ts2938 500ma ultra low dropout voltage regulator with inhibit function 1/6 version: e11 sop - 8 general description the ts2938 series of fixed-voltage monolithic micro -power voltage regulators is designed for a wide ra nge of applications. this device excellent choice of use i n battery-power application. furthermore, the quies cent current increases on slightly at dropout, which prolongs ba ttery life. this series of fixed-voltage regulators features very low ground current (200ua typ.), very low drop outp ut voltage (typ. 60mv at light load and 600mv at 50 0ma) and output inhibit control. this includes a tight i nitial tolerance of 2%, extremely good line regulat ion of 0.05% typ., and very low output temperature coefficient. features dropout voltage typically 0.5v @io=500ma output current up to 500ma logic control electronic shutdown output voltage trimmed before assembly -18v reverse peak voltage +30v input over voltage protection +60v transient peak voltage low quiescent current 100ua (typ.) (on mode) internal current limitthermal shutdown protection block diagram ordering information note: where xx denotes voltage option, available are 12 = 12v 50 = 5.0v 33 = 3.3v part no. package packing ts2938cs xx rl sop-8 2.5kpcs / 13 reel absolute maximum rating (note 1) parameter symbol limit unit input supply voltage (note 2) v in -18 ~ +60 v operation input supply voltage v opr 26 v power dissipation (note 3) p d internally limited w operating junction temperature range t j -40 ~ + 125 o c thermal resistance junction to case t jc 20 o c/w storage temperature range t stg -65 ~ +150 o c pin definition : 1. output 8. input 2. ground 7. ground 3. ground 6. ground 4. n/c 5. inhibit
ts2938 500ma ultra low dropout voltage regulator with inhibit function 2/6 version: e11 electrical characteristics ( v in =v out +1v, i l =5ma, c o =10uf, t a =25 o c , unless otherwise noted) parameter conditions min typ max unit output voltage t a =25 o c 0.980|v o| v out 1.020|v o| v t a =25~85 o c 0.960|v o| 1.040|v o| v output voltage temperature coefficient -- 50 150 p pm/ o c line regulation vo+1v v in 26v -- 0.05 0.5 % load regulation 5ma i l 500ma -- 0.2 1.0 % dropout voltage (note 4) i l =100ma i l =300ma i l =500ma -- -- -- 100 300 500 200 400 600 mv quiescent current (note 5) i l =100ua i l =300ma i l =500ma -- -- -- 200 12 25 300 20 50 ua ma ma short circuit current (note 6) v out =0 -- 0.9 1.3 a output noise, 10hz to 100khz, i l =10ma c l =2.2uf c l =3.3uf c l =33uf -- -- -- 500 350 120 -- -- -- uvrms ripple rejection ratio 60 -- -- db shutdown input input logic voltage low (regulator on) -- 1.3 0.7 v high (regulator off) 2.0 -- -- shutdown pin input current vinhibit = 2.4v -- 30 50 ua vinhibit = 26v -- 450 600 regulator output current in shutdown vinhibit 2v, vin 26v vout=0v -- -- 200 note 1: absolute maximum rating is limits beyond wh ich damage to the device may occur. for guaranteed specifications and test conditions see the electrical characteristics. note 2: maximum positive supply voltage of 60v must be limited duration (<100ms) and duty cycle (<1%). note 3: the maximum allowable power dissipation is a function of the maximum junction temperature, tj, the junction to ambient thermal resistance, ja, and the ambient temperature, ta. exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into th ermal shutdown. the effective value of ja can be reduced by using a heatsink. note 4: dropout voltage is defined as the input to output differential at which the output voltage dro ps 2% below its nominal value measured at 1v different ial. note 5: ground pin current is the regulator quiesce nt current. the total current drawn from the source is the sum of the ground pin current and output load cur rent. note 6: output current will decrease with increasin g temperature, but it will be not dropped below 500 ma at the maximum specified temperature.
