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mic5254 dual 150ma cap ldo with error flag outputs micrel inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel +1 ( 408 ) 944-0800 ? fax + 1 (408) 474-1000 ? http://www.micrel.com december 2007 m9999-121107 general description the mic5254 is an efficient, precise, dual cmos voltage regulator. it offers better than 1% initial accuracy, extremely low dropout voltage (typically 135mv at 150ma) and low ground current (typically 90a) over load. the mic5254 features two independent ldos with error flags that indicate an output fault condition such as overcurrent, thermal shut-down and dropout. designed specifically for handheld and battery-powered devices, the mic5254 provides a ttl-logic-compatible enable pin. when disabled, power consumption drops nearly to zero. the mic5254 also works with low-esr ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. key features include current lim it, thermal shutdown, faster transient response, and an active clamp to speed up device turnoff. the mic5254 is available in the 10-pin msop package and is rated over a ?40c to +125c junction temperature range. data sheets and support doc umentation can be found on micrel?s web site at www.micrel.com. features ? input voltage range: 2.7v to 6.0v ? dual, independent 150ma ldos ? error flags indicate fault condition ? stable with ceramic output capacitor ? ultra-low dropout: 135mv @ 150ma ? high output accuracy: 1.0% initial accuracy 2.0% over temperature ? low quiescent current: 90a each ldo ? tight load and line regulation ? thermal shutdown and current limit protection ? ?zero? off-mode current ? ttl logic-controlled enable input ? 10-pin msop package applications ? cellular phones and pagers ? cellular accessories ? battery-powered equipment ? laptop, notebook, and palmtop computers ? consumer/personal electronics ___________________________________________________________________________________________________________ typical application mic5254 vina vina ena gnda enb outa flga outb flgb gndb v ina v inb v outa v outb 1f 1f 1f ceramic 1f ceramic flga flgb 9 2 3 6 5 10 1 8 4 7 dual output ldo with error flag
micrel, inc. mic5254 december 2007 2 m9999-121107 ordering information part number vouta voutb temperature range package lead finish MIC5254-SJBMM 3.3v 2.5v ?40 to +125c 10-pin msop standard mic5254-sjymm 3.3v 2.5v ?40 to +125c 10-pin msop pb-free note: other voltages available. cont act micrel marketing for details. pin configuration 10-pin msop (mm) pin description pin number pin name channel pin name 1 flga a error flag (output): open-drain outpu t. active low indicates an output undervoltage condition. 2 ena a enable/shutdown (input): cmos co mpatible input. logic high = enable; logic low = shutdown. do not leave open. 3 gnda a ground 9 ina a supply input 10 outa a regulator output 4 flgb b error flag (output): open-drain outpu t. active low indicates an output undervoltage condition. 5 enb b enable/shutdown (input): cmos co mpatible input. logic high = enable; logic low = shutdown. do not leave open. 7 gndb b ground 6 inb b supply input 8 outb b regulator output
micrel, inc. mic5254 december 2007 3 m9999-121107 absolute maximum ratings (1) supply input voltage (v in ).................................... 0v to +7v enable input voltage (v en )................................... 0v to +7v power dissipation (p d ) ................... internal limited, note 3 junction temperature (t j ) ........................?40c to +125c lead temperature (solde ring, 5 se c.) ........................ 260c storage temperature (t s ) .........................?65c to +150c esd rating (4) .................................................................. 2kv operating ratings (2) supply input voltage (v in )............................... +2.7v to +6v enable input voltage (v en )..................................... 0v to v in junction temperature (t j ) ........................ ?40c to +125c thermal resistance msop-10 ( ja ) .................................................200 c/w electrical characteristics (5) v in = v out + 1v; v en = v in ; i out = 100; t j = 25c, bold values indicate ?40c t j +125c, unless noted. symbol parameter condition min typ max units v o output voltage accuracy i out = 100a ?1 ?2 +1 +2 % % ? v lnr line regulation v in = v out + 1v to 6v 0.02 0.075 %/v ? v ldr load regulation i out = 0.1ma to 150ma, note 6 1.5 2.5 % i out = 100a 0.1 mv i out = 100ma 90 150 mv v in ? v out dropout voltage, note 7 i out = 150ma 135 200 250 mv mv i q quiescent current v en 0.4v (shutdown) 0.2 1 a i out = 0ma 90 150 a i gnd ground pin current, note 8 i out = 150ma 117 a f = 10hz, v in = v out + 1v; c out = 1f 60 db f = 100hz, v in = v out + 0.5v; c out = 1f 60 db psrr power supply rejection f = 10khz, v in = v out + 0.5v 45 db i lim current limit v out = 0v 160 425 ma e n output voltage noise 30 v rms enable input v il enable input logic-low voltage v in = 2.7v to 5.5v, regulator shutdown 0.4 v v ih enable input logic-high voltage v in = 2.7v to 5.5v, regulator enabled 1.6 v v il 0.4v, regulator shutdown 0.01 a i en enable input current v ih 1.6v, regulator enabled 0.01 a shutdown resistance discharge 500 ? error flag v flg low threshold high threshold % of v out (flag on) % of v out (flag off) 90 96 % % v ol output logic-low voltage i l = 100a, fault condition 0.02 0.1 v i fl flag leakage current flag off, v flg = 6v 0.01 a thermal protection thermal shutdown temperature 150 c thermal shutdown hysteresis 10 c
