AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter General Description Features The AAT1299 is a high efficiency, synchronous, fixed frequency, step-up converter with start-up inrush current limit and short-circuit protection. The input voltage ranges from 1.0V to the output voltage. • • • • • • The high 2MHz switching frequency and completely integrated control circuitry minimize the total solution footprint area while maintaining excellent regulation, ripple, and transient response throughout the full load range. • • • Light load switching frequency modulation and low quiescent current maintain high efficiency performance for light load and sleep mode conditions. • • • • • • With a 1A peak switch current limit, the AAT1299 is capable of delivering 200mA to the load from a 1.8V input. The AAT1299 is available in a Pb-free, space-saving 2.0x2.1mm 8-pin SC70JW or 2.2x2.2mm 10pin STDFN package, or in die form and is rated over the -40°C to +85°C temperature range. SwitchReg™ 200mA Output from a 1.8V Input VIN Operation Range: 1.0V to VOUT Up to 93% Efficiency Low Start-Up Voltage: 1.0V Typical Internal Synchronous Rectifier Current Mode Control with Internal Feedback and Compensation 2MHz Fixed Switching Frequency 1A Current Limit Maintains High Efficiency Over the Output Current Range for Improved Battery Life Low 40µA No Load Bias Current Short-Circuit and Over-Current Protection Inrush Current Limit and Soft Start Low Shutdown Current: <1.0µA -40°C to +85°C Temperature Range 2.0x2.1mm SC70JW-8 or 2.2x2.2mm 10-pin STDFN Package or Die Applications • • • • • Bluetooth™ Headsets Digital Cameras Medical Instruments Mobile Handsets MP3 and Portable Music Players Typical Application VIN VOUT AAT1299 2.2μH LX VCC VIN OUT 4.7μF 4.7μF 1299.2007.06.1.0 EN GND 1 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Pin Descriptions Pin # SC70JW-8 STDFN-10 Symbol 1 2 5 4 VCC EN 3 4 3 1, 2 VIN LX 5 9 OUT 6, 7, 8 N/A N/A 7 6, 8, 10 EP GND N/C Function Bias supply voltage after start-up and feedback to the output voltage error amplifier. Enable pin. Logic high enables the IC. Logic low disables the IC and disconnects the load from the input. Shutdown current is <1µA. Input voltage. Supplies the IC at start-up. Inductor connection. Ties to the drains of the P-channel synchronous rectifier and the N-channel MOSFET switch. Boost converter output voltage; connects to the P-channel synchronous MOSFET source. Bypass with ceramic capacitor to GND. Signal and power ground. Connect output capacitor return. Not connected. Exposed paddle (bottom). Connect to ground as closely as possible to the device. Pin Configuration SC70JW-8 (Top View) VCC EN VIN LX 1 8 2 7 3 6 4 5 STDFN-10 (Top View) GND GND GND OUT LX LX VIN EN VCC 1 10 2 8 3 8 4 7 5 6 N/C OUT N/C GND NC Die Contact your local AnalogicTech Sales representative. 2 1299.2007.06.1.0 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Absolute Maximum Ratings1 Symbol VN VEN TJ TLEAD Description VIN, OUT, VCC, LX to GND EN to GND Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6.0 -0.3 to VIN -40 to 150 300 V V °C °C Value Units Thermal Characteristics2 Symbol Description θJA Thermal Resistance PD Maximum Power Dissipation SC70JW-8 STDFN-10 SC70JW-8 STDFN-10 160 50 625 2 °C/W mW W 1. Stresses above those listed in Absolute Maximum Ratings may cause 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 a FR4 board. 