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lxd c2scaab - 352 micro dc - dc converter 1 sep , 2 015 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. 0 v ? output voltage:3.3v ? maximum load current: 1, 2 00ma ? automatic transition between buck m ode 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 lxdc2sc aab - 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 lxdc2sc aab - 352 ma xi mizes the overall operating voltage from the lithium battery . 3. typical application circuit
lxd c2scaab - 352 micro dc - dc converter 2 sep , 2 015 4 4 - 1 outline unit mm 4 - 2 pin function pin no, symbol i/o description 1 mode input mode=h: auto pfm mode mode=l: forced pwm mode 2, 5,6,9 gnd g round pin 3,4 v out output regulated voltage output pin. 7 en input on/off control pin en=h: device on, en=l: device off 8 v in input vin pin supplies current to the lxdc 2sc internal regulator. 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. 15 max f 0. 4 0.1 g 0 .5 0.1 a 0.2 6 0.2 h 0. 39 0.1 b 0. 49 0.1 i 0. 3 6 0.2 c 0.4 0.1 j 0. 44 0.1
lxd c2scaab - 352 micro dc - dc converter 3 sep , 2 015 4 - 3 functional block diagram 5. ordering infor mation part number device specific feature moq lxdc2scaab - 352 standard type t/r, 2,5 00 pcs/r
lxd c2scaab - 352 micro dc - dc converter 4 sep , 2 015 6 . electrical specification 6 - 1 absolute maximum ratings parameter symbol rating unit input voltage v in 6 . 3 v pin voltage en, mode 6. 3 v operating ambient temperature t op - 4 0 to +85 o c operating ic temperature t ic - 4 0 to + 125 o c storage temperature t sto - 4 0 to +85 o c 6 - 2 el ectrical characteristics (ta=25 parameter symbol condition min. typ. max. unit input voltage v in 2 .8 5 . 0 v uvlo voltage uvlo rising 1.7 5 1.7 95 v falling 1. 6 0 1. 71 input leak current iinoff vin=3. 8 v, en=0v 2 ua output voltage accuracy vout p wm mode 3.217 3.3 3.383 v load current range iout vin=3. 8 v 1. 2 a ripple voltage vrpl vin=3. 8 v, iout= 1 00ma, bw=100mhz 20 mv pp efficiency eff vin=3. 8 v, io ut = 1 00ma en=h, mode=h 95 % en control voltage venh on enable 1.4 vin v venl off disable 0 0.4 mode control voltage vmodeh automatic pfm/pwm mode 1.4 - vin v vmodel forced pwm mode 0 - 0.4 sw frequency fosc 2.5 mhz (*1) external capacitors (cout: 22 uf 2 ) sh ould be placed near the module for proper operation. (*2) the above characteristics are tested using the test circuit in section 8.
lxd c2scaab - 352 micro dc - dc converter 5 sep , 2 015 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 muratas ev aluation board of this device at no air - flow condition. 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 - r ating is highly dependent on the environmental thermal conditions, i.e. pcb design, nearby components or effective air flows. care should especially be taken in applications where the device temperature exceeds 85 o c . the ic temperature of the device must be kept low er than the maximum rating of 12 5 o 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 capacitors reliability and lif etime 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 mlccs 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. 0 100 200 300 400 500 600 700 800 0 200 400 600 800 1000 1200 power dissipation [mw] iout[ma] io - loss characteristics (vin=3.8v) 0 5 10 15 20 25 30 35 40 45 50 0 100 200 300 400 500 600 t [ ] power dissipation [mw] loss - t characteristics (vin=3.8v)
lxd c2scaab - 352 micro dc - dc converter 6 sep , 2 015 the following steps sho uld be taken before the design fix of users set for a reliable operation. 1. the ambient temperature of the device should be kept below 85 o c 2. the ic temperature should be measured on the worst condition of each application. the temperature must be kept below 125 o 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 i s acceptable or not. 0.1 1 10 100 1000 10000 100000 20 40 60 80 100 120 capacitor b1 life (thousand hours) capacitor case temperature ( ) capacitor b1 life vs capacitor case temperature vin=5v vin=3.8v vin=2.8v
lxd c2scaab - 352 micro dc - dc converter 7 sep , 2 015 7 . detailed description automatic buck - boost operations the lxdc 2sc aa b 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 automatic ally. 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 t o logic low forces the device into shutdown mode . m ode 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 oper ates in pfm mode at light load current, and when the load current increase , th e 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 th at 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. uvlo (under voltage lock out) the under voltage lockout circuit prevents the device from malfunctioning at low input voltages and the b attery from excessive discharge. it disables the output stage of the converter once the falling v in trips the under - voltage lockout threshold v uvlo which is typically 1.65 v. the device starts operation once the rising v in trips v uvlo threshold plus its hys teresis of 75 mv at typ. 1.725 v . 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 op eration. because of th is function, the output voltage increases gradually from zero to nominal voltage at start - up event. th e nominal soft - start time is 3 msec. pfm mode at light load pwm mode at heavy load nominal output voltage
lxd c2scaab - 352 micro dc - dc converter 8 sep , 2 015 discharge function to make sure the device starts up under defined conditions, the output ge ts discharged with a typical discharge resistor of 12 0 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 protecti on 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 as soon as the internal ic s junction temperature exceeds 1 5 0 o c (typ), the device goes into thermal shutdown. the device returns to its normal operation when the inter nal ics junction temperature again falls below 120 o c (typ).
