Figure 1: Fully Assembled AAT4621EV Evaluation Kit.

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1 General Description The AAT4621EV evaluation kit is a fully assembled and tested circuit board designed to demonstrate the features of the AAT4621 SmartSwitch supercapacitor charger. The board accepts a 3V to 5.5V supply and provides the power control loop, reverse blocking and temperature foldback required to charge high capacitance supercapacitors for applications such as PC cards and other portable high current requirements. Numerous test points are available to connect input/ output control signals for system integration and to ease measurements of key parameters. Jumpers are included to enable/disable the device or to connect to a logic level for on/off control. The AAT4621 uses very few external components. The current limit is set by two external resistors allowing a ±10% current limit accuracy over the normal operating temperature range. The switch can be controlled from either of the two enable inputs and in the off condition will block currents in both directions. The AAT4621 also incorporates a System READY (RDY) function which can advise the system that the super capacitor is fully charged and ready for use. Adjustable hysteresis is provided with the addition of an external resistor. The AAT4621EV kit is shipped with the AAT4621IWO and a 550mF CAPXX supercapacitor installed and the device is programmed to the high charge current limit level. Features V IN Range: 3.0V to 5.5V Dual Independent Current Limits 75mA to 1200mA Reverse Current Blocking Protection Power Loop with Temp Foldback 50mΩ Typical R DS(ON) at 3V Figure 1: Fully Assembled AAT4621EV Evaluation Kit. 1

2 PCB Layout Figure 2: Top Assembly Layer. Figure 3: Bottom Assembly Layer. P2 P4 GND EN IL IN J2 TB1 EN IU J1 C1 10µF EN IU EN IL R1 D1 1.5K LED RED U1 EN IU RDY 1 EN IL RHYS 2 GND ISETU 3 ISETL AAT 4621_TDFN33-14 RHYS ISETU ISETL RDY C2 10µF + + P1 RDY R2 200K R3 1M SC1 0.55F R4 120K R5 47.5K R6 47.5K P3 TB2 P5 GND Figure 4: AAT4621EV Kit Schematic. 2

3 Quick Start Guide Recommended Equipment Variable power supply: 0V to 2A DVM voltmeter DVM ammeter Load resistors or electronic load up to 1.2A Current probes 4-channel oscilloscope Quick Start Operating Procedure The following procedure should be used when operating the AAT4621EV for the first time to verify correct operation. Use Figure 5 as a guide. 1. Preset the power supply to 3.7V. 2. Turn off the power supply. Do not turn the power supply on until all connections have been made. 3. Connect the power supply positive lead to the positive connector on a DVM set as a ammeter. 4. Connect the negative connector on the ammeter to the pin connector of the AAT4621EV. 5. Connect the power supply negative lead to the GND pin connector near the pin connector on the AAT4621EV. 6. Make sure J1 and J2 are connected to Pins 1 to 2 initially to disable the AAT Turn on the power supply. 8. Remove the jumper on J1 and J2 and set to Pins 2 and 3; verify that the V voltage level is 3.7V using the voltmeter. 9. Reinstall J1 and check enable/disable function, no load and shutdown current. Figure 5: Measurement Setup to Verify Correct AAT4621EV Operation. 3

4 Detailed Description Detailed Operating Procedure The following procedures are provided as optional steps that can be used to test the AAT4621 device functions using the AAT4621EV evaluation kit. Use Figure 6 as a guide. Check Ramp Rate and Charge Current Connect a 3.7V supply to the pin and an electronic load set to CC mode on V. Connect voltage probes to, V, and RDY. Connect a current probe on the input wire. Measure rise time on the supercapacitor and the input charge current value. Monitor the RDY pin, which goes low when the SC is fully charged. See Figure 7 for the 800mA charge current example. Set the ISETU to Pins 1 and 2 to lower the charge current to 96mA and see Figure 8. Check Startup with Pulsed Load Remove the RDY voltage probe and connect a current probe to the output load wire. Set the CC load to a transient current pulse and measure V voltage droop as shown in Figures 9 and 10. Check GSM Performance Set the CC load to transient and set the current to 1.1A for 1.1ms and then 0A for 4.612ms to simulate a GPRS Transmit, 2-slot signal as shown in Figure 9. Current draw from supercapacitor = 1.1A for 1.154ms every 4.615ms. 2 slots/frame = 2X 577ms or 1.154ms / 4.615ms = 25% duty cycle. This represents a power amplifier power consumption = +33dBm (50% efficiency) = 2W / 50% = 4W and current during transmit is 4W / 3.75V = 1.1A, Average current: 1.1A x 25% = 275mA. Figure 6: Measurement Setup to Verify Detailed AAT4621EV Operation. 4

