page no. : 1/10 ds-rs7225-02 september, 2009 www.orister.com rs7225 1a adjustable & fixed voltage ldo linear regul ator with enable, fast discharge & soft-start general description the rs7225 series is a low-dropout linear regulator with on/o ff control that operates in the input voltage range from +2.4v to +7.0v and delivers 1.0a output current. the rs7225 is available fixed output voltag e type is preset at an internally trimmed voltage 1.8v, 2.5v, or 3.3v. other options 1.0v, 1.2v, 1.5v, 2.85v, 3.0v and 3.6v are available by special order only. the rs7225 series consists of a 0.95v bandgap reference, an e rror amplifier, and a p-channel pass transistor. other features include soft-start function, short-circuit protection and therma l shutdown protection. the rs7225 series devices are available in sot-223-5, & to-252-5 packages. features applications operating voltage range +2.4v to +7.0v output voltages +1.0v to +5.0v (0.1 v step) (fixed), +1.25v to +5.0 v (adj type) dropout voltage 700mv@600ma (fixed) fast response in power-on 35us low current consumption 60 a (typ.) low esr capacitor compatible high ripple rejection 55db (typ.) short circuit protection 600ma (typ.) thermal overload shutdown protection sot-223-5 & to-252-5 packages rohs compliant and 100% lead (pb)-free and green (halogen free with commercial standard) battery-powered equipments graphic card, peripheral card pcmcia & new card mini pci & pci-express cards digital still camera cdma/gsm cellular handsets laptop, palmtops, notebook computers portable information application application circuits soft-start function this integrated circuit can be damaged by esd. orister corporation recommends that all integrated circuits be handled with appropriate precautions. failure to observe proper handling and installation procedures can cause damage. esd damage can range from subtle performance degradation to complete device failure. precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
page no. : 2/10 ds-rs7225-02 september, 2009 www.orister.com pin assignments sot-223-5 to-252-5 package pin symbol description 1 vin regulator input pin 2 vout regulator output pin 3 ss soft-start function 4 en enable pin sot-223-5 5 gnd/adj ground pin or adj terminal pin for adjustable. package pin symbol description 1 vin regulator input pin 2 vout regulator output pin 3 gnd/adj ground pin or adj terminal pin for adjustable. 4 ss soft-start function to-252-5 5 en enable pin ordering information device device code rs7225-xx eee yy z xx is nominal output voltage (for example, ad=adj, 18 = 1.8v, 33 = 3.3v, 285 = 2.85v). eee is ce input logic & discharge function selecti on : (see ce & discharge function selection table ) yy is package designator : ne : sot-25 sc : sc-70-5 s : sop-8 z is lead free designator : p: commercial standard, lead (pb) free and phosphorous (p) free package g: green (halogen free with commercial standard) ce & discharge function selection table en type en type eee code type 1 type 2 discharge eee code type 1 type 2 discharge nhf none high active fast uhn pull high high active normal nlf none low active fast uln pull high low active normal nhn none high active normal dhf pull low high active fast nln none low active normal dlf pull low low active fast uhf pull high high active fast dhn pull low high active normal ulf pull high low active fast dln pull low low active normal
page no. : 3/10 ds-rs7225-02 september, 2009 www.orister.com block diagram absolute maximum ratings parameter symbol ratings units input voltage v in to gnd v in 9.0 v output current limit, i (limit) i limit 1.3 a junction temperature t j +155 o c sot-223-5 155 thermal resistance to-252-5 ja 90 o c/w sot-223-5 900 power dissipation to-252-5 p d 1200 mw operating ambient temperature t opr -40 ~ +85 o c storage temperature t stg -55~+150 o c lead temperature (soldering, 10sec) - +260 o c notes 1 the power dissipation values are based on the condition that junction temperature t j and ambient temperature t a difference is 100c. 2 stresses beyond those listed under ?absolute maximum ratings? may cause permanent damage to the device. these are stress rating s only, and function operation of the device at these or any other conditions beyond those indicated under ?recommended operating condition s? is not implied. exposure to absolute-maximum ?rated conditions for extended periods may affect device reliability.
