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| AME, Inc. AME5170 n General Description The AME5170 is a fixed off-time step-up DC/DC converter in a small SOT-25 package. The AME5170 is ideal for LCD panels requiring low current and high efficiency as well as LED application for cellular phone backlighting, PDAs, and other hand-held devices. The low 400ns off time allows the use of tiny external components. AME5170 is designed to drive up to four white LEDs in series with a constant current from a single Li-lon battery. To control LED brightness, the LED current can be adjusted by applying a PWM (pulse width modulated) signal with a frequency range of 100Hz to 50KHz to the EN pin. Low Cost Micro Power Boost DC/DC Converter n Typical Application VIN 1.5V to 5V CIN 4.7F L1 2.2H VOUT = 5V COUT 4.7F R1 100K EN CF 20pF IN SW AME5170 FB GND R2 33K Figure.1 Typical 5V Application VIN 1.5V to 5.5V CIN 4.7F L1 10H n Features l 0.7 Internal Switch l Use Small Surface Mount Components l Adjust Output Voltage up to 28V l Input under Voltage Lockout l 0.1A Shutdown Current Typical l Small SOT-25 Package l All AME's Lead Free Products Meet RoHS Standards VOUT = 12V COUT 1F R1 240K IN SW AME5170 EN GND FB R2 27K Figure.2 Typical 12V Application n Applications l LCD Bias Supplies l White LED Back-Lighting l Handheld Devices l Digital Cameras l Portable Applications EN VIN 1.5V to 5.5V CIN 4.7F L1 10H VOUT = 20V COUT 1F R1 510K IN SW AME5170 FB R2 33K GND Figure.3 Typical 20V Application Rev.A.02 1 AME, Inc. AME5170 n Typical Application VIN 2.7V to 5.5V C IN 4.7F L1 10H VOUT COUT 1F Low Cost Micro Power Boost DC/DC Converter IN SW EN AME5170 FB R2 62 GND Figure.4 White LED Application n Function Block Diagram IN SW + FB Enable Comp 1:8 VREF VIN CL Adjust Current Limit 400ns one Shot Cs UVP 2 + Logic Control Driver EN GND Figure.5 Function Block Diagram Rev.A.02 AME, Inc. AME5170 n Pin Configuration SOT-25/TSOT-25 Top View 5 4 Low Cost Micro Power Boost DC/DC Converter AME5170AEEV 1. SW 2. GND AME5170 3. FB 4. EN 5. IN 1 2 3 Die Attach: Conductive Epoxy n Pin Description Pin Number 1 Pin Name SW Pin Description Power Switch input. This is the drain of the internal NMOS power switch. Minimize the metal trace area connected to this pin to minimize EMI. Ground. Tie directly to ground plane. Output voltage feedback input. Set the output voltage by selecting values for R1 and R2 using: 2 GND 3 FB V R 1 = R 2 out - 1 1 . 23 V Connect the ground of the feedback network to an AGND(Analog Ground) plane which should be tied directly to the GND pin. 4 EN Enable control input, active high. The enable pin is an active high control. Tie this pin above 1.5V to enable the device. Tie this pin below 0.4V to turn off the device. Analog and Power input. Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible. 5 IN Rev.A.02 3 AME, Inc. AME5170 n Ordering Information AME5170 x x x x xxx x Special Feature Output Voltage Number of Pins Package Type Operating Ambient Temperature Range Pin Configuration Number of Pins V: 5 Low Cost Micro Power Boost DC/DC Converter Pin Configuration A (SOT-25) (TSOT-25) Operating Ambient Temperature Range E: -40OC to 85OC Package Type E: SOT-2X Output Voltage Special Feature 1. SW 2. GND 3. FB 4. EN 5. IN ADJ: Adjustable Z: Lead free Y: Lead free & Low profile n Ordering Information Part Number AME5170AEEVADJZ AME5170AEEVADJY Marking* BLEww BLEww Output Voltage ADJ ADJ Package SOT-25 TSOT-25 Operating Ambient Temperature Range -40OC to 85OC -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 BLEww. Please consult AME sales office or authorized Rep./Distributor for the availability of package type. 4 Rev.A.02 AME, Inc. AME5170 n Absolute Maximum Ratings Parameter Input Supply Voltage EN, FB Voltages SW Voltage N-Channel Switch Sink Current ESD Classification Low Cost Micro Power Boost DC/DC Converter Symbol VIN EN,VFB VSW ISW Maximum 6 VIN VOUT + 0.3 600 B* Unit V V V mA Caution: Stress above the listed absolute rating may cause permanent damage to the device. * HBM B: 2000~3999V n Recommented Operating Conditions Parameter Ambient Temperature Range Junction Temperature Range Storage Temperature Range