lxd c2scaab - 352 micro dc - dc converter 9 sep , 2 015 8 . test circuit cout : 22 uf/6.3v grm155r60j226m / grm188r60j226m
lxd c2scaab - 352 micro dc - dc converter 10 sep , 2 015 9 . measurement data micro dc - dc converter evaluation board measurement setup th e 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 dont 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. wh en it is short ed 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 th rough 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 tes t cables .
lxd c2scaab - 352 micro dc - dc converter 11 sep , 2 015 typical measurement data (reference purpose only) (ta=25 efficency v in= 3.8 v, pfm/pwm operation output ripple - noise v in= 3.8 v, bw : 100mhz pfm/pwm operation 75 80 85 90 95 100 1 10 100 1000 eff[%] iout[ma] 0 5 10 15 20 25 30 35 40 45 50 0 200 400 600 800 1000 1200 vrpl [mv] iout [ma]
lxd c2scaab - 352 micro dc - dc converter 12 sep , 2 015 load regulation v in= 3.8 v pfm/pwm operation load transient response vin= 3.8 v , pfm/pwm operation 3.218 3.259 3.300 3.341 3.383 0 200 400 600 800 1000 1200 vout [v] iout [ma] io=1.2a 152mv
lxd c2scaab - 352 micro dc - dc converter 13 sep , 2 015 10 .reliability tests no. items specifications test methods qty result (ng) 1 vibration resistance appearance : no severe damages solder specimens on the testing jig (glass fl uo rine 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. frequency : 10~2000 hz acceleration : 196 m/s 2 direction : x,y,z 3 axis period : 2 h on each direction total 6 h . 18 g (0) 2 deflection 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 solderi ng is uniform and free of defect such as by heat shock. d eflection : 1.6 mm 18 g (0) 3 soldering strength (push strength) 9.8 n minimum solder specimens onto test jig shown below. apply pushing force at 0.5m m/s until electrode pads are pe e led off or cera mics are broken. pushing force is applied to longitudinal direction. 18 g (0) 4 solderability of termination 75% of the terminations is to be soldered evenly and continuously. immerse specimens first a n ethanol solution of rosin, then in a pb free solder solution for 3 0. 5 sec. at 2 45 5 c. preheat : 150 c , 60 s ec. solder paste : sn - 3.0ag - 0.5cu flux : solution of ethanol and rosin (25 % rosin in weight proportion) 18 g (0) 5 resistance to soldering heat (reflow) appearance electrical specifications no severe damages satisfy spec ifications listed in paragraph 6 - 2. preheat temperature : 150 - 180 c preheat period : 90+/ - 30 sec. high temperature : 2 2 0 c high temp. period : 20sec. pe ak temperature : 260+5/ - 0 c specimens are soldered twice with the above condition, and then kept in room condition for 24 h before measurements. 18 g (0) pushing direction jig specimen
lxd c2scaab - 352 micro dc - dc converter 14 sep , 2 015 no. items specifications test methods qty result (ng) 6 high temp. exposure a ppearance electrical specifications no severe damages satisfy spec ifications listed in paragraph 6 - 2. temperature 8 52 period 1000+ 48 / - 0 h room condition 2 24h 18 g (0) 7 temperature cycle condition 100 cycles in the following table step temp(c) time(min) 1 min. operating temp.+0/ - 3 303 2 max. operating temp.+3/ - 0 303 18 g (0) 8 humidity (stea dy state) temperature 852 humidity 80 90%rh period 1000+48/ - 0 h room condition 2 24h 18 g (0) 9 low temp. exposure temperature - 402 period 1000+48/ - 0 h room condition 2 24h 18 g (0) 10 esd(machine model) c 200pf r 0 test voltage +/ - 1 00v nu mber of electric discharges 1 5 g (0) 11 esd(human body model) c 100pf r 1500 test voltage +/ - 1 000v number of electric discharges 1 5 g (0)