1299.2007.06.1.0 3 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Electrical Characteristics1 VIN = 1.8V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C. Symbol VIN VOUT IQ ISHDN RDS(ON)H RDS(ON)L ILIMIT ILL η ΔVOUT/VOUT ΔVOUT/VOUT/ΔVIN FOSC DTYMAX VTH(L-IN) VTH(H-IN) Description Conditions Minimum Start-Up Voltage Operating Input Voltage Range ILOAD = 1mA Output Voltage Accuracy Quiescent Supply Current (Light Load Operation)2 Shutdown Current PMOS On-Resistance NMOS On-Resistance NMOS Current Limit Light Load Current Threshold Efficiency Load Regulation Line Regulation Switching Frequency Maximum Duty Cycle Logic Input Low Threshold for EN Logic Input High Threshold for EN VIN = 1.0V to 2.5V, PWM Mode Min Max 1.0 1.0 VOUT 0.1 No Load VOUT VOUT + 0.1 40 EN = 0V, VIN = 5.5V TA = 25°C TA = 25°C IOUT = 50mA, L = 2.2µH ILOAD = 0 to 100mA VIN = 1.0V to 2.5V TA = 25°C Typ 1.8 750 400 1.0 30 85 1.5 0.2 2.0 90 V V 70 µA 1.0 µA mΩ mΩ A mA % % %/V MHz % V V 2.2 0.4 1.0 Units 1. The AAT1299 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 2. IQ = IQ_VOUT = IQ_VCC. 4 1299.2007.06.1.0 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Typical Characteristics Single-Cell to 3.3V Efficiency Dual-Cell to 3.3V Efficiency 100 100 VIN = 3.0V 90 VIN = 1.5V Efficiency (%) Efficiency (%) 90 80 70 VIN = 1.2V 80 VIN = 2.4V 70 60 60 50 50 0.1 1 10 100 0.1 1000 1 Output Current (mA) 10 2.0 1.5 1.5 1.0 1.0 VOUT Error (%) VOUT Error (%) (VO = 3.3V) 2.0 0.5 0.0 VIN = 1.5V -1.0 -1.5 0.1 0.5 VIN = 3.0V 0.0 VIN = 2.4V -0.5 -1.0 -1.5 VIN = 1.2V -2.0 1000 Dual-Cell Load Regulation (VO = 3.3V) -0.5 100 Output Current (mA) Single-Cell Load Regulation VIN = 2.0V -2.0 1 10 0.1 100 1 Output Current (mA) 10 100 1000 Output Current (mA) Minimum Start-Up Voltage vs. Load Current Light Load Mode Output Current Threshold vs. Input Voltage 120 2.4 Output Current (mA) 2.2 Constant Current Load 2.0 Voltage (V) VIN = 2.0V 1.8 1.6 1.4 Resistive Load 1.2 1.0 100 Increasing Load 80 60 40 Decreasing Load 20 0 0.8 0 2 40 60 80 100 Current (mA) 1299.2007.06.1.0 120 140 160 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 Input Voltage (V) 5 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Typical Characteristics Switching Frequency vs. Temperature Input Current (µA) 200 160 120 80 40 0 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 Switching Frequency Change (%) No Load Input Current vs. Input Voltage 0.5 0.0 -0.5 -1.0 -1.5 -2.0 -2.5 -40 -15 10 35 60 85 Temperature (°°C) Input Voltage (V) Load Transient Response Maximum Load Current Capacity for a 4% Drop in Output Voltage vs. Input Voltage (VIN = 1.2V; L = 2.2µH; CO = 4.7µF) (VOUT = 3.3V) 3.40 Output Current (A) 500 400 300 200 100 0 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.35 3.30 3.25 3.20 0.15 0.10 100mA 0.05 50mA 0.00 3.0 Time (50µs/div) Input Voltage (V) Output Voltage vs. Temperature Line Transient Response (VIN = 1.5V; IO = 10mA) (IO = 50mA; L = 2.2µH; CO = 4.7µF) 2.50 2.4V Output Voltage (V) 0.20 0.00 -0.20 -0.40 -0.60 -20 0 20 40 Temperature (°°C) 6 60 80 2.25 2.00 1.9V 3.34 1.75 1.50 3.32 3.30 Input Voltage (V) Output Voltage Error (%) 0.40 -0.80 -40 Output Voltage (V) Load Current (mA) 600 3.28 3.26 Time (50µs/div) 1299.2007.06.1.0 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Soft-Start Inrush Current (VIN = 2.4V; IO = 100mA; VO = 3.3V) 1.75 4 3 Output Voltage 1.5 1 Enable 0 0.75 0.5 -1 -2 1 Input Current 0.25 -3 0 -4 -0.25 3 Output Voltage 1.5 1.25 2 1 1 Enable 0 -1 -3 0.75 0.5 -2 0.25 Input Current -4 Time (500µs/div) 0 -0.25 Time (500µs/div) Full Load Output Ripple Light Load Output Ripple (VIN = 1.2V; 100mA Load) (VIN = 1.2V; 10mA