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april 2001 1 mic5219 mic5219 micrel typical applications mic5219 500ma-peak output ldo regulator general description the mic5219 is an efficient linear voltage regulator with high peak output current capability, very low dropout voltage, and better than 1% output voltage accuracy. dropout is typically 10mv at light loads and less than 500mv at full load. the mic5219 is designed to provide a peak output current for startup conditions where higher inrush current is demanded. it features a 500ma peak output rating. continuous output current is limited only by package and layout. the mic5219 can be enabled or shut down by a cmos or ttl compatible signal. when disabled, power consumption drops nearly to zero. dropout ground current is minimized to help prolong battery life. other key features include reversed- battery protection, current limiting, overtemperature shut- down, and low noise performance with an ultra-low-noise option. the mic5219 is available in adjustable or fixed output volt- ages in space-saving sot-23-5 and mm8? 8-lead power msop packages. for higher power requirements see the mic5209 or mic5237. features ? 500ma output current capability sot-23-5 package - 500ma peak msop-8 package - 500ma continuous ? low 500mv maximum dropout voltage at full load ? extremely tight load and line regulation ? tiny sot-23-5 and mm8? power msop-8 package ? ultra-low-noise output ? low temperature coefficient ? current and thermal limiting ? reversed-battery protection ? cmos/ttl-compatible enable/shutdown control ? near-zero shutdown current applications ? laptop, notebook, and palmtop computers ? cellular telephones and battery-powered equipment ? consumer and personal electronics ? pc card v cc and v pp regulation and switching ? smps post-regulator/dc-to-dc modules ? high-efficiency linear power supplies 1 2 3 4 8 7 6 5 mic5219-5.0bmm 2.2f tantalum v out 5v v in 6v enable s hutdown 470pf 5v ultra-low-noise regulator 15 2 3 4 2.2f tantalum 470pf v out 3.3v mic5219-3.3bm5 v in 4v enable shutdown 3.3v ultra-low-noise regulator micrel, inc. 1849 fortune drive san jose, ca 95131 usa tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 http://www.micrel.com
mic5219 micrel mic5219 2 april 2001 ordering information part number marking volts junction temp. range package mic5219-3.0bmm 3.0v C 40 c to +125 c msop-8 mic5219-3.3bmm 3.3v C 40 c to +125 c msop-8 mic5219-3.6bmm 3.6v C 40 c to +125 c msop-8 mic5219-5.0bmm 5.0v C 40 c to +125 c msop-8 mic5219bmm adj. C 40 c to +125 c msop-8 mic5219-2.5bm5 lg25 2.5v C 40 c to +125 c sot-23-5 mic5219-2.6bm5 lg26 2.6v C 40 c to +125 c sot-23-5 mic5219-2.7bm5 lg27 2.7v C 40 c to +125 c sot-23-5 mic5219-2.8bm5 lg28 2.8v C 40 c to +125 c sot-23-5 mic5219-2.9bm5 lg29 2.9v C 40 c to +125 c sot-23-5 mic5219-3.0bm5 lg30 3.0v C 40 c to +125 c sot-23-5 mic5219-3.1bm5 lg31 3.1v C 40 c to +125 c sot-23-5 mic5219-3.3bm5 lg33 3.3v C 40 c to +125 c sot-23-5 mic5219-3.6bm5 lg36 3.6v C 40 c to +125 c sot-23-5 mic5219-5.0bm5 lg50 5.0v C 40 c to +125 c sot-23-5 mic5219bm5 lgaa adj. C 40 c to +125 c sot-23-5 other voltages available. consult micrel for details. 1 2 3 4 8 7 6 5 gnd gnd gnd gnd en in out byp mic5219-x.xbmm mm8 msop-8 fixed voltages 1 2 3 4 8 7 6 5 gnd gnd gnd gnd en in out adj mic5219bmm mm8 msop-8 adjustable voltage in out byp en lgxx 1 3 45 2 gnd mic5219-x.xbm5 sot-23-5 fixed voltages part identification in out adj en lgaa 1 3 45 2 gnd mic5219bm5 sot-23-5 adjustable voltage pin configuration
april 2001 3 mic5219 mic5219 micrel pin description pin no. pin no. pin name pin function msop-8 sot-23-5 2 1 in supply input 5 C 8 2 gnd ground: msop-8 pins 5 through 8 are internally connected. 3 5 out regulator output 1 3 en enable (input): cmos compatible control input. logic high = enable; logic low or open = shutdown. 4 (fixed) 4 (fixed) byp reference bypass: connect external 470pf capacitor to gnd to reduce output noise. may be left open. 4 (adj.) 4 (adj.) adj adjust (input): feedback input. connect to resistive voltage-divider network.