page no. : 4/10 ds-rs7225-02 september, 2009 www.orister.com electrical characteristics (t a =25c, v in =5.0v unless otherwise specified) symbol parameter conditions min. typ. max. unit v in input voltage - 2.4 - 7.0 v v in =v out +1.0v, i out =1ma, v out R 1.8v -2% +2% v fixed type v in =v out +1.0v, i out =1ma, v out 1.8v, v in 2.4v -35 +35 mv v in =v out +1.2v, i out =1ma, v out R 1.8v -2% +2% v v out output voltage adj type v in =v out +1.2v, i out =1ma, v out 1.8v, v in 2.4v -50 v out +50 mv i max output current (see note) v out +1.0v Q v in Q 7.0v, v out R 2.4v 1.0 - - a i out =100ma, v out >3.0v - 50 - v drop dropout voltage i out =1000ma, v out >3.0v - 700 - mv v line line regulation v out +1.0v Q v in Q 7v, i out =1ma - 0.2 0.3 %/v v load load regulation v in =v out +1v, 1ma Q i out Q 100ma - 0.01 0.02 %/ma i q ground pin current i load =0ma to 1.0a, v in =v out +1.0v - 60 - ua i sd shutdown current v in =v out +1v, en=0v, no load 0.7 - ua i sc short circuit current - - 600 - ma psrr ripple rejection i out =30ma, f=1khz, c out =10uf - 55 - db e n output noise i out =100ma , f=1khz, c out =10uf - 40 - uv (rms) v ih en pin input voltage ?h? v in Q 5.0v 1.6 - - v v il en pin input voltage ?l? v in Q 5.0v - - 0.3 v r dis discharge resistor v en =0v, for fixed voltage type - 30 100 ? t dis discharge time v out =3.3v to 0v, c out =1uf, for fixed voltage type - 70 100 us t ss soft-start time v out =3.3v, c ss =0.1uf, c in =c out =1uf - 20 - ms t sd thermal shutdown temperature - - 150 - o c t hys thermal shutdown hysteresis - - 20 - o c note measured using a double sided board with 1? x 2? square inches of copper area connected to the gnd pins for ?heat spreading?.
page no. : 5/10 ds-rs7225-02 september, 2009 www.orister.com detail description the rs7225 is a low-dropout linear regulato r. the device provides preset 1.8v, 2.5v and 3.3v output voltages for output current up to 600ma. other mask options for special output voltages are also available. as illustrated in function block diagra m, it consists of a 0.95v bandgap reference, an error amplifier, a p-channel pass transistor and an internal feedback voltage divider. the 0.95v bandgap reference is connected to the error amplifier, which compares this reference with the feedback voltage and amplifies the voltage difference. if the feedback voltage is lowe r than the reference voltage, the pass-transistor gate is pull ed lower, which allows more current to pass to the output pin and increases the output voltage. if the feedback voltage is too hig h, the pass transistor gate is pulled up to decrease the output voltage. the output voltage is feedback through an internal resistive divider connected to v out pin. additional bl ocks include an output current limiter, thermal sensor, and shutdown logic. internal p-channel pass transistor the rs7225 features a p-channel mosfet pass transistor. un like similar designs using pnp pass transistors, p-channel mosfets require no base drive, which reduces quiescent curren t. pnp-based regulators also waste considerable current in dropout when the pass transistor saturates, and use high base-drive currents under large loads. the rs7225 does not suffer from these problems and consumes only 60 a (typ.) of current consumption under heavy loads as well as in dropout conditions. enable function en pin starts and stops the regulator. when the en pin is switch ed to the power off level, the operation of all internal circui t stops, the build-in p-channel mosfet output transistor between pins v in and v out is switched off, allowi ng current consumption to be drastically reduced. the v out pin enters the gnd level through the internal discharge path between v out and gnd pins. soft start function the capacitor can be connected be tween the bypass pin and gnd. th is capacitor can be a low cost polyester film variety. a larger capacitor improves the ac ripple rejection, but also makes the output come up slowly. this "soft" turn-on is desirable i n some applications to limit turn-on surges. fast discharge function the rs7225 fixed type has fast discharge function on en pin di sable. when user turns off the device, its internal pull-low resistor will discharge output capacitor charge. it?ll avoid other device to arise wrong motions. output voltage selection for fixed voltage type of rs7225, the output voltage is preset at an internally trimmed voltage. the first two digits of part number suffix identify the output voltage (see ordering informat ion). for example, the rs7225-33 has a preset 3.3v output voltage. current limit the rs7225 also includes a fold back current limiter. it monitors and controls the pass transistor?s gate voltage, estimates th e output current, and limits the output current within 1.3a (typ.) thermal overload protection thermal overload protection limits total power dissipation in the rs7225. when the junction temperature exceeds t j =+165c, a thermal sensor turns off the pass transistor, allowing the ic to cool down. the thermal sensor turns the pass transistor on aga in after the junction temperature cools down by 20c, resulting in a pulsed output during continuous thermal overload conditions. thermal overload protection is designed to protect the rs7225 in the event of fault conditions. for continuous operation, the absolute maximum operating junction temperature rating of t j =+125c should not be exceeded.
