PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter General Description Features The AAT1218 is a general purpose DC/DC synchronous boost (step-up) converter providing a tightly regulated DC output voltage for continuous output currents up to 1A (minimum). The maximum peak current in the boost switch is limited to a value of 2A (minimum). Operating input voltage must be less than the output voltage and in the 0.5V to 5.5V range, making the device well suited to portable equipment and consumer appliances. * * * * * * * * * The boost output voltage is programmed from 2.5V to 5.5V with an external resistor divider. Optimized internal compensation provides fast transient response with no external components. Synchronous rectification eliminates the need for an external rectifier for output voltage less than 4.5V. Low on-resistance internal switches provide efficiency up to 95%, which minimizes losses and simplifies packaging and circuit board layout. An inductor, two resistors and two ceramic output capacitors are all that are required to implement a DC/DC boost solution. The switching frequency is internally set to 1.2MHz to minimize external filter size and optimize switching losses. * * * * * * * Integrated soft-start ensures minimal inrush current. The "anti-ring" circuit reduces stray EMI during light load, discontinuous operation. Input quiescient current is less than 400A at no load. * The device provides cycle-by-cycle current limit and overtemperature protection to prevent device over-stress. * * * * * * The AAT1218 is available in a Pb-free, 12-pin low profile TDFN33 package with rating from -40C to 85C. 2.5V to 5.5V Adjustable Output Voltage 0.5V Minimum Input Voltage 2% Output Accuracy No Schottky Diode Required (VOUT < 4.5V) Up to 95% Efficiency 400A Standby Current <1A Shutdown Current Integrated Soft-Start Circuitry Limits Inrush Current Constant Frequency 1.2MHz Operation Inductor Height <1.8mm Small Ceramic Capacitors Anti-ring Circuit Reduces EMI Current Mode Control Fast, Stable Transient Response No External Compensation Cycle-by-Cycle Current Limit Low Inrush Current with 0.7ms Soft-start Low Output Ripple: <80mVpp for all Loading Conditions (BW = 25MHz) Over-Temperature Protection Adjustable and Fixed Output Versions Available Delivers 1A to 5V Output from a Single Cell Li+ Battery Low-profile TDFN33-12 Package Applications DVD Players Hard Disk Drive MP3 Players PDA Portable Computers Smart Phones Typical Application V IN: 3.6V L1 2.2H V OUT: 5V @ 1A LX VIN: 3.6V AAT1218-1.2 EN FB COUT 44F (2x22F) 0805 CIN 22F 0805 PGND 1218.2009.12.1.4 OUT VIN AAT1218-5.0 GND VOUT: 5V @ 1A LX OUT VIN C IN 22F 0805 L1 2.2H R2 1.02M EN FB GND R3 324k COUT 44F (22F x2) 0805 PGND www.analogictech.com 1 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Pin Description Pin # Symbol 1 LX 2, 5 3 4 6, 7 NC VIN EN GND 8 FB 9. 10 11, 12 OUT PGND Description Switching node tied to drain of internal N-channel MOSFET and source of internal P-channel MOSFET. Connect this pin to the external power inductor. No connect. Input voltage for the controller. Input enable pin. Non-power signal ground pin. Feedback input pin. This pin is connected to an external resistor divider which determines the output voltage setpoint. Output pin; connected to the positive terminal of the output capacitor and to the external resistor divider. Power ground pin. Connect this pin directly to input and output capacitors. Pin Configuration TDFN33-12 (Top View) 2 LX 1 12 PGND N/C 2 11 PGND VIN 3 10 OUT EN 4 9 OUT N/C 5 8 FB GND 6 7 GND www.analogictech.com 1218.2009.12.1.4 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Absolute Maximum Ratings1 Symbol Description LX, VIN, EN, FB Voltage to PGND PGND Voltage to GND Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6.0 -0.3 to 0.3 -40 to 150 300 V V C C Value Units 2000 50 mW C/W Thermal Information Symbol PD JA Description Maximum Power Dissipation2 Maximum Thermal Resistance TDFN33-123 TDFN33-12 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 1.6mm thick FR4 circuit board. 