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ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 1 description description description description features features features features A7530 is cmos-based pfm step-up dc-dc converter. the converter can start up by supply voltage as low as 0.8v input voltage. quiescent current drawn from power s ource is as low as 7ua. all of these features make A7530 be suitable for the portable devices, which are suppli ed by a single battery to four-cell batteries. to reduce the noise caused by the switch regulator, A7530 is well considerate in circuit design and manufactu re. so that the interferer to other circuits by the device is reduced greatly. A7530 integrates stable reference circuits and trim ming technology, so it can afford high precision and low temperature-drift coefficient of the output voltage . A7530 can be switch on or off easily by ce pin, to minimize the standby supply current in sot-25 package. A7530 is available in sot-25 and sot-89 packages. deliver 200ma at 3.3v output voltage with 1.8v input voltage low start-up voltage(when the output current is 1ma ) 0.8v the converter output voltage can be adjusted from 2.5v~6.0v (in 0.1v step) output voltage accuracy (2%) low temperature-drift coefficient of the output voltage (100ppm/) only three external components are necessary: an inductor, a schottky diode and an output filter capacitor high power conversion efficiency (85%) low quiescent current drawn from power source (<7ua) available in sot-25 and sot-89 package application application application application power source for pda, dsc, mp3 player, electronic toy and wireless mouse power source for a single or dual-cell battery-powered equipments power source for led typical application typical application typical application typical application ordering information ordering information ordering information ordering information package package package package type type type type part number part number part number part number sot-25 e5 A7530e5r-xxy sot-89-3 k3 A7530k3r-xxy note xx: output voltage 25=2.5v, 33=3.3v60= 6.0v y: function type 1: w/o enable circuit 2: with enable circuit r: tape & reel ait provides all pb free products free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 2 pin description pin description pin description pin description top view top view pin# pin# pin# pin# symbol symbol symbol symbol function function function function sot sot sot sot- -- -25 2525 25 sot sot sot sot- -- -25 2525 25 sot sot sot sot- -- -89 8989 89 4 1 v ss (gnd) 4 2 2 v out 2 5 3 lx (ext) 5 3 -- nc 3 1 ce 1 function type function type function type function type type (y) type (y) type (y) type (y) function function function function 1 internal tr. driver, w/o enable circuit 2 internal tr. driver, w/enable circuit free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 3 absolute maximum ratings absolute maximum ratings absolute maximum ratings absolute maximum ratings input voltage range 0.3v~+6v input voltage: vi(lx) 0.3v ~ (vout+0.3v) ce pin voltage 0.3v ~ (vout+0.3v) lx pin output current 0.7a maximum power dissipation, pd t=25 o c sot-25 0.15w sot-89 0.5w maximum junction temperature +150 o c operating free-air temperature range -20 o c ~+80 o c storage temperature range -40 o c ~ +125 o c lead temperature and time 260 o c ,10s stresses above may cause permanent damage to the de vice. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicate d in the electrical characteristics is not implied. exposure to absolute maximum rating conditions for extended periods may affect d evice reliability. recommended operation conditions recommended operation conditions recommended operation conditions recommended operation conditions min. min. min. min. nom nom nom nom max. max. max. max. unit unit unit unit input voltage range 0.8 v out v inductor 10 27 100 h input capacitor 0 R10 f output capacitor 47 100 220 f operating junction temperature -20 85 o c suggestion: use tantalum capacitor to reduce the ri pple of the output voltage. free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 4 electrical characteristics electrical characteristics electrical characteristics electrical characteristics parameter parameter parameter parameter symbol symbol symbol symbol conditions conditions conditions conditions min min min min typ typ typ typ max max max max unit unit unit unit v out output voltage 2.450 2.5 2.55 v 2.646 2.7 2.754 2.94 3.0 3.06 3.234 3.3 3.366 3.528 3.6 3.672 3.920 4.0 4.080 4.900 5.0 5.100 5.880 6.0 6.120 v in input voltage 6 v i in input current i out = 0ma, v in = v out x 0.6 12 15 ua v start start-up voltage i out = 1ma, v in = 0 2v 0.8 0.9 v v hold hold-on voltage i out = 1ma, v in = 2 0v 0.6 0.7 i dd quiescent current drawn from power source without external components, v out = v out x 1.05 4 7 ua r swon switch on resistance 0.4 0.5 ? ilx leak lx leakage current v out = vlx= 6v 0.5 ua v ceh ce h threshold voltage v ce : 0 2v 0.6 0.9 v v cel ce l threshold voltage v ce : 2 0v 0.3 0.6 v fosc oscillator frequency lx on l side, v out = v out x 0.96 300 350 400 khz max dty oscillator duty cycle on (vlx l) side 70 75 80 % efficiency 85 % note: 1. diode: schottky type, such as: 1n5817, 1n5819, 1n58 22 2. inductor: 27uh (r<0.5) 3. capacitor: 100uf (tantalum type) free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 5 typical performance characteristics typical performance characteristics typical performance characteristics typical performance characteristics c in =47uf, c out =100uf, l=10uh, t opt =25 o c, unless otherwise noted. 