AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n General Description The AME5172 is a high-efficiency, current mode, synchronous PWM Boost DC-DC Converter with fixed 3.3V output voltage for system applications powered by single or double cell NiMH or Alkaline battery pack. Built-in 0.35Ω NMOS switch and 0.45Ω PMOS synchronous rectification significantly improves efficiency and reduces external components count. High switching frequency (at 1.2MHz) allows easy filtering and faster loop performance. AME5172 uses SOT-25 package that gives a small size solution. n Typical Application L1 4.7µH VIN CIN 4.7µF 1 IN SW 5 AME5172 OUT OFF ON 3 EN GND 4 2 VOUT 3.3V up to 200mA COUT 4.7µF n Features l PWM Control with 1.2MHz Fixed Frequency l Up to 92% Efficiency l 0.85V Low Start-up Input Voltage l Internal Synchronous Rectifier l Fixed 3.3V Output Voltage Options l 0.8A, 0.35Ω Power MOSFET l 1µA Shutdown Current l True Shutdown l SOT-25 Package l All AME's Lead Free Products Meet RoHS Standards n Applications l Hand-held Devices l Digital Cameras l Portable Applications l MP3 Players l LCD Bias Power l Wireless Handsets Rev. A.02 1 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Function Block Diagram IN EN SW Enable VOUT Good Start-UP OSC Bandgap 2.3V OUT Erroramp Σ PWM COMP PWM Control SYNC Driver OSC Ramp Current Limit COMP Current sense GND 2 Rev. A.02 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Pin Configuration SOT-25 Top View 5 4 AME5172AEEV 1. IN 2. GND AME5172 3. EN 4. OUT 5. SW 1 2 3 * Die Attach: Conductive Epoxy n Pin Description Pin Number Pin Name 1 IN 2 GND 3 EN 4 OUT Power Output Pin. PCB layout from output capacitor should be as short and wide as possible.. 5 SW This is the switch pin and is connected to the drain of the internal NMOS power switch. Minimize the metal trace area connected to this pin to minimize EMI. Rev. A.02 Pin Description Input Supply Pin. Place bypass capacitor as close to VIN as possible. Ground connection Pin. Enable Control Input Pin. (Active High) 3 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Ordering Information AME5172 x x x x xxx x Special Feature Output Voltage Number of Bumps Package Type Operating Ambient Temperature Range Pin Configuration Pin Configuration A (SOT-25) 1. IN 2. GND 3. EN 4. OUT 5. SW Operating Ambient Temperature Range Package Type Number of Pins Output Voltage Special Feature E: -40OC to 85OC E: SOT-2x V: 5 330: 3.3V Z: Lead free n Ordering Information Part Number Marking* Output Voltage Package Operating Ambient Temperature Range AME5172AEEV330Z BTWww 3.3V SOT-25 -40OC to 85OC Note: ww represents the date code and pls refer to Date Code Rule on Package Dimension. * A line on top of the first letter represents lead free plating such as BTW. Please consult AME sales office or authorized Rep./Distributor for the availability of package type. 4 Rev. A.02 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Absolute Maximum Ratings Parameter Symbol Maximum Unit V IN -0.3 to 6 V VEN ,VOUT -0.3 to 6 V VSW -0.3 to 6 V Input Voltage EN, Output Voltages Switch Voltage B* ESD Classification Caution: Stress above the listed absolute maximum rating may cause permanent damage to the device. * HBM B:2000V~3999V exclude SW pin. n Recommended Operating Conditions Parameter Symbol Rating Ambient Temperature Range TA -40 to 85 Junction Temperature Range TJ -40 to 125 Storage Temperature Range TSTG -65 to 150 Unit o C n Thermal Information Parameter Package Die Attach Thermal Resistance* (Junction to Case) Symbol Maximum θJC 81 Unit o Thermal Resistance (Junction to Ambient) SOT-25 Conductive Epoxy Internal Power Dissipation Solder Iron (10Sec)** θJA 260 PD 400 350 C/W mW o C * Measure θJC on backside center of molding compund if IC has no tab. ** MIL-STD-202G 210F Rev. A.02 5 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Electrical Specifications VIN = 1.2 V, EN = VIN, VOUT=3.3V, TA = 25OC unless otherwise noted. Parameter Input Voltage Output Voltage Minimum Start-Up Voltage Symbol Test Condition Min V IN 0.85 V OUT 3.217 Typ Max Units Note 1 3.3 3.383 V ST ILOAD = 1mA Quiescent Current IQ Measured on VOUT 500 Shutdown Current ISD EN = GND 1 NMOS Switch Current Limit ICL V 0.85 600 800 NMOS Switch RDSON RON,N VOUT = 3.3V 0.35 PMOS Switch RDSON RON,P VOUT = 3.3V 0.45 Switching Frequency fSW 0.85 1.2 Maximum Duty Cycle DMAX 80 87 µA mA Ω 1.5 MHz % EN Input Current IEN EN = GND or VIN 1 µA N/PMOS Leakage Current ISW VSW = 5V for NMOS, 0V for PMOS 5 µA EN Input Threshold (High) (Enable the device) EN Input Threshold (Low) (Shutdown) EN Threshold 1 VIN V 0.35 Note 1: VIN<VOUT 6 Rev. A.02 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Detailed Description n Application Information The AME5172 is a fixed frequency synchronous boost converter in SOT-25 package. The feature include current mode PWM control with internal frequency compensation, low RDS(ON) MOSFET switch, synchronous rectification and 800mA peak switching