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1 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc temperature ( c) ?0 minimum input voltage (v) 1.1 1.0 0.9 0.8 0.6 0.7 0.5 0.4 0.3 0.2 0.1 0 3020 ta02 25 0 ?5 50 75 125 100 i l = 100ma applicatio s u features typical applicatio u descriptio u 100ma, low voltage, very low dropout linear regulator v in range: 0.9v to 10v minimum input voltage: 0.9v dropout voltage: 150mv typical output current: 100ma adjustable output (v ref = v out(min) = 200mv) fixed output voltages: 1.2v, 1.5v, 1.8v stable with low esr, ceramic output capacitors (2.2 f minimum) 0.2% load regulation from 1ma to 100ma quiescent current: 120 a (typ) 3 a typical quiescent current in shutdown current limit protection reverse-battery protection no reverse current thermal limiting with hysteresis 8-lead dfn (3mm 3mm) and msop packages 1.8v to 1.5v, 100ma vldo regulator low current regulators battery-powered systems cellular phones pagers wireless modems the lt 3020 is a very low dropout voltage (vldo tm ) linear regulator that operates from input supplies down to 0.9v. this device supplies 100ma of output current with a typical dropout voltage of 150mv. the lt3020 is ideal for low input voltage to low output voltage applications, providing comparable electrical efficiency to that of a switching regulator. the lt3020 regulator optimizes stability and transient response with low esr, ceramic output capacitors as small as 2.2 f. other lt3020 features include 0% typical line regulation and 0.2% typical load regulation. in shut- down, quiescent current drops to 3 a. internal protection circuitry includes reverse-battery pro- tection, current limiting, thermal limiting with hysteresis, and reverse-current protection. the lt3020 is available as an adjustable output device with an output range down to the 200mv reference. three fixed output voltages, 1.2v, 1.5v and 1.8v, are also available. the lt3020 regulator is available in the low profile (0.75mm) 8-lead (3mm 3mm) dfn package with ex- posed pad and the 8-lead msop package. in shdn 2.2 f 3020 ta01 out v in 1.8v gnd lt3020-1.5 v out 1.5v 100ma 2.2 f minimum input voltage , ltc and lt are registered trademarks of linear technology corporation. vldo is a trademark of linear technology corporation. all other trademarks are the property of their respective owners.
2 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc (note 1) in pin voltage ........................................................ 10v out pin voltage .................................................... 10v input-to-output differential voltage ....................... 10v adj pin voltage .................................................... 10v shdn pin voltage ................................................. 10v output short-circut duration .......................... indefinite operating junction temperature range (notes 2, 3) .......................................... 40 c to 125 c storage temperature range dd .................................................... 65 c to 125 c ms8 .................................................. 65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c absolute axi u rati gs w ww u package/order i for atio uu w t jmax = 125 c, ja = 35 c/ w*, jc = 3 c/ w exposed pad is gnd (pin 9) connect to pin 4 *see the applications information section top view 9 dd package 8-lead (3mm 3mm) plastic dfn 5 6 7 8 4 3 2 1 out out adj gnd in in nc shdn 1 2 3 4 out out adj gnd 8 7 6 5 in in nc shdn top view ms8 package 8-lead plastic msop t jmax = 150 c, ja = 125 c/ w, jc = 40 c/ w see the applications information section lt3020edd lt3020idd order part number dd part marking laex lbyh lt3020edd-1.2 lt3020edd-1.5 lt3020edd-1.8 lt3020idd-1.2 lt3020idd-1.5 lt3020idd-1.8 dd part marking lbkc lbkd lbkf lbyj lbyk lbym t jmax = 125 c, ja = 35 c/ w*, jc = 3 c/ w exposed pad is gnd (pin 9) connect to pin 4 *see the applications information section lt3020ems8 lt3020ims8 lt3020ems8-1.2 lt3020ems8-1.5 lt3020ems8-1.8 lt3020ims8-1.2 lt3020ims8-1.5 lt3020ims8-1.8 ms8 part marking ltbkg ltbkh ltbkj ltbyp ltbyq ltbyr ms8 part marking ltagl ltbyn t jmax = 150 c, ja = 125 c/ w, jc = 40 c/ w see the applications information section 1 2 3 4 out out out gnd 8 7 6 5 in in nc shdn top view ms8 package 8-lead plastic msop top view 9 dd package 8-lead (3mm 3mm) plastic dfn 5 6 7 8 4 3 2 1 out out out gnd in in nc shdn order part number order part number order part number order options tape and reel: add #tr lead free: add #pbf lead free tape and reel: add #trpbf lead free part marking: http://www.linear.com/leadfree/ consult ltc marketing for parts specified with wider operating temperature ranges.
