3a low-voltage low-dropout regulator lm39300/39301/39302 features 3a minimum g uaranteed out p ut curren t 500mv t yp ical dro p out at 3 a ideal for 3.0v to 2.5v conversion ideal for 2.5v to 1.8v or 1.5v conversio n 1% initial accurac y low g round current current limitin g and thermal shutdown reversed-batter y p rotection reversed-leaka g e p rotection fast transient res p onse ttl/cmos com p atible enable p in => lm39301 error fla g out p ut - lm39301 onl y ad j ustable version - lm39302 onl y to-263 and to-220 p acka g in g moisture sensitivit y level 3 application s ldo linear re g ulator for pc add-in cards hi g h-efficienc y linear p ower su pp lies multimedia and pc p rocessor su pp lies smps p ost re g ulato r low-volta g e microcontrollers stron g arm? p rocessor su pp l y ordering information description 2008 - ver 1.0 htc lm39302t-adj lm39302-adj LM39300T-x.x to-220 lm39301t-x.x to-220 lm39301r-x.x to-263 lm39301-x.x lm39302r-adj lm39300r- x.x lm39301-x.x regulator output adj out device marking flag (output): open-collector error flag output. 183 to-220 gnd flg ground pin and tab are internally connected. lm39300-x.x adjustment input: feedback input. package lm39302-adj to-263 pin description enable (input) in cmos-compatible control input. logic high = enable, logic logic low or open = shutdown supply (input): +16v maximum supply to-263 lm39300-x.x * x.x = fixed vout = 1.5v, 1.8v, 2.5v, 3.3v, 5.0v the lm39300/1/2 is ideal for pc add-in cards that need to conv ert from standard 5v or 3.3v down to new, lower core voltages. a guaranteed maximum dropout voltage of 500mv over all operating conditions allows the lm39300/1/2 to pro-vide 2.5v from a supply as low as 3v. the lm39300/1/2 also has fast transient response for heavy swi tching applications.the device requires only 47f of output capacitance to maintain stability and achiev e fast transient responsethe lm39300/1 is fully protected with over current limiting,thermal shutdown, re versed-battery protection, reversed-leakage protection, and reversed-lead insertion. the lm39301 offers a t tl-logic compatible enable pin and an error flag that indicates under voltage and over current condit ions. offered in fixed voltages, the lm39300/1/2 comesin the to-220 and to-263 packages and is an id eal upgrade to older, npn-based linear volta g e re g ulators. to263-3l / to220-3l (39300-x.x fixed only) 1. in 2. gnd 3. out 1. en 2. in 3. gnd 4. out 5. flg or adj to263-5l / to220-5l (39301-x.x & 39302 only) the lm39300, lm39301 and lm39302 are 3.0a low-dropout linear voltage regulators that provide a low voltage, high-current output with a minimum of external components. the lm39300/1 offers extremely low dropout (typically 400mv at 3.0a) and low ground current (typically 36ma at 3.0a). 1 3 1 5 1 3 1 5
3a low-voltage low-dropout regulator lm39300/39301/39302 t yp ical a pp lication circuit htc 184 absolute maximum ratings (note 1) supply voltage (vin) : C20v to +20v enable voltage (ven) : +20v storage temperature (ts) : C65c to +150c lead temperature (soldering, 5 sec) : 260c esd, note 3 operating ratings (note 2) supply voltage (vin) : +2.25v to +16v enable voltage (ven) : +16v maximum power dissipation (pd(max)) note 4 junction temperature (tj) : C40c to +125c package thermal resistance to-263( jc ) : 5c/w to-220( jc ) : 2c/w lm39300 lm39301 lm39302
3a low-voltage low-dropout regulator lm39300/39301/39302 htc 185 block dia g ram lm39301 fixed with flag and enable lm39302 adjustable lm39300 fixed (1.5v,1.8v,2.5v,3.3v,5.0v)
3a low-voltage low-dropout regulator lm39300/39301/39302 htc 186 550 lm39302 onl y
3a low-voltage low-dropout regulator lm39300/39301/39302 note 1. exceeding the absolute maximum ratings may damage the d evice. note 2. the device is not guaranteed to function outside its op erating rating. note 3. devices are esd sensitive. handling precautions recomm ended. note 4. p d(max) = (t j(max) C t a ) ja , where ja depends upon the printed circuit layout. see applications inf ormation. note 5.vout temperature coefficient is ?v out(worst case) (t j(max) C t j(min) ) where t j(max) is +125 and t j(min) is 0 note 6. v do = v in C v out when v out decreases to 99% of its nominal output voltage with v in = v out + 1v. note 7. i gnd is the quiescent current. iin = i gnd + i out . note 8. v en 0.8v, v in 8v, and v out = 0v note 9. for a 2.5v device, v in = 2.250v (device is in dropout). note 10.vref vout (vin C 1v), 2.25v vin 16v, 10ma il 3a, tj = tmax. typical performance characteristic s htc 187
3a low-voltage low-dropout regulator lm39300/39301/39302 htc 188
3a low-voltage low-dropout regulator lm39300/39301/39302 htc 189 application information the lm39300/1 is a high-performance low-dropout voltage regulat or suitable for moderate to high-current voltage regu-lator applications. its 500mv dropout voltage at full load makes it especially valuable in battery-powered systems and as a high-efficiency noise filter in post-regulator applications. unlike older npn-pass transistor designs, where the mini-mum dropout voltage is limited by the b ase-to-emitter voltage drop and collector-to- emitter saturation voltage, dropout per-formance of the pnp out put of these devices is limited only by the low v ce saturation voltage.a trade-off for the low dropout voltage is a varying base drive requirement. the lm39300/1/2 regulator is fully protected from damage due to fault condition s. current limiting is provided. this limiting is linear output current during overload conditions is constant. thermal shutdown disables the device when the die temperature exceeds the maximum safe operating tem-perature. tr ansient protection allows device (and load) sur- vival even when the input voltage spikes