC power source or USB port up to an input voltage of 6.5V. It requires just one external component. The AAT3684 precisely regulates battery charge voltage and current for 4.2V (4.375V option) lithium-ion/polymer battery cells. When charged from an AC adapter or USB port, the battery charging current can be set by an external resistor up to 500mA. Battery charge state is continuously monitored for fault conditions. In the event of an over-voltage, short-circuit, or over-temperature failure, the device will automatically shut down, 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. The AAT3684 is available in a Pb-free, thermally enhanced, space-saving 10-pin 2.2x2.2mm STDFN package and is specified for operation over the -40°C to +85°C temperature range. • Automatic Current Sensing • Automatic Recharge Sequencing • Full Battery Charge Auto Turn Off/Sleep Mode/Charge Termination • Shutdown Current VUVLO Yes Shut Down Yes Fault Conditions Monitoring OV, OT Charge Control No (AAT3684) No (AAT3684-1) Preconditioning Test V MIN > VBAT Yes Preconditioning (Trickle Charge) No No Recharge Test V RCH > VBAT Yes Current Phase Test VBAT_EOC > VBAT Yes Constant Current Charge Mode No Voltage Phase Test IBAT > ITERM Yes Constant Voltage Charge Mode No Charge Completed 10 www.analogictech.com 3684.2007.12.1.2 PRODUCT DATASHEET AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger Nominal ICHARGE (mA) 500 450 400 350 300 250 200 150 100 50 40 30 20 15 Application Information Adapter or USB Power Input Constant current charge levels up to 500mA may be programmed by the user when powered from a sufficient input power source. The AAT3684 will operate from the adapter input over a 4.0V to 6.5V range. The constant current fast charge current for the adapter input is set by the RSET resistor connected between ISET and ground. Refer to Table 1 for recommended RSET values for a desired constant current charge level. Set Resistor Value (kΩ) 3.24 3.57 4.12 4.64 5.36 6.49 8.06 10.7 16.2 31.6 38.3 53.6 78.7 105 Adapter Input Charge Inhibit and Resume The AAT3684 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 re-applied to the ADP 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. Table 1: RSET Values. 1000 Enable / Disable The AAT3684 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, AAT3684 is enabled. When left open or pulled to a logic low level, the AAT3684 will be shut down and forced into the sleep state. 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. ICH (mA) 100 10 1 1 10 100 1000 RSET (kΩ) Figure 2: Constant Charging Current vs. Set Resistor Values. Protection Circuitry 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 over-voltage protection threshold (VOVP). If an over-voltage condition occurs, the AAT3684 charge control will shut down the device until voltage on the BAT pin drops below VOVP. The AAT3684 will resume normal charging operation after the over-voltage condition is removed. Programming Charge Current The fast charge constant current charge level is user programmed with a set resistor placed between the ISET pin and ground. The accuracy of the fast charge, 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. Fast charge constant current levels from 15mA to 500mA may be set by selecting the appropriate resistor value from Table 1. 3684.2007.12.1.2 www.analogictech.com 11 PRODUCT DATASHEET AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger Thermal Considerations The AAT3684 is offered in the STDFN2.2x2.2-10 package, which can provide up to 2W of power dissipation when it is properly bonded to a printed circuit board and has 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: Over-Temperature Shutdown The AAT3684 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, the normal operation will resume the previous charging state. Charge Status Output The AAT3684 provides battery charge status via a status pin. This pin is internally connected to an N-channel open drain MOSFET, which can be used to drive an external LED. The status pin can indicate the following conditions: Event Description No battery charging activity Battery charging via adapter or USB port Charging completed Status OFF ON OFF Table 2: LED Status Indicator. 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 lowcost green or red LEDs. It is not recommended to exceed 8mA for driving an individual status LED. The required ballast resistor values can be estimated using the following formulas: PD(MAX) = Where: (TJ(MAX) - TA) θJA PD(MAX) = Maximum Power Dissipation (W) θJA = Package Thermal Resistance (°C/W) TJ(MAX) = Maximum Device Junction Temperature (°C) [135°C] TA = Ambient Temperature (°C) Figure 3 shows the relationship of maximum power dissipation and ambient temperature of AAT3684. 