3. Derate 25mW/C above 25C ambient temperature. 1218.2009.12.1.4 www.analogictech.com 3 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Electrical Characteristics VIN = 1.2V, VOUT = 3.3V, COUT = 44F, TA = 25C unless otherwise noted. Symbol VIN VOUT_RANGE VFB IQ FOSC DC ILIMIT TSS NMOS Leakage PMOS Leakage NMOS On-Resistance PMOS On-Resistance Description Conditions Minimum Start-Up Voltage Minimum Start-Up Voltage Loaded ILOAD = 1mA ILOAD = 300mA (Resistive) Operating Input Voltage Range TA = -40C to +85C 0.5 TA = -40C to +85C 2.5 1.164 Output Voltage Range Feedback Voltage Quiescient Current Switching, No Load Operation, Measured from VOUT Quiescient Current Device Disabled (Shut Down) Switching Frequency Minimum Operating Duty Cycle Maximum Operating Duty Cycle NMOS Current Limit Soft-Start Time NMOS Switch Leakage PMOS Switch Leakage NMOS Switch On-Resistance PMOS Switch On-Resistance VOUT Line Regulation VOUT Load Regulation VOUT(LINE_TRANSIENT) Line Transient Response1 VOUT(LOAD_TRANSIENT) Load Transient Response1 Min Typ Max Units 0.85 1.4 1 V V 1.200 VOUT 0.5 5.5 1.236 0.5 < VIN < VOUT - 0.5V, ILOAD = 0mA 300 700 A 0.5 < VIN < VOUT - 0.5V, VEN = 0 0.01 1 A 1.2 1.5 0 MHz % % A ms A A m m 0.95 TA = -40C to +85C VIN = 3.3V, VOUT = 5V, COUT = 10F VIN = 1.5 - (VOUT - 0.5), ILOAD = 0mA to 1000mA VIN = 1.5 - (VOUT - 0.5), ILOAD = 0mA to 1000mA VIN = 2.5V - 4.5V, VIN = 1V, dVIN/dt = 0.2V/s VIN = 2.5V, ILOAD = 50mA to 500mA, dILOAD/dt = 0.5A/s, CFF = 100pF 80 2.0 2.5 0.7 0.1 0.1 180 250 5.0 5.0 V V V 0.1 % 0.5 % -3 3 % VOUT -10 10 % VOUT 0.6 V EN VEN(L) VEN(H) IEN Logic Input Low Threshold for EN Logic Input High Threshold for EN Enable Input Low Current VOUT = 3.3V VOUT = 5.0V VIN = VOUT = 5.5V 0.85 1.0 -1.0 V 1.0 A 1. Specifications are guaranteed by design and characterization. 4 www.analogictech.com 1218.2009.12.1.4 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Typical Characteristics CIN = 22F, COUT = 44F; L = 2.2H; TA = 25C, unless otherwise noted. AAT1218 ISD vs. Temperature AAT1218 IQ vs. Temperature (VOUT = 5.5V, Measured From VOUT) 1 390 385 IQ_5.5V (A) ISD (A) 0.8 0.6 0.4 0.2 0 -40 380 375 370 365 -15 10 35 60 360 -40 85 -15 10 VEN(H) vs. Temperature 85 60 85 VEN(L) vs. Temperature (VOUT = 5.0V) (VOUT = 5V) 0.94 0.86 0.9 0.82 VEN(L) (V) VEN(H) (V) 60 Temperature (C) Temperature (C) 0.86 0.82 0.78 0.74 0.70 0.78 0.74 -40 35 -15 10 35 60 0.66 -40 85 -15 10 35 Temperature (C) Temperature (C) Maximum Load Current vs. VIN AAT1218 VFB vs. Temperature 1.236 10000 Load Current (mA) 1.227 VFB (V) 1.218 1.209 1.200 1.191 1.182 1.173 1.164 -40 -15 10 35 60 1000 100 85 VOUT = 3.3V VOUT = 5V 1.35 1.85 2.35 2.85 3.35 3.85 4.35 4.85 Input Voltage (V) Temperature (C) 1218.2009.12.1.4 10 0.85 www.analogictech.com 5 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Typical Characteristics CIN = 22F, COUT = 44F; L = 2.2H; TA = 25C, unless otherwise noted. Maximum Load Current at Startup vs. VIN AAT1218 3.3V Output Efficiency 10000 100 80 Efficiency (%) Load Current (mA) 90 