3 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc minimum input voltage (note 14) i load = 100ma, t j > 0 c 0.9 1.05 v i load = 100ma, t j < 0 c 0.9 1.10 v adj pin voltage (notes 4, 5) v in = 1.5v, i load = 1ma 196 200 204 mv 1.15v < v in < 10v, 1ma < i load < 100ma 193 200 206 mv regulated output voltage lt3020-1.2 v in = 1.5v, i load = 1ma 1.176 1.200 1.224 v (note 4) 1.5v < v in < 10v, 1ma < i load < 100ma 1.157 1.200 1.236 v lt3020-1.5 v in = 1.8v, i load = 1ma 1.470 1.500 1.530 v 1.8v < v in < 10v, 1ma < i load < 100ma 1.447 1.500 1.545 v lt3020-1.8 v in = 2.1v, i load = 1ma 1.764 1.800 1.836 v 2.1v < v in < 10v, 1ma < i load < 100ma 1.737 1.800 1.854 v line regulation (note 6) ? v in = 1.15v to 10v, i load = 1ma ?.75 0 1.75 mv lt3020-1.2 ? v in = 1.5v to 10v, i load = 1ma ?0.5 0 10.5 mv lt3020-1.5 ? v in = 1.8v to 10v, i load = 1ma ?3 0 13 mv lt3020-1.8 ? v in = 2.1v to 10v, i load = 1ma ?5.8 0 15.8 mv load regulation (note 6) v in = 1.15v, ? i load = 1ma to 100ma ? 0.4 1 mv lt3020-1.2 v in = 1.5v, ? i load = 1ma to 100ma ? 1 6 mv lt3020-1.5 v in = 1.8v, ? i load = 1ma to 100ma ?.5 1.5 7.5 mv lt3020-1.8 v in = 2.1v, ? i load = 1ma to 100ma ? 2 9 mv dropout voltage (notes 7, 12) i load = 10ma 85 115 mv i load = 10ma 180 mv i load = 100ma 150 180 mv i load = 100ma 285 mv gnd pin current i load = 0ma 120 250 a v in = v out(nominal) i load = 1ma 570 a (notes 8, 12) i load = 10ma 920 a i load = 100ma 2.25 3.5 ma output voltage noise c out = 2.2 f, i load = 100ma, bw = 10hz to 100khz, v out = 1.2v 245 v rms adj pin bias current v adj = 0.2v, ripple = 1.2v (notes 6, 9) 20 50 na shutdown threshold v out = off to on 0.61 0.9 v v out = on to off 0.25 0.61 v shdn pin current (note 10) v shdn = 0v, v in = 10v 1 a v shdn = 10v, v in = 10v 3 9.5 a quiescent current in shutdown v in = 6v, v shdn = 0v 3 9 a ripple rejection (note 6) v in ?v out = 1v, v ripple = 0.5v p-p , f ripple = 120hz, i load = 100ma 64 db lt3020-1.2 v in ?v out = 1v, v ripple = 0.5v p-p , f ripple = 120hz, 60 db i load = 100ma lt3020-1.5 v in ?v out = 1v, v ripple = 0.5v p-p , f ripple = 120hz, 58 db i load = 100ma lt3020-1.8 v in ?v out = 1v, v ripple = 0.5v p-p , f ripple = 120hz, 56 db i load = 100ma the denotes specifications which apply over the full operating temperature range, otherwise specifications are t j = 25 c. electrical characteristics parameter conditions min typ max units
4 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc current limit (note 12) v in = 10v, v out = 0v 360 ma v in = v out(nominal) + 0.5v, ? v out = 5% 110 310 ma input reverse leakage current v in = 10v, v out = 0v 1 10 a reverse output current v out = 1.2v, v in = 0v 3 5 a (notes 11, 13) lt3020-1.2 v out = 1.2v, v in = 0v 10 15 a lt3020-1.5 v out = 1.5v, v in = 0v 10 15 a lt3020-1.8 v out = 1.8v, v in = 0v 10 15 a the denotes specifications which apply over the full operating temperature range, otherwise specifications are t j = 25 c. electrical characteristics parameter conditions min typ max units note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired. note 2: the lt3020 regulators are tested and specified under pulse load conditions such that t j t a . the lt3020e is 100% production tested at t a = 25 c. performance at 40 c and 125 c is assured by design, characterization and correlation with statistical process controls. the lt3020i is guaranteed over the full 40 c to 125 c operating junction temperature range. note 3: this ic includes overtemperature protection that is intended to protect the device during momentary overload conditions. junction temperature will exceed 125 c when overtemperature protection is active. continuous operation above the specified maximum operating junction temperature may impair device reliability. note 4: maximum junction temperature limits operating conditions. the regulated output voltage specification does not apply for all possible combinations of input voltage and output current. limit the output current range if operating at maximum input voltage. limit the input voltage range if operating at maximum output current. note 5: typically the lt3020 supplies 100ma output current with a 1v input supply. the guaranteed minimum input voltage for 100ma output current is 1.10v. note 6: the lt3020 is tested and specified for these conditions with an external resistor divider (20k and 30.1k) setting v out to 0.5v. the external resistor divider adds 10 a of output load current. the line regulation and load regulation specifications refer to the change in the 0.2v reference voltage, not the 0.5v output voltage. specifications for fixed output voltage devices are referred to the output voltage. note 7: dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. in dropout the output voltage equals: (v in ?v dropout ). note 8: gnd pin current is tested with v in = v out(nominal) and a current source load. the device is tested while operating in its dropout region. this condition forces the worst-case gnd pin current. gnd pin current decreases at higher input voltages. note 9: adjust pin bias current flows out of the adj pin. note 10: shutdown pin current flows into the shdn pin. note 11: reverse output current is tested with in grounded and out forced to the rated output voltage. this current flows into the out pin and out of the gnd pin. for fixed voltage devices this includes the current in the output resistor divider. note 12: the lt3020 is tested and specified for these conditions with an external resistor divider (20k and 100k) setting v out to 1.2v. the external resistor divider adds 10 a of load current. note 13: reverse current is higher for the case of (rated_output) < v out < v in, because the no-load recovery circuitry is active in this region and is trying to restore the output voltage to its nominal value. note 14: minimum input voltage is the minimum voltage required by the control circuit to regulate the output voltage and supply the full 100ma rated current. this specification is tested at v out = 0.5v. at higher output voltages the minimum input voltage required for regulation will be equal to the regulated output voltage v out plus the dropout voltage.
