AIC3412 Low IQ High Light Load Efficiency Synchronous Boost Converter FEATURES DESCRIPTION Deliver 3.3V at 60mA from a Single Alkaline/Ni-MH or 3.3V at 120mA from Two Cells Up to 94% Efficiency Low Shutdown Current: < 1μA Low Quiescent Current: 12μA. Low No-load Input Current (see Typical Performance Characteristics for detail) Output Disconnect by Shutdown Function Small SOT23-6 Package APPLICATIONS Wireless Mice Medical Instruments Smart Phones Bluetooth Devices The AIC3412 is a synchronous step-up DC/DC converter. That is base on constant Off Time/PSM controller topology. The IC enters PSM mode automatically at light load, the goal is to improve efficiency and reduce quiescent current. The AIC3412 provide a complete power supply solution for products powered by one or two Alkaline, Ni-Cd, or Ni-MH battery cells. It stays in operation with supply voltages down to 0.7V. The implemented boost converter is based on a constant Off Time/PSM controller topology using an internal synchronous rectifier to obtain maximum efficiency. A low-EMI mode is implemented to reduce ringing and in effect lower radiated electromagnetic energy when the converter enters the discontinuous conduction mode. TYPICAL APPLICATION CIRCUITS Fig. 1 Analog Integrations Corporation One Cell Step-Up DC/DC Converter 3A1, 1 Lihsin 1st Rd., Science Park, Hsinchu 300, Taiwan, R.O.C. TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw DS-3412G-03 20141105 1 AIC3412 ORDERING INFORMATION AIC3412X XX XX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL BG: BAG SOT-23-6 (G6) TOP VIEW VIN VOUT FB 6 PACKAGE TYPE G6: SOT-23-6 5 4 AIC3412 G: GREEN PACKAGE 1 2 3 SW GND SHDN Example: AIC3412GG6TR in SOT-23-6 Green Package & Taping & Reel Packing Type Note: Pin1 is determined by orienting the package marking as shown. ABSOLUTE MAXIMUM RATINGS Pin Voltage: FB, SHDN , OUT, VIN -0.3 V to 6V Pin Voltage: SW DC -0.3 V to 6V Pulsed < 100ns -0.3 V to 7V Operating Ambient Temperature Range TA -40°C to 85°C Operating Maximum Junction Temperature TJ 150°C Storage Temperature Range TSTG -65°C to 150°C Lead Temperature (Soldering 10 Sec.) 260°C Thermal Resistance Junction to Ambient 250°C/W (Assume no Ambient Airflow, no Heatsink) Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. TEST CIRCUIT Fig. 2 Test Circuit 2 AIC3412 ELECTRICAL CHARACTERISTICS (Typical application circuit, and the ambient temperature=25°C, VIN=1.2V, VOUT=3.3V, unless otherwise specified) (Note1) PARAMETER TEST CONDITION Output Voltage Range Minimum Start Up Voltage SYMBOL MIN VOUT 1.65 MAX UNIT 5.5 V 0.9 V 5 V 0.5 0.7 V IQ 12 25 μA ISD 0.01 1 μA 500 510 mV IFB 1 50 nA ILH 200 mA TOFF 400 ns RL= 3.3kOhm 0.75 0.7 Input Operation Voltage UVLO of Vin Quiescent Current (PSM) IC Shut Down Current Vin decreasing VOUT VIN=1.2V, VOUT=3.3V, VFB=0.55V (Note 2) SHDN = 0V, VOUT =1.1V Feedback Voltage FB Input Leakage Current TYP VFB VFB=1.3V Inductor current ripple 490 Constant off time VIN=1.2V, VOUT=3.3V Line Regulation VIN<VOUT (Note 3) 0.5% Load Regulation VIN<VOUT (Note 3) 0.5% NMOS Switch Leakage VSW=5V 0.1 5 μA PMOS Switch Leakage VSW=5V, VOUT=0V 0.1 10 μA NMOS Switch On Resistance VIN=1.2V, VOUT=3.3V 480 mΩ PMOS Switch On Resistance VIN=1.2V, VOUT=3.3V 800 mΩ SHDN High Threshold Voltage VIN=1.2V SHDN Low Threshold Voltage VIN=1.2V SHDN Pin Input Current SHDN = 5.5V NMOS Current Limit VIN=1.2V, VOUT=3.3V 0.8 ISHDN 0.28 V 0.2 V 0.01 1.0 μA 0.48 0.68 A Over Temperature Protection 150 °C Over Temperature Hysteresis 30 °C Note 1: Specifications are production tested at TA=25°C. Specifications over the -40°C to 85°C operating temperature range are assured by design, characterization and correlation with Statistical Quality Controls (SQC). Note 2: The test circuit shown in Fig. 2. Note 3: Guarantee by Design. 3 AIC3412 TYPICAL PERFORMANCE CHARACTERISTICS Fig. 3 Efficiency vs. Output Current Fig. 4 Efficiency vs. Output Current Fig. 5 Output Voltage vs. Output Current Fig. 6 Output Voltage vs. Output Current Fig. 7 Output Voltage vs. Output Current Fig. 8 Output Voltage vs. Output Current 4 AIC3412 TYPICAL PERFORMANCE CHARACTERISTICS(Continued) Fig. 9 Input Supply Current vs. Supply Voltage 1.2Vin/ 3.3Vout Iout= 10mA~ 70mA Fig. 10 Output Current vs. Supply Voltage 2V/div. 20mV/div. VOUT 2V/div. IOUT 50mA/div. 50mA/div. Fig. 11 Load Transient Fig. 12 Start up and Shutdown 1.2Vin/ 3.3Vout, Iout= 10mA 10mV/div. VOUT, Ripple ILX 100mA/div. Fig. 13 Output Voltage Ripple 5 AIC3412 FUNCTIONAL BLOCK DIAGRAM PIN DESCRIPTIONS 1. SW - Switch Pin. Connect Inductor between VIN and this pin. 2. GND- Signal and Power Ground 3. SHDN - Logic Controlled Shutdown Input. SHDN = High: Normal Operation SHDN = Low: IC shutdown 4. FB - Feedback Input to Error Amplifier. Connect resistor divider tap to this pin. 5. VOUT- Output Voltage Sense and Drain of the Internal Synchronous Rectifier. 