1000 100 10 0.85 1.85 2.35 2.85 3.35 3.85 4.35 60 50 40 30 VIN = 1.2V VIN = 1.5V VIN = 1.8V VIN = 2.4V 20 VOUT = 3.3V VOUT = 5V 1.35 70 10 0 0.1 4.85 1 10 AAT1218 5.0V Output Efficiency AAT1218 5.0V Output Efficiency 100 100 90 90 80 70 60 50 40 30 VIN = 1.2V VIN = 1.5V VIN = 2.4V 20 10 0 0.1 1 10 100 1000 Efficiency (%) 80 Efficiency (%) 1000 ILOAD (mA) Input Voltage (V) 70 60 50 40 VIN = 3.0V VIN = 3.3V VIN = 3.6V VIN = 4.2V 30 20 10 0 0.1 1 ILOAD (mA) 10 100 1000 Load Transient Soft Start Waveform (VIN = 2.0V; VOUT = 3.3V; COUT = 44F; CFF = 100pF) (VIN = 1.5V; VOUT = 5V; Load = 100mA) VOUT (200mV/div) 3.3V VOUT (4V/div) 500mA ILOAD (0.25A/div) IIN (0.5A/div) 50mA 10000 ILOAD (mA) LX (4V/div) VEN (1V/div) Time (100s/div) 6 100 0 0 0 0 Time (200s/div) www.analogictech.com 1218.2009.12.1.4 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Typical Characteristics VIN = 3.6V, VOUT = 3.6V, CIN = 22F, COUT = 44F; L = 2.2H; TA = 25C, unless otherwise noted. VOUT (AC Coupled) (20mV/div) LX (2V/div) Anti-Ringing Operation Power Saving Mode Waveform (VIN = 3V; VOUT = 5V; Load = 10mA) (VIN = 3.6V; VOUT = 5V; Load = 5mA) IL (250mA/div) VIN (AC Coupled) (20mV/div) VOUT (AC Coupled) (20mV/div) 0 0 0 0 0 LX (2V/div) 0 Time (0.2s/div) Time (4s/div) PWM Mode Waveform (VIN = 3.6V; VOUT = 5V; Load = 1A) IL (1A/div) VIN (AC Coupled) (20mV/div) VOUT (AC Coupled) (20mV/div) LX (2V/div) 0 0 0 0 Time (0.4s/div) 1218.2009.12.1.4 www.analogictech.com 7 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Functional Block Diagram Soft Start VIN 1.4V-5.5V VIN L1 Slope Compensation Vss Start-Up Current Limit - LX MUX VOUT GOOD - 2.3V VOUT OUT Current Sense CIN COUT Antiringing Control To VIN Bandgap 1.2V + FB R1 R2 PWM Logic + Comp EA - - Enable Logic EN Shutdown Control Functional Description The AAT1218 is a synchronous step-up DC-DC converter. It utilizes internal MOSFETs to achieve high efficiency over the full load current range. It operates at a fixed switching frequency of 1.2MHz, and uses the slope compensated current mode architecture. The device can operate at 0.5V input after start up. The typical start-up voltage is 0.85V. Synchronous Rectification The AAT1218 integrates a synchronous rectifier to improve efficiency and eliminate the external rectifier diode if output voltage is lower than 4.5V. The synchronous rectifier is used to reduce conduction loss contributed by the forward voltage of the external rectifier 8 + Start-Up Oscillator PGND SHUTDOWN Oscillator 1.2MHz GND diode. It is implemented by a PMOS driven by a gate driver with break-before-make timing. When the output voltage is greater than 4.5V, an external rectifier diode is necessary for proper operation. Low Voltage Start-Up The AAT1218 can start up at supply voltages as low as 1V. During the start-up phase, the internal low voltage start-up circuitry controls the NMOS switch to soft-start the device. A comparator (VOUT GOOD Comp) monitors the output voltage. If VOUT exceeds 2.3V, the device exits start-up phase and enters normal operation mode. The internal circuitry power supply of the device is connected to VIN during start-up phase and automatically switches to VOUT during normal operation. www.analogictech.com 1218.2009.12.1.4 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Application Information Integrated Soft-Start During start-up, the AAT1218's integrated soft-start circuitry gradually increases the peak inductor current until it reaches normal operating value. The inrush current during start-up can thus be minimized. Current