february 2005 1 mic5233 mic5233 micrel, inc. mic5233 high input voltage, low iq cap ldo regulator general description the mic5233 is a 100ma highly accurate, low dropout regulator with high input voltage and ultra-low ground current. this combination of high voltage and low ground current makes the mic5233 ideal for multi-cell li-ion battery systems. a cap ldo design, the mic5233 is stable with either ceramic or tantalum output capacitor. it only requires a 2.2 f capacitor for stability. features of the mic5233 include enable input, thermal shut- down, current limit, reverse battery protection, and reverse leakage protection. available in fixed and adjustable output voltage versions, the mic5233 is offered in the ittybitty? sot-23-5 package with a junction temperature range of C40 c to +125 c. micrel, inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel + 1 (408) 944-0800 ? fax + 1 (408) 474-1000 ? http://www.mic rel.com ittybitty is a trademark of micrel, inc. features ?w ide input voltage range: 2.3v to 36v ?u ltra low ground current: 18 a ? low dropout voltage of 270mv at 100ma ?h igh output accuracy of 2.0% over temperature ? cap: stable with ceramic or tantalum capacitors ? excellent line and load regulation specifications ? zero shutdown current ? reverse battery protection ? reverse leakage protection ? thermal shutdown and current limit protection ? ittybitty? sot-23-5 package applications ? keep-alive supply in notebook and portable computers ? usb power supply ? logic supply for high-voltage batteries ? automotive electronics ? battery powered systems ?3 -4 cell li-ion battery input range t ypical application 15 2 34 c out =2.2 f ceramic i gnd =18 a c in =1.0 f en mic5233bm5 v in v out r 1 r 2 off on ultra-low current adjustable regulator application ordering information standard pb-free junction part number marking part number marking voltage temp range package mic5233-1.8bm5 l318 mic5233-1.8ym5 l318 1.8v C40 c to +125 c sot-23-5 mic5233-2.5bm5 l325 mic5233-2.5ym5 l325 2.5v C40 c to +125 c sot-23-5 mic5233-3.0bm5 l330 mic5233-3.0ym5 l330 3.0v C40 c to +125 c sot-23-5 mic5233-3.3bm5 l333 mic5233-3.3ym5 l333 3.3v C40 c to +125 c sot-23-5 mic5233-5.0bm5 l350 mic5233-5.0ym5 l350 5.0v C40 c to +125 c sot-23-5 mic5233bm5 l3aa mic5233ym5 l3aa adj. C40 c to +125 c sot-23-5 10 15 20 25 30 35 40 4812 16 20 24 28 32 36 40 ground current ( a) input voltage (v) i out = 10 a i out = 1ma i out = 100 a ground current vs. input voltage
mic5233 micrel, inc. mic5233 2 february 2005 pin configuration in out nc or adj. en l3xx 1 3 45 2 gnd sot-23-5 pin description sot-23-5 pin name pin function 1i n supply input. 2 gnd ground. 3e n enable (input): logic low = shutdown; logic high = enable 4 nc (fixed) no connect. adj (adj.) adjust (input): feedback input. connect to resistive voltage-divider network. 5 out regulator output.
february 2005 3 mic5233 mic5233 micrel, inc. electrical characteristics (note 4) t a = 25 c with v in = v out + 1v; i out = 100 a; v en 2v; bold values indicate C40 c mic5233 micrel, inc. mic5233 4 february 2005 t ypical characteristics 0 10 20 30 40 50 60 70 0.01 0.1 1 10 100 1000 psrr (db) frequency (khz) power supply rejection ratio i out = 100ma 0 50 100 150 200 250 300 350 0204 06080100 dropout voltage (mv) output current (ma) dropout voltage vs. output current 0 50 100 150 200 250 300 350 400 450 500 -40 -20 0 20 40 60 80 100 120 dropout voltage (mv) temperature ( c) dropout voltage vs. temperature i out = 100ma 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 00.511 .5 2 2.5 3 3.5 4 output voltage (v) input voltage (v) dropout characteristics i load = 100 a i load = 50ma i load = 100ma 0 100 200 300 400 500 600 700 800 900 1000 010203 0405060708090100 ground current ( a) output current (ma) ground pin current vs. output current v in = 4v 10 12 14 16 18 20 22 24 26 28 30 0 100 200 300 400 500 ground current ( a) output current ( a) ground pin current vs. output current v in = 24v v in = 12v v in = 4v v in = 36v 40 45 50 55 60 65 70 75 80 -40 -20 0 20 40 60 80 100 120 ground current ( a) temperature ( c ) ground pin current vs. temperature i load = 10ma 200 220 240 260 280 300 320 340 360 380 400 -40 -20 0 20 40 60 80 100 120 ground current ( a) temperature ( c ) ground pin current vs. temperature i load = 50ma 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 -40 -20 0 2 0406080100120 ground current (ma) temperature ( c) ground pin current vs. temperature i load = 100ma 0 10 20 30 40 50 60 70 80 90 100 1.5 2 2.5 3 3.5 4 ground current ( a) input voltage (v) ground pin current vs. input voltage i out = 10 a i out = 1ma i out = 100 a i out = 10 a 200 300 400 500 600 700 800 900 1000 1100 1200 1.5 2 2.5 3 3.5 4 ground current ( a) input voltage (v) ground pin current vs. input voltage i out =100ma i out = 50ma 10 15 20 25 30 35 40 4812 16 20 24 28 32 36 40 ground current ( a) input voltage (v) ground pin current vs. input voltage i out = 10 a i out = 1ma i out = 100 a
february 2005 5 mic5233 mic5233 micrel, inc. 0 20 40 60 80 100 120 -20 -10 0 10 input current (ma) supply voltage (v) input current vs. supply voltage v en = 5v r load = 30 ? 2.95 2.96 2.97 2.98 2.99 3.00 3.01 3.02 3.03 3.04 3.05 -40 -20 0 20 40 60 80 100 120 output voltage (v) temperature ( c ) output voltage vs. temperature i load = 100 a 0 50 100 150 200 250 300 -40 -20 0 20 40 60 80 100 120 short circuit current (ma) temperature ( c) short circuit current vs. temperature v in = 4v load transient response time (400 s/div.) output current (100ma/div.) output voltage (200mv/div.) v in = 4v v out = 3v c out = 4.7 f ceramic 100ma 0ma
mic5233 micrel, inc. mic5233 6 february 2005 functional diagrams in en out r1 r2 gnd enable v ref block diagram C fixed output voltage in en r1 r2 adj out gnd enable v ref block diagram C adjustable output voltage
