LXDC2SCAAB-352 Micro DC-DC converter 1. Features Buck-Boost DC-DC converter Low EMI noise and small footprint using inductor-embedded ferrite substrate High efficiency using synchronous rectifier technology at 2.5MHz operation Wide Input voltage range : 2.8~5.0V Output voltage:3.3V Maximum load current: 1,200mA Automatic transition between buck mode and boost mode Fully protected for short-circuit, over-temperature, and under voltage 2. Description The LXDC2SCAAB-352 is a buck-boost DC-DC converter, which is suitable for a space-limited or a noise-sensitive portable application. The device utilizes an inductor-embedded ferrite substrate, and the substrate eliminates radiated EMI noise and conduction noise efficiently. The LXDC2SCAAB-352 has automatic buck-boost operations to prolong Li-ion battery life and efficiency. By switching automatically between the buck-mode operation (stepping down the voltage) when the battery is fully charged and the boost-mode operation (stepping up the voltage) as the battery is discharged, the LXDC2SCAAB-352 maximizes the overall operating voltage from the lithium battery. 3. Typical Application Circuit 1 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 4．Mechanical details 4-1 Outline Unit：mm 4-2 Symbol Dimension Symbol Dimension L 2.8±0.2 d 0.5±0.1 W 2.9±0.2 e 0.54±0.1 T 1.15MAX f 0.4±0.1 g 0.5±0.1 a 0.26±0.2 h 0.39±0.1 b 0.49±0.1 i 0.36±0.2 c 0.4±0.1 j 0.44±0.1 Pin Function Pin No, Symbol I/O MODE Input 2,5,6,9 GND － 3,4 Vout Output 7 EN Input 1 Description Mode=H: auto PFM mode Mode=L: Forced PWM mode Ground pin Regulated voltage output pin. ON/OFF control pin EN=H: Device ON, EN=L: Device OFF 8 Vin Input Vin pin supplies current to the LXDC2SC internal regulator. 2 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 4-3 Functional Block Diagram 5. Ordering Information Part number LXDC2SCAAB-352 Device Specific Feature MOQ Standard Type T/R, 2,500pcs/R 3 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 6. Electrical Specification 6-1 Absolute maximum ratings Parameter symbol rating Unit Vin 6.3 V EN, MODE 6.3 Input voltage Pin voltage V Operating Ambient temperature TOP -40 to +85 o Operating IC temperature TIC -40 to +125 o TSTO -40 to +85 o Condition Min. Storage temperature 6-2 C C C Electrical characteristics (Ta=25℃) Parameter Symbol Input voltage Vin UVLO voltage UVLO Typ. 2.8 Rising 1.75 Max. Unit 5.0 V 1.795 V Falling 1.60 1.71 Input leak current Iinoff Vin=3.8V, EN=0V Output voltage accuracy Vout PWM mode Load current range Iout Vin=3.8V Ripple voltage Vrpl Vin=3.8V, Iout=100mA, BW=100MHz 20 mVpp Efficiency EFF Vin=3.8V, Iout=100mA EN=H, MODE=H 95 % VENH ON：Enable VENL OFF：Disable 3.217 3.3 2 uA 3.383 V 1.2 A 1.4 Vin 0 0.4 V EN control voltage MODE control Voltage VMODEH Automatic PFM/PWM mode VMODEL Forced PWM mode SW Frequency Fosc 1.4 - Vin 0 - 0.4 V 2.5 MHz (*1) External capacitors (Cout: 22uF×2) should be placed near the module for proper operation. (*2) The above characteristics are tested using the test circuit in section 8. 4 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 6-3 Thermal and Current De-rating Information The following figure shows the power dissipation and temperature rise characteristics example. These data are measured on Murata’s evaluation board of this device at no air-flow condition. Loss-ΔT Characteristics (Vin=3.8V) Io - Loss Characteristics (Vin=3.8V) 800 600 500 ΔT[℃] Power Dissipation[mW] 700 400 300 200 100 0 0 200 400 600 800 Iout[mA] 1000 50 45 40 35 30 25 20 15 10 5 0 0 1200 100 200 300 400 Power Dissipation [mW] 500 600 The output current of the device may need to be de-rated if it is operated in a high ambient temperature or in a continuous power delivering application. The amount of current de-rating is highly dependent on the environmental thermal conditions, i.e. PCB design, nearby components or effective air flows. Care should o especially be taken in applications where the device temperature exceeds 85 C. o The IC temperature of the device must be kept lower than the maximum rating of 125 C. It is generally recommended to take an appropriate de-rating to IC