description gm6156 is an efficient linear voltage regulator with ultralow - noise output, very low dropout voltage (typically 17mv at light loads and 165mv at 50ma), and very low ground cur- rent (600a at 100ma output). gm6156 provides better than 1% initial accuracy. designed especially for hand-held, battery-powered de- vices, gm6156 includes a cmos or ttl compatible en- able/ shutdown control input. when shutdown, power con- sumption drops nearly to zero. regulator ground current in- creases only slightly in dropout, further prolonging battery life. key features of gm6156 include a reference bypass pin to improve its excellent low-noise performance, re- versed-battery protection, current limiting, and over- temperature shutdown. the gm6156 is available in sot-25 package. application features very low noise output high output voltage accuracy extremely accurate output voltage guaranteed 150ma output low quiescent current low dropout voltage extremely tight load and line regulation very low temperature coefficient current and thermal limiting reverse-battery protection "zero" off-mode current logic-controlled electronic enable typical applica tion circuits g m 6 1 5 6 v 0 . 1 www.gammamicro.com 1 cellular telephones laptop, notebook, and palmtop computers battery-powered equipment pcmcia v and v regulation/ switching cc pp consumer/ personal electronics smps post-regulator/ dc-to-dc modules high-efficiency linear power supplies low-noise operation: c = 470pf , c 2.2f byp out basic operation: c = not used, c 1f byp out g m 6 1 5 6 - 3 . 3 1 2 3 4 5 en gnd v out c = 2.2f in (tantalum) enable shutdown byp v in
marking information & pin configura tions (top view) package shipping ordering number output v oltage g m 6 1 5 6 2 ordering information sot-25 sot-25 sot-25 sot-25 sot-25 sot-25 sot-25 sot-25 sot-25 3,000 units/ t ape & reel 3,000 units/ t ape & reel 3,000 units/ t ape & reel 3,000 units/ t ape & reel 3,000 units/ t ape & reel 3,000 units/ t ape & reel 3,000 units/ t ape & reel 3,000 units/ t ape & reel 3,000 units/ t ape & reel gm 6156-ast25r gm 6156-2.5st25r gm 6156-2.7st25r gm 6156-2.8st25r gm 6156-3.0st25r gm 6156-3.3st25r gm 6156-3.6st25r gm 6156-4.0st25r gm 6156-5.0st25r 2.5v 2.7v 2.8v 3.0v 3.3v 3.6v 4.0v 5.0v voltage code en gnd byp v out v in sot-25 (sot-23-5) xx = marking code v = voltage code y = y ear w = weekly ( ja = gm6156) pin number pin name pin description 5 2 1 3 v in gnd en byp function supply input ground enable/ shutdown(input): coms compatible input. logic high = enable, logic low or open = shutdown. reference bypass: connect external 470pf capacitor to gnd to reduce output noise. may be left open. 4 v out regulator output adj a g t h j k l m q xxvyw 1 3 2 5 4 xxvyw 1 3 2 5 4 sot-25 (sot-23-5) adjustable voltage part identification fixed voltages v out v in en gnd adj * for detail ordering number identification, please see last page.