mic5219 micrel mic5219 4 april 2001 electrical characteristics v in = v out + 1.0v; c out = 4.7 f, i out = 100 a; t j = 25 c, bold values indicate C 40 c t j +125 c; unless noted. symbol parameter conditions min typical max units v out output voltage accuracy variation from nominal v out C 11% 22% ? v out / ? t output voltage note 2 40 ppm/ c temperature coefficient ? v out /v out line regulation v in = v out + 1v to 12v 0.009 0.05 %/v 0.1 ? v out /v out load regulation i out = 100 a to 500ma note 3 0.05 0.5 % 0.7 v in C v out dropout voltage, note 4 i out = 100 a1060mv 80 i out = 50ma 115 175 mv 250 i out = 150ma 175 300 mv 400 i out = 500ma 350 500 mv 600 i gnd ground pin current, notes 5, 6 v en 3.0v, i out = 100 a 80 130 a 170 v en 3.0v, i out = 50ma 350 650 a 900 v en 3.0v, i out = 150ma 1.8 2.5 ma 3.0 v en 3.0v, i out = 500ma 12 20 ma 25 ground pin quiescent current, v en 0.4v 0.05 3 a note 6 v en 0.18v 0.10 8 a psrr ripple rejection f = 120hz 75 db i limit current limit v out = 0v 700 1000 ma ? v out / ? p d thermal regulation note 7 0.05 %/w e no output noise i out = 50ma, c out = 2.2 f, c byp = 0 500 nv/ hz i out = 50ma, c out = 2.2 f, c byp = 470pf 300 nv/ hz enable input v enl enable input logic-low voltage v en = logic low (regulator shutdown) 0.4 v 0.18 v en = logic high (regulator enabled) 2.0 v i enl enable input current v enl 0.4v 0.01 C 1 a v enl 0.18v 0.01 2 a i enh v enh 2.0v 2 5 20 a 25 absolute maximum ratings supply input voltage (v in ) ............................ C 20v to +20v power dissipation (p d ) ............................ internally limited junction temperature (t j ) ....................... C 40 c to +125 c lead temperature (soldering, 5 sec.) ...................... 260 c operating ratings supply input voltage (v in ) ........................... +2.5v to +12v enable input voltage (v en ) .................................. 0v to v in junction temperature (t j ) ....................... C 40 c to +125 c package thermal resistance ......................... see table 1
april 2001 5 mic5219 mic5219 micrel note 1: absolute maximum ratings indicate limits beyond which damage to the component may occur. electrical specifications do not apply when operating the device outside of its operating ratings. the maximum allowable power dissipation is a function of the maximum jun ction temperature, t j(max) , the junction-to-ambient thermal resistance, ja , and the ambient temperature, t a . the maximum allowable power dissipation at any ambient temperature is calculated using: p d(max) = (t j(max) C t a ) ja . exceeding the maximum allowable power dissipa- tion will result in excessive die temperature, and the regulator will go into thermal shutdown. see table 1 and the thermal considerations section for details. note 2: output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. note 3: regulation is measured at constant junction temperature using low duty cycle pulse testing. parts are tested for load regulatio n in the load range from 100 a to 500ma. changes in output voltage due to heating effects are covered by the thermal regulation specification. note 4: dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value mea sured at 1v differential. note 5: ground pin current is the regulator quiescent current plus pass transistor base current. the total current drawn from the suppl y is the sum of the load current plus the ground pin current. note 6: v en is the voltage externally applied to devices with the en (enable) input pin. note 7: thermal regulation is defined as the change in output voltage at a time t after a change in power dissipation is applied, excluding load or line regulation effects. specifications are for a 500ma load pulse at v in = 12v for t = 10ms. note 8: c byp is an optional, external bypass capacitor connected to devices with a byp (bypass) or adj (adjust) pin.