temperature for a reliable operation. A general de-rating for the temperature of semiconductor is 80%. MLCC capacitor’s reliability and lifetime are also depending on temperature and applied voltage stress. Higher temperature and/or higher voltage cause shorter lifetime of MLCC, and the degradation can be described by the Arrhenius model. The most critical parameter of the degradation is IR (Insulation Resistance). The below figure shows MLCC’s B1 life based on a failure rate reaching 1%. It should be noted that wear-out mechanisms in MLCC capacitor is not reversible but cumulative over time. 5 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter Capacitor B1 Life vs Capacitor Case temperature 100000 Capacitor B1 Life (Thousand Hours) Vin=5V Vin=3.8V 10000 Vin=2.8V 1000 100 10 1 0.1 20 40 60 80 100 Capacitor Case Temperature (℃ ) 120 The following steps should be taken before the design fix of user’s set for a reliable operation. o 1. The ambient temperature of the device should be kept below 85 C 2. The IC temperature should be measured on the worst condition of each application. The temperature must be o kept below 125 C. An appropriate de-rating of temperature and/or output current should be taken. 3. The MLCC temperature should be measured on the worst condition of each application. Considering the above figure, it should be checked if the expected B1 life of MLCC is acceptable or not. 6 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 7. Detailed Description Automatic buck-boost operations The LXDC2SCAAB uses 4-switch buck-boost circuit topology. The device compares the input and output voltage, and chooses the buck converter mode or boost converter mode automatically. Its transition is very smooth and seamless. Enable The device starts operation when EN is set high and starts up with soft start. For proper operation, the EN pin must be terminated to logic high and must not be left floating. Pulling the EN pin to logic low forces the device into shutdown mode. Mode selection The MODE pin allows selecting the operating mode. If the MODE pin is pulled to logic high voltage (VMODH), the converter operates automatic PFM and PWM mode. In this mode, the converter operates in PFM mode at light load current, and when the load current increase, the operating mode will change to PWM mode automatically. In this mode, the converter can work in high efficiency over wide load current range. If the MODE pin is pulled to logic low voltage (VMODL), the device operates in PWM forced mode. In this mode, the converter operates in PWM mode with the full load current range. The advantage of this mode is that the converter operates with the fixed frequency that allows simple filtering of switching frequency. In this mode, the efficiency is lower compared to the PFM mode at light load current. PFM mode at light load PWM mode at heavy load Nominal output voltage UVLO (Under Voltage Lock Out) The under voltage lockout circuit prevents the device from malfunctioning at low input voltages and the battery from excessive discharge. It disables the output stage of the converter once the falling V IN trips the under-voltage lockout threshold VUVLO which is typically 1.65V. The device starts operation once the rising VIN trips VUVLO threshold plus its hysteresis of 75 mV at typ. 1.725V. Soft Start The device has an internal soft-start function that limits the inrush current during start-up. The soft-start system progressively increases the switching on-time from a minimum pulse-width to that of normal operation. Because of this function, the output voltage increases gradually from zero to nominal voltage at start-up event. The nominal soft-start time is 3msec. 7 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter Discharge Function To make sure the device starts up under defined conditions, the output gets discharged with a typical discharge resistor of 120 Ω whenever the device shuts down. This happens when the device is disabled or any of the protection function (thermal shutdown, under voltage lockout, over current) is triggered. Over Current Protection The converter has a hiccup-mode over current protection function. When the current in the P-Channel MOSFET is sensed to reach the current limit for 16 consecutive switching cycles, the internal protection circuit is triggered, and switching is stopped for approximately 40ms. The device then performs a soft-start cycle. Thermal Shutdown o As soon as the internal IC’s junction temperature exceeds 150 C (typ), the device goes into thermal shutdown. The device returns to its normal operation when the Internal IC’s junction temperature again falls below o 120 C(typ). 