5 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc temperature ( c) ?0 adj pin voltage (mv) 206 204 202 198 200 196 194 3020 g04 25 0 ?5 50 75 125 100 i l = 1ma adj pin voltage typical perfor a ce characteristics uw input voltage (v) 0 quiescent current ( a) 1000 900 800 600 700 500 400 300 200 100 0 8 3020 g05 2 13579 4 6 10 v out = 1.2v i l = 0 t j = 25 c v shdn = v in v shdn = 0v input voltage (v) 0 gnd pin current ( a) 2500 2250 2000 1500 1750 1250 1000 750 500 250 0 8 3020 g06 2 13579 4 6 10 v out = 1.2v t j = 25 c r l = 12 ? i l = 100ma r l = 24 ? i l = 50ma r l = 120 ? i l = 10ma r l = 1.2k, i l = 1ma quiescent current gnd pin current temperature ( c) ?0 output voltage (v) 1.830 1.820 1.810 1.800 1.790 1.780 1.770 25 75 3020 g22 ?5 0 50 100 125 i l = 1ma temperature ( c) ?0 output voltage (v) 1.530 1.520 1.510 1.500 1.490 1.480 1.470 25 75 3020 g23 ?5 0 50 100 125 i l = 1ma temperature ( c) ?0 output voltage (v) 1.230 1.220 1.210 1.200 1.190 1.180 1.170 25 75 3020 g24 ?5 0 50 100 125 i l = 1ma output voltage output voltage output voltage typical dropout voltage dropout voltage quiescent current output current (ma) 0 dropout voltage (mv) 250 225 200 150 175 125 100 75 50 25 0 80 3020 g01 20 10 30 50 70 90 40 60 100 t j = 125 c t j = 25 c temperature ( c) ?0 dropout voltage (mv) 250 225 200 150 175 125 100 75 50 25 0 3020 g02 25 0 ?5 50 75 125 100 i l = 1ma i l = 100ma i l = 50ma i l = 10ma v out = 1.2v temperature ( c) ?0 quiescent current ( a) 250 225 200 150 175 125 100 75 50 25 0 3020 g03 25 0 ?5 50 75 125 100 v shdn = v in v shdn = 0v v in = 6v v out = 1.2v i l = 0
6 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc gnd pin current vs i load shdn pin threshold shdn pin input current shdn pin input current ( a) adj pin bias current output current (ma) 0 gnd pin current ( a) 2000 1800 1600 1200 1400 1000 800 600 400 200 0 80 3020 g07 20 10 30 50 70 90 40 60 100 v in = 1.7v v out = 1.2v t j = 25 c temperature ( c) ?0 shdn pin threshold (v) 1.0 0.9 0.8 0.6 0.7 0.5 0.4 0.3 0.2 0.1 0 3020 g08 25 0 ?5 50 75 125 100 i l = 1ma shdn pin voltage (v) 0 shdn pin input current ( a) 5.0 4.5 4.0 3.0 3.5 2.5 2.0 1.5 1.0 0.5 0 8 3020 g09 2 13579 4 6 10 t j = 25 c temperature ( c) ?0 0 3020 g10 25 0 ?5 50 75 125 100 v shdn = 10v shdn pin input current ( a) 5.0 4.5 4.0 3.0 3.5 2.5 2.0 1.5 1.0 0.5 0 temperature ( c) ?0 adj pin bias current (na) 25 20 15 5 10 0 3020 g11 25 0 ?5 50 75 125 100 typical perfor a ce characteristics uw input voltage (v) 2500 2250 2000 1750 1500 1250 1000 750 500 250 0 gnd pin current ( a) 3020 g28 0123 4 5 67 8910 v out = 1.5v (lt 3020-1.5) t j = 25 c r l = 15 ? i l = 100ma r l = 30 ? i l = 50ma r l = 150 ? i l = 10ma r l = 1.5k i l = 1ma gnd pin current input voltage (v) 1000 900 800 700 600 500 400 300 200 100 0 quiescent current ( a) 3020 g25 0123 4 5 67 8910 v out = 1.8v (lt 3020-1.8) i l = 0 t j = 25 c v shdn = v in v shdn = 0v input voltage (v) 2500 2250 2000 1750 1500 1250 1000 750 500 250 0 gnd pin current ( a) 3020 g26 0123 4 5 67 8910 v out = 1.8v (lt 3020-1.8) t j = 25 c r l = 18 ? i l = 100ma r l = 36 ? i l = 50ma r l = 180 ? i l = 10ma r l = 1.8k i l = 1ma input voltage (v) 1000 900 800 700 600 500 400 300 200 100 0 quiescent current ( a) 3020 g27 0123 4 5 67 8910 v out = 1.5v (lt 3020-1.5) i l = 0 t j = 25 c v shdn = v in v shdn = 0v quiescent current gnd pin current quiescent current
7 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc temperature ( c) ?0 minimum input voltage (v) 1.1 1.0 0.9 0.8 0.6 0.7 0.5 0.4 0.3 0.2 0.1 0 3020 g16 25 0 ?5 50 75 125 100 i l = 100ma temperature ( c) ?0 load regulation (mv) 1.0 0.8 0.6 0.2 0.4 0 ?.2 ?.4 ?.6 ?.8 ?.0 3020 g17 25 0 ?5 50 75 125 100 v in = 1.15v v out = 0.5v *load regulation number refers to change in the 200mv reference voltage minimum input voltage load regulation ? i l = 1ma to 100ma typical perfor a ce characteristics uw temperature ( c) ?0 ripple rejection (db) 100 90 80 60 70 50 40 30 20 10 0 3020 g15 25 0 ?5 50 75 125 100 v in = 1.5v + 0.5v p-p ripple at f = 120hz v out = 0.5v i l = 100ma transient response v out 50mv/div i out 100ma/div 50 s/div 3020 g21 i out = 10ma to 100ma v out = 1.5v input ripple rejection current limit temperature ( c) ?0 0 3020 g12 25 0 ?5 50 75 125 100 v out = 0v v in = 1.7v v in = 10v current limit (ma) 500 450 400 300 350 250 200 150 100 50 0 reverse output current input ripple rejection temperature ( c) ?0 0 3020 g13 25 0 ?5 50 75 125 100 v in = 0v v out = 1.2v reverse output current ( a) 500 450 400 300 350 250 200 150 100 50 0 frequency (hz) 10 ripple rejection (db) 20 30 60 50 40 70 10 1k 10k 1m 3020 g14 0 100 100k v in = 1.5v + 50mv rms ripple v out = 0.5v i l = 100ma c out = 2.2 f c out = 10 f output noise spectral density frequency (hz) 10 output noise spectral density ( v/ hz) 10 1 0.1 0.01 1k 100k 1m 100 10k 3020 g18 v out = 1.2v i l = 100ma c out = 2.2 f
