mic37139 1.5a, low-voltage cap ldo regulator super eta is a registered trademark of micrel, inc powerpc is a registered trademark of ibm corporation. micrel inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel +1 ( 408 ) 944-0800 ? fax + 1 (408) 474-1000 ? http://www.micrel.com november 2009 m9999-110209 general description the micrel mic37139 is a 1.5a low-dropout linear voltage regulator that provides a low- voltage, high-current output with a minimum of external components. it offers high precision, ultra-low dropout (500mv overtemperature), and low ground current. the mic37139 operates from an input of 2.25v to 6.0v. it is designed for a wide variety of applications including digital circuits requiring low-voltage at high currents (i.e., plds, dsps, microcontrollers, etc.). it is available in a fixed output voltage of 1.8v, and as low as 1.5v. features of the mic37139 ldo include thermal and current-limit protection, and reverse-current and reverse- battery protection. it?s junction temperature range of the is from ?40c to +125c. data sheets and support documentation can be found on micrel?s web site at: www.micrel.com. features ? 1.5a minimum guaranteed output current ? 500mv maximum dropout voltage over temperature ? stable with ceramic or tantalum capacitor ? wide input voltage range: v in :2.25v to 6.0v ? +1.0% initial output tolerance ? fixed 1.8v output voltage ? excellent line and load regulation specifications ? thermal shutdown and current-limit protection ? reverse-leakage protection ? low profile sot-223 package applications ? ldo linear regulator for low-voltage digital ic ? pc add-in cards ? high-efficiency linear power supplies ? smps post regulator ? battery charger ? set-top boxes ? digital video recorders ? powerpc ? power supplies ? multimedia and pc processor supplies ___________________________________________________________________________________________________________ typical application 1.8v/1.5a regulator
micrel, inc. mic37139 november 2009 2 m9999-110209 ordering information part number output current voltage* junction temperature range package lead finish mic37139-1.8bs 1.5a 1.8v ?40 to +125c sot-223 standard mic37139-1.8ys 1.5a 1.8v ?40 to +125c sot-223 pb-free mic37139-2.5ys 1.5a 2.5v ?40 to +125c sot-223 pb-free note: for other voltage options. contact micrel for details. pin configuration out out gnd in sot-223 (s) pin description pin number pin name pin function 1 gnd ground 2 out regulator output 3 in regulator input
micrel, inc. mic37139 november 2009 3 m9999-110209 absolute maximum ratings (1) supply voltage (v in ) ......................................................6.5v enable input voltage (v en )............................................6.5v power dissipation .....................................in ternally limited junction temperature (t j ) ..................?40c t j +125c lead temperature (solde ring, 5 se c.)........................ 260c storage temperature (t s ) ...................?65c t j +150c esd rating (3) operating ratings (2) supply voltage (v in )....................................... 2.25v to 6.0v enable input voltage (v en ).................................. 0v to 6.0v junction temperature (t j ) ..................?40c t j +125c maximum power dissipation (4) package thermal resistance sot-223 ( jc ) ....................................................50c/w electrical characteristics (5) t a = 25c with v in = v out + 1v; v en = v in ; bold values indicate ?40c< t j < +125c, unless noted. parameter condition min typ max units i l = 10ma ?1 +1 % output voltage accuracy 10ma < i out < i l(max) , v out + 1 v in 6v ?2 +2 % output voltage line regulation v in = v out +1.0v to 6.0v 0.06 0.5 % output voltage load regulation i l = 10ma to 1.5a 0.2 1 % i l = 750ma 350 mv vin ? vout; dropout voltage (6) i l = 1.5a 500 mv ground pin current (7) i l = 1.5a 17 30 ma ground pin current in shutdown v il 0.5v, v in = v out + 1v 1.0 a current limit v out = 0 2.25 4 a notes: 1. exceeding the absolute maxi mum rating may damage the device. 2. the device is not guaranteed to function outside its operating rating. 3. devices are esd sensitive. handling precautions recommended. 4. p d(max) = (t j(max) ? t a ) ja , where ja , depends upon the printed circuit layou t. see ?applications information.? 5. specification for packaged product only. 6. v do = v in ? v out when v out decreased to 98% of its nominal output voltage with v in = v out +1v. for output voltages below 1.75v, dropout voltage specification does not apply due to a minimum input operating voltage of 2.25v. 7. i gnd is the quiescent current. i in = i gnd + i out .