Symbol TA TJ TSTG Rating - 40 to 85 - 40 to 125 - 65 to 150 Unit O C n Thermal Information Parameter Thermal Resistance* (Junction to Case) Thermal Resistance (Junction to Ambient) Internal Power Dissipation Solder Iron (10Sec)** SOT-25 TSOT-25 Conductive Epoxy Package Die Attach Symbol JC JA PD Maximum 81 Unit o C/W 260 400 350 mW o C * Measure JC on backside center of molding compund if IC has no tab. ** MIL-STD-202G 210F Rev.A.02 5 AME, Inc. AME5170 n Electrical Specifications VIN = 3.6V, EN = VIN, TA = 25oC, CIN = 4.7F, IL = 0A, unless otherwise noted. Parameter Input Voltage Output Voltage Line Regulation Quiescent Current Shutdown Current FB Regulation Voltage FB Comparator Hysteresis Switch Current Limit FB Pin Bias Current Switch RDSON Switch Off Time Input Undervoltage Lockout EN Input Threshold (High) (Enable the device) EN Input Threshold (Low) (Shutdown) IQ ISD VFB VFB Hysteresis ICL IFB RDSON t OFF UVLO 1.5 EN Threshold 0.4 V VFB = 1.23V 0.6 1.0 400 1.2 1.4 300 VIN = 2V EN = 0V 1.20 Symbol VIN Test Condition Min 1.5 0.05 65 0.1 1.23 5 375 450 1.0 1.4 75 1 1.26 Typ Max 5.5 Units V %V A A V mV mA A nS V Low Cost Micro Power Boost DC/DC Converter 6 Rev.A.02 AME, Inc. AME5170 n Detailed Description The AME5170 features a constant off-time control scheme. Operation can be best understood by referring to Figure 5. When the voltage at the FB pin is less than 1.23V, the Enable Comp in Figure.5 enables the device and the NMOS switch is turned on, pulling the SW pin to ground. When the NMOS switch is on, load current is supplied by the output capacitor COUT. Once the current in the inductor reaches the peak current limit, the 400ns One Shot turns off the NMOS switch. The SW voltage will then rise to the output voltage plus a diode drop and inductor current will begin to decrease as shown in Figure3. During this time the energy stored in the inductor is transferred to COUT and the load. After the 400ns offtime the NMOS switch is turned on and energy is stored in the inductor again. This energy transfer from the inductor to the output causes a stepping effect in the output ripple. This cycle is continued until the voltage at FB pin reaches 1.23V. When FB pin reaches this voltage, the enable comparator then disables the device turning off the NMOS switch and reducing the quiescent current of the device to 65A typical. The load current is then supplied solely by COUT indicated by the gradually decreasing slope at the output. When the FB pin drops slightly below 1.23V, the enable comparator enables the device and begins the cycle described previously. The EN pin can be used to turn off the AME5170 and reduce the IQ to 0.1A. In shutdown mode the output voltage will be a diode drop lower than the input voltage. DIODE SELECTION To maintain high efficiency, the average current rating of the schottky diode should be larger than the peak inductor current. Schottky diodes with a low forward drop and fast switching speeds are ideal for increasing efficiency in portable applications. Choose a reverse breakdown of the schottky diode larger than the output voltage CAPACITOR SELECTION Choose low ESR capacitors for the output to minimize output voltage ripple. Multilayer ceramic capacitors are the best choice. For most applications, a 1F ceramic capacitor is sufficient. For some applications a reduction in output voltage ripple can be achieved by increasing the output capacitor. Local bypassing for the input is needed on the AME5170. Multilayer ceramic capacitors are a good choice for this as well. A 4.7F capacitor is sufficient for most applications. For additional bypassing, a 100nF ceramic capacitor can be used to shunt high frequency ripple on the input. LAYOUT CONSIDERATIONS The input bypass capacitor CIN, as shown in Figure 3, must be placed close to the IC. This will reduce copper trace resistance which effects input voltage ripple of the IC. For additional input voltage filtering, a 100nF bypass capacitor can be placed in parallel with CIN to shunt any high frequency noise to ground. The output capacitor, COUT, should also be placed close to the IC. Any copper trace connections for the C OUT capacitor can increase