Load) VOUT (AC Coupled) (20mV/div) VOUT (AC Coupled) (20mV/div) IL (100mA/div) IL (200mA/div) VLX (2V/div) VLX (2V/div) Time (250ns/div) 1299.2007.06.1.0 1.75 4 Input Current (A) 1.25 2 Enable and Output Voltage (V) Soft-Start Inrush Current (VIN = 1.2V; IO = 40mA; VO = 3.3V) Input Current (A) Enable and Output Voltage (V) Typical Characteristics Time (1µs/div) 7 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Functional Block Diagram VCC VIN Start-Up Inrush Control OUT Low Voltage Start-Up VREF Voltage Reference DH Mode Control 2MHz Oscillator Current Sense Comp. LX Logic DL Error Amp. GND Functional Description The AAT1299 synchronous step-up converter is targeted for single- or dual-cell alkaline, NiMH, and NiCd battery applications. It has a 1V typical startup voltage. The high 2MHz switching frequency of the AAT1299 facilitates output filter component size reduction for improved power density and reduced overall footprint. It also provides greater bandwidth and improved transient response over other lower 8 EN GND frequency step-up converters. The compensation and feedback is integrated with only three external components (CIN, COUT, L). Low RDS(ON) synchronous power switches provide high efficiency for heavy load conditions. Switching frequency modulation and low quiescent current maintains this high efficiency for light load and sleep mode conditions. In addition to the improved efficiency, the synchronous boost has the added performance advantage of inrush current limit and short-circuit protection. 1299.2007.06.1.0 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter PWM / Light Load Control The AAT1299 is a fixed frequency PWM peak current mode control step-up converter. For light load conditions (10 to 20mA and below), the converter transitions to a light load mode to reduce the dominant switching losses. In addition to light load operation, a zero current comparator blocks reverse current in the P-channel synchronous MOSFET, forcing DCM operation at light load. These controls, along with very low quiescent current, help to maintain high efficiency over the complete load range without the compromise of increased output voltage ripple during light load conditions. Start-up and Inrush Current Limit The start-up sequence of the AAT1299 varies depending upon whether the input voltage is greater than or less than 2V. Above 1V, a start-up oscillator operating at 25% duty cycle controls the synchronous power stage and charges the output to 2V. For an input voltage greater than 2V, the output is charged at a constant current of 300mA until the output reaches a voltage level just below the input voltage. The step-up converter then takes control and continues to charge the output to the steady-state voltage. The step-up converter Nchannel switch current is limited to 1A and the typical start-up time is 2.5ms. Short-Circuit Protection The P-channel synchronous MOSFET body diode gives the AAT1299 the ability to provide output short-circuit current limit protection. Applications Information Inductor Selection The AAT1299 is designed to operate with a 2.2µH inductor for all input/output voltage combinations. The inductor saturation current rating should be greater than the NMOS current limit specification listed in the Electrical Characteristics table. If necessary, the peak inductor current can exceed the saturation level by a small amount with no significant effect on performance. Table 1 provides a list of some suggested inductor manufacturers and their part numbers. Output