1. output voltage vs. output current A7530k3-251 2. output voltage vs. output current A7530k3-331 3. output voltage vs. output current A7530k3-401 4. efficiency vs. output current A7530k3-251 5. efficiency vs. output current A7530k3-331 6. efficiency vs. output current A7530k3-401 free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 6 7. ripple vs. output current A7530k3-251 8. ripple vs. output current A7530k3-331 9. ripple vs. output current A7530k3-401 10. ino load vs. input voltage A7530k3 (quiescent current) free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 7 block diagram block diagram block diagram block diagram free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 8 detailed information detailed information detailed information detailed information the A7530 is boost structure, voltage-type pulse-fr equency modulation (pfm) step-up dc-dc converter. only three external components are necessary: an in ductor, a output fitter capacitor and a schottky di ode. and the converters low noise and low ripple output voltage can be adjusted from 2.5v to 5.0v, 0.1v st ep. by using the depletion techniques, the quiescent curre nt drawn from power source is lower than 7ua. the h igh efficiency device consists of resistors for output voltage detection and trimming, a start-up voltage circuit, an oscillator, a reference circuit, a pfm control circ uit, a switch protection circuit and a driver trans istor. the pfm control circuit is the core of the A7530 ic . this block controls power switch on duty cycle to stabilize output voltage by calculating results of other bloc ks which sense input voltage, output voltage, outpu t current and load conditions. in pfm modulation system, the frequency and pulse width is fixed. the duty cycle is adjusted by skipping pulses, so that switch on-time is changed based on the conditions such as input v oltage, output current and load. the oscillate block inside A7530 provides fixed frequency and pulse width wav e. the reference circuit provides stable reference vol tage to output stable output voltage. because inter nal trimming technology is used, the chip output change s less than 2%. at the same time, the problem of temperature-drift coefficient of output voltage is considered in design, so temperature-drift coeffici ent of output voltage is less than 100ppm/ . high-gain differential error amplifier guarantees s table output voltage at difference input voltage an d load. in order to reduce ripple and noise, the error amplifi er is designed with high band-with. tough at very low load condition, the quiescent cur rent of chip does affect efficiency certainly. the four main energy loss of boost structure dc-dc converter in f ull load are the esr of inductor, the voltage of sc hottky diode, on resistor of internal n-channel mosfet and its driver. in order to improve the efficiency, a7 530 integrates low on-resistor n-channel mosfet and wel l design driver circuits. the switch energy loss is limited at very low level. selection of the external components. thus it can be seen, the inductor and schottky diod e affect the conversion efficiency greatly. the ind uctor and the capacitor also have great influence on the outp ut voltage ripple of the converter. so it is necess ary to choose a suitable inductor, a capacitor and a right schottky diode, to obtain high efficiency, low rip ple and low noise. free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 9 before discussion, we define d v d v d v d v out out out out C CC C v vv v in inin in / v / v/ v / v out out out out . 1. 1.1. 1. inductor selection inductor selection inductor selection inductor selection above all, we should define the minimum value of th e inductor that can ensure the boost dc-dc to opera te in the continuous current-mode condition. l ll l min min min min R [d( 1 R [d( 1 R [d( 1 R [d( 1- -- -d) d)d) d) 2 22 2 r rr r l ll l ] / 2f ] / 2f ] / 2f ] / 2f the above expression is got under conditions of con tinuous current mode, neglect schottky diodes volt age, esr of both inductor and capacitor. the actual valu e is greater that it. if inductors value is less t han l min , the efficiency of dc-dc converter will drop greatly, an d the dc-dc circuit will not be stable. secondly, consider the ripple of the output voltage , i = d i = d i = d i = d v vv v in inin in / lf / lf / lf / lf i ii i max max max max = v = v= v = v in inin in / (1 / (1/ (1 / (1- -- -d) d)d) d) 2 22 2 r rr r l ll l + d v + d v + d v + d v in inin in / 2lf / 2lf / 2lf / 2lf if inductor value is too small, the current ripple through it will be great. then the current through diode and power switch will be great. because the power switc h on chip is not ideal switch, the energy of switch will