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preliminary RT9183 ds9183-00 july 2003 www.richtek.com 1 ultra low dropout 1.5a linear regulator general description the RT9183 series are high performance linear voltage regulators that provide ultra low-dropout voltage, high output current with low ground current. it operates from an input of 2.3v to 5.5v and provides output current up to 1.5a thus is suitable to drive digital circuits requiring low voltage at high currents. the RT9183 has superior regulation over variations in line and load. also it provides fast respond to step changes in load. other features include over-current and over-temperature protection. the adjustable version has enable pin to reduce power consumption in shutdown mode. the devices are available in fixed output voltages of 1.8v, 2.5v, 3.3v and as an adjustable device with a 0.8v reference voltage. the RT9183 regulators are available in 3-lead sot-223 and to-263 packages (fixed output only for the 3-lead option). also available are 5-lead to-263 and fused sop-8 packages with two external resistors to set the output voltage ranges from 0.8v to 4.5v. ordering information RT9183 - features 330mv dropout @ 1.5a 380 a low ground pin current excellent line and load regulation 0.1 a quiescent current in shutdown mode guaranteed 1.5a output current fixed output voltages: 1.8v, 2.5v, 3.3v adjustable output voltage from 0.8v to 4.5v over-temperature/over-current protection applications battery-powered equipment mother board/graphic card peripheral cards pcmcia card pin configurations part number pin configurations RT9183- cg (plastic sot-223) top view 1. vin 2. gnd (tab) 3. vout RT9183 - cs (plastic sop-8) top view RT9183- cm (plastic to-263) top view 1. vin 2. gnd (tab) 3. vout RT9183 - cm5 (plastic to-263-5) top view 1. en 2. vin 3. gnd (tab) 4. vout 5. adj operating temperature range c: commercial standard package type g : sot-223 s : sop-8 m : to-263 m5 : to-263-5 output voltage default : adjustable 18 : 1.8v 25 : 2.5v 33 : 3.3v h : chip enable high l : chip enable low 12345 123 en vin vout adj gnd gnd gnd gnd 1 2 3 4 8 7 6 5 123
RT9183 preliminary www.richtek.com ds9183-00 july 2003 2 typical application circuit figure 1. 3.3v to 2.5v regulator v out = 0.8 x (1 + ) volts figure 2. adjustable operation figure 3. fixed operation with sop-8 and to-263-5 packages pin description pin name pin function en chip enable control input. note that the device will be in the unst able state if the pin is not connected. vin supply input gnd common ground vout regulator output adj the output voltage is set by the inter nal feedback resistors when this pin grounded. if external feedback resistors are applied, the output voltage will be: v out = 0.8 (1 + ) volts 2 1 r r 2 1 r r note: the value of r2 should be less than 80k to maintain regulation. v in = 3.3v vi n vou t gnd c out 10 f v out 2.5v, 1.5a c in 10 f RT9183 (sot- 223 & to -263) v in = 3.3v vi n vou t gnd c out 10 f v out 2.5v, 1.5a c in 10 f RT9183 (sot- 223 & to -263) enable v out vin vout en gnd adj RT9183 v in c 2 10 f c 1 10 f (sop-8 & to-263- 5) c 3 0.1 f enable v out vin vout en gnd adj RT9183 v in c 2 10 f c 1 10 f (sop-8 & to-263- 5) c 3 0.1 f enable v out vin vout en gnd adj RT9183 v in r 1 r 2 c 2 10 f c 1 10 f (sop-8 & to-263- 5) c 3 0.1 f enable v out vin vout en gnd adj RT9183 v in r 1 r 2 c 2 10 f c 1 10 f (sop-8 & to-263- 5) c 3 0.1 f
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 3 function block diagram thermal shutdown vout shutdown logic en gnd output mode comparator + - adj vin error amplifier + - 0.8v reference current limit sensor + - 100mv
RT9183 preliminary www.richtek.com ds9183-00 july 2003 4 absolute maximum ratings (note 1) supply input voltage 6v package thermal resistance sot-223, jc 15 c/w sop-8, jc 15.7 c/w to-263, jc 8 c/w lead temperature (soldering, 10 sec.) 260 c junction temperature 150 c storage temperature range ? 65 c to 150 c esd susceptibility (note 2) hbm 2kv mm 200v recommended operating conditions (note 3) supply input voltage 2.3v to 5.5v junction temperature range ? 40 c to 125 c electrical characteristics (v in = v out + 0.7v, c in =c out = 10f (ceramic), t a = 25 c unless otherwise specified) parameter symbol test conditions min typ max units output voltage accuracy (fixed output voltage) ? v out i out = 10ma ? 