8 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc uu u pi fu ctio s out (pins 1, 2): these pins supply power to the load. use a minimum output capacitor of 2.2 f to prevent oscillations. applications with large load transients require larger out- put capacitors to limit peak voltage transients. see the applications information section for more information on output capacitance and reverse output characteristics. out (pin 3, fixed voltage device only): this pin is the sense point for the internal resistor divider. it should be tied directly to the other out pins (1, 2) for best results. adj (pin 3, adjustable device only): this pin is the inverting terminal to the error amplifier. its typical input bias current of 20na flows out of the pin (see curve of adj pin bias current vs temperature in the typical perfor- mance characteristics). the adj pin reference voltage is 200mv (referred to gnd). gnd (pin 4): ground. shdn (pin 5): the shdn pin puts the lt3020 into a low power state. pulling the shdn pin low turns the output off. drive the shdn pin with either logic or an open collector/ drain device with a pull-up resistor. the pull-up resistor supplies the pull-up current to the open collector/drain logic, normally several microamperes, and the shdn pin current, typically 2.3 a. if unused, connect the shdn pin to v in . the lt3020 does not function if the shdn pin is not connected. in (pins 7, 8): these pins supply power to the device. the lt3020 requires a bypass capacitor at in if it is more than six inches away from the main input filter capacitor. the output impedance of a battery rises with frequency, so include a bypass capacitor in battery-powered circuits. a bypass capacitor in the range of 2.2 f to 10 f suffices. the lt3020 withstands reverse voltages on the in pin with respect to ground and the out pin. in the case of a reversed input, which occurs if a battery is plugged in backwards, the lt3020 acts as if a diode is in series with its input. no reverse current flows into the lt3020 and no reverse volt- age appears at the load. the device protects itself and the load. gnd (pin 9, dd8 package only): ground. solder pin 9 (the exposed pad) to the pcb. connect directly to pin 4 for best performance. rms output noise vs load current (10hz to 100khz) load current (ma) output noise ( v rms ) 300 250 200 150 100 50 0 0.01 1 10 100 3020 g19 0.1 v out = 1.2v c out = 2.2 f no-load recovery threshold output overshoot (%) 0 output current sink (ma) 18 16 12 14 10 8 6 4 2 0 3020 g20 15 10 5 20 typical perfor a ce characteristics uw
9 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc applicatio s i for atio wu uu the lt3020 is a very low dropout linear regulator capable of 0.9v input supply operation. devices supply 100ma of output current and dropout voltage is typically 150mv. quiescent current is typically 120 a and drops to 3 a in shutdown. the lt3020 incorporates several protection features, making it ideal for use in battery-powered sys- tems. the device protects itself against reverse-input and reverse-output voltages. in battery backup applications where the output is held up by a backup battery when the input is pulled to ground, the lt3020 acts as if a diode is in series with its output which prevents reverse current flow. in dual supply applications where the regulator load is returned to a negative supply, the output can be pulled below ground by as much as 10v without affecting start- up or normal operation. adjustable operation the lt3020? output voltage range is 0.2v to 9.5v. figure 1 shows that the output voltage is set by the ratio of two external resistors. the device regulates the output to maintain the adj pin voltage at 200mv referenced to ground. the current in r1 equals 200mv/r1 and the current in r2 is the current in r1 minus the adj pin bias current. the adj pin bias current of 20na flows out of the pin. use the formula in figure 1 to calculate output voltage. an r1 value of 20k sets the resistor divider current to 10 a. note that in shutdown the output is turned off and the divider current is zero. curves of adj pin voltage vs temperature and adj pin bias current vs temperature appear in the typical performance characteristics section. specifications for output voltages greater than 200mv are proportional to the ratio of desired output voltage to 200mv; (v out /200mv). for example, load regulation for block diagra w shutdown + + current gain thermal shutdown r3 r2 r1 3020 bd d1 q1 d2 q2 error amp no-load recovery q3 in (7, 8) out (1, 2) out sense (3) note: for lt3020 adjust pin 3 is connected to the adjust pin, r1 and r2 are external. for lt3020-1.x pin 3 is connected to the output sense pin, r1 and r2 are internal. gnd (4,9) adj (3) 25k shdn (5) 200mv 212mv bias current and reference generator fixed v out 1.2v 1.5v 1.8v r1 20k 20k 20k r2 100k 130k 160k in shdn r2 r1 3020 f01 out v in adj gnd lt3020-adj v out + r2 r1 v out = 200mv v adj = 200mv i adj = 20na at 25 c output range = 0.2v to 9.5v 1 + ?i adj (r2) () figure 1. adjustable operation