mic5219 micrel mic5219 6 april 2001 typical characteristics -100 -80 -60 -40 -20 0 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 psrr (db) frequency (hz) power supply rejection ratio i out = 100 a c out = 1 f v in = 6v v out = 5v 10 100 1k 10k 100k 1m 10m -100 -80 -60 -40 -20 0 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 psrr (db) frequency (hz) power supply rejection ratio i out = 1ma c out = 1 f v in = 6v v out = 5v 10 100 1k 10k 100k 1m 10m -100 -80 -60 -40 -20 0 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 psrr (db) frequency (hz) power supply rejection ratio i out = 100ma c out = 1 f v in = 6v v out = 5v 10 100 1k 10k 100k 1m 10m -100 -80 -60 -40 -20 0 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 psrr (db) frequency (hz) power supply rejection ratio i out = 100 a c out = 2.2 f c byp = 0.01 f v in = 6v v out = 5v 10 100 1k 10k 100k 1m 10m -100 -80 -60 -40 -20 0 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 psrr (db) frequency (hz) power supply rejection ratio i out = 1ma c out = 2.2 f c byp = 0.01 f v in = 6v v out = 5v 10 100 1k 10k 100k 1m 10m -100 -80 -60 -40 -20 0 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 psrr (db) frequency (hz) power supply rejection ratio i out = 100ma c out = 2.2 f c byp = 0.01 f v in = 6v v out = 5v 10 100 1k 10k 100k 1m 10m 0 10 20 30 40 50 60 0 0.1 0.2 0.3 0.4 ripple rejection (db) voltage drop (v) power supply ripple rejection vs. voltage drop i out = 100ma 10ma 1ma c out = 1 f 0 10 20 30 40 50 60 70 80 90 100 0 0.1 0.2 0.3 0.4 ripple rejection (db) voltage drop (v) power supply ripple rejection vs. voltage drop i out = 100ma 10ma 1ma c out = 2.2 f c byp = 0.01 f 0.0001 0.001 0.01 0.1 1 10 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 noise ( v/ hz) frequency (hz) noise performance 10 100 1k 10k 100k 1m 10m 10ma, c out = 1 f v out = 5v 0.0001 0.001 0.01 0.1 1 10 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 noise ( v/ noise performance 10ma 1ma 100ma 10 100 1k 10k 100k 1m 10m v out = 5v c out = 10 f electrol y tic 0.0001 0.001 0.01 0.1 1 10 1e+1 1e+2 1e+3 1e+4 1e+5 1e+6 1e+7 noise ( v/ noise performance 10ma 1ma 100ma 10 100 1k 10k 100k 1m 10m v out = 5v c out = 10 f electrolytic c byp = 100pf 0 100 200 300 400 0 100 200 300 400 500 dropout voltage (mv) output current (ma) dropout voltage vs. output current
april 2001 7 mic5219 mic5219 micrel 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0123456789 output voltage (v) input voltage (v) dropout characteristics i l =100 a i l =100ma i l =500ma 0 2 4 6 8 10 12 0 100 200 300 400 500 ground current (ma) output current (ma) ground current vs. output current 0 0.5 1.0 1.5 2.0 2.5 3.0 02468 ground current (ma) input voltage (v) ground current vs. supply voltage i l =100 ma i l =100 a 0 5 10 15 20 25 0123456789 ground current (ma) input voltage (v) ground current vs. supply voltage i l =500ma
mic5219 micrel mic5219 8 april 2001 block diagrams in en out byp c byp (optional) gnd v ref bandgap ref. current limit thermal shutdown c out v out v in mic5219-x.xbm5/mm ultra-low-noise fixed regulator in en out c byp (optional) gnd v ref bandgap ref. current limit thermal shutdown c out v out v in r1 r2 mic5219bm5/mm [adj.] ultra-low-noise adjustable regulator
april 2001 9 mic5219 mic5219 micrel applications information the mic5219 is designed for 150ma to 200ma output current applications where a high current spike (500ma) is needed for short, startup conditions. basic application of the device will be discussed initially followed by a more detailed discus- sion of higher current applications. enable/shutdown forcing en (enable/shutdown) high (> 2v) enables the regu- lator. en is compatible with cmos logic. if the enable/ shutdown feature is not required, connect en to in (supply input). see figure 5. input capacitor a 1 f capacitor should be placed from in to gnd if there is more than 10 inches of wire between the input and the ac filter capacitor or if a battery is used as the input. output capacitor an output capacitor is required between out and gnd to prevent oscillation. the minimum size of the output capacitor is dependent upon whether a reference bypass capacitor is used. 1 f minimum is recommended when c byp is not used (see figure 5). 