micrel, inc. mic5254 december 2007 4 m9999-121107 notes: 1. exceeding the absolute maximum rating may damage the device. 2. the device is not guaranteed to function outside its operating rating. 3. the maximum allowable power dissipation of any t a (ambient temperature) is p d(max) = (t j(max) ? t a ) / ja . exceeding the maximum allowable power dissipation will result in excessive die temperat ure, and the regulator will go into thermal shutdown. the ja of the MIC5254-SJBMM is 200c/w on a pc board (see ?thermal consi derations? section for further details). 4. devices are esd sensitive. handling precautions recommended. 5. specification for packaged product only. 6. regulation is measured at constant j unction temperature using low duty cycle puls e testing. parts are tested for load regu lation in the load range from 0.1ma to 150ma. changes in output voltage due to heat ing effects are covered by the thermal regulation specification . 7. dropout voltage is defined as the input to output differentia l at which the output voltage drops 2% below its nominal value measured at 1vdifferential. for outputs below 2.7v, dropout voltage is the input-to- output voltage differential with the minimum input voltage 2.7v. minimum input operating voltage is 2.7v. 8. ground pin current is the regulator quiescent current. the to tal current drawn from the supply is the sum of the load curr ent plus the ground pin current. test circuit mic5254 vina vina ena gnda enb outa flga outb flgb gndb v ina v inb v outa v outb 1f 1f 1f ceramic 1f ceramic flga flgb 9 2 3 6 5 10 1 8 4 7 0.01f 0.01f
micrel, inc. mic5254 december 2007 5 m9999-121107 typical characteristics for each ldo channel 0 10 20 30 40 50 60 70 ) b d ( r r s p frequency (hz) 100a* 50ma* 100ma* 150ma* power supply rejection ratio *i load c out = 1.0f ceramic 10 100 1k 10k 100k 1m 100 105 110 115 120 125 130 0.1 1 10 100 1000 ( t n e r r u c d n u o r g) a output current (ma) ground pin current v in = v out + 1v 0 20 40 60 80 100 120 140 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 ( t n e r r u c d n u o r g) a input voltage (v) ground pin current i load = 150ma 0 0.5 1 1.5 2 2.5 3 3.5 012 3 456 ) v ( e g a t l o v t u p t u o input voltage (v) dropout characteristics 100a 150ma 0 20 40 60 80 100 120 140 160 180 -40 -20 0 20 40 60 80 100120140 ) v m ( e g a t l o v t u o p o r d dropout voltage i load = 150ma 0 20 40 60 80 100 120 140 160 180 0 20 40 60 80 100 120 140 160 ) v m ( e g a t l o v t u o p o r d output current (ma) dropout voltage t = ?40c t = 25c t = 125c
micrel, inc. mic5254 december 2007 6 m9999-121107 typical characteristics (continued) for each ldo channel 0 100 200 300 400 500 600 33.544.555.56 ) a m ( t n e r r u c t i u c r i c t r o h s input voltage (v) short circuit current
micrel, inc. mic5254 december 2007 7 m9999-121107 functional characteristics for each ldo channel
micrel, inc. mic5254 december 2007 8 m9999-121107 functional diagram reference voltage en a quickstart under- voltage lockout thermal sensor ina fault gnda active shutdown overcurrent dropout detection out of regulation detection flga outa current amplifier startup/ shutdown control error amplifier reference voltage enb quickstart under- voltage lockout thermal sensor inb fault gndb active shutdown overcurrent dropout detection out of regulation detection flgb outb current amplier startup/ shutdown control error amplifier
micrel, inc. mic5254 december 2007 9 m9999-121107 application information enable/shutdown the mic5254 comes with an active-high enable pin for each regulator that allows t he regulator to be disabled. forcing the enable pin low disables the regulator and sends it into a ?zero? off-mode- current state. in this state, current consumed by the regulator goes nearly to zero. forcing the enable pin high enables the output voltage. this part is cmos and the enable pin cannot be left floating; a floating enable pin may cause an indeterm- inate state on the output. input capacitor the mic5254 is a high performance, high bandwidth device. therefore, it requ ires a well-bypassed input supply for optimal performance. a 1f capacitor is required from the input to ground to provide stability. low esr ceramic capacitors provide optimal perform- ance at a minimum of space. additional high-frequency capacitors, such as small-valued npo dielectric type capacitors, help filter out high frequency noise and are good practice in any rf based circuit. output capacitor the mic5254 require s an output capacitor for stability. the design requires 1f or greater on the output to maintain stability. the design is optimized for use with low esr ceramic chip capacitors. high esr capacitors may cause high frequency oscillation. the maximum recommended esr is 300m ? . the output capacitor can be increased, but performance has been optimized for a 1f ceramic output capacitor and does not improve significantly with larger capacitance. x7r/x5r dielectric-type ceramic capacitors are recom- mended because of their temperature performance. x7r-type capacitors change c apacitance 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 t heir 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 capaci- tance over the equivalent oper ating temperature