10 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc applicatio s i for atio wu uu an output current change of 1ma to 100ma is typically 0.4mv at v adj = 200mv. at v out = 1.5v, load regulation is: (1.5v/200mv) ?(0.4mv) = 3mv output capacitance and transient response the lt3020? design is stable with a wide range of output capacitors, but is optimized for low esr ceramic capaci- tors. the output capacitor? esr affects stability, most notably with small value capacitors. use a minimum output capacitor of 2.2 f with an esr of 0.3 ? or less to prevent oscillations. the lt3020 is a low voltage device, and output load transient response is a function of output capacitance. larger values of output capacitance decrease the peak deviations and provide improved transient re- sponse for larger load current changes. for output capaci- tor values greater than 20 f a small feedforward capacitor with a value of 300pf across the upper divider resistor (r2 in figure 1) is required. give extra consideration to the use of ceramic capacitors. manufacturers make ceramic capacitors with a variety of dielectrics, each with a different behavior across tempera- ture and applied voltage. the most common dielectrics are z5u, y5v, x5r and x7r. the z5u and y5v dielectrics provide high c-v products in a small package at low cost, but exhibit strong voltage and temperature coefficients. the x5r and x7r dielectrics yield highly stable characterisitics and are more suitable for use as the output capacitor at fractionally increased cost. the x5r and x7r dielectrics both exhibit excellent voltage coefficient char- acteristics. the x7r type works over a larger temperature range and exhibits better temperature stability whereas x5r is less expensive and is available in higher values. figures 2 and 3 show voltage coefficient and temperature coefficient comparisons between y5v and x5r material. voltage and temperature coefficients are not the only sources of problems. some ceramic capacitors have a piezoelectric response. a piezoelectric device generates voltage across its terminals due to mechanical stress, simi- lar to the way a piezoelectric accelerometer or microphone works. for a ceramic capacitor, the stress can be induced by vibrations in the system or thermal transients. the re- sulting voltages produced can cause appreciable amounts of noise. a ceramic capacitor produced figure 4? trace in dc bias voltage (v) change in value (%) 3020 f02 20 0 ?0 ?0 ?0 ?0 100 0 4 8 10 26 12 14 x5r y5v 16 both capacitors are 16v, 1210 case size, 10 f temperature ( c) ?0 40 20 0 ?0 ?0 ?0 ?0 ?00 25 75 3020 f03 ?5 0 50 100 125 y5v change in value (%) x5r both capacitors are 16v, 1210 case size, 10 f figure 2. ceramic capacitor dc bias characteristics figure 3. ceramic capacitor temperature characteristics 1ms/div 3020 f04 1mv/div v out = 1.3v c out = 10 f i load = 0 figure 4. noise resulting from tapping on a ceramic capacitor
11 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc response to light tapping from a pencil. similar vibration induced behavior can masquerade as increased output voltage noise. no-load/light-load recovery a possible transient load step that occurs is where the output current changes from its maximum level to zero current or a very small load current. the output voltage responds by overshooting until the regulator lowers the amount of current it delivers to the new level. the regulator loop response time and the amount of output capacitance control the amount of overshoot. once the regulator has decreased its output current, the current provided by the resistor divider (which sets v out ) is the only current remaining to discharge the output capacitor from the level to which it overshot. the amount of time it takes for the output voltage to recover easily extends to milliseconds with microamperes of divider current and a few microfar- ads of output capacitance. to eliminate this problem, the lt3020 incorporates a no-load or light-load recovery circuit. this circuit is a voltage-controlled current sink that significantly improves the light load transient response time by discharging the output capacitor quickly and then turning off. the current sink turns on when the output voltage exceeds 6% of the nominal output voltage. the current sink level is then proportional to the overdrive above the threshold up to a maximum of approximately 15ma. consult the curve in the typical performance characteristics for the no-load recovery threshold. if external circuitry forces the output above the no load recovery circuit? threshold, the current sink turns on in an attempt to restore the output voltage to nominal. the current sink remains on until the external circuitry releases the output. however, if the external circuitry pulls the output voltage above the input voltage, or the input falls below the output, the lt3020 turns the current sink off and shuts down the bias current/reference generator circuitry. thermal considerations the lt3020? power handling capability is limited by its