micrel, inc. mic37139 november 2009 4 m9999-110209 typical characteristics
micrel, inc. mic37139 november 2009 5 m9999-110209 typical characteristics
micrel, inc. mic37139 november 2009 6 m9999-110209 functional characteristics
micrel, inc. mic37139 november 2009 7 m9999-110209 functional diagram mic37139 fixed regulator block diagram
micrel, inc. mic37139 november 2009 8 m9999-110209 application information the mic37139 is a high-performance low-dropout voltage regulator suitable for moderate to high-current regulator applications. its 500mv dropout voltage at full load and overtemperature makes it especially valuable in battery-powered systems and as high-efficiency noise filters in post-regulator applications. unlike older npn- pass transistor designs, there the minimum dropout voltage is limited by the based-to-emitter voltage drop and collector-to-emitter saturation voltage, dropout performance of the pnp out put of these devices is limited only by the low vce saturation voltage. a trade-off for the low-dropout voltage is a varying base drive requirement. micrel?s super ?eta pnp ? process reduces this drive requirement to only 2% to 5% of the load current. the mic37139 regulator is fully protected from damage due to fault conditions. 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 temperature. transient protection allows device (and load) survival even when the input voltage spikes above and below nominal. the output structure of these regulators allows voltages in excess of the desired output voltage to be applied wi thout reverse current flow. thermal design linear regulators are simple to use. the most complicated design parameters to consider are thermal characteristics. thermal design requires the following application-specific parameters: ? maximum ambient temperature (ta) ? output current (iout) ? output voltage (vout) ? input voltage (vin) ? ground current (ignd) first, calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet. pd = (vin ? vout) iout + vin ignd where the ground current is approximated by using numbers from the ?electrical characteristics? or ?typical characteristics.? then, the heat sink thermal resistance is determined with this formula: sa = ((tj(max) ? ta)/ pd) ? ( jc + cs) where tj(max) 125c and cs is between 0c and 2c/w. the heat sink may be significantly reduced in applications where 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 properties of micrel super ?eta pnp ? regulators allow significant reductions in regulator power dissipation and the associated heat sink without compromising performance. when this technique is employed, a capacitor of at least 1.0f is needed directly between the input and regulator ground. refer to ?application note 9? for further details and examples on thermal design and heat sink applications. output capacitor the mic37139 requires an output capacitor for stable operation. as a cap ldo, the mic37139 can operate with ceramic output capacitors as long as the amount of capacitance is 47f or greater. for values of output capacitance lower than 47f, the recommended esr range is 200m ? to 2 ? . the minimum value of output capacitance recommended for the mic37139 is 10f. for 47f or greater, the esr range recommended is less than 1 ? . ultra-low esr ceramic capacitors are recommended for output capacitance of 47f or greater to help improve transient response and noise reduction at high frequency. x7r/x5r dielectric-type ceramic capacitors are recommended because of their temperature performance. x7r-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. z5u and y5v dielectric capacitors change value by as much as 50% and 60%, respectively, over their operating temperature ranges. to use a ceramic chip capacitor with y5v dielectric, the value must be much higher than an x7r ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. figure 1. capacitor requirements input capacitor an input capacitor of 1.0f or greater is recommended when the device is more than 4 inches away from the bulk and supply capacitance, or when the supply is a battery. small, surface-mount chip capacitors can be used for the bypassing. the capacitor should be place within 1? of the device for optimal performance. larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the output voltage.
micrel, inc. mic37139 november 2009 9 m9999-110209 transient response and 3.3v to 2.5v, 2.5v to 1.8v or1.65v, or 2.5v to 1.5v conversions the mic37139 has excellent transient response to variations 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 10f output capacitor, preferably tantalum, is all that is required. lar ger values help to improve performance even further. by virtue of its low-dropout voltage, this device does not saturate into dropout as readily as similar npn-based designs. when converting from 3.3v to 2.5v, 2.5v to 1.8v or 1.65v, or 2.5v to 1.5v, the npn-based regulators are already operating in dropout, with typical dropout requirements of 1.2v or greater. to convert down to 2.5v without operating in dropout, npn-based regulators require an input vo ltage of 3.7v at the very least. the mic37139 regulator will provide excellent performance with an input as low as 3.0v or 2.25v, respectively. this gives the pnp-based regulators a distinct advantage over older, npn-based linear regulators. minimum load current the mic37139 regulator is specified between finite loads. if the output current is too small, leakage currents dominate and the output voltage rises. a 10ma minimum load current is necessary for proper operation.
micrel, inc. mic37139 november 2009 10 m9999-110209 package information sot-223 (s) micrel, inc. 2180 fortune drive san jose, ca 95131 usa tel +1 (408) 944-0800 fax +1 (408) 474-1000 web http://www.micrel.com the information furnished by micrel in this data sheet is belie ved to be accurate and reliable. however, no responsibility is a ssumed by micrel for its use. micrel reserves the right to change circuitry and specifications at any time without notification to the customer. micrel products are not designed or authori zed for use as components in life support app liances, devices or systems where malfu nction of a product can reasonably be expected to result in pers onal injury. life support devices or system s are devices or systems that (a) are in tended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significan t injury to the user. a purchaser?s use or sale of micrel produc ts for use in life support app liances, devices or systems is a purchaser?s own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ? 2003 micrel, incorporated.
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