8 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 8. Test Circuit Cout : 22uF/6.3V GRM155R60J226M / GRM188R60J226M 9 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 9. Measurement Data Micro DC-DC Converter evaluation board Measurement setup The enable switch has three positions. 1. When it is toggled “ON”, the device starts operation. 2. When it is toggled “OFF”, the device stops operation and stays in shut down mode. 3. When it is set to the middle of “ON” and “OFF”, the EN pin becomes floating and can be can have an external voltage applied through the EN terminal pin on the EVB. If you don’t apply an external voltage to the EN pin, the enable switch should not to be set to the middle position. The mode switch has three states (PWM, PFM, and Open). 1. When it is shorted to “PWM” side, the device operates in PWM forced mode. 2. When it is shorted to “PFM” side, the device operates in PFM/PWM automatic mode. 3. When it is set to open, the mode pin becomes floating and can have an external voltage applied to it through the Mode terminal pin on the EVB. If you don’t apply external voltage to the Mode pin, the mode switch should not to be set to the middle position. ※The 47uF capacitor is for the evaluation kit only, and has been added to compensate for the long test cables. 10 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter Typical Measurement Data (reference purpose only) (Ta=25℃) Efficency Vin=3.8V, PFM/PWM Operation 100 95 EFF[%] 90 85 80 75 1 10 100 1000 Iout[mA] Output Ripple-Noise Vin=3.8V, BW : 100MHz Vrpl [mV] PFM/PWM Operation 50 45 40 35 30 25 20 15 10 5 0 0 200 400 600 800 Iout [mA] 1000 1200 11 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter Load Regulation Vin=3.8V PFM/PWM Operation 3.383 Vout [V] 3.341 3.300 3.259 3.218 0 200 400 600 800 Iout [mA] 1000 1200 Load Transient Response Vin=3.8V, PFM/PWM Operation 152mV ΔIo=1.2A 12 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 10.Reliability Tests No. 1 2 3 Items Vibration Resistance Result (NG) 18 G (0) Frequency : 10~2000 Hz 2 Acceleration : 196 m/s Direction : X,Y,Z 3 axis Period : 2 h on each direction Total 6 h. Solder specimens on the testing jig (glass epoxy boards) shown in appended Fig.2 by a Pb free solder. The soldering shall be done either by iron or reflow and be conducted with care so that the soldering is uniform and free of defect such as by heat shock. Deflection : 1.6mm Solder specimens onto test jig shown below. Apply pushing force at 0.5mm/s until electrode pads are peeled off or ceramics are broken. Pushing force is applied to longitudinal direction. 18 G (0) Pushing Direction 18 G (0) 18 G (0) 18 G (0) Test Methods Appearance : No severe damages Solder specimens on the testing jig (glass fluorine boards) shown in appended Fig.1 by a Pb free solder. The soldering shall be done either by iron or reflow and be conducted with care so that the soldering is uniform and free of defect such as by heat shock. Deflection Soldering strength (Push Strength) QTY Specifications 9.8 N Minimum Specimen 4 5 Solderability of Termination Resistance to Soldering Heat (Reflow) 75% of the terminations is to be soldered evenly and continuously. Appearance No severe damages Electrical specifications Satisfy specifications listed in paragraph 6-2. Jig Immerse specimens first an ethanol solution of rosin, then in a Pb free solder solution for 3±0.5 sec. at 245±5 °C. Preheat : 150 °C, 60 sec. Solder Paste : Sn-3.0Ag-0.5Cu Flux : Solution of ethanol and rosin (25 % rosin in weight proportion) Preheat Temperature : 150-180 °C Preheat Period : 90+/-30 sec. High Temperature : 220 °C High Temp. Period : 20sec. Peak Temperature : 260+5/-0 °C Specimens are soldered twice with the above condition, and then kept in room condition for 24 h before measurements. 