maximum rated junction temperature of 125 c. the power dissipated by the device is comprised of two components: 1. output current multiplied by the input-to-output volt- age differential: (i out )(v in ?v out ) and 2. gnd pin current multiplied by the input voltage: (i gnd )(v in ). gnd pin current is found by examining the gnd pin current curves in the typical performance characteristics. power dissipation is equal to the sum of the two compo- nents listed above. the lt3020 regulator has internal thermal limiting (with hysteresis) designed to protect the device during overload conditions. for normal continuous conditions, do not exceed the maximum junction temperature rating of 125 c. carefully consider all sources of thermal resistance from junction to ambient including other heat sources mounted in proximity to the lt3020. the underside of the lt3020 dd package has exposed metal (4mm 2 ) from the lead frame to where the die is attached. this allows heat to directly transfer from the die junction to the printed circuit board metal to control maximum operating junction temperature. the dual-in-line pin ar- rangement allows metal to extend beyond the ends of the package on the topside (component side) of a pcb. con- nect this metal to gnd on the pcb. the multiple in and out pins of the lt3020 also assist in spreading heat to the pcb. the lt3020 ms8 package has pin 4 fused with the lead frame. this also allows heat to transfer from the die to the printed circuit board metal, therefore reducing the thermal resistance. copper board stiffeners and plated through- holes can also be used to spread the heat generated by power devices. the following tables list thermal resistance for several different board sizes and copper areas for two different packages. measurements were taken in still air on 3/32" fr-4 board with one ounce copper. table 1. measured thermal resistance for dd package copper area thermal resistance topside* backside board area (junction-to-ambient) 2500mm 2 2500mm 2 2500mm 2 35 c/w 900mm 2 2500mm 2 2500mm 2 40 c/w 225mm 2 2500mm 2 2500mm 2 55 c/w 100mm 2 2500mm 2 2500mm 2 60 c/w 50mm 2 2500mm 2 2500mm 2 70 c/w applicatio s i for atio wu uu
12 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc table 2. measured thermal resistance for ms8 package copper area thermal resistance topside* backside board area (junction-to-ambient) 2500mm 2 2500mm 2 2500mm 2 110 c/w 1000mm 2 2500mm 2 2500mm 2 115 c/w 225mm 2 2500mm 2 2500mm 2 120 c/w 100mm 2 2500mm 2 2500mm 2 130 c/w 50mm 2 2500mm 2 2500mm 2 140 c/w *device is mounted on topside. calculating junction temperature example: given an output voltage of 1.8v, an input voltage range of 2.25v to 2.75v, an output current range of 1ma to 100ma, and a maximum ambient temperature of 70 c, what will the maximum junction temperature be for an application using the dd package? the power dissipated by the device is equal to: i out(max) (v in(max) ?v out ) + i gnd (v in(max) ) where i out(max) = 100ma v in(max) = 2.75v i gnd at (i out = 100ma, v in = 2.75v) = 3ma so p = 100ma(2.75v ?1.8v) + 3ma(2.75v) = 0.103w the thermal resistance is in the range of 35 c/w to 70 c/w depending on the copper area. so the junction temperature rise above ambient is approximately equal to: 0.103w(52.5 c/w) = 5.4 c the maximum junction temperature equals the maximum junction temperature rise above ambient plus the maxi- mum ambient temperature or: t jmax = 70 c + 5.4 c = 75.4 c protection features the lt3020 incorporates several protection features that make it ideal for use in battery-powered circuits. in addi- tion to the normal protection features associated with monolithic regulators, such as current limiting and ther- mal limiting, the device also protects against reverse- input voltages, reverse-output voltages and reverse output-to-input voltages. applicatio s i for atio wu uu current limit protection and thermal overload protection protect the device against current overload conditions at the output of the device. for normal operation, do not exceed a junction temperature of 125 c. the in pins of the device withstand reverse voltages of 10v. the lt3020 limits current flow to less than 1 a and no negative voltage appears at out. the device protects both itself and the load against batteries that are plugged in backwards. the lt3020 incurs no damage if out is pulled below ground. if in is left open circuit or grounded, out can be pulled below ground by 10v. no current flows from the pass transistor connected to out. however, current flows in (but is limited by) the resistor divider that sets the output voltage. current flows from the bottom resistor in the divider and from the adj pin? internal clamp through the top resistor in the divider to the external circuitry pulling out below ground. if in is powered by a voltage source, out sources current equal to its current limit capability and the lt3020 protects itself by thermal limiting. in this case, grounding shdn turns off the