ts2938 500ma ultra low dropout voltage regulator with inhibit function 3/6 version: e11 application circuit application information application the ts2938 series is a high performance with low dr opout voltage regulator suitable for moderate to hi gh current and voltage regulator application. its 500mv (typ) dropout voltage at full load and over temperature m akes it especially valuable in battery power systems and as high efficiency noise filters in post regulator ap plications. unlike normal npn transistor design, where the base to emitter voltage drop and collector to emitter s aturation voltage limit the minimum dropout voltage, dropout performance of the pnp output of these devices is l imited only by low vce saturation voltage. the ts2938 series is fully protected from damage du e to fault conditions. linear current limiting is p rovided. output current during overload conditions is consta nt. thermal shutdown the device when the die temper ature exceeds the maximum safe operating temperature. tra nsient protection allows device survival even when the input voltage spikes above and below nominal. the o utput structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. output capacitor the ts2938 series requires an output capacitor to m aintain stability and improve transient response. p roper capacitor selection is important to ensure proper o peration. the output capacitor selection is depende nt upon the esr of the output capacitor the maintain stability. when the output capacitor is 6.8uf or greater, the output capacitor should have an esr less than 2 ohm. this will improve transient response as well as promoted stability. ultra low esr capacitors (<100mohm), such as cerami c chip capacitors may promote instability. these ve ry low esr levels may cause an oscillation and/or under da mped transient response. a low esr solid tantalum capacitor works extremely well and provide good tra nsient response and stability over temperature. alu minum electrolytic can also be used, as long as the esr o f the capacitor is <2ohm. the value of the output c apacitor can be increased without limit. higher capacitance values help to improved transient response and ripp le rejection and reduce output noise. minimum load current the ts2938 series is specified between finite loads . if the output current is too small leakage curren ts dominate and the output voltage rises. a 5ma minimum load cu rrent is necessary for proper regulation. input capacitor an input capacitor of 1uf or greater is recommended when the device is more that 4 inches away from th e bulk ac supply capacitance or when the supply is a batte ry. small and surface mount ceramic chip capacitors can be used for bypassing. larger values will help to impr ove ripple rejection by bypassing the input to the regulator, further improving the integrity of the output volta ge. fixed output voltage type
ts2938 500ma ultra low dropout voltage regulator with inhibit function 4/6 version: e11 application information (continue) thermal characteristics a heatsink may be required depending on the maximum power dissipation and maximum ambient temperature of the application. under all possible operating condi tions, the junction temperature must be within the range specified under absolute maximum ratings. to determ ine if the heatsink is required, the power dissipat ed by the regulator, p d must be calculated. the below formula shows the voltages and currents f or calculating the p d in the regulator: i in = i l / i g p d = (v in -v out ) * i l + (v in ) * i g ex. p d = (3.3v-2.5v) * 0.5a + 3.3v * 11ma = 400mw + 36mw = 436mw the next parameter which must be calculated the max imum allowable temperature rise. t r (max) is calculated by the using to formula: t r (max) = t j (max) C t a (max) where: t j (max) is the maximum allowable junction temperature , which is 125 o c for commercial grade parts. t a (max) is the maximum ambient temperature which will be encountered in the application. using the calculated values for t a (max) and p d , the maximum allowable value for the junction to a mbient thermal resistance, ja , can now be found: ja = t r (max) / p d inhibit input ts2938 feature an active-low (inhibit) input that a llows on/off control of the regulator. the inhibit input has ttl/cmos compatible thresholds for simple interfaci ng with logic interfacing. inhibit should be direc tly tied to ground or keep open (not connected).
ts2938 500ma ultra low dropout voltage regulator with inhibit function 5/6 version: e11 sop-8 mechanical drawing marking diagram y = year code m = month code ( a =jan, b =feb, c =mar, d =apl, e =may, f =jun, g =jul, h =aug, i =sep, j =oct, k =nov, l =dec) l = lot c ode xx = voltage code (3.3=3.3v, 5.0=5v, 12=12v) sop-8 dimension dim millimeters inches min max min max. a 4.80 5.00 0.189 0.196 b 3.80 4.00 0.150 0.157 c 1.35 1.75 0.054 0.068 d 0.35 0.49 0.014 0.019 f 0.40 1.25 0.016 0.049 g 1.27bsc 0.05bsc k 0.10 0.25 0.004 0.009 m 0o 7o 0o 7o p 5.80 6.20 0.229 0.244 r 0.25 0.50 0.010 0.019
ts2938 500ma ultra low dropout voltage regulator with inhibit function 6/6 version: e11 notice specifications of the products displayed herein are subject to change without notice. tsc or anyone on its behalf, assumes no responsibility or liability for any erro rs or inaccuracies. information contained herein is intended to provide a product description only. no license, express or implied, to any intellectual property rights is granted by this document. except as provided in tscs terms and co nditions of sale for such products, tsc assumes no liability wh atsoever, and disclaims any express or implied warr anty, relating to sale and/or use of tsc products includi ng liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, cop yright, or other intellectual property right. the products shown herein are not designed for use in medical, life-saving, or life-sustaining applica tions. customers using or selling these products for use i n such applications do so at their own risk and agr ee to fully indemnify tsc for any damages resulting from such i mproper use or sale.
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