tc1108 tc1108-2 1/25/00 telcom semiconductor reserves the right to make changes in the circuitry and specifications of its devic es. evaluation kit available 300ma cmos ldo general description the tc1108 is a fixed output, high accuracy (typically 0.5%) cmos low dropout regulator. total supply current is typically 50 a at full load (20 to 60 times lower than in bipolar regulators !). tc1108 key features include ultra low noise, very low dropout voltage (typically 240mv at full load), and fast response to step changes in load. the tc1108 incorporates both over-temperature and over-current protection. the tc1108 is stable with an output capacitor of only 1 f and has a maximum output current of 300ma. it is available in a sot-223 package. features extremely low supply current (50 a, typ.) very low dropout voltage guaranteed 300ma output high output voltage accuracy standard or custom output voltages over-current and over-temperature protection applications battery-operated systems portable computers medical instruments instrumentation cellular / gsm / phs phones linear post-regulator for smps pagers typical application pin configuration tc1108 1 2 3 v in v out c1 1 f gnd v out v in sot-223 3 2 1 v out gnd v in tc1108vdb ordering information part junction number package temp. range tc1108-xxvdb 3-pin sot-223 40 c to +125 c tc1015ev evaluation kit for cmos ldo family available output voltages: 2.5, 2.8, 3.0, 3.3, 5.0 xx indicates output voltages other output voltages are available. please contact telcom semiconductor for details.
2 tc1108-2 1/25/00 tc1108 300ma cmos ldo electrical characteristics: v in = v out + 1v, i l = 100 a, c l = 3.3 f, t a = 25 c, unless otherwise specified. boldface type specifications apply for junction temperatures of ?40 c to +125 c. symbol parameter test conditions min typ max units v in input operating voltage 6.0 v i out max maximum output current 300 ma v out output voltage note 1 v r 0.5% v v r ?2.5% v r + 2.5% ? v out / ? tv out temperature coefficient note 2 40 ppm/ c ? v out / ? v in line regulation (v r + 1v) < v in < 6v 0.05 0.35 % ? v out /v out load regulation i l = 0.1ma to i out max (note 3) 1.1 2.0 % v in ?v out dropout voltage i l = 0.1ma 20 30 mv i l = 100ma 80 160 i l = 300ma 270 480 (note 4) i dd supply current 50 90 a psrr power supply rejection ratio f re 1khz 60 db i out sc output short circuit current v out = 0v 550 650 ma ? v out / ? p d thermal regulation note 5 0.04 v/w en output noise f = 10khz, c out = 1 f, r load = 50 ? 260 nv/ hz notes: 1. v r is the regulator output voltage setting. 2. t c v out = (v out max v out min ) x 10 6 v out x ? t 3. regulation is measured at a constant junction temperature using low duty cycle pulse testing. load regulation is tested over a load range from 0.1ma to the maximum specified output current. changes in output voltage due to heating effects are covered by the t hermal regulation specification. 4. dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value m easured at a 1v differential. 5. thermal regulation is defined as the change in output voltage at a time t after a change in power dissipation is applied, exc luding load or line regulation effects. specifications are for a current pulse equal to i lmax at v in = 6v for t = 10msec. 6. the maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction temperature, and the thermal resistance from junction-to-air (i.e. t a , t j , ja ). exceeding the maximum allowable power dissipation causes the device to initiate thermal shutdown. please see thermal considerations section of this data sheet for more details. absolute maximum ratings* input voltage .............................................................. 6.5v output voltage ........................... (v ss ?0.3) to (v in + 0.3) power dissipation .................... internally limited (note 7) operating temperature .................... ?40 c < t j < 125 c storage temperature ............................ ?65 c to +150 c maximum voltage on any pin ........... v in + 0.3v to ?0.3v lead temperature (soldering, 10 sec.) ................ +260 c *absolute maximum ratings indicate device operation limits beyond dam- age may occur. device operation beyond the limits listed in electrical characteristics is not recommended.
3 tc1108-2 1/25/00 300ma cmos ldo tc1108 p d (v in max ?v out min )i load max where: p d = worst case actual power dissipation v in max = maximum voltage on v in v out min = minimum regulator output voltage i load max = maximum output (load) current equation 1. the maximum allowable power dissipation (equation 2) is a function of the maximum ambient temperature (t a max ), the maximum allowable die temperature (t jmax ) and the thermal resistance from junction-to-air ( ja ). p d max = (t j max ?t a max ) ja where all terms are previously defined. equation 2. table 1 shows various values of ja for the tc1108 mounted on a 1/16 inch, 2-layer pcb with 1 oz. copper foil. table 1. thermal resistance guidelines for tc1108 copper copper thermal area area board resistance (topside)* (backside) area ( ja ) 2500 sq mm 2500 sq mm 2500 sq mm 45 c/w 1000 sq mm 2500 sq mm 2500 sq mm 45 c/w 225 sq mm 2500 sq mm 2500 sq mm 53 c/w 100 sq mm 2500 sq mm 2500 sq mm 59 c/w 1000 sq mm 1000 sq mm 1000 sq mm 52 c/w 1000 sq mm 0 sq mm 1000 sq mm 55 c/w notes: *tab of device attached to topside copper equation 1 can be used in conjunction with equation 2 to ensure regulator thermal operation is within limits. for example: given: v in max = 3.3v + 10% v out min = 2.7v - 0.5% i loadmax = 275ma t jmax = 125 c t a max =95 c ja =59 c/w find: 1. actual power dissipation 2. maximum allowable dissipation figure 1: typical application circuit output capacitor a 1 f (min) capacitor from v out to ground is required. the output capacitor should have an effective series resis- tance of 5 ? or less. a 1 f capacitor should be connected from v in to gnd if there is more than 10 inches of wire between the regulator and the ac filter capacitor, or if a battery is used as the power source. aluminum electrolytic or tantalum capacitor types can be used. (since many aluminum electrolytic capacitors freeze at approximately 30 c, solid tantalums are recommended for applications operating below ?25 c.) when operating from sources other than batteries, supply-noise rejection and transient response can be improved by increasing the value of the input and output capacitors and employing passive filtering techniques. thermal considerations thermal shutdown integrated thermal protection circuitry shuts the regula- tor off when die temperature exceeds 150 c. the regulator remains off until the die temperature drops to approximately 140 c. power dissipation the amount of power the regulator dissipates is prima- rily a function of input and output voltage, and output current. the following equation is used to calculate worst case actual power dissipation: c1 1 f battery tc1108 1 2 3 v in v out c2 1 f gnd v out detailed description the tc1108 is a precision, fixed output ldo. unlike bipolar regulators, the tc1108 supply current does not increase with load current. in addition, v out remains stable and within regulation at very low load currents (an important consideration in rtc and cmos ram battery backup applications). figure 1 shows a typical application circuit.