Mode PWM Control The AAT1218 is based on a slope compensated current mode control topology. It operates at a fixed frequency of 1.2MHz. At the beginning of each clock cycle, the main switch (NMOS) is turned on and the inductor current starts to ramp up. After the maximum duty cycle or if the sense current signal is equal to the error amplifier (EA) output, the main switch is turned off and the synchronous switch (PMOS) is turned on. This control scheme has intrinsic cycle-by-cycle current limiting, which can prevent the main switch from overstress and prevent saturation of the external inductor. Power Saving Mode At very light load, the AAT1218 automatically switches into Power Saving Mode to improve efficiency. In this mode, the PWM control will skip some pulses to maintain regulation. If load increases and output voltage drops, the device will automatically switch back to regular PWM mode and maintain regulation. Anti-ringing Control Anti-ringing circuitry is included to remove the high frequency ringing that appears on the LX pin when the inductor current decreases to zero. In this case, ringing on the LX pin is caused by energy stored in parasitics of the MOSFETs and the inductor. The anti-ringing circuitry clamps the voltage to battery voltage internally and thus dampens the ringing. Setting the Output Voltage An external resistor divider is used to set the output voltage. The output voltage of the switching regulator (VOUT) is determined by the following equation: R1 VOUT = 1.20V * 1 + R2 VOUT R1 () R2 () 3.3V 5.0V 1.02M 1.02M 576k 324k Table 1: Resistor Selection Example for Output Voltage Setting. Fixed output voltage devices are also available for 3.3V and 5V outputs. These devices integrate the feedback network into the die and can save two external resistors. Do not connect any component to the FB pin and leave it floating. Inductor Selection The AAT1218's high switching frequency of 1.2MHz allows for small surface mount inductors. For most designs, the AAT1218 operates with inductors of 2.2H to 10H depending on input/output voltage and load current. First determine the worst case VIN, VOUT, and IOUT. Then use the equation below to select the proper inductor value; assume the converter is operating in continuous current mode and is in steady state: VIN D=1- V OUT I IPEAK = IRMS + 2 Device Enable When EN is set logic high, the AAT1218 begins operation. If EN is set logic low, the device is goes into shutdown mode and consumes less than 1A current. After startup, the internal circuitry is supplied by VOUT during normal operation. However, if shutdown mode is enabled, the internal circuitry will again be supplied by the battery. 1218.2009.12.1.4 VIN * D I = L * f SW is the converter efficiency, IPEAK is the peak inductor current, I is the peak-peak inductor ripple current, IRMS is the RMS current of the inductor current. fsw is the switching frequency, L is the inductance value and D is the steady state duty cycle. www.analogictech.com 9 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Fit the proper L into the equations to meet the following criteria: 1. The DC current rating of the inductor must be higher than IPEAK to avoid magnetic saturation. Cored inductor devalues when core temperature increases, so verify the inductor of choice with its temperature characteristics in mind. 2. The inductor ripple current I is typically set for 20% to 40% of the peak inductor current. Higher inductance means less inductor ripple current; larger size inductors can handle more power. However, larger