lt3020 and stops out from sourcing current. the lt3020 incurs no damage if the adj pin is pulled above or below ground by 10v. if in is left open circuit or grounded and adj is pulled above ground, adj acts like a 25k resistor in series with a 1v clamp (one schottky diode in series with one diode). adj acts like a 25k resistor in series with a schottky diode if pulled below ground. if in is powered by a voltage source and adj is pulled below its reference voltage, the lt3020 attempts to source its current limit capability at out. the output voltage in- creases to v in ?v dropout with v dropout set by whatever load current the lt3020 supports. this condition can potentially damage external circuitry powered by the lt3020 if the output voltage increases to an unregulated high voltage. if in is powered by a voltage source and adj is pulled above its reference voltage, two situations can occur. if adj is pulled slightly above its reference voltage, the lt3020 turns off the pass transistor, no output current is sourced and the output voltage decreases to either the voltage at adj or less. if adj is pulled above its no load recovery threshold, the no load recovery circuitry turns on and attempts to sink current. out is actively pulled low
13 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc applicatio s i for atio wu uu and the output voltage clamps at a schottky diode above ground. please note that the behavior described above applies to the lt3020 only. if a resistor divider is con- nected under the same conditions, there will be additional v/r current. in circuits where a backup battery is required, several different input/output conditions can occur. the output voltage may be held up while the input is either pulled to ground, pulled to some intermediate voltage or is left open circuit. in the case where the input is grounded, there is less than 1 a of reverse output current. if the lt3020 in pin is forced below the out pin or the out pin is pulled above the in pin, input current drops to less than 10 a typically. this occurs if the lt3020 input is connected to a discharged (low voltage) battery and either a backup battery or a second regulator circuit holds up the output. the state of the shdn pin has no effect on the reverse output current if out is pulled above in. input capacitance and stability the lt3020 is designed to be stable with a minimum capacitance of 2.2 f placed at the in pin. ceramic capaci- tors with very low esr may be used. however, in cases where a long wire is used to connect a power supply to the input of the lt3020 (and also from the ground of the lt3020 back to the power supply ground), use of low value input capacitors combined with an output load current of 20ma or greater may result in an unstable application. this is due to the inductance of the wire forming an lc tank circuit with the input capacitor and not a result of the lt3020 being unstable. the self-inductance, or isolated inductance, of a wire is directly proportional to its length. however, the diameter of a wire does not have a major influence on its self- inductance. for example, the self inductance of a 2-awg isolated wire with a diameter of 0.26 in. is about half the inductance of a 30-awg wire with a diameter of 0.01 in. one foot of 30-awg wire has 465nh of self inductance. the overall self-inductance of a wire can be reduced in two ways. one is to divide the current flowing towards the lt3020 between two parallel conductors. in this case, the farther the wires are placed apart from each other, the more inductance will be reduced, up to a 50% reduction when placed a few inches apart. splitting the wires basi- cally connects two equal inductors in parallel. however, when placed in close proximity from each other, mutual inductance is added to the overall self inductance of the wires. the most effective way to reduce overall inductance is to place the forward and return-current conductors (the wire for the input and the wire for ground) in very close proximity. two 30-awg wires separated by 0.02 in. re- duce the overall self-inductance to about one-fifth of a single isolated wire. if the lt3020 is powered by a battery mounted in close proximity on the same circuit board, a 2.2 f input capaci- tor is sufficient for stability. however, if the lt3020 is powered by a distant supply, use a larger value input capacitor following the guideline of roughly 1 f (in addi- tion to the 2.2 f minimum) per 8 inches of wire length. as power supply output impedance may vary, the minimum input capacitance needed to stabilize the application may also vary. extra capacitance may also be placed directly on the output of the power supply; however, this will require an order of magnitude more capacitance as opposed to placing extra capacitance in close proximity to the lt3020. furthermore, series resistance may be placed between the supply and the input of the lt3020 to stabilize the appli- cation; as little as 0.1 ? to 0.5 ? will suffice.