2.2 f minimum is recommended when c byp is 470pf (see figure 6). for applications <3v, the output capacitor should be increased to 22 f minimum to reduce start-up overshoot. larger values improve the regulator s transient response. the output capacitor value may be in- creased without limit. the output capacitor should have an esr (equivalent series resistance) of about 5 ? or less and a resonant frequency above 1mhz. ultra-low-esr capacitors could cause oscilla- tion and/or underdamped transient response. most tantalum or aluminum electrolytic capacitors are adequate; film types will work, but are more expensive. many aluminum electrolyt- ics have electrolytes that freeze at about C 30 c, so solid tantalums are recommended for operation below C 25 c. at lower values of output current, less output capacitance is needed for stability. the capacitor can be reduced to 0.47 f for current below 10ma or 0.33 f for currents below 1ma. no-load stability the mic5219 will remain stable and in regulation with no load (other than the internal voltage divider) unlike many other voltage regulators. this is especially important in cmos ram keep-alive applications. reference bypass capacitor byp is connected to the internal voltage reference. a 470pf capacitor (c byp ) connected from byp to gnd quiets this reference, providing a significant reduction in output noise (ultra-low-noise performance). c byp reduces the regulator phase margin; when using c byp , output capacitors of 2.2 f or greater are generally required to maintain stability. the start-up speed of the mic5219 is inversely proportional to the size of the reference bypass capacitor. applications requiring a slow ramp-up of output voltage should consider larger values of c byp . likewise, if rapid turn-on is necessary, consider omitting c byp . thermal considerations the mic5219 is designed to provide 200ma of continuous current in two very small profile packages. 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 thermal resistance, junction-to-ambient, of the device and the following basic equation. p = t C t d (max) j(max) a ja () c, and t a is the ambient operating temperature. ja is layout dependent; table 1 shows examples of thermal resis- tance, junction-to-ambient, for the mic5219. package ja recommended ja 1" square jc minimum footprint 2 oz. copper mm8 ? (mm) 160 c/w 70 c/w 30 c/w sot-23-5 (m5) 220 c/w 170 c/w 130 c/w table 1. mic5219 thermal resistance the actual power dissipation of the regulator circuit can be determined using one simple 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, if we are operating the mic5219-3.3bm5 at room temperature, with a minimum footprint layout, we can deter- mine the maximum input voltage for a set output current. p = 125 c C 25 c c/w d(max) () 220 p d(max) = 455mw the thermal resistance, junction-to-ambient, for the mini- mum footprint is 220 c/w, taken from table 1. the maximum power dissipation number cannot be exceeded for proper operation of the device. using the output voltage of 3.3v, and an output current of 150ma, we can determine the maximum input voltage. ground current, maximum of 3ma for 150ma of output current, can be taken from the electrical character- istics section of the data sheet. 455mw = (v in C 3.3v) 150ma + v in 3ma 455mw = (150ma) v in + 3ma v in C 495mw 950mw = 153ma v in v in = 6.2v max therefore, a 3.3v application at 150ma of output current can accept a maximum input voltage of 6.2v in a sot-23-5 package. for a full discussion of heat sinking and thermal effects on voltage regulators, refer to the regulator thermals section of micrel s designing with low-dropout voltage regu- lators handbook.