above and below nomina l. the output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. thermal design linear regulators are simple to use. the most complicated desig n parameters to consider are thermal characteristics.thermal design requires four application-specif ic param-eters: ?maximum ambient temperature (t a ) ?output current (i out ) ?output voltage (v out ) ?input voltage (v in ) ?ground current (i gnd ) calculate the power dissipation of the regulator from these num bers and the device parameters from this datasheet,where the ground current is taken from the data sheet . pd = (v in C v out ) i out + v in i gnd the heat sink thermal resistance is determined by: sa= (t jmax -t a )/p d -( jc + cs ) where tj (max) 125 and cs is between 0 and 2/w. the heat sink may be significantly reduced in applications wher e the minimum input voltage is known and is large compared with the dropout voltage. use a series input resistor to drop excessive voltage and distribute the heat between this resistor and the regulator. the low dropout proper ties of taejin regulators allow signifi-cant reductions in regulator power dissipation and the asso-ciated heat sink wi thout compromising performance. when this technique is employed, a capacitor of at least 1.0f is needed d irectly between the input and regulator ground.refer to application note 9 for further details and examples on therm al design and heat sink specification. output capacitor the lm39300/1/2 requires an output capacitor to maintain stabil ity and improve transient response. proper capacitor selection is important to ensure proper operation. the lm39300/ 1/2 output capacitor selection is dependent upon the esr (equivalent series resistance) of the output capacitor to maintain stability. when the output capacitor is 47f or greater, the output capacitor should have less than 1 of esr . this will improve transient response as well as promote stability. ultralow esr capacitors, such as ceramic chi p capacitors may promote instability. these very low esr levels may cause an oscillation and/or underdamped tran-sie nt response. a low-esr solid tantalum capacitor works extremely well and provides good transient response and s tability over temperature. aluminum electrolytics can also be used, as long as the esr of the capacitor is < 1.the va lue of the output capacitor can be increased without limit. higher capacitance values help to improve transient resp onse and ripple rejection and reduce output noise. input capacitor an input capacitor of 1f or greater is recommended when the dev ice is more than 4 inches away from the bulk ac supply capacitance, or when the supply is a battery. small, sur face-mount, ceramic chip capacitors can be used for the bypass-ing. larger values will help to improve ripple rejec tion by bypassing the input to the regulator, further improving the integrity of the output voltage.transient respons e and 3.3v. fig 1. capacitor requirements
3a low-voltage low-dropout regulator lm39300/39301/39302 htc 190 minimum load current the lm39300/1/2 regulator is specified between finite loads. if the output current is too small, leakage currents dominate a nd the output voltage rises. a 10ma minimum load current is necessary for proper regulation. transient response and 3.3v to 2.5v conversion the lm39300/1/2 has excellent transient response to varia-tions in input voltage and load current. the device has been designed to respond quickly to load current variations and input voltage variations. large output capacitors are not required to obtain this performance. a standard 47f output capacitor, preferably tantalum, is all that is required. larger values help to improve performance even further.by virtu e of its low-dropout voltage, this device does not saturate into dropout as readily as similar npn-based de-signs. when converting from 3.3v to 2.5v, the npn-based regulators are already operating in dropout, with typical dropo ut requirements of 1.2v or greater. to convert down to 2.5v without operating in dropout, npn-based regulators require an input voltage of 3.7v at the very least. the lm39300/1/2 regulator will provide excellent performance with a n input as low as 3.0v. this gives the pnp-based regulators a distinct advantage over older, npn-based linear re gulators. error flag the lm39301 version features an error flag circuit which monito rs the output voltage and signals an error condition when the voltage drops 5% below the nominal output voltage. the error flag is an open-collector output that can sink 10ma during a fault condition.low output voltage can be caused by a number of problems, including an overcurrent fault (device in current limit) or low input voltage. the flag is inoperative during overtemperature shutdown. enable input the lm39301 version features an enable input for on/off control of the device. its shutdown state draws zero current (only microamperes of leakage). the enable input is ttl/ cmos c ompatible for simple logic interface, but can be connected to up to 20v. when enabled, it draws approxi-mately 1 5a. adjustable regulator design the lm39302 allows programming the output voltage any-where bet ween 1.25v and the 16v maximum operating rating of the family. two resistors are used. resistors can be quite large, up to 1m?, because of the very high input impedance and low bias current of the sense comparator: the res istor values are calculated by : r1=r2(vout/1.250- 1) where vo is the desired output voltage. figure 1 shows componen t definition. applications with widely varying load currents may scale the resistors to draw the minimum load curre nt required for proper operation (see below).
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