range. error flag the error flag output is an active-low, open-drain output that drives low when a fault condition and an under- voltage detection occurs. inter nal circuitry intelligently monitors overcurrent, overtemperature and dropout conditions and ors these outputs together to indicate some fault condition. the output of that or gate is anded with an output voltage monitor that detects an undervoltage condition. t hat output drives the open- drain transistor to indicate a fault. this prevents chattering or inadvertent triggering of the error flag. the error flag must be pulled-up using a resistor from the flag pin to either the input or the output. the error flag circuit was designed essentially to work with a capacitor to ground to act as a power-on reset generator, signaling a power-good situation once the regulated voltage was up and/or out of a fault condition. this capacitor delay s the error signal from pulling high, allowing the downstream circui ts time to stabilize. when the error flag is pulled-up to the input without using a pull-down capacitor, there can be a glitch on the error flag upon start up of the device. this is due to the response time of the error fl ag circuit as the device starts up. when the device comes out of the ?zero? off mode current state, all the various nodes of the circuit power up before the device begins suppl ying full current to the output capacitor. the error flag drives low immediately and then releases after a few microseconds. the intelligent circuit that triggers an error detects the output going into current limit a nd the output being low while charging the output capacitor. the error output then pulls low for the duration of the turn-on time. a capacitor from the error flag to ground will filter out this glitch. the glitch does not occur if the error flag pulled up to the output. active shutdown the mic5254 also features an active shutdown clamp, which is an n-channel mosfet that turns on when the device is disabled. this allows the output capacitor and load to discharge, de-energizing the load. no load stability the mic5254 will remain stable and in regulation with no load unlike many other volt age regulators. this is especially important in cmos ram keep-alive applications. thermal considerations the mic5254 is a dual ldo voltage regulator designed to provide two output voltages from one package. both regulator outputs are capable of sourcing 150ma of output current. proper thermal evaluation needs to be done to ensure that the junction temperature does not exceed its maximum value, 125c. maximum power dissipation can be calculated based on the output current and the voltage drop across each regulator. the sum of the power dissipation of each regulator determines the total power dissipation. the maximum power dissipation that this package is capable of handling can be determined using thermal resistance, junction to ambient, and the following basic equation: ? ? ? ? ? ? ? ? ? = ja a j(max) d(max) t t p t j(max) is the maximum junction temperature of the die,
micrel, inc. mic5254 december 2007 10 m9999-121107 125c and t a is the ambient operating temperature of the die. ja is layout dependent. table 1 shows the typical thermal resistance fo r a minimum footprint layout for the mic5254. package ja at recommended minimum footprint msop-10 200c table 1. thermal resistance the actual power dissipati on of each regulator output can be calculated using the following simple equation: p d = (v in ? v out ) i out + v in i gnd each regulator contributes power dissipation to the overall power dissipation of the package. p d(total) = p d(reg1) + p d(reg2) each output is rated for 150ma of output current, but the application may limit the amount of output current based on the total power dissipation and the ambient temperature. a typical application may call for one 3.3v output and one 2.5v output from a single li-ion battery input. this input can be as high as 4.2v. when operating at high ambient temperatures, the output current may be limited. when operating at an ambient of 60c, the maximu m power dissipation of the package is calculated as follows: ? ? ? ? ? ? = c/w 200 c 60 - c 125 p d(max) p d = 325mw for the application mentioned a bove, if regulator 1 is sourcing 150ma, it contributes the following to the overall power dissipation: p d(reg2) = (v in ? v out ) i out + v in i gnd p d(reg1) = (4.2v ? 3.3v)150ma + 4.2v 100a p d(reg1) = 135.5mw since the total power dissi pation allowable is 325mw, the maximum power dissipation of the second regulator is limited to: p d(max) = p d(reg1) + p d(reg2) ) 325mw = 135.5mw + p d(reg2) p d(reg2) = 189.5mw the maximum output current of the second regulator can be calculated using the same equations but solving for the output current (ground curre nt is constant over load and simplifies the equation): p d(reg2) = (v in ? v out ) i out + v in i gnd 189.5mw = (4.2v ? 2.5v) i out + 4.2v 100a i out = 111.2ma the second output is limited to 110ma due to the total power dissipation of the system when operating at 60c ambient temperature.
micrel, inc. mic5254 december 2007 11 m9999-121107 package information 10-pin msop (mm) 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 personal injury. life suppo rt devices or systems 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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