mic5219 micrel mic5219 10 april 2001 peak current applications the mic5219 is designed for applications where high start- up currents are demanded from space constrained regula- tors. this device will deliver 500ma start-up current from a sot-23-5 or mm8 package, allowing high power from a very low profile device. the mic5219 can subsequently provide output current that is only limited by the thermal characteris- tics of the device. you can obtain higher continuous currents from the device with the proper design. this is easily proved with some thermal calculations. if we look at a specific example, it may be easier to follow. the mic5219 can be used to provide up to 500ma continuous output current. first, calculate the maximum power dissipa- tion of the device, as was done in the thermal considerations section. worst case thermal resistance ( ja = 220 c/w for the mic5219-x.xbm5), will be used for this example. p = t C t d (max) j(max) a ja () assuming a 25 c room temperature, we have a maximum power dissipation number of p = 125 c C 25 c c/w d(max) () 220 p d(max) = 455mw then we can determine the maximum input voltage for a five- volt regulator operating at 500ma, using worst case ground current. p d(max) = 455mw = (v in C v out ) i out + v in i gnd i out = 500ma v out = 5v i gnd = 20ma 455mw = (v in C 5v) 500ma + v in 20ma 2.995w = 520ma v in v 2.955w 520ma 5.683v in(max) == therefore, to be able to obtain a constant 500ma output current from the 5219-5.0bm5 at room temperature, you need extremely tight input-output voltage differential, barely above the maximum dropout voltage for that current rating. you can run the part from larger supply voltages if the proper precautions are taken. varying the duty cycle using the enable pin can increase the power dissipation of the device by maintaining a lower average power figure. this is ideal for applications where high current is only needed in short bursts. figure 1 shows the safe operating regions for the mic5219-x.xbm5 at three different ambient temperatures and at different output currents. the data used to determine this figure assumed a minimum footprint pcb design for minimum heat sinking. figure 2 incorporates the same factors as the first figure, but assumes a much better heat sink. a 1" square copper trace on the pc board reduces the thermal resistance of the device. this improved thermal resistance improves power dissipation and allows for a larger safe operating region. figures 3 and 4 show safe operating regions for the mic5219- x.xbmm, the power msop package part. these graphs show three typical operating regions at different tempera- tures. the lower the temperature, the larger the operating region. the graphs were obtained in a similar way to the graphs for the mic5219-x.xbm5, taking all factors into con- sideration and using two different board layouts, minimum footprint and 1" square copper pc board heat sink. (for further discussion of pc board heat sink characteristics, refer to application hint 17, designing pc board heat sinks .) the information used to determine the safe operating regions can be obtained in a similar manner to that used in determin- ing typical power dissipation, already discussed. determin- ing the maximum power dissipation based on the layout is the first step, this is done in the same manner as in the previous two sections. then, a larger power dissipation number multiplied by a set maximum duty cycle would give that maximum power dissipation number for the layout. this is best shown through an example. if the application calls for 5v at 500ma for short pulses, but the only supply voltage available is 8v, then the duty cycle has to be adjusted to determine an average power that does not exceed the maximum power dissipation for the layout. avg.p = % dc 100 v C v i v i din out out in gnd ? ? ? ? ? ? () + 455mw = % dc 100 8v C 5v 500ma 8v 20ma ? ? ? ? ? ? () + 455mw = % duty cycle 100 1.66w ? ? ? ? ? ? 0.274 = % duty cycle 100 % duty cycle max = 7.4% 2 with an output current of 500ma and a three-volt drop across the mic5219-xxbmm, the maximum duty cycle is 27.4%. applications also call for a set nominal current output with a greater amount of current needed for short durations. this is a tricky situation, but it is easily remedied. calculate the average power dissipation for each current section, then add the two numbers giving the total power dissipation for the regulator. for example, if the regulator is operating normally at 50ma, but for 12.5% of the time it operates at 500ma output, the total power dissipation of the part can be easily determined. first, calculate the power dissipation of the device at 50ma. we will use the mic5219-3.3bm5 with 5v input voltage as our example. p d 50ma = (5v C 3.3v) 50ma + 5v 650 a p d 50ma = 173mw however, this is continuous power dissipation, the actual on-time for the device at 50ma is (100%-12.5%) or 87.5% of the time, or 87.5% duty cycle. therefore, p d must be multiplied by the duty cycle to obtain the actual average power dissipation at 50ma.