and Input Capacitor Selection Surface mount X5R or X7R ceramic capacitors are suggested for both the output and the input. For the output capacitor (C1 in Figure 4) a 4.7µF, 10V, X5R ceramic capacitor is necessary for stability, transient response, and ripple performance. The same 0805 sized capacitor is used for the input (C2 of Figure 4). If desired, a smaller, 0603 sized, 4.7µF, 6.3V, X5R ceramic capacitor can be substituted for the input capacitor (C2). Suggested ceramic capacitor suppliers are listed in Table 1. PCB Layout Guidelines Figures 1, 2, and 3 display the evaluation board layout and suggested component placement. Due to the high switching speed of the AAT1299, it is important that the evaluation board layout be followed. Even the best switch-mode power supply design cannot overcome the problems that can be caused by a poor layout. For the AAT1299, it is necessary that C1 and C2 be placed as close as possible to the IC with a good low impedance path to the GND pins of the IC. It is also good practice to minimize the length of the trace from the OUT pin to the output inductor. This prevents switching noise from radiating into other high noise sensitive, high impedance circuits. 1299.2007.06.1.0 9 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Figure 1: AAT1299 Evaluation Board Top Side. Figure 2: Component Placement. Figure 3: AAT1299 Evaluation Board Bottom Side. VIN U1 AAT1299 1 1 2 3 2 3 Enable 4 L1 2.2μH C2 4.7μF VCC GND EN GND VIN GND LX OUT 8 7 6 VOUT 5 C1 4.7μF U1 AAT1299 SC70JW-8 L1 SD3118-2R2 C1, C2 4.7μF 10V 0805 X5R Figure 4: AAT1299 Evaluation Board Schematic. 10 1299.2007.06.1.0 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Manufacturer Murata www.murata.com TDK www.tdk.com Taiyo Yuden www.t-yuden.com Manufacturer Sumida www.sumida.com Cooper Electronics www.cooperet.com Value Part Voltage Case Size 10V 6.3V 10V 6.3V 10V 6.3V 0805 0603 0805 0603 0805 0603 ISAT DCR Case Size Output or Input Capacitor Input Capacitor Output or Input Capacitor Input Capacitor Output or Input Capacitor Input Capacitor 4.7µF 4.7µF 4.7µF Part Number GRM21BR61A475KA73L GRM188R60J475KE19D C2012X5R1A475K C1608X5ROJ475K LMK212BJ475MG JMK107BJ475MA Value Part Part Number 2.2µH Inductor 1.50A 75mΩ 3.2 x 3.2 x 1.55 CDRH2D14-2R2 2.2µH Inductor 1.62A 69mΩ 3.1 x 3.1 x 1.85 SD3118-2R2 Table 1: Suggested Component Selection. 1299.2007.06.1.0 11 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter Ordering Information Voltage Package Marking1 Part Number (Tape and Reel)2 3.3V 3.3V 3.3V SC70JW-8 2.2x2.2mm STDFN-10 Die YRXYY YQXYY AAT1299 AAT1299IJS-3.3-T1 AAT1299IOQ-3.3-T1 AAT1299IZZ-3.3 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. Package Information3 SC70JW-8 2.20 ± 0.20 1.75 ± 0.10 0.50 BSC 0.50 BSC 0.50 BSC 0.225 ± 0.075 2.00 ± 0.20 0.100 7° ± 3° 0.45 ± 0.10 4° ± 4° 0.05 ± 0.05 0.15 ± 0.05 1.10 MAX 0.85 ± 0.15 0.048REF 2.10 ± 0.30 All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 3. 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. 12 1299.2007.06.1.0 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter STDFN-10 2.200 ± 0.050 1.000 ± 0.050 Detail "A" 1.710 ± 0.050 2.200 ± 0.050 Index Area Top View Bottom View 0.400 BSC 0.025 ± 0.025 0.152 REF 0.550 ± 0.050 0.350 ± 0.050 Side View 0.210 ± 0.050 Pin 1 Indicator (optional) R0.200 Detail "A" Die Please contact your local AnalogicTech Sales representative. 1299.2007.06.1.0 13 AAT1299 Low Voltage 2MHz Step-Up DC/DC Converter © 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 14 1299.2007.06.1.0