size inductors also have higher profiles and are more expensive. For optimum load transient and efficiency performance, low DCR inductors should be selected. Table 2 lists some surface mount inductors which are suitable for typical AAT1218 applications. Input Capacitor Select a 4.7F to 10F X7R or X5R ceramic capacitor for the input. The input capacitor provides a low impedance loop for the edges of pulsed current drawn by the AAT1218. Low ESR/ESL X7R and X5R ceramic capacitors are ideal for this function. To minimize stray inductance, the capacitor should be placed as close as possible to the IC. This keeps the high frequency content of the input current localized, minimizing EMI and input voltage ripple. Always examine the ceramic capacitor DC voltage coefficient characteristics to derive the proper value. For example, the capacitance of a 10F, 6.3V, X5R ceramic capacitor with 5.0V DC applied is actually about 6F. Manufacturer Part Number 2D14 CR54 Sumida CDRH4D22/HP CDRH5D14/HP Output Capacitor The output capacitor limits the output ripple and provides holdup during large load transitions. When choosing the output capacitor, first consider the acceptable output ripple level (Vtoatal) and solve for COUT from the equations below; assume that output current remains constant in steady state: VTOTAL = V + VESR = V + IOUT * RESR V = IOUT * D COUT * FSW A 10F to 47F X5R or X7R ceramic capacitor typically provides sufficient bulk capacitance to stabilize the output during large load transitions and has the ESR and ESL characteristics necessary for low output ripple. In addition, the output voltage droop during load transient is related to the capacitance of the ceramic output capacitor. A larger output capacitor helps to reduce voltage droop. Rectifier Diode Selection A rectifier diode must be added (D1 in Figure 1) when the output voltage is greater than 4.5V. The Schottky diode is optional for output voltages less than 4.5V, but can improve efficiency by about 2% to 3%. A low forward voltage Schottky diode is recommended. Its voltage rating should be higher than the output voltage. Thus, diodes with 10V or more reverse voltage are recommended. The diode rated current can be slightly less than the peak inductor current to save cost and board space. L (H) Max DCR (m) Rated DC Current (A) 2.2 3.3 4.7 2.2 3.3 5.0 2.2 3.5 4.7 2.0 3.3 5.1 94 125 169 23.4 28.6 44.2 44.3 65.1 82.6 57 96 140 1.50 1.2 1.0 3.84 3.20 2.60 3.2 2.5 2.2 3.2 2.6 2.0 Size WxLxH (mm) 3.2x3.2x1.55 5.6x6.1x4.85 5.0x5.0x2.4 6.0x6.3x1.5 Table 2: AAT1218 Typical Surface Mount Inductors. 10 www.analogictech.com 1218.2009.12.1.4 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Load Disconnect in Shutdown In a conventional synchronous step-up converter, a conduction path exists from battery to output through the body diode of the PMOS during shutdown. To avoid output side circuitry drawing current from VIN, special application circuitry such as that shown in Figure 1 is necessary to disconnect the output from VIN during shutdown. PCB Layout Guidance The AAT1218 typically operates at 1.2MHz. Since this is a high frequency for DC-DC converters, PCB layout is critical to guarantee satisfactory performance. It is recommended to make traces of the power loop as short and wide as possible, especially where the switching L1 2.2H node is involved. First, the inductor and input and output capacitors should be placed close to the IC. Feedback and shutdown traces should avoid proximity to large AC signals, e.g. the power inductor and