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power management very low input /very low dropout 3 amp regulator with enable SC4217 features input voltage range from .8v to 5.5v typical 300mv dropout @ 3a adjustable output from .24v over-current and over-temperature protection enable pin 0a shutdown current full industrial temperature range to263-5 package, fully weee and rohs compliant applications telecom/networking equipment motherboards/peripheral cards industrial equipment wireless infrastructure set-top boxes medical equipment ? ? ? ? ? ? ? ? ? ? ? ? ? ? description the sc42 7 is a 3a, high performance ldo designed for use in applications requiring very low input voltage and very low dropout voltage. it operates with an input volt - age as low as .8v and a programmable output voltage from .24v. the sc42 7 features ultra- low dropout, ideal for applications where v out is very close to v in . addi - tionally, the sc42 7 has an enable pin to further reduce power dissipation while shut down. the sc42 7 provides excellent regulation over line, load and temperature. the sc42 7 is available in a to263-5 package and is fully weee and rohs compliant. typical application circuit october 29, 2007 0 vin r2 c2 en r1 c1 SC4217 2 3 5 4 1 vin gnd adj vo en 0 vo
SC4217 2 pin confguration marking information ordering information device package sc42 7mtrt ()(2) to263-5 sc42 7evb evaluation board notes: available in tape and reel only. a reel contains 800 devices. device is weee and rohs compliant. ) 2) eyww sc 4217 xxxxxxxxx marking for to 263 5 lead package : xxxxxxxxx = semtech lot # ( example : ea 0180101 ) eyww = datecode ( example : e 752 ) top mark 9 / 9 / 9 char 3 rows top view (to263-5l) 1 3 5 tab 2 4
SC4217 3 note ( ) 2 square inch of fr-4, double sided, oz. minimum copper weight. other notes: tested according to jedec standard jesd22-a 4-b. calculated from package in still air, mounted to 3 x 4.5, 4 layer fr4 pcb with thermal vias under the exposed pad per jesd5 standards. exceeding the above specifcations may result in permanent damage to the device or device malfunction. operation outside of the parameters specifed in the electrical characteristics section is not recommended. absolute maximum ratings vin, vo, adj to gnd 6v en -0.3v to vin+0.3v lead temperature (soldering) 0s 300c esd protection level 2kv recommended operating conditions vin range .8v to 5.5v maximum output current 3a operating ambient temperature range -40 to +85c operating junction temperature range -40 to + 25c storage temperature range -65 to + 50c thermal information thermal resistance, junction to case j () jc 7c/w thermal resistance, junction to ambient j ja 30c/w unless otherwise noted, ven = vin. vin = .8v to 5.5v, vin = vo+0.5v, and io = 0a to 3a. values in bold apply over the full operating temperature range. ) 2) parameter symbol conditions min typ max units vin quiescent current i q v in = 3.3v 0.75 1.75 ma v in = 5.5v, v en = 0v 0 50 a vo output voltage () v o v in = v o + 0.5v -2% +2% v -3% +3% line regulation () reg (line) i o = 0ma 0.2 0.4 %/v load regulation () reg (load) i o = 0ma to 3a 0.5 1.0 % dropout voltage (, 2) v d i o = a 90 300 mv 400 i o = .5a 200 400 500 dropout voltage (, 2) v d i o = 3a, v in = v o + 0.5v 300 500 mv 600 minimum load current (3) i o v in = v o +0.5v 10 a current limit i cl 3.3 4.5 6.75 a electrical characteristics