5 Channel 4: V CC (1V/div) Channel 3: V (1V/div) Channel 1: RDY (1V/div) Channel 2: I IN (500mA/div) Channel 4: V CC (1V/div) Channel 3: V (1V/div) Channel 1: RDY (1V/div) Channel 2: I IN (500mA/div) Time (500µs/div) Figure 7: Startup Waveform No Load, 800mA Current Limit. Time (5s/div) Figure 8: Startup Waveform No Load, 96mA Current Limit. Channel 4: V CC (1V/div) Channel 3: V (1V/div) Channel 1: I (500mA/div) Channel 2: I IN (500mA/div) Channel 4: V CC (1V/div) Channel 3: V (50mV/div, AC Coupled) Channel 2: I IN (500mA/div) Channel 1: I (500mA/div) Time (1s/div) Figure 9: Startup Waveform Pulsed 1.2A Load. Time (1ms/div) Figure 10: GPRS Transmit 2-Slot Ch975, 33dBm. Designator Description Default Setting Additional Current ENIU (J1) Enable (ENIU Input) Pins 2 and 3 enable the AAT4621 and upper current limit ENIL (J2) Enable (ENIL Input) Pins 2 and 3 enable AAT4621 and lower current limit (TB1 or P2) Input Voltage Connect to 3.7V GND (TB1 or P4) VIN ground connections Connect to ground (TB2 or P3) Output Voltage Connect to load GND (TB2 or P5) V ground connections Connect to ground 1.282mA both pins 2-3 connected 0.97µA both pins 1-2 connected 1.282mA both pins 2-3 connected 0.97µA both pins 1-2 connected Table 1: Jumper Settings, Test Points and Connector Locations on PCB Shown in Figures 2, 3 and 4. 5

6 Figure 11: Top Layer Routing. Figure 12: Bottom Layer Routing/Ground Plane. 6

7 Item Description Manufacturer Quantity Reference 1 Resistor, 1.5kΩ, 5%, SMT, R1 2 Resistor, 200kΩ, 5%, SMT, R2 RHYS 3 Resistor, 1MΩ, 5%, SMT, 0402 FengHua, Neohm, Yageo, Vishay 1 R3 ISETU 4 Resistor, 120kΩ, 5%, SMT, R4 ISETL 5 Resistor, 47.5kΩ, 5%, SMT, R5, R6 6 SuperCapacitor, HS206, 550mF / 5.5V, 85mW ESR, SMT, 39mm x 17mm CAPXX 1 SC1 7 Capacitor, Ceramic, 10µF / 16V, X7R, SMT, 1206 AVX, Panasonic, Kemet, Murata, TDK, FengHua, Taiyo Yuden 2 C1, C2 8 LED, CMD15-21SRC/TR8, Super RED, SMT, 1206 CML Innovative Technologies 1 D1 9 IC, AAT4621IWO-T1, TDFN33-14 Skyworks 1 U1 10 Pin Connector VIN, V, LDO, 5 Molex, Hirose GND (3) mm, 3 Pin Jumper 2 J , Conn. Term Block 2.54MM 2POS Phoenix Contact 2 TB1, TB2 Table 2: Component List (BOM). Manufacturer Web Sites Distributor Web Sites

8 Ordering Information Part Number I IN IC Package Pins Kit Contents AAT4621EV-TDFN 800/96mA TDFN AAT4621EV User Guide Fully Assembled 2 Layer PCB Copyright 2012 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 WITH 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, IN- CLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITH 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 are incorporated by reference. 8