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Document overview
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Technical content
Features
Input voltage range: 4.3 to 6.0 V Up to 2.0 A charging current capability 1.5 MHz PWM/linear charger Over 90% full rate charging efficiency Integrated switching device “No BAT” detect Safety timer Integrated sense resistor Built-in reverse blocking feature Battery preconditioning/constant-voltage/constant-current charging mode Programmable end-of-charging current 1% constant-voltage mode regulation Built-in programmable charging timer Charging current indication pin Over-voltage, over-current, and over-temperature protection Battery over-temperature protection Power-on reset and soft-start Space-saving TDFN (14-pin, 3 mm 3 mm) package (MSL1, 260 ºC per JEDEC J-STD-020) Skyworks Green™ products are compliant with all applicable legislation and are halogen-free. For additional information, refer to Skyworks Definition of Green™ , document number SQ04-0074.
Description
The BatteryManager™ AAT3620 is an ideal solution for charging high-capacity Li+ batteries. The AAT3620 can supply up to 2.0 A charging current with minimal thermal impact to mobile systems with features such as color display, camera with flash, organizer, video, etc., that requires battery capacity to keep pace with the power requirements. The AAT3620 is a pulse-width modulation (PWM) switch mode/linear charger with high charging efficiency at the full constant-current (fast charge) rate. Based on a 1.5 MHz PWM step-down buck converter, the AAT3620 PWM switch mode controls the constant-current charging mode up to 2.0 A, and automatically switches to linear mode charging during the battery conditioning low level current and the light load end-of-charging current termination region. The full charging rate and the end-of- charging current can be programmed with separate external resistors. A shared charging current indication pin is available for a Coulomb counter. Battery charger temperature and charging state are fully monitored for fault conditions. In the event of an over-current, over-voltage, short-circuit or over-temperature failure, the device automatically shuts down. Two status monitor output pins are provided to indicate the battery charging status and power source status through two display LEDs. The AAT3620 also has a no- battery detection feature, "No BAT", which requires the safety timer. The AAT3620 is available in a thermally enhanced, space-saving 14-pin, 3 mm 3 mm TDFN package. A typical application circuit is shown in Figure 1. The pin configurations are shown in Figure 2. Signal pin assignments and functional pin descriptions are provided in Table 1.
Table 1. AAT3620 Signal Descriptions 1 VPIN In Adapter power input. 2 P GND Ground Power ground. 3 GND Ground Analog ground connection. 5 EN In Charging enable input, active high, with internal pull-up (to VPIN). 6 ISET In Connect R SET resistor to pin to set constant-current charging current. 7 CT In/Out Timer pin. Connect timing ca pacitor here for charging timer function. 8 STAT2 Out Battery charging status 2 indicator pin to drive an LED, open-drain. 9 STAT1 Out Battery charging status 1 indicator pin to drive an LED, open-drain. set to 200 mA default termination current. 11 TS In/Out Battery pack temperature sensing input. To disable TS function, pull up to V CC through 10 k resistor. 12 BAT Out Battery positive terminal connecting pin. 13 CS In Return pin for inductor for internal current sensing. 14 LX In/Out Switching node. include a large exposed copper pad under the package for thermal dissipation (see package outline). specifications are provided in Table 4. Table 2. AAT3620 Absolute Maximum Ratings (Note 1) parameters set at or below their nominal value. Exceeding any of the limits listed may result in permanent damage to the device. Table 3. AAT3620 Thermal Information Note 1: Mounted on an FR4 board. Note 2: Derate 2.7 mW/ C above 25 C ambient temperature. or equipment, which can discharge without detection. Industry-standard ESD precautions should be used at all times.
Table 4. AAT3620 Electrical Specifications (1 of 2) (Note 1)
1 A to 2 A 15% I CH_CC +15 %
above or below the ITERM range.
Figure 11. AAT3620 Functional Block Diagram when the charging current drops below 300 mA. A functional block diagram is shown in Figure 11.
termination current set pin also monitors the charging current. differential is at its highest. programmed using a resistor from the ISET pin to ground. reaches the output charging voltage regulation point VBAT_REG. programmed end-of-charging termination current. charging in the most appropriate mode. pin is cycled high while VIN is greater than VIN_SLEEP.
2 A can be set by selecting the appropriate resistor value from
Table 5. ISET Resistor vs Constant-Current Mode Current
Figure 13. System Operation Flowchart for the Battery Charger
recovered from the fault condition. when the charging current voltage level = 1 A/V. can indicate the conditions shown in Table 6. should be placed between the LED cathode and the STAT pins. Note: red LED forward voltage (VF) is typically 2.0 V @ 2 mA.