current limit. Inductor Selection Synchronous Rectification Built-in 0.35Ω NMOS switch and 0.45Ω PMOS synchronous rectification significantly improves efficiency and eliminates the need for an external Schottky diode. High switching frequency (at 1.2MHz) also allows easy filtering and faster loop performance. Low Voltage Start-Up The AME5172 will start-up at typical input voltage of 0.85V. At start-up, switching frequency is determined by the start-up oscillator and start-up current limit. When VOUT exceeds 2.3V, the start-up circuit will disabled and the PWM mode is initiated. An inductor value of 4.7µH performs well in most application. Larger values of inductance can reduce the inductor ripple current. Choosing inductors with low ESR decrease power loss and increase efficiency. The approximate output current capability versus inductance value is given in the equation below: V ×D I OUT (max) = η (1 − D ) I CL − IN 2 × L × f SW where: η = efficiency D= VOUT − VIN VOUT ICL=switching peak current limit VIN=input voltage L=inductance value FSW =switching frequency Output Capacitor Selection Thermal Shutdown Protection The AME5172 has thermal shutdown protection at 160OC (Typ.). If the device temperature rises above 160OC, the internal power MOSFET will turn off. Once the temperature falls below 140OC, the device resumes normal operation. However, device functionality is only guaranteed to a maximum junction temperature of +125OC. A single ceramic capacitor of value 4.7µF to 10µF will provide sufficient output capacitance for most applications. Larger capacitance with low ESR can be used to improve ripple and transient response. An output capacitor with excessive ESR can also reduce phase margin and cause instability. In general, if electrolytic are used, it is recommended to parallel with ceramic capacitors to reduce ringing, switching losses, and output voltage ripple. Input Capacitor Selection An input capacitor is required to serve as an energy reservoir for the current which must flow into the coil each time the switch turns ON. This capacitor must have extremely low ESR, so ceramic is the best choice. We recommend a nominal value of 4.7µF, but larger values can be used. Since this capacitor reduces the amount of voltage ripple seen at the input pin, it also reduces the amount of EMI passed back to other circuitry. Rev. A.02 7 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 VOUT vs Temperature Star-up Voltage vs Load Current 1.4 3.377 3.357 Start-up Voltage (V) 1.3 VOUT (V) 3.337 3.317 3.297 3.277 3.257 1.2 1.1 1.0 0.9 3.237 3.217 -40 -20 0 20 40 o 60 0.8 0.1 80 1 10 100 Temperature ( C) IOUT (mA) Output Voltage vs Load Current Normalized Frequency vs Temperature 3.377 3.357 Frequency (MHz) 1.40 3.337 VIN = 2.4V VOUT 3.317 3.297 VIN = 1.2V VIN = 1.5V 3.277 3.257 1.29 1.18 1.07 0.96 3.237 3.217 0.1 1 10 100 0.85 -40 1000 60 80 900 850 70 60 VIN = 1.5V VIN = 2.4V 40 30 VIN = 1.2V Current Limit (mA) Efficiency (%) 40 Current Limit vs Temperature 80 800 750 700 650 600 20 1 10 100 Load Current (mA) 8 20 Efficiency vs Load Current 90 10 0 0 Temperature (oC) 100 50 -20 Load Current (mA) 1000 550 -40 -20 0 20 40 60 80 Temperature (oC) Rev. A.02 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 SW Pin Operation VOUT(AC) VOUT Transient Response VSW 1V/Div 100mV/Div 100mA IOUT 0V 100ns/Div VIN = 1.3V VOUT = 3.3V IOUT = 10mA L = 6.8µH COUT = 4.7µF 40mA 100ns/Div VIN = 1.3V VOUT = 3.3V IOUT = 40mA to 100mA L = 6.8µH COUT = 4.7µF SW Pin Fixed Frequency Continuous Inductor Current Operation VSW 1V/Div 0V 100ns/Div VIN = 1.3V VOUT = 3.3V IOUT = 50mA L = 6.8µH COUT = 4.7µF Rev. A.02 9 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Date Code Rule Marking Date Code Year A A A W W xxx0 A A A W W xxx1 A A A W W xxx2 A A A W W xxx3 A A A W W xxx4 A A A W W xxx5 A A A W W xxx6 A A A W W xxx7 A A A W W xxx8 A A A W W xxx9 n Tape and Reel Dimension SOT-25 P W AME AME PIN 1 Carrier Tape, Number of Components Per Reel and Reel Size 10 Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size SOT-25 8.0±0.1 mm 4.0±0.1 mm 3000pcs 180±1 mm Rev. A.02 AME, Inc. 0.85V Single Cell Boost DC-DC Converter AME5172 n Package Dimension SOT-25 Top View Side View SYMBOLS D MILLIMETERS MAX MIN MAX L MIN INCHES E H A θ1 S1 0.00 0.15 0.0000 0.0059 b 0.30 0.55 0.0118 0.0217 D 2.70 3.10 0.1063 0.1220 E 1.40 1.80 0.0551 0.0709 e L Front View A θ1 Rev. A.02 S1 1.90 BSC 2.60 3.00 0.37BSC 0o 10 o 0.95BSC 0.07480 BSC 0.10236 0.11811 0.0146BSC 0o 10 o 0.0374BSC A1 b 0.0472REF A1 H e 1.20REF 11 www.ame.com.tw E-Mail: [email protected] Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. AME, Inc. , September 2007 Document: 1233-DS5172-A.02 Corporate Headquarter U.S.A. (Subsidiary) AME, Inc. Analog Microelectronics, Inc. 2F, 302 Rui-Guang Road, Nei-Hu District Taipei 114, Taiwan. 3100 De La Cruz Blvd., Suite 201 Santa Clara, CA. 95054-2438 Tel: 886 2 2627-8687 Fax: 886 2 2659-2989 Tel : (408) 988-2388 Fax: (408) 988-2489