SC4217 4 parameter symbol conditions min typ max units adj reference voltage () v ref v in = 3.3v, v adj = v out , i o = 0ma .227 .24 .252 v 1.215 1.265 adjust pin current (4) i adj v adj = v ref 80 200 na adjust pin threshold (5) v th(adj) 0.05 0.6 0.40 v en enable pin current i en v en = 0v, v in = 3.3v .5 10 a enable pin theshold v ih v in = 3.3v 1.6 v v il v in = 3.3v 0.4 over temperature protection high trip level t hi 60 c hysteresis t hyst 0 notes: low duty cycle pulse testing with kelvin connections required. defined as the input to output differential at which the output voltage drops to .5% below the value measured at a differential of 0.8v. required to maintain regulation. voltage set resistors r and r2 are usually utilized to meet this requirement. adjustable versions only. guaranteed by design. when v adj exceeds this threshold, the sense select switch disconnects the internal feedback chain from the error amplifier and connects v adj instead. ) 2) 3) 4) 5) electrical characteristics (continued)
SC4217 5 pin descriptions pin # pin name pin function en enable input. pulling this pin below 0.4v turns of the regulator reducing the quiescent current to a franction of its operating value. the device will be enabled if this pin is left open. connect to v in if not being used. 2 vin input voltage. for regulation at full load, the input to this pin must be between (v o +0.5v) and 5.5v. minimum v in = .8v. a large bulk capacitance should be placed closey to this pin to ensure that the input supply does not sag below .8v. a minimum of 4.7f ceramic capacitors should be placed directly at this pin. 3 gnd reference ground. the gnd pin and the exposed die pad must be connected together at the ic pin. 4 vo the pin is the power output of the device. a minimum of 0f capactor should be placed directly at this pin. 5 adj use external feedback resistors to program the output voltage. see application circuit on page . v o = [(r 2 +r )* .24v]/r 2 . the adj pin cannot be tied directly either to vo pin or to gnd pin. t thermal pad thermal pad should be connected to pcb ground plane for thermal and electrical purposes. 1 . 5 ua reverse voltage shutdown thermal shutdown vout vin 1 . 24 v ref vdd en current limit reference vpump rsense vin gnd adj vo block diagram
SC4217 6 typical characteristics unless otherwise noted, typical values are taken under the conditions: t ambient =25 c, v in =3.3v, v o =2.5v, i o =2a, c in =c out =0. m f(ceramic)+ 0 m f(tantalum) ) dropout voltage vs output current 0 50 100 150 200 250 300 350 0 1 2 3 4 output current (a) 25c dropout voltage vs temperature 50 100 150 200 250 300 350 400 -50 -25 0 25 50 75 100 temperature ( c ) i out =1a i out =3a adj pin leakage current vs temperature 80 82 84 86 88 90 -50 -25 0 25 50 75 100 temperature ( c ) v adj =1.24v quiescent current vs input voltage 0.0 0.5 1.0 1.5 2.0 3 3.5 4 4.5 5 5.5 6 6.5 input voltage ( v ) t ambient = 85 c t ambient = 25 c enable voltage high vs temperature 0.50 0.75 1.00 1.25 1.50 1.75 -50 -25 0 25 50 75 100 temperature ( c ) v in =5.5v v in =3.3v v in =1.8v enable voltage low vs temperature 0.50 0.75 1.00 1.25 1.50 -50 -25 0 25 50 75 100 temperature ( c ) v in =5.5v v in =3.3v v in =1.8v
SC4217 7 typical characteristics unless otherwise noted, typical values are taken under the conditions: t ambient =25 c, v in =3.3v, v o =2.5v, i o =2a, c in =c out =0. m f(ceramic)+ 0 m f(tantalum) ) output voltage output current load transient test en pin voltage output voltage input voltage soft start performance
SC4217 8 introduction the sc42 7 is intended for applications where high cur - rent capability and very low dropout voltage are required. it provides a very simple, low cost solution that uses very little pcb real estate. additional features include an enable pin to allow for a very low power consumption standby mode, and a fully adjustable output. component selection input capacitor a minimum of 4.7f ceramic or tantalum capacitor is recommended to be placed directly next to the vin pin. this allows for the device being some distance from any bulk capacitance on the rail. additionally, bulk capaci - tance of about 0f may be added closely to the input supply pin