14 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc u package descriptio dd package 8-lead plastic dfn (3mm 3mm) (reference ltc dwg # 05-08-1698) 3.00 0.10 (4 sides) note: 1. drawing to be made a jedec package outline m0-229 variation of (weed-1) 2. drawing not to scale 3. all dimensions are in millimeters 4. dimensions of exposed pad on bottom of package do not include mold flash. mold flash, if present, shall not exceed 0.15mm on any side 5. exposed pad shall be solder plated 6. shaded area is only a reference for pin 1 location on top and bottom of package 0.38 0.10 bottom view?xposed pad 1.65 0.10 (2 sides) 0.75 0.05 r = 0.115 typ 2.38 0.10 (2 sides) 1 4 8 5 pin 1 top mark (note 6) 0.200 ref 0.00 ?0.05 (dd8) dfn 1203 0.25 0.05 2.38 0.05 (2 sides) recommended solder pad pitch and dimensions 1.65 0.05 (2 sides) 2.15 0.05 0.50 bsc 0.675 0.05 3.5 0.05 package outline 0.25 0.05 0.50 bsc
15 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc u package descriptio ms8 package 8-lead plastic msop (reference ltc dwg # 05-08-1660) msop (ms8) 0204 0.53 0.152 (.021 .006) seating plane note: 1. dimensions in millimeter/(inch) 2. drawing not to scale 3. dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.152mm (.006") per side 4. dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.152mm (.006") per side 5. lead coplanarity (bottom of leads after forming) shall be 0.102mm (.004") max 0.18 (.007) 0.254 (.010) 1.10 (.043) max 0.22 ?0.38 (.009 ?.015) typ 0.127 0.076 (.005 .003) 0.86 (.034) ref 0.65 (.0256) bsc 0 ?6 typ detail ? detail ? gauge plane 12 3 4 4.90 0.152 (.193 .006) 8 7 6 5 3.00 0.102 (.118 .004) (note 3) 3.00 0.102 (.118 .004) (note 4) 0.52 (.0205) ref 5.23 (.206) min 3.20 ?3.45 (.126 ?.136) 0.889 0.127 (.035 .005) recommended solder pad layout 0.42 0.038 (.0165 .0015) typ 0.65 (.0256) bsc information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
16 lt3020/lt3020-1.2/ lt3020-1.5/lt3020-1.8 3020fc lt/lt 0905 rev c ?printed in usa ? linear technology corporation 2004 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com part number description comments lt1121/lt1121hv 150ma, micropower ldos v in : 4.2v to 30v/36v, v out(min) = 3.75v, v do = 0.42v, i q = 30 a, i sd = 16 a, reverse-battery protection, sot-223, s8, z packages lt1129 700ma, micropower ldo v in : 4.2v to 30v, v out(min) = 3.75v, v do = 0.4v, i q = 50 a, i sd = 16 a, dd, sot-223, s8, to220-5, tssop20 packages lt1761 100ma, low noise micropower ldo v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.3v, i q = 20 a, i sd < 1 a, low noise: < 20 v rms , stable with 1 f ceramic capacitor, thinsot package lt1762 150ma, low noise micropower ldo v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.3v, i q = 25 a, i sd < 1 a, low noise: <20 v rms , ms8 package lt1763 500ma, low noise micropower ldo v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.3v, i q = 30 a, i sd < 1 a, low noise: < 20 v rms , s8 package lt1764/lt1764a 3a, low noise, fast transient response ldos v in : 2.7v to 20v, v out(min) = 1.21v, v do = 0.34v, i q = 1ma, i sd < 1 a, low noise: <40 v rms , ??version stable with ceramic capacitors, dd, to220-5 packages ltc1844 150ma, low noise, micropower vldo v in : 1.6v to 6.5v, v out(min) = 1.25v, v do = 0.09v, i q = 35 a, i sd < 1 a, low noise: < 30 v rms , thinsot package lt1962 300ma, low noise micropower ldo v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.27v, i q = 30 a, i sd < 1 a, low noise: < 20 v rms , ms8 package LT1963/LT1963a 1.5a, low noise, fast transient response ldos v in : 2.1v to 20v, v out(min) = 1.21v, v do = 0.34v, i q = 1ma, i sd < 1 a, low noise: < 40 v rms , ??version stable with ceramic capacitors, dd, to220-5, sot223, s8 packages lt1964 200ma, low noise micropower, negative ldo v in : ?.2v to ?0v, v out(min) = 1.21v, v do = 0.34v, i q = 30 a, i sd = 3 a, low noise: <30 v rms , stable with ceramic capacitors, thinsot package lt3010 50ma, high voltage, micropower ldo v in : 3v to 80v, v out(min) = 1.2v, v do = 0.3v, i q = 30 a, i sd < 1 a, low noise: <100 v rms , stable with 1 f output capacitor, exposed ms8e package ltc3025 300ma, low voltage, micropower ldo v in : 0.9v to 5.5v, v out(min) = 0.4v, v do = 0.05v, i q = 54 a, stable with 1 f ceramic capacitors, dfn-6 package lt3150 low v in , fast transient response, vldo controller v in : 1.1v to 10v, v out(min) = 1.23v, v do = set by external mosfet r ds(on) , 1.4mhz boost converter generates gate drive, ssop16 package related parts

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