g m 6 1 5 6 3 para mete r sym bol ratin gs unit s -20 ~ +20 intern ally l imite d -40 ~ +125 260 -60 ~ +150 v v w c v in v en p d t j t lead t s absolute maximum ratings block diagram supp ly inp ut v oltag e enab le inp ut v oltag e powe r diss ipatio n (no te 3) junct ion t empe rature lead t empe rature (sold ering , 5 se cond s) stora ge t empe rature c c para mete r sym bol ratin gs unit s +2.5 to +1 6 0 to v in -40 ~ + 12 5 (note 3) v v c c/ w v in v en operating ra tings supp ly inp ut v oltag e enab le inp ut v oltag e junct ion t empe rature therm al re sistan ce t j r q ja ou t v ou t c ou t + gn d in v in by p c by p (o ptio na l) en + - ban dga p re f. cu rren t li mit the rma l sh utd ow n figure 1. ultra-low-noise fixed regulator ou t v ou t c ou t + gn d in v in en + - ban dga p re f. cu rren t li mit the rma l sh utd ow n c by p (o ptio na l) figure 2. ultra-low-noise adjustable regulator v = v (1 + r2/ r1) out ref adj r1 r2 -20 ~ + 20
g m 6 1 5 6 4 parameter symbol min typ max unit test condition output voltage accuracy output voltage t emperature coefficient v o variation from specified v out (note 4) -1 -2 1 2 % ppm/ c d v/ d t o 40 line regulation load regulation dropout voltage (note 6) d v/ o v o d v/ o v o v- in v o v = v + 1v to 16v in out i = 0.1ma to 150ma, (note 5) l i = 100a l i = 50ma l i = 100ma l i = 150ma l 0.004 0.02 10 110 140 165 0.012 0.05 0.2/ 0.5 50 70 150 230 250 300 275 350 %/ v mv quiescent current ground pin current (note 7) i gnd i gnd 1 5 125 150 600 800 1000 1500 1900 2500 a a v 0.4v (shutdown) en v 0.18v (shutdown) en 0.01 80 350 600 1300 ripple rejection current limit thermal regulation psrr i limt f = 100hz, i = 0.1ma l v = 0v out (note 8) 75 320 0.05 db ma %/ w 500 d v/ d p od output noise e no i = 50ma, c = 2.2f , ll 470pf from byp to gnd 260 enable input enable input logic-low voltage v il i il regulator shutdown v 0.4 0.18 -1 -2 enable input logic-high voltage enable input current v ih i ih regulator enabled v 2.0 2 v 0.4v il v 0.18v il v 2.0v ih 0.01 5 20 25 a note 1. exceeding the absolute maximum rating may damage the device. note 2. the device is not guaranteed to function outside its operating rating. note 3: the maximum allowable power dissipation at any t (ambient temperature) is p (max) = (t (max) -t ) . exceeding the maximum ad j a j a allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. note 4: output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. note 5: regulation is measured at constant junction temperature using low duty cycle pulse testing. parts are tested for load regulation in the load range from 0.1ma to 150ma. changes in output voltage due to heating effects are covered by the thermal regulation specification. note 6: dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1v differential. note 7: ground pin current is the regulator quiescent current plus pass transistor base current. the total current drawn from the supply is the sum of the load current plus the ground pin current. note 8: 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 150ma load pulse at v = 16v for t = 10ms. in q electrical characteristics (v = v + 1v; i = 100a; c = 1.0f; v 2.0; t = 25c, bold values indicate -40c t +125c; in out l l en j j unless otherwise noted) v 2.0v, i = 0.1ma en l i = 50ma l i = 100ma l i = 150ma l %/v nv/ hz a
g m 6 1 5 6 5 applications information enable/ shutdown forcing en (enable/ shutdown) high (>2v) enables the regulator. en is compatible with cmos logic gates. if enable shutdown feature is not required, connect en (pin 1) to in (supply input, pin 5). see figure 3. input capacitor a 1f 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 . reference bypass capacitor byp (reference bypass) is connected to the internal voltage reference. a 470pf capacitor (c ) connected byp from byp to gnd quiets this reference, providing a significant reduction in output noise. c reduces the byp regulator phase margin. when using c , output capacitors of 2.2f or greater are generally required to byp maintain stability. the start-up speed of gm6156 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 . likewise, if byp rapid turn-on is necessary, consider omitting c . byp if output noise is not a major concern, omit c and leave byp open. byp 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. 1.0f minimum is recommended when c is not used (see figure 2). 