13 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter No. 6 7 8 9 Items Specifications Test Methods High Temp. Exposure Temperature：85±2 ℃ Period：1000+48/-0 h Room Condition：2～24h Temperature Cycle Condition：100 cycles in the following table Humidity (Steady State) Appearance No severe damages Electrical specifications Satisfy specifications listed in paragraph 6-2. Step Temp(°C) Time(min) 1 Min. Operating Temp.+0/-3 30±3 2 Max. Operating Temp.+3/-0 30±3 Temperature：85±2 ℃ Humidity：80～90%RH Period：1000+48/-0 h Room Condition：2～24h Temperature：-40±2 ℃ Period：1000+48/-0 h Room Condition：2～24h Low Temp. Exposure QTY Result (NG) 18 G (0) 18 G (0) 18 G (0) 18 G (0) 10 ESD(Machine Model) C：200pF、R：0Ω TEST Voltage ：+/-100V Number of electric discharges：1 5 G (0) ESD(Human Body Model) C：100pF、R：1500Ω TEST Voltage ：+/-1000V Number of electric discharges：1 5 G (0) 11 14 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter Fig.1 Land Pattern d a e f e d 3 1 2 1 3 48 9 8 4 57 6 7 5 b c b a g h Unit：mm Symbol Dimension Symbol Dimension a 0.55 e 0.4 b 0.4 f 0.5 c 0.5 g 0.45 d 0.6 h 0.5 ・Reference purpose only. 15 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter Fig.2 Testing board 100 Unit：mm 40 ■： Land pattern is same as figure1 Glass-fluorine board t＝1.6mm Copper thickness over 35 m Mounted situation Unit：mm チップ Device 45 45 Test method Unit：mm 20 50 R230 deflection 16 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 11. Tape and Reel Packing 1）Dimensions of Tape (Plastic tape) Φ1.5+0.1 0 Unit：mm (0.3) 1.75±0.1 (3.5) 8.0±0.2 (3.2) (1.4) 2.0±0.05 4.0±0.1 (3.2) 4.0±0.1 引き出し方向 Feeding direction 2） Dimensions of Reel Unit：mm 2±0.5 Φ180 Φ60 Φ13±0.2 (9.0) 13.0±1.4 17 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 3）Taping Diagrams [1] Feeding Hole : As specified in (1) [2] Hole for chip : As specified in (1) [3] Cover tape : 50um in thickness [4] Base tape : As specified in (1) [3] [1] [2] [3] [4] Feeding Hole 引き出し穴 Feeding derection 引き出し方向 Chip 部品 18 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 4）Leader and Tail tape A B Components 部品収納部 C Symbol Items Ratings(mm) A No components at trailer min 160 B No components at leader min 100 C Whole leader min 400 5）The tape for modules is wound clockwise with the feeding holes to the right side as the tape is pulled towards the user. 6）Packaging unit: ：2,500 pcs./ reel 7） Material： Base Tape … Plastic Reel … Plastic Antistatic coating for both base tape and reel 8）Peeling of force 0.7 N max. 0.1~1.0N 165 to 180 ° Cover Tape カバーテープ ベーステープ Base Tape 19 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter NOTICE 1. Storage Conditions: To avoid damaging the solderability of the external electrodes, be sure to observe the following points. - Store products where the ambient temperature is 15 to 35 °C and humidity 45 to 75% RH. (Packing materials, In particular, may be deformed at the temperature over 40 °C.). - Store products in non corrosive gas (Cl2, NH3,SO2, Nox, etc.). - Stored products should be used within 6 months of receipt. Solderability should be verified if this period is exceeded This product is applicable to MSL1 (Based on IPC/JEDEC J-STD-020) 2. Handling Conditions: Be careful in handling or transporting the product. Excessive stress or mechanical shock may damage the product because of the nature of ceramics structure. Do not touch the product, especially the terminals, with bare hands. Doing so may result in poor solderability. 