february 2005 7 mic5233 mic5233 micrel, inc. applications information enable/shutdown the mic5233 comes with an active-high enable pin that allows the 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. input capacitor the mic5233 has high input voltage capability up to 36v. the input capacitor must be rated to sustain voltages that may be used on the input. an input capacitor may be required when the device is not near the source power supply or when supplied by a battery. small, surface mount, ceramic capaci- tors can be used for bypassing. a larger value may be required if the source supply has high ripple. output capacitor the mic5233 requires an output capacitor for stability. the design requires 2.2 f 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 3 ? . the output capacitor can be increased without limit. larger valued capacitors help to improve transient response. x7r/x5r dielectric-type ceramic capacitors are recom- mended because of their temperature performance. x7r- type capacitors change capacitance by 15% over their oper- ating 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 capaci- tor with y5v dielectric, the value must be much higher than an x7r ceramic capacitor to ensure the same minimum capaci- tance over the equivalent operating temperature range. no-load stability the mic5233 will remain stable and in regulation with no load unlike many other voltage regulators. this is especially important in cmos ram keep-alive applications. thermal consideration the mic5233 is designed to provide 100ma of continuous current in a very small package. maximum power dissipation can be calculated based on the output current and the voltage drop across the part. to determine the maximum power dissipation of the package, use the junction-to-ambient ther- mal resistance of the device and the following basic equation: p tt d(max) j(max) a ja = ? ? ? ? ? ? ? t j(max) is the maximum junction temperature of the die, 125 c, and t a is the ambient operating temperature. ja is layout dependent; table 1 shows examples of the junction- to-ambient thermal resistance for the mic5233. package ja recommended minimum footprint sot-23-5 235 c/w table 1. sot-23-5 thermal resistance the actual power dissipation of the regulator circuit can be determined using the equation: p d = (v in C v out )i out + v in i gnd substituting p d(max) for p d and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. for example, when operating the mic5233-3.0bm5 at 50 c with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: p 125 c 50 c 235 c/w d(max) = ? ? ? ? ? ? ? ja ) thermal resistance for the minimum footprint is 235 c/w, from table 1. it is important that the maximum power dissipation not be exceeded to ensure proper operation. since the mic5233 was designed to operate with high input voltages, careful consideration must be given so as not to overheat the device. with very high input-to-output voltage differentials, the output current is limited by the total power dissipation. total power dissipation is calculated using the following equation: p d = (v in C v out )i out + v in x i gnd due to the potential for input voltages up to 36v, ground current must be taken into consideration. if we know the maximum load current, we can solve for the maximum input voltage using the maximum power dissipa- tion calculated for a 50 c ambient, 319mv. p dmax = (v in C v out )i out + v in x i gnd 319mw = (v in C 3v)100ma + v in x 2.8ma ground pin current is estimated using the typical character- istics of the device. 619mw = v in (102.8ma) v in = 6.02v for higher current outputs only a lower input voltage will work for higher ambient temperatures. assuming a lower output current of 10ma, the maximum input voltage can be recalculated: 319mw = (v in C 3v)10ma + v in x 0.1ma 349mw = v in x 10.1ma v in = 34.9v maximum input voltage for a 10ma load current at 50 c ambient temperature is 34.9v, utilizing virtually the entire operating voltage range of the device.
mic5233 micrel, inc. mic5233 8 february 2005 adjustable regulator application the mic5233bm5 can be adjusted from 1.24v to 20v by using two external resistors (figure 1). the resistors set the output voltage based on the following equation: vv r r out ref 1 2 =+ ? ? ? ? ? ? ? ? ? ? ? ? 1 where v ref = 1.24v. feedback resistor r2 should be no larger than 300k ? . out adj. v in r 1 r 2 2.2 f 1.0 f en in v out gnd mic5233bm5 figure 1. adjustable voltage application
february 2005 9 mic5233 mic5233 micrel, inc. package information 0.20 (0.008) 0.09 (0.004) 0.60 (0.024) 0.10 (0.004) 3.02 (0.119) 2.80 (0.110) 10 0 3.00 (0.118) 2.60 (0.102) 1.75 (0.069) 1.50 (0.059) 0.95 (0.037) ref 1.30 (0.051) 0.90 (0.035) 0.15 (0.006) 0.00 (0.000) dimensions: mm (inch) 0.50 (0.020) 0.35 (0.014) 1.90 (0.075) ref sot-23-5 (m5) 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 this information furnished by micrel in this data sheet is believed 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 authorized for use as components in life support appliances, devices or systems where malfu nction of a product can reasonably be expected to result in personal injury. life support devices or systems are devices or systems that (a) are intend ed 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 significant inj ury to the user. a purchasers use or sale of micrel products for use in life support appliances, devices or systems is a purchasers own risk and purchaser a grees to fully indemnify micrel for any damages resulting from such use or sale. ? 2003 micrel, incorporated.
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