of the sc42 7 to ensure that vin does not sag, improving load transient response. output capacitor a minimum bulk capacitance of 0f, along with a 0. f ceramic decoupling capacitor is recommended. increasing the bulk capacitance will improve the over - all transient response. the use of multiple lower value ceramic capacitors in parallel to achieve the desired bulk capacitance will not cause stability issues. although designed for use with ceramic output capacitors, the sc42 7 is extremely tolerant of output capacitor esr values and thus will also work comfortably with tantalum output capacitors. noise immunity in very electrically noisy environments, it is recom mended that 0. f ceramic capacitors be placed from in to gnd and out to gnd as close to the device pins as possible. external voltage selection resistors the use of % resistors, and designing for a current flow 0a is recommended to ensure a well regulated output (thus r2 50k?). enable pulling this pin below 0.4v turns the regulator off, reduc - ing the quiescent current to a fraction of its operating value. thermal considerations the power dissipation in the sc42 7 is approximately equal to the product of the output current and the input to output voltage diferential: o d i vout) (vin p u | the absolute worst-case dissipation is given by: q(max) in(max) (min) (max) i v i ) vout (vin p o(max) d u u | for a typical scenario, v in = 3.3v 5%, v out = 2.8v and i o = .5a, therefore: v in(max) = 3.465v, v out(min) = 2.744v and i q(max) = .75ma, thus p d(max) = .09w. using this fgure, and assuming t a(max) = 70c, we can calculate the maximum thermal impedance allowable to maintain t j 50c: c/w 73.4 1.09 70) (150 p ) t (t r d(max) a(max) j(max) a)(max) th(j q this should be achievable for the to263-5 package us - ing pcb copper area to aid in conducting the heat away, such as one square inch of copper connected to the exposed die pad of the device. internal ground/power planes and air fow will also assist in removing heat. for higher ambient temperatures it may be necessary to use additional copper area. applications information
SC4217 9 typical application circuits vo=2.5v c2 0.1uf(ceramic) agnd c1 1uf vin=3.3v c3 10uf (tantalum) r2 10.2k r1 10k c4 0.1uf(ceramic) 0 r3 10k 0 c5 10uf (tantalum) gnd SC4217 2 3 5 4 1 vin gnd adj vo en 0 gnd pgnd figure 1: application circuit with 3.3v input and 2.5v output
SC4217 0 e 1 d 1 a 1 a 0 e e / 2 l 1 d 01 l see detail c 1 c h . 575 - . 625 14 . 61 - 15 . 88 a aaa b a plane seating b . 380 10 . 67 9 . 65 . 420 - - - - 1 . 68 . 066 4 . 06 . 160 - - - - - - - - - - 0 . 25 . 010 - - . 270 - - 6 . 86 - - plated copper heat spreader aaa n 01 0 d 1 h l 1 l e e 1 e c d c 1 b a 1 a dim millimeters inches dimensions min nom max min max nom b x n ( l 1 ) . 067 bsc detail 5 a . 326 . 020 - 5 a 1 . 70 bsc . 380 8 . 28 . 039 0 . 51 9 . 65 0 . 99 - - . 070 . 015 - . 000 - - 15 - 15 . 110 . 029 1 . 78 0 . 38 . 190 . 010 0 . 00 0 . 74 2 . 79 - 0 . 25 4 . 83 - - dimensions " d " and " e " do not include mold flash , protrusions or gate burrs . controlling dimensions are in inches ( angles in degrees ). notes : 1 . 2 . side view e 1 . 14 . 065 . 045 - 1 . 65 - - - 8 0 8 0 . 245 6 . 22 1 2 3 5 4 outline drawing to263-5
semtech corporation power management products division 200 flynn road, camarillo, ca 930 2 phone: (805) 498-2 fax: (805) 498-3804 www.semtech.com contact information SC4217 land pattern to263-5 k x y z notes : 1 . this land pattern is for reference purposes only consult your manufacturing group to ensure your company ' s manufacturing guidelines are met . g p dimensions millimeters inches h z x p k y g dim . 420 . 140 . 615 . 042 . 067 . 350 . 125 10 . 67 3 . 56 15 . 62 1 . 07 1 . 70 8 . 89 3 . 17 h

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