page no. : 6/10 ds-rs7225-02 september, 2009 www.orister.com operating region and power dissipation maximum power dissipation of the rs7225 depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of airflow. the power dissipation across the devices is p=i out x (v in -v out ). the resulting maximum power dissipation is: ja a j ca jc a j max t t t t p ) ( ) ( ? = + ? = where (t j -t a ) is the temperature difference between the rs7301 die junction and the surrounding air, jc is the thermal resistance of the package chosen, and ca is the thermal resistance through the prin ted circuit board, copper traces and other materials to the surrounding air. for better heat-sinking, the copper area should be equally shared between the v in , v out , and gnd pins. dropout voltage a regulator?s minimum input-output voltage differential, or dropou t voltage, determines the lowest usable supply voltage. in battery-powered systems, this will determi ne the useful end-of-life battery voltage . the rs7225 use a p-channel mosfet pass transistor, its dropout voltage is a function of drain-to-source on-resistance r ds(on) multiplied by the load current. out on ds out in dropout i r v v v = ? = ) (
page no. : 7/10 ds-rs7225-02 september, 2009 www.orister.com sot-223-5 dimension notes: a. all linear dimensions are in millimeters. b. this drawing is subject to change without notice. c. body dimensions do not include mold flash or protrusion.
page no. : 8/10 ds-rs7225-02 september, 2009 www.orister.com to-252-5 dimension notes: a. all linear dimensions are in millimeters. b. this drawing is subject to change without notice. c. body dimensions do not include mold flash or protrusion.
page no. : 9/10 ds-rs7225-02 september, 2009 www.orister.com soldering methods for orister?s products 1. storage environment: temperature=10 o c~35 o c humidity=65%15% 2. reflow soldering of surface-mount devices profile feature sn-pb eutectic assembly pb-free assembly average ramp-up rate (t l to t p ) <3 o c/sec <3 o c/sec preheat - temperature min (ts min ) - temperature max (ts max ) - time (min to max) (ts) 100 o c 150 o c 60~120 sec 150 o c 200 o c 60~180 sec tsmax to t l - ramp-up rate <3 o c/sec <3 o c/sec time maintained above: - temperature (t l ) - time (t l ) 183 o c 60~150 sec 217 o c 60~150 sec peak temperature (t p ) 240 o c +0/-5 o c 260 o c +0/-5 o c time within 5 o c of actual peak temperature (t p ) 10~30 sec 20~40 sec ramp-down rate <6 o c/sec <6 o c/sec time 25 o c to peak temperature <6 minutes <8 minutes 3. flow (wave) soldering (solder dipping) products peak temperature dipping time pb devices. 245 o c 5 o c 5sec 1sec pb-free devices. 260 o c +0/-5 o c 5sec 1sec figure 1: temperature profile t p t l ramp-down ramp-up ts max ts min critical zone t l to t p t s preheat t l t p 25 t 25 o c to peak time temperature
page no. : 10/10 ds-rs7225-02 september, 2009 www.orister.com important notice: ? orister corporation orister cannot assume responsibility for use of any circuitry ot her than circuitry entirely embodied in an orister product. no circuit patent licenses, copyrights, mask work rights, or ot her intellectual property rights are implied. orister reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. except as provided in orister?s terms and conditions of sale, orister assumes no liability whatsoever, and orister disclaims an y express or implied warranty relating to the sale and/or use of orister pr oducts including liability or warranties relating to fitness f or a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. in order to minimize r isks associated with the customer?s applications, adequate design and operating safeguar ds must be provided by the customer to minimize inheren t or procedural hazards. testing and other quality control techniques ar e utilized to the extent orister deems necessary to support this warranty. specific testing of all parameters of each device is not necessarily performed. orister and the orister logo are trademarks of orister corporat ion. all other brand and product names appearing in this documen t are registered trademarks or trademarks of their respective holders.
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