lxd c2scaab - 352 micro dc - dc converter 15 sep , 2 015 fig.1 land pattern unit mm symbol dimension symbol d imension a 0. 55 e 0.4 b 0. 4 f 0.5 c 0. 5 g 0.45 d 0. 6 h 0.5 ? re ference purpose only. a c d e f g h b a d e 1 2 3 8 9 4 7 6 5 1 2 3 5 4 6 7 9 8 b
lxd c2scaab - 352 micro dc - dc converter 16 sep , 2 015 fig.2 testing board unit mm mounted situation unit mm test method unit mm land pattern is same as figure1 glass - fl uo rine board t 1.6mm copper thickness over 35 ? m device deflection r230 50 20 100 40 45 45 ?
lxd c2scaab - 352 micro dc - dc converter 17 sep , 2 015 11 . tape and reel packing 1 dimensions of tape (plastic tape) unit mm 2 dimensions of reel unit mm 13.0 1.4 ( 9.0 ) 13 0 .2 60 2 0.5 180 feeding direction 8 . 0 0 . 2 1 . 7 5 0 . 1 ( 3 . 5 ) 1 . 5 + 0 . 1 0 ( 3 . 2 ) 4 . 0 0 . 1 2 . 0 0 . 0 5 4 . 0 0 . 1 ( 1 . 4 ) ( 3 . 2 ) ( 0 . 3 )
lxd c2scaab - 352 micro dc - dc converter 18 sep , 2 015 3 taping diagrams [1] feeding hole : as specified in (1) [2] hole for chip : as specified in (1) [3] cover tape : 50 um in thickness [4] base tape : as specified in (1) feeding hole feeding derection chip [ 1 ] [ 2 ] [ 3 ] [ 3 ] [ 4 ] ? ?
lxd c2scaab - 352 micro dc - dc converter 19 sep , 2 015 4 leader and tail tape symb ol 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 packag ing unit: 2,50 0 pcs./ reel 7 material base tape plastic reel plastic antistatic coating for both base tape and reel 8 peeling of force components 0.1~1.0n cover tape base tape ?{ b c a 165 to 180 0.7 n max. ?`?` `?`
lxd c2scaab - 352 micro dc - dc converter 20 sep , 2 015 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 4 0 c.) . - store products in non corrosive gas (cl 2 , nh 3 ,so 2 , no x , 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 . e xcessive stress or mechanical shock may damage the product because of the nature of ceramics structure. do not touch the product , especially the terminals, with b are 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 p u rpose only. electrical, mechanical and thermal characteristics of the product shall dep end 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.
lxd c2scaab - 352 micro dc - dc converter 21 sep , 2 015 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. use rosin type flux or weakly active flux with a chlorine content of 0.2 wt % or less. reflow soldering standard conditions (example) reflow soldering standard conditions (example)
lxd c2scaab - 352 micro dc - dc converter 22 sep , 2 015 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 pr essure). 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 ( cl 2, nh 3, so x, no x 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 afte r 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 tak en, 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 . i nput 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 .
lxd c2scaab - 352 micro dc - dc converter 23 sep , 2 015 8 . limitation of applications: the produc ts are designed and produce d 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 mura ta 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 bran d of car manufacture , car factory - installed option and dealer - installed option. - traffic signal equipment. - disaster prevention / crime prevention equipment. - d ata - 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 . not e: 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. !

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