improve. the efficiency will fall. thirdly, in general, smaller inductor values supply more output current while larger values start up w ith lower input voltage and acquire high efficiency. an inductor value of 3uh to 1mh works well in most applications. if dc-dc converter delivers large out put current (for example: output current is great than 50ma), large inductor value is recommended in order to improve efficiency. if dc-dc must output very large current at low input supply voltage, small inducto r value is recommended. the esr of inductor will effects efficiency greatly . suppose esr value of inductor is r l , r load is load resistor, then the energy can be calculated by following expr ession: ? ??? ? r rr r l ll l / r / r/ r / r load load load load (1 (1 (1 (1 C CC C d) d)d) d) 2 22 2 for example: input 1.5v, output is 3.0v, r load =20, r l =0.5. the energy loss is 10%. consider all above, inductor value of 47uh, esr<0.5 is recommended in most applications. large value is recommended in high efficiency applications and smaller value is r ecommended. free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 10 2. 2.2. 2. capacitor capacitor capacitor capacitor selection selection selection selection ignore esr of capacitor, the ripple of output volta ge is: r = v r = v r = v r = v out out out out / v / v/ v / v out out out out = d / r = d / r = d / r = d / r load load load load cf cfcf cf so large value capacitor is needed to reduce ripple . but too large capacitor value will slow down syst em reaction and cost will improve. so 100uf capacitor is recommended. larger capacitor value will be used in large output current system. if output current is s mall (<10ma), small value is needed. consider esr of capacitor, ripple will increase: r = r + (i r = r + (i r = r + (i r = r + (i max max max max r rr r esr esr esr esr ) / v ) / v ) / v ) / v out out out out when current is large, ripple caused by esr will be main factor. it may be greater than 100mv. the esr will affect efficiency and increase energy loss. so low- esr capacitor (for example: tantalum capacitor) is recommend or connect two or more filter capacitors in parallel. 3. diode select 3. diode select 3. diode select 3. diode selection ionion ion rectifier diode will affect efficiency greatly, tho ugh a common diode (such as 1n4148) will work well for light load, it will reduce about 5%~10% efficiency for he avy load. for optimum performance, a schottky diode (such as 1n5817, 1n5819, 1n5822) is recommended. 4. input capacitor 4. input capacitor 4. input capacitor 4. input capacitor if supply voltage is stable, the dc-dc circuit can output low ripple, low noise and stable voltage wit hout input capacitor. if voltage source is far away form dc-dc circuit, input capacitor value greater than 10uf i s recommended. free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 11 test circuits: test circuits: test circuits: test circuits: a). output voltage test circuit ( i load = 1ma) b). start-up voltage test circuit ( i load = 1ma) c). hold-on voltage test circuit ( i load = 1ma) free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 12 d). quiescent current test circuit note: v out =v out x1.05, r=1k?, c=0.1uf e). oscillator frequency and duty cycle test circui t note: v in =v out x0.95, r=1k? free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 13 package information package information package information package information dimension in sot-25 (unit: mm) tape dimension reel dimension free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 14 dimension in sot-89-3 (unit: mm) tape dimension reel dimension free datasheet http://
ait semiconductor i ait semiconductor i ait semiconductor i ait semiconductor inc. nc. nc. nc. www.ait-ic.com a aa A7530 7530 7530 7530 350khz pfm step-up dc-dc converter internal switch w/high efficiency and low noise rev1.2 - jun 2007 released C jun 2008 revised - 15 important notice important notice important notice important notice ait semiconductor inc. (ait) reserves the right to make changes to any its product, specifications, to discontinue any integrated circuit product or servi ce without notice, and advises its customers to obt ain the latest version of relevant information to verify, b efore placing orders, that the information being re lied on is current. ait semiconductor inc.'s integrated circuit product s are not designed, intended, authorized, or warran ted to be suitable for use in life support applications, d evices or systems or other critical applications. use of ait products in such applications is understood to be f ully at the risk of the customer. as used herein may involve potential risks of death, personal injury, or servere property, or environmental damage. in order to minimize risks associated with the customer's appli cations, the customer should provide adequate desig n and operating safeguards. ait semiconductor inc. assumes to no liability to c ustomer product design or application support. ait warrants the performance of its products of the spe cifications applicable at the time of sale. free datasheet http://

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