2.6 V (typical) before the safety timer expires, the cell is
assumed to be damaged and the charging cycle terminates. timer, the charging cycle proceeds into fast charging. There are three time-out periods, as shown in Table 7. Table 6. LED Status Indicator STAT1 and STAT2
Table 7. Summary for a 0.1 F Ceramic Capacitor Used for the
1 Hz signal with 50% duty cycle at the STAT2 pin in the event of
a time-out while in trickle charging mode. F value, the time-out periods are doubled. The AAT3620 has the no-battery detection function, "No-BAT". consecutive times, the battery is considered disconnected. F for every 100 nF on the CT pin. charging operation after the over-voltage condition is removed. operation resumes the previous charging state. 0.30 VCC and the VTS2 threshold = 0.60 VCC. range, with Beta constant values in the 3000 to 5000 range.
should be tied to VCC using a 10 k resistor.
0.6 VCC
0.3 VCC
Figure 14. AAT3620 Battery Temperature Sense Circuit achievable under all operating parameters.
- The maximum power dissipation for a given situation
- The power dissipation for both the linear charging mode
- The power dissipation for the linear charging mode can
DATA SHEET • AAT3620 SINGLE CELL LI+ SWITCH MODE BATTERY CHARGER Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com 14 October 21, 2013 • Skyworks Proprietary Information • Pro ducts and Product Information are Subject to Change Without Notice • 201904D PD(MAX) = total power dissipation by the device VPIN = input voltage VBAT = battery voltage as seen at the BAT pin ICH_BC = battery conditioning charging current programmed for the application IQOP = quiescent current consumed by the charger IC for normal operation [5 mA]. By substitution, the maximum charging current before reaching the thermal limit condition (thermal loop) can be derived. The maximum charging current is the key factor when designing battery charger applications: BATPIN QOPPIN)MAX(D CH_BC(MAX) VV IVPI BATIN QOPPIN JA AJ CH(MAX) VV IVTT I 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 entering Constant- Current (CC) switching charging mode. Example Worst-Case Power Dissipation The worst-case power dissipation can be calculated using the lowest battery voltage level when the charger enters CC charging mode and the charging current is set to 2 A: I CH_CC = 2 A VPIN =6 V RDS(ON)HS = 0.3 RDS(ON)LS = 0.25 tSW = 5 10-9 IQOP = 0.005 A fSW = 1.5 106 TA = 85 °C JA = 50 °C/W V8.2V625.0V8.23.0A2p D(MAX) W213.1pD(MAX) )C(213.15085TJ(MAX) )C(65.145TJ(MAX) For the linear mode: IQOP = 0.005 A VPIN = 6 V VBAT = 2 V ICH_BC = 0.2 A W83.0pD(MAX) PCB Layout Guidance When laying out the PC board, follow the guidelines below to ensure proper operation of the AAT3620: Solder the exposed pad EP reliably to PGND/AGND and multilayer GND. Connect the exposed thermal pad to board ground plane and pins 2 and 3. Include a large exposed copper pad under the package in the ground plane with vias to all board layers for thermal dissipation. Keep the power traces, including GND traces, the LX traces and the VIN trace short, direct and wide to allow large current flow. Make the L1 connection to the LX and CS pins as short as possible. Use several via pads when routing between layers. Connect the input capacitors (C1, C4, and C5) as close as possible to VPIN (pin 1), VCC (pin 4) and GND/PGND (pins 2, 3) to get good power filtering. It is recommended to add a resistor R7 between VIN and VCC to create a low-pass RC filter on VCC. Connect the output capacitors C2, C6 and C7 and inductor L1 as close as possible, and do not route any signal lines under the inductor. Keep the resistance of the trace from the load return to the PGND (pin 2) to a minimum. This helps to minimize any error in DC regulation due to differences in the potential of the internal signal ground and the power ground. Evaluation Board Description The AAT3620 Evaluation Board is used to test the performance of the AAT3620. An Evaluation Board schematic diagram is provided in Figure 15. Layer details for the Evaluation Board are shown in Figure 16. The Evaluation Board has additional components for easy evaluation; the actual bill of materials required for the system is shown in Table 8.
Package Information
in Figure 17. Tape and reel dimensions are shown in Figure 18.
0.203 REF
t0060All dimensions are in millimeters. Figure 17. AAT3620 14-pin TDFN Package Dimensions Figure 18. AAT3620 Tape and Reel Dimensions
DATA SHEET • AAT3620 SINGLE CELL LI+ SWITCH MODE BATTERY CHARGER Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com 201904D • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • October 21, 2013 17
Ordering Information
Model Name Part Marking (Note 2) Manufacturing Part Number (Note 1) Evaluation Board Part Number AAT3620 Single Cell Li+ Switch Mode Battery Charger 6WXYY AAT3620IWO-4.2-T1 AAT3620IWO-4.2-EVB Note 1: XYY = assembly and date code. Note 2: Sample stock is generally held on part numbers listed in BOLD. Copyright © 2012-2013 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes. No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale. THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or environmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper use or sale. Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters. Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.