6. VIN - Input Supply Pin. 6 AIC3412 APPLICATION INFORMATION The AIC3412 is a synchronous step-up DC-DC con- Where VFB is 0.5V reference voltage. verter. It is based on constant Off Time/PSM controller Input Inductor Selection topology. At the beginning of each clock cycle, the main A 2.2μH~6.8μH input inductor is commanded for most switch (NMOS) is turned on and the inductor current AIC3412 applications. The 4.7µH input inductor can get starts to ramp. After the sense current signal equals the the good performance over the whole converter ratio error amplifier (EA) output, the main switch is turned off cases. The inductor which is smaller than 2.2 µH is not and the synchronous switch (PMOS) is turned on. The recommended to use. It is important to ensure the in- device can operate with an input voltage below 1V; the ductor saturation current exceeding the peak inductor typical start-up voltage is 0.75V. current in application to prevent core saturation. Current Limit Input Capacitor Selection The over current protection is to limit the switch current. Surfaces mount 4.7μF or greater, X5R or X7R, ceramic The output Voltage will be dropped when over current capacitor is suggested for the input capacitor. The input is happened. The current limit amplifier will turn off capacitor provides a low impedance loop for the edges switch once the current exceeds its threshold. of pulsed current drawn by the AIC3412. Low ESR/ESL Zero Current Comparator X7R and X5R ceramic capacitors are ideal for this The zero current comparator monitors the inductor function. To minimize stray inductance, the capacitor current to the output and shuts off the synchronous should be placed as close as possible to the IC. This rectifier, This prevents the inductor current from re- keeps the high frequency content of the input current versing in polarity improving efficiency at light loads. localized, minimizing EMI and input voltage ripple. Al- Device Shutdown ways examine the ceramic capacitor DC voltage coef- When SHDN is set logic high, the AIC3412 is put into ficient characteristics to get the proper value. active mode operation. If SHDN is set logic low, the Output Capacitor Selection device is put into shutdown mode and consumes less The output capacitor limits the output ripple and pro- than 1μA of current. At the shutdown mode, the syn- vides holdup during large load transitions. A 4.7μF to chronous switch will turn off and the output voltage of 10μF, X5R or X7R, ceramic capacitor is suggested for AIC3412 step-up converter will reduce to 0V.After the output capacitor. Typically the recommended ca- start-up, the internal circuitry is supplied by VOUT, pacitor range provides sufficient bulk capacitance to however, if shutdown mode is enabled, the internal stabilize the output voltage during large load transitions circuitry will be supplied by the input source again. and has the low ESR and ESL characteristics neces- Adjustable Output Voltage sary for low output voltage ripple. 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: R VOUT = VFB × 1 + 1 R2 PCB Layout Guidance This is a considerably high frequency for DC-DC converters. PCB layout is important to guarantee satisfac- 7 AIC3412 tory performance. It is recommended to make traces of as possible to the device. Feedback and shutdown the power loop, especially where the switching node is circuits should avoid the proximity of large AC signals involved, as short and wide as possible. First of all, the involving the power inductor and switching node. inductor, input and output capacitor should be as close 8 AIC3412 PHYSICAL DIMENSIONS SOT-23-6 D E1 A A E e e1 SEE VIEW B WITH PLATING c A A2 b SECTION A-A A1 BASE METAL 0.25 S Y M B O L GAUGE PLANE SEATING PLANE L1 θ L VIEW B Note : 1. Refer to JEDEC MO-178AB. 2. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold flash, protrusion or gate burrs shall not exceed 10 mil per side. 3. Dimension "E1" does not include inter-lead flash or protrusions. 4. Controlling dimension is millimeter, converted inch dimensions are not necessarily exact. SOT-23-6 MILLIMETERS MIN. MAX. A 0.95 1.45 A1 0.00 0.15 A2 0.90 1.30 b 0.30 0.50 c 0.08 0.22 D 2.80 3.00 E 2.60 3.00 E1 1.50 e e1 L 1.90 BSC 0.30 L1 θ 1.70 0.95 BSC 0.60 0.60 REF 0° 8° Note: Information provided by AIC is believed to be accurate and reliable. However, we cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AIC product; nor for any infringement of patents or other rights of third parties that may result from its use. We reserve the right to change the circuitry and specifications without notice. Life Support Policy: AIC does not authorize any AIC product for use in life support devices and/or systems. Life support devices or systems are devices or systems which, (I) are intended for surgical implant into the body or (ii) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 9