the series resistance, which directly effects output voltage ripple. The feedback network, resistors R1 and R2, should be kept close to the FB pin to minimize copper trace connections that can inject noise into the system. The ground connection for the feedback resistor network should connect directly to an analog ground plane. The analog ground plane should tie directly to the GND pin. If no analog ground plane is available, the ground connection for the feedback network should tie directly to the GND pin. Trace connections made to the inductor and schottky diode should be minimized to reduce power dissipation and increase overall efficiency. Low Cost Micro Power Boost DC/DC Converter Rev.A.02 7 AME, Inc. AME5170 n Characterization Curve(For reference only) Efficiency vs. Loading 90 700 Low Cost Micro Power Boost DC/DC Converter Switch off Time vs. Temperature 85 VIN=4.2V VIN=3.3V VIN=2.7V 650 80 Switch off time (ns) VOUT=12V Efficiency(%) 600 75 550 70 500 65 450 60 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 400 -40 -15 10 35 o 60 85 IOUT(mA) Temperature( C) IFB vs. Temperature 1.0 0.9 0.8 0.7 60 75 IQ vs. Temperature I FB(A) 0.6 0.5 0.4 0.3 0.2 0.1 -40 I Q(A) -15 10 35 60 85 45 30 15 0 -40 -15 10 35 Temperature(oC) Temperature( C) o 60 85 EN Thershold High vs. Temperature 1.5 1.4 1.3 EN Threshold Low vs. Temperature 1. 5 1. 4 1. 3 EN Threshold(V) EN Threshold(V) -15 10 35 60 85 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 -40 1. 2 1. 1 1. 0 0. 9 0. 8 0. 7 0. 6 0. 5 0. 4 -40 -15 10 35 60 85 Temperature(oC) Temperature(oC) 8 Rev.A.02 AME, Inc. AME5170 n Characterization Curve(For reference only) Switch Current Limit vs Temperature 700 Low Cost Micro Power Boost DC/DC Converter RDSON vs Temperature 1.4 1.3 Switch Current Limit(mA) 600 1.2 500 RDSON([ ) -15 10 35 60 85 1.1 1.0 0.9 0.8 400 300 0.7 0.6 200 -40 Temperature( C) o 0.5 -40 -15 10 35 60 85 Temperature(oC) VFB vs. Temperature 1.26 1. 50 1.45 UVLO vs. Temperature 1.25 1. 40 1.35 1.24 UVLO(V) VFB(V) 1. 30 1.25 1. 20 1.15 1. 10 1.23 1.22 1.21 1.05 1.20 -40 -15 10 35 o 60 85 1. 00 -40 -15 10 Temperature( C) Temperature( C) 35 o 60 85 Rev.A.02 9 AME, Inc. AME5170 n Date Code Rule Marking A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A Date Code W W W W W W W W W W W W W W W W W W W W Year xxx0 xxx1 xxx2 xxx3 xxx4 xxx5 xxx6 xxx7 xxx8 xxx9 Low Cost Micro Power Boost DC/DC Converter n Tape and Reel Dimension SOT-25 P W AME PIN 1 AME Carrier Tape, Number of Components Per Reel and Reel Size Package SOT-25 Carrier Width (W) 8.00.1 mm Pitch (P) 4.00.1 mm Part Per Full Reel 3000pcs Reel Size 1801 mm 10 Rev.A.02 AME, Inc. AME5170 n Tape and Reel Dimension TSOT-25 P Low Cost Micro Power Boost DC/DC Converter W AME PIN 1 AME Carrier Tape, Number of Components Per Reel and Reel Size Package TSOT-25 Carrier Width (W) 8.00.1 mm Pitch (P) 4.00.1 mm Part Per Full Reel 3000pcs Reel Size 1801 mm Rev.A.02 11 AME, Inc. AME5170 n Package Dimension SOT-25 Top View D c1 Side View Low Cost Micro Power Boost DC/DC Converter SYMBOLS A A1 b D E L MILLIMETERS MIN MAX INCHES MIN MAX 1.20REF 0.00 0.30 2.70 1.40 0.15 0.55 3.10 1.80 0.0472REF 0.0000 0.0118 0.1063 0.0551 0.0059 0.0217 0.1220 0.0709 H E S1 e e H L 1 1.90 BSC 2.60 3.00 0.07480 BSC 0.10236 0.11811 0.0146BSC o 0.37BSC 0 o Front View A 10 0o 10o S1 0.95BSC 0.0374BSC b TSOT-25 Top View D c1 Side View A1 SYMBOLS A+A1 MILLIMETERS MIN 0.90 0.30 2.70 1.40 INCHES MIN 0.0354 0.0118 0.1063 0.0551 MAX 1.25 0.50 3.10 1.80 MAX 0.0492 0.0197 0.1220 0.0709 H E b D E e H L Front View A L S1 e 1.90 BSC 2.40 3.00 0.07480 BSC 0.09449 0.11811 0.0138BSC o 0.35BSC 0 o 1 S1 10 0 o 10 o 0.95BSC 0.0374BSC b A1 12 Rev.A.02 www.ame.com.tw E-Mail: sales@ame.com.tw 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. (c) AME, Inc. , December 2007 Document: 1231-DS5170-A.02 Corporate Headquarter AME, Inc. 2F, 302 Rui-Guang Road, Nei-Hu District Taipei 114, Taiwan, R.O.C. Tel: 886 2 2627-8687 Fax: 886 2 2659-2989 U.S.A.(Subsidiary) Analog Microelectronics, Inc. 3100 De La Cruz Blvd., Suite 201 Santa Clara, CA. 95054-2438 Tel : (408) 988-2388 Fax: (408) 988-2489 |
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