3. Standard PCB Design (Land Pattern and Dimensions): All the ground terminals should be connected to ground patterns. Furthermore, the ground pattern should be provided between IN and OUT terminals. Please refer to the specifications for the standard land dimensions. The recommended land pattern and dimensions are shown for a reference purpose only. Electrical, mechanical and thermal characteristics of the product shall depend on the pattern design and material / thickness of the PCB. Therefore, be sure to check the product performance in the actual set. When using underfill materials, be sure to check the mechanical characteristics in the actual set. 20 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 4. Soldering Conditions: Soldering is allowed up through 2 times. Carefully perform preheating ：△ T less than 130 °C. When products are immersed in solvent after mounting, pay special attention to maintain the temperature difference within 100 °C. Soldering must be carried out by the above mentioned conditions to prevent products from damage. Contact Murata before use if concerning other soldering conditions. Reflow soldering standard conditions (example) Reflow soldering standard conditions (Example) Use rosin type flux or weakly active flux with a chlorine content of 0.2 wt % or less. 21 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 5. Cleaning Conditions: The product is not designed to be cleaned after soldering. 6. Operational Environment Conditions: Products are designed to work for electronic products under normal environmental conditions (ambient temperature, humidity and pressure). Therefore, products have no problems to be used under the similar conditions to the above-mentioned. However, if products are used under the following circumstances, it may damage products and leakage of electricity and abnormal temperature may occur. - In an atmosphere containing corrosive gas ( Cl2, NH3, SOx, NOx etc.). - In an atmosphere containing combustible and volatile gases. - In a dusty environment. - Direct sunlight - Water splashing place. - Humid place where water condenses. - In a freezing environment. If there are possibilities for products to be used under the preceding clause, consult with Murata before actual use. If static electricity is added to this product, degradation and destruction may be produced. Please use it after consideration enough so that neither static electricity nor excess voltage is added at the time of an assembly and measurement. If product malfunctions may result in serious damage, including that to human life, sufficient fail-safe measures must be taken, including the following: (1) Installation of protection circuits or other protective device to improve system safety (2) Installation of redundant circuits in the case of single-circuit failure 7. Input Power Capacity: Products shall be used in the input power capacity as specified in this specifications. Inform Murata beforehand, in case that the components are used beyond such input power capacity range . 22 Sep, 2015 LXDC2SCAAB-352 Micro DC-DC converter 8. Limitation of Applications: The products are designed and produced for application in ordinary electronic equipment (AV equipment, OA equipment, telecommunication, etc). If the products are to be used in devices requiring extremely high reliability following the application listed below, you should consult with the Murata staff in advance. - Aircraft equipment. - Aerospace equipment - Undersea equipment. - Power plant control equipment. - Medical equipment. - Transportation equipment (vehicles, trains, ships, etc.). - Automobile equipment which includes the genuine brand of car manufacture, car factory-installed option and dealer-installed option. - Traffic signal equipment. - Disaster prevention / crime prevention equipment. - Data-procession equipment. - Application which malfunction or operational error may endanger human life and property of assets. - Application which related to occurrence the serious damage - Application of similar complexity and/ or reliability requirements to the applications listed in the above. ! Note: Please make sure that your product has been evaluated and confirmed against your specifications when our product is mounted to your product. Product specifications are subject to change or our products in it may be discontinued without advance notice. This catalog is for reference only and not an official product specification document, therefore, please review and approve our official product specification before ordering this product. 23 Sep, 2015