4 tc1108-2 1/25/00 tc1108 300ma cmos ldo typical characteristics output noise frequency (khz) noise ( v/ / hz) 10.0 1.0 0.01 0.01 1 10 100 1000 0.1 0.0 r load = 50 ? c out = 1 f 0.012 0.010 0.008 0.004 0.002 0.000 0.002 0.004 0.006 40 20 0 20 40 60 80 100 120 temperature ( c) line regulation line regulation (%) 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 0 50 100 150 200 250 300 load current (ma) dropout voltage vs. load current dropout voltage (v) power supply rejection ratio frequency (hz) 30db 35db 40db 45db 50db 55db 60db 65db 70db 75db 80db 100 1k 10k 10 1m 100k v out = 5v r load = 50 ? v inac = 50mv p-p c out = 1 f 100.0 90.0 70.0 80.0 50.0 40.0 60.0 40 20 0 20 40 60 80 100 120 temperature ( c) supply current supply current ( a) psrr (db) 2.00 1.80 1.60 1.20 1.00 0.80 0.60 0.40 0.20 0.00 1.40 40 20 0 20 40 60 80 100 120 temperature ( c) load regulation load regulation (%) 1 to 300ma 1 to 50ma 1 to 100ma 3.075 3.025 2.925 2.975 40 20 0 20 40 60 80 100 120 temperature ( c) v out vs. temperature v out (v) 125 c 85 c 70 c 25 c 0 c 40 c v in = 4v i load = 100 a c load = 3.3 f
5 tc1108-2 1/25/00 300ma cmos ldo tc1108 actual power dissipation: p d (v in max ?v out min )i load max = [(3.3 x 1.1) ?(2.7 x .995)]275 x 10 -3 = 260mw maximum allowable power dissipation: p d max = (t j max ?t a max ) ja = (125 ?95) 59 = 508mw in this example, the tc1108 dissipates a maximum of only 260mw; far below the allowable limit of 508mw. in a similar manner, equation 1 and equation 2 can be used to calculate maximum current and/or input voltage limits. for example, the maximum allowable v in is found by substitut- ing the maximum allowable power dissipation of 508mw into equation 1, from which v in max = 4.6v. taping form part number code represents temperature + date code + lot identity + subcontractor identity markings 3-pin sot-223 tc1108 (v) code tc1108-2.5vdb 110825 tc1108-2.8vdb 110828 tc1108-3.0vdb 110830 tc1108-3.3vdb 110833 tc1108-5.0vdb 110850 user direction of feed user direction of feed device marking component taping orientation for 3-pin sot-223 devices device marking pin 1 pin 1 standard reel component orientation for tr suffix device (mark right side up) reverse reel component orientation for rt suffix device (mark upside down) w p package carrier width (w) pitch (p) part per full reel reel size 3-pin sot-223 12 mm 8 mm 4000 13 in carrier tape, number of components per reel and reel size
6 tc1108-2 1/25/00 tc1108 300ma cmos ldo package dimensions dimensions: inches (mm) telcom semiconductor h.k. ltd. 10 sam chuk street, ground floor san po kong, kowloon hong kong tel: (011) 852-2350-7380 fax: (011) 852-2354-9957 sales offices telcom semiconductor, inc. 1300 terra bella avenue p.o. box 7267 mountain view, ca 94039-7267 tel: 650-968-9241 fax: 650-967-1590 e-mail: liter@telcom-semi.com telcom semiconductor, gmbh lochhamer strasse 13 d-82152 martinsried germany tel: (011) 49 89 895 6500 fax: (011) 49 89 895 6502 2 .264 (6.70) .248 (6.30) .122 (3.10) .114 (2.90) .287 (7.30) .264 (6.70) .146 (3.70) .130 (3.30) .091 (2.30) typ. .071 (1.80) max. .181 (4.60) typ. .036 (0.91) min. .041 (1.04) .033 (0.84) pin 1 .013 (0.33) .009 (0.24) .031 (0.80) .024 (0.60) .004 (0.10) .001 (0.02) 10 max. 3-pin sot-223
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