2.2f minimum is recommended when c is 470pf (see figure 1). byp byp larger values improve the regulator's transient response, the output capacitor value may be increased without limit. the output capacitor should have an esr (effective series resistance) of about 5w or less and a resonant frequency above 1mhz. ultra-low-esr capacitors can cause a low amplitude oscillation on the output and/ or underdamped transient response. most tantalum or aluminum electrolytic capacitors are adequate; film types will work, but are more expensive. since many aluminum electrolytics have electrolytes that freeze at about -30c, solid tantalums ate recommended for operation below -25c. at lower values for output current, less output capacitance is required for output stability. the capacitor can be reduced to 0.47f for current below 10ma or 0.33f for current below 1ma. no-load stability gm6156 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. thermal considerations gm6156 is designed to provide 150ma 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. t o determine the maximum power dissipation of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation: t is the maximum junction temperature of the die, 125c, and ta is the ambient operating temperature. j(max) r is layout dependent; t able 1 shows examples of junction-to-ambient thermal resistance for the gm6156. ja q p = d(max) (t - t ) j(max) a r q ja
g m 6 1 5 6 6 the actual power dissipation of the regulator circuit can be determined using by the equation: p = (v - v ) i + v i d in out out in gnd substituting p for p and solving for the operating conditions that are critical to the application will give d(max) d the maximum operating conditions for the regulator circuit. for example, when operating the gm6156 at room temperature with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: the junction-to-ambient thermal resistance for the minimum footprint is 220c/ w, from t able 1. the maximum power dissipation must not be exceeded for proper operation. using the output voltage of 3.3v and an output current of 150ma, the maximum input voltage can be determined. from the electrical characteristics table, the maximum ground current for150ma output current is 2500 or 2.5ma. 455mw = (v - 3.3v) 150ma + v ? 2.5ma in in 455mw = v ? 150ma - 495ma + v ? 2.5ma in in 950mw = v ? 152.5ma in v = 6.23v in(max) therefore, a 3.3v application at 150ma of output current can accept a maximum input voltage of 6.2v in a sot-25 package. for a full discussion of heat sinking and thermal effects on voltage regulators. fixed regulator applications figure 3. ultra-low-noise fixed voltage application figure 4. low-noise fixed v oltage application adjustable regulator applications the gm6156 can be adjusted to a specific output voltage by using two externa resistors (figure 5). the resistors set the output voltage based on the following equation: p = d(max) p = 455mw d(max) (125c - 25c) 220c/w figure3 includes a 470pf capacitor for low-noise operation and shows en (pin 3) connected to in (pin 1) for an application where enable/ shutdown is not required. c = 2.2f minimum. out g m 6 1 5 6 1 2 3 4 5 v in v out 2.2f 470pf enable shutdown figure 4 is an example of a low-noise configuration where c is not required. c = 1f minimum. byp out v = 1.242v x ( +1) out r2 r1 parameter r recommended ja q minimum footprint r 1" square ja q copper clad r jc q sot-23-5 220c/ w 170c/ w 130c/ w table 1. sot -25 thermal resistance g m 6 1 5 6 1 2 3 4 5 v in v out 1.0f en byp
g m 6 1 5 6 7 this equation is correct due to the configuration of the bandgap reference. the bandgap voltage is relative to the output, as seen in the block diagram. traditional regulators normally have the reference voltage relative to ground and have a different v equation. out resistor values are not critical because adj(adjust) has a high input impedance, but use resistors of 470k w or less for best results. a capacitor from adj to ground provides greatly improved noise performance. figure 5. ultra-low- noise adjustable v oltage application figure 5 includes the optional 470pf noise bypass capacitor from adj to gnd to reduce output noise. dual-supply operation when used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode clamped to ground. typical characteristics 0 -20 -40 -60 -80 -100 10 100 1k 10k 100k 1m 10m figure 6. power supply rejection ratio frequency(hz) p s r r ( d b ) v = 6v in v = 5v out i =100ma out c = 1f out 0 -20 -40 -60 -80 -100 10 100 1k 10k 100k 1m 10m figure 7. power supply rejection ratio frequency(hz) p s r r ( d b ) v = 6v in v = 5v out i =100ma out c = 2.2f out c = 0.01f byp 320 280 240 200 160 120 80 40 0 0 40 80 120 160 figure 8. dropout voltage vs. output current output current (ma) d r o p o u t v o l t a g e ( m v ) 125c 25c -40c figure 9. noise performance frequency(hz) 10 1 0.1 0.01 0.001 0.0001 10 100 1k 10k 100k 1m 10m n o i s e ( v / h z ) 100ma 10ma 1ma v =5v out c =10f out electrolytic c =10nf byp r1 r2 g m 6 1 5 6 1 2 3 4 5 v in v out 470pf
g m 6 1 5 6 8 ordering number gm 6156 a st25 r gamma micro. circuit type output voltage a: adj, 2.5: 2.5v 2.7: 2.7v , 2.8: 2.8v 3.0: 3.0v , 3.3: 3.3v , 3.6: 3.6v , 4.0: 4.0v package st25: sot-25 shipping r: t ape & reel sot-25(sot -23-5) p ackage outline dimensions pad layout 2.9 0.1 0.074 1.9 0.037 0.95 0.037 0.95 0.094 2.4 0.028 0.7 inches mm ( ) 1.9 0.05 0.95 0.038 2.8 0.1 1.5 0.05 0.65 0.05 0.35 0.03 0.13 0~0.1 0.8 0.05 1.10 0.1 5 5 unit: mm 0.039 1.0
g m 6 1 5 6 9
|