switching nodes. The optional rectifier diode (D1 in Figure 1 and Figure 2) can improve efficiency and alleviate the stress on the integrated PMOS device. The diode should also be close to the inductor and the chip to form the shortest possible switching loop. While the two layer PCB shown in Figures 3 and 4 is sufficient for low to moderate power applications, large and integral multi-layer ground planes are ideal for high power applications since the large area of copper has lower resistance and higher thermal dissipation capability. The converter's grounds should join at one point only. Figure 1 illustrates the schematic for a typical AAT1218 application. D1 (Optional) VOUT 3.3V LX Q1 Si2305DS VIN CIN 22F VOUT AAT1218 EN PGND ON/OFF Control GND COUT1 22F R4 510k R1 1.02M FB R3 510k COUT2 2.2F R2 576k Q2 2N3904 Figure 1: AAT1218 Application Schematic with Load Disconnect Circuit. 1218.2009.12.1.4 www.analogictech.com 11 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Evaluation Board Schematic LX VOUT D1 B230LA L1 2.2H VIN U1 AAT1218-TDFN33-12 LX 1 2 C1 22F PGND VIN EN R3 1M PGND 3 4 5 6 LX N/C VIN EN N/C GND PGND PGND OUT OUT FB GND C2 22F 12 11 C4 100pF Opt. 10 9 8 7 VOUT C3 22F R2 . R1 FB 1.02M 576K VOUT = 3.3V 470K VOUT = 3.8V 324K VOUT = 5V EXP PAD JP2 3 2 1 PGND ENABLE GND R10 0R GND GND PGND Figure 2: AAT1218 Evaluation Board Schematic. 12 www.analogictech.com 1218.2009.12.1.4 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Evaluation Board Layout Figure 3: AAT1218 Evaluation Board Top Side Layout. Figure 4: AAT1218 Evaluation Board Bottom Side Layout. Designator Description Footprint Comment C1 C2 C3 C4 D1 JP2 L1 R1 R2 R3 R10 U1 Capacitor, Ceramic, Murata, GRM21BR60J226ME39, X5R, 22F, 20%, 6.3V Capacitor, Ceramic, Murata, GRM21BR60J226ME39, X5R, 22F, 20%, 6.3V Capacitor, Ceramic, Murata, GRM21BR60J226ME39, X5R, 22F, 20%, 6.3V Capacitor, Ceramic, Murata, GRM1885C1H101JA01B, C0G, 100pF, 5%, 50V Schottky Diode, Vishay, B230LA Header, 3-Pin Inductor, Sumida Chip Resistor, Panasonic, 1.02M, 1/16W, 1% Chip Resistor, Panasonic, 590K, 1/16W, 1% Chip Resistor, Panasonic, 1M, 1/16W, 5% Chip Resistor, Panasonic, 0R, 1/16W, 5% AAT1218-TDFN33-12, AnalogicTech 0805 0805 0805 0603 Diode SMALLHDR1X3 CDRH4D28 0603 0603 0603 0603 TDFN33-12 22F 22F 22F 100pF 2.2H 1.02M 590K 1M 0R Boost Reg. Table 3: AAT1218 Evaluation Board Bill of Materials. 1218.2009.12.1.4 www.analogictech.com 13 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Ordering Information Description Package Marking1 Part Number (Tape and Reel)2 Adjustable Output Voltage Fixed 3.3V Output Voltage Fixed 5V Output Voltage TDFN33-12 TDFN33-12 TDFN33-12 2EXYY 5PXYY 5RXYY AAT1218IWP-1.2-T13 AAT1218IWP-3.3-T13 AAT1218IWP-5.0-T13 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/aboutus/quality.php. Package Information TDFN33-124 Index Area 0.43 0.05 0.1 REF C0.3 0.45 0.05 2.40 0.05 3.00 0.05 Detail "A" 3.00 0.05 1.70 0.05 Top View Bottom View 0.23 0.05 Pin 1 Indicator (optional) 0.05 0.05 0.23 0.05 0.75 0.05 Detail "A" Side View All dimensions in millimeters. 1. 2. 3. 4. XYY = assembly and date code. Sample stock is generally held on part numbers listed in BOLD. Product not available for U.S. market. 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. 14 www.analogictech.com 1218.2009.12.1.4 PRODUCT DATASHEET AAT1218 SwitchRegTM High Current, 1.2MHz Synchronous Boost Converter Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 (c) 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. 1218.2009.12.1.4 www.analogictech.com 15