april 2001 11 mic5219 mic5219 micrel 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma 0 2 4 6 8 10 0 20406080100 voltage drop (v) duty cycle (%) 500ma 400ma 300ma 200ma 100ma a. 25 c ambient b. 50 c ambient c. 85 c ambient figure 4. mic5219-x.xbmm (msop-8) on 1-inch 2 copper cladding a. 25 c ambient b. 50 c ambient c. 85 c ambient figure 3. mic5219-x.xbmm (msop-8) on minimum recommended footprint a. 25 c ambient b. 50 c ambient c. 85 c ambient figure 2. mic5219-x.xbm5 (sot-23-5) on 1-inch 2 copper cladding a. 25 c ambient b. 50 c ambient c. 85 c ambient figure 1. mic5219-x.xbm5 (sot-23-5) on minimum recommended footprint
mic5219 micrel mic5219 12 april 2001 p d 50ma = 0.875 173mw p d 50ma = 151mw the power dissipation at 500ma must also be calculated. p d 500ma = (5v C 3.3v) 500ma + 5v 20ma p d 500ma = 950mw this number must be multiplied by the duty cycle at which it would be operating, 12.5%. p d = 0.125 950mw p d = 119mw the total power dissipation of the device under these condi- tions is the sum of the two power dissipation figures. p d(total) = p d 50ma + p d 500ma p d(total) = 151mw + 119mw p d(total) = 270mw the total power dissipation of the regulator is less than the maximum power dissipation of the sot-23-5 package at room temperature, on a minimum footprint board and there- fore would operate properly. multilayer boards with a ground plane, wide traces near the pads, and large supply-bus lines will have better thermal conductivity. for additional heat sink characteristics, please refer to micrel application hint 17, designing p.c. board heat sinks , included in micrel s databook . for a full discussion of heat sinking and thermal effects on voltage regulators, refer to regulator thermals section of micrel s designing with low- dropout voltage regulators handbook. fixed regulator circuits mic5219-x.x in out gnd 1f v in v out en byp figure 5. low-noise fixed voltage regulator figure 5 shows a basic mic5219-x.xbmx fixed-voltage regu- lator circuit. a 1 f minimum output capacitor is required for basic fixed-voltage applications. mic5219-x.x in out gnd 470pf v in en byp 2.2f v out figure 6. ultra-low-noise fixed voltage regulator figure 6 includes the optional 470pf noise bypass capacitor between byp and gnd to reduce output noise. note that the minimum value of c out must be increased when the bypass capacitor is used. adjustable regulator circuits mic5219 in out gnd v in en adj 1f v out r1 r2 figure 7. low-noise adjustable voltage regulator figure 7 shows the basic circuit for the mic5219 adjustable regulator. the output voltage is configured by selecting values for r1 and r2 using the following formula: v 1.242v r2 r1 1 out =+ ? ? ? ? ? ? although adj is a high-impedance input, for best perfor- mance, r2 should not exceed 470k ? . mic5219 in out gnd v in en adj 2.2f v out r1 r2 470pf figure 8. ultra-low-noise adjustable application. figure 8 includes the optional 470pf bypass capacitor from adj to gnd to reduce output noise.
april 2001 13 mic5219 mic5219 micrel package information 0.008 (0.20) 0.004 (0.10) 0.039 (0.99) 0.035 (0.89) 0.021 (0.53) 0.012 (0.03) r 0.0256 (0.65) typ 0.012 (0.30) r 5 max 0 min 0.122 (3.10) 0.112 (2.84) 0.120 (3.05) 0.116 (2.95) 0.012 (0.03) 0.007 (0.18) 0.005 (0.13) 0.043 (1.09) 0.038 (0.97) 0.036 (0.90) 0.032 (0.81) dimensions: inch (mm) 0.199 (5.05) 0.187 (4.74) 8-pin msop (mm) 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. 1849 fortune drive san jose, ca 95131 usa tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 web http://www.micrel.com this information is believed to be accurate and reliable, however no responsibility is assumed by micrel for its use nor for an y infringement of patents or other rights of third parties resulting from its use. no license is granted by implication or otherwise under any patent or pat ent right of micrel inc. ? 2000 micrel incorporated

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