3.00 2.50 PD(MAX) (mW) R 1= Example: (VADP - VF(LED)) ILED 2.00 1.50 1.00 0.50 0.00 R1 = (5.5V - 2.0V) = 1.75kΩ 2mA 0 20 40 60 80 100 Note: Red LED forward voltage (VF) is typically 2.0V @ 2mA. TA (°C) Figure 3: Maximum Power Dissipation. 12 www.analogictech.com 3684.2007.12.1.2 PRODUCT DATASHEET AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger Capacitor Selection Input Capacitor In general, it is good design practice to place a decoupling capacitor between the ADP 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 AAT3684 adapter input is to be used in a system with an external power supply source, such as a typical AC-toDC 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. Next, the power dissipation can be calculated by the following equation: PD = [(VIN - VBAT) · ICC + (VIN · IOP)] Where: PD VIN VBAT ICC IOP = = = = Total Power Dissipation by the Device Input Voltage Battery Voltage as Seen at the BAT Pin Constant Charge Current Programmed for the Application = Quiescent Current Consumed by the Charger IC for Normal Operation [0.5mA] By substitution, we can derive the maximum charge current before reaching the thermal limit condition (thermal cycling). The maximum charge current is the key factor when designing battery charger applications. Output Capacitor The AAT3684 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 AAT3684 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. ICC(MAX) = (PD(MAX) - VIN · IOP) VIN - VBAT (TJ(MAX) - TA) - V · I IN OP θJA ICC(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. Figure 4 shows the maximum charge current in different ambient temperatures. 500 450 400 350 300 250 200 150 100 50 0 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 6.75 Printed Circuit Board Layout Considerations For the best results, it is recommended to physically place the battery pack as close as possible to the AAT3684 BAT pin. To minimize voltage drops on the PCB, keep the high current carrying traces adequately wide. Refer to the AAT3684 evaluation board for a good layout example (see Figures 5 and 6). For better thermal enhancement, solder the exposed paddle of the IC onto the thermal landing of the PCB, where the thermal landing is connected to the ground plane. If heat is still an issue, multi-layer boards with dedicated ground planes are recommended. Adding more thermal vias on the thermal landing will also help transfer heat to the PCB effectively. Figure 7 illustrates the exploded view of the layout at the bottom of the IC. TA = 60°C TA = 45°C TA = 85°C ICC(MAX) (mA) VIN (V) Figure 4: Maximum Charging Current Before Thermal Cycling Becomes Active. 3684.2007.12.1.2 www.analogictech.com 13 PRODUCT DATASHEET AAT3684 AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger Figure 5: AAT3684 Evaluation Board Top Layer. Figure 6: AAT3684 Evaluation Board Bottom Layer. Figure 7: Exploded View of the Layout. 14 www.analogictech.com 3684.2007.12.1.2 PRODUCT DATASHEET AAT3684 AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger VIN(ADP) JP2 Enable C1 10μF JP1 D1 RED LED R1 1.5K STDFN2.2x2.2-10 1 2 3 4 5 VBAT N/C EN N/C ISET N/C BAT STAT N/C GND ADP U1 AAT3684 10 9 8 7 6 R2 8.06K C2 4.7μF C1 10μF 10V 10% X5R 0805 GRM21BR61A106KE19 C2 4.7μF 6.3V 10% X5R 0603 GRM188R60J475KE19 Figure 8: AAT3684 Evaluation Board Schematic. Component U1 R1 R2 C1 C2 JP1, JP2 LED1 Part Number AAT3684IOQ-T1 Chip Resistor Chip Resistor GRM21BR61A106KE19 GRM188R60J475KE19 PRPN401PAEN CMD15-21SRC/TR8 Description 500mA USB Port or AC Adapter Battery Charger; STDFN2.2x2.2-10 Package 1.5KΩ, 5%, 1/4W; 0603 8.06KΩ, 1%, 1/4W; 0603 CER 10μF 10V 10% X5R 0805 CER 4.7μF 6.3V 10% X5R 0603 Conn. Header, 2mm zip Red LED; 1206 Manufacturer AnalogicTech Vishay Vishay Murata Murata Sullins Electronics Chicago Miniature Lamp Table 3: AAT3684 Evaluation Board Bill of Materials. 3684.2007.12.1.2 www.analogictech.com 15 PRODUCT DATASHEET AAT3684 AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger Ordering Information Trickle Charge Yes No Package STDFN2.2x2.2-10 STDFN2.2x2.2-10 Marking1 TNXYY TXXYY Part Number (Tape and Reel)2 AAT3684IOQ-4.2-T1 AAT3684IOQ-4.2-1-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. 16 www.analogictech.com 3684.2007.12.1.2 PRODUCT DATASHEET AAT3684 AAT3684 BatteryManagerTM 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger Package Information 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. Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 © 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. 3684.2007.12.1.2 www.analogictech.com 0.210 ± 0.050 0.400 BSC 17