2 0 +2 % output voltage range (adjustable) v out_adj 0.8 -- 4.5 v quiescent current (note 6) i q i out = 0ma, enable -- 380 -- a standby current (note 7) i stby v in = 5.5v, shutdown -- 0.1 -- a current limit i lim -- 3.2 -- a i out = 0.5a -- 110 -- i out = 1.0a -- 220 -- dropout voltage (note 4) v drop i out = 1.5a -- 330 -- mv line regulation ? v line v out + 0.7v < v in < 5.5v i out = 10ma -- 0.035 -- %/v load regulation (note 5) (fixed output voltage) ? v load 1ma < i out < 1.5a -- 22 -- mv thermal shutdown temperature t sd -- 170 -- c thermal shutdown hysteresis ? t sd -- 30 -- c logic-low voltage v il v in = 5.5v -- -- 0.6 en threshold logic-high voltage v ih v in = 5.5v 1.8 -- -- v enable pin current i en v in = 5.5v, enable -- 0.1 -- a to be continued
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 5 parameter symbol test conditions min typ max units adj reference voltage tolerance v ref 0.784 0.8 0.816 v adjust pin current i adj v adj = v ref -- 10 -- na adjust pin threshold v th(adj) -- 0.1 -- v note 1. stresses beyond those listed under ?absolute maximum ratings? may cause permanent damage to the device. these are stress ratings only, and functi onal operation of the devic e at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. note 2. devices are esd sensitive. handling precaution re commended. the human body model is a 100pf capacitor discharged through a 1.5k ? resistor into each pin. note 3. the device is not guaranteed to func tion outside its operating conditions. note 4. dropout voltage is defined as the input to output differential at which the out put voltage drops 2% below its nominal value measured at 0.7v differential. note 5. regulation is measured at constant j unction temperature by using a 20ms current pulse. devices are tested for load regulation in the load range from 10ma to 1.5a. note 6. quiescent, or ground current, is the difference be tween input and output currents. it is defined by i q = i in ? i out under no load condition (i out = 0ma). the total current drawn from the suppl y is the sum of the load current plus the ground pin current. note 7. standby current is the input current drawn by a regulato r when the output voltage is disabled by a shutdown signal ( v en 1.8v or v en 0.6v). it is measured with v in = 5.5v.
RT9183 preliminary www.richtek.com ds9183-00 july 2003 6 typical operating characteristics output voltage vs. temperature 1.7 1.75 1.8 1.85 1.9 -50-25 0 25 50 75100125 temperature output voltage (v) v in = 5v, r l = c in = c out =10 uf (ceramic, y5v) RT9183h-18cs (o c) -40 output voltage vs. temperature 2.4 2.45 2.5 2.55 2.6 -50 -25 0 25 50 75 100 125 temperature output voltage (v) v in = 5v, r l = c in = c out =10 uf (ceramic, y5v) RT9183-25cg (o c) -40 quiescent current vs. temperature 300 320 340 360 380 400 -50 -25 0 25 50 75 100 125 temperature quiescent current (ua) 1 (o c) v in = 5v, r l = c in = c out =10 uf (ceramic, y5v) RT9183h-18cs -40 quiescent current vs. temperature 300 320 340 360 380 400 -50 -25 0 25 50 75 100 125 temperature quiescent current (ua) 1 (o c) v in = 5v, r l = c in = c out =10 uf (ceramic, y5v) RT9183-25cg -40 current limit vs. temperature 3 3.2 3.4 3.6 3.8 4 -50 -25 0 25 50 75 100 125 temperature current limit (a) (o c) RT9183-25cg -40 v in = 5v, c in = c out =10 uf (ceramic, y5v) current limit vs. temperature 3 3.2 3.4 3.6 3.8 4 -50 -25 0 25 50 75 100 125 temperature current limit (a) (o c) v in = 5v, c in = c out =10 uf (ceramic, y5v) -40 RT9183l-33cm5
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 7 copper area vs. power dispation 50 100 150 200 250 300 350 11.5 22.53 power dissipation (w) copper area t j = 125 ? c (mm 2 ) RT9183h-18cs t a = 65 ? c t a = 25 ? c t a = 50 ? c RT9183h-18cs load transient response time (100s/div) load transient ( a ) o utput voltage (mv) c out = 47f/low esr, i load = 1ma ~ 750ma 1 0.5 0 20 0 -20 RT9183h-18cs load transient response time (100s/div) c out = 47f/low esr, i load = 1ma ~ 1.5a load transient ( a ) o utput voltage (mv) 50 0 -50 2 1 0 line transient response RT9183h-18cs time (100s/div) c out = 47f/low esr, i load = 100ma input voltage (v) o utput voltage (mv) 10 0 -10 5 4 RT9183-25cg t j = 125 c t j = 25 c t j = ? 40 c dropout voltage 0 100 200 300 400 500 0 0.3 0.6 0.9 1.2 1.5 load current (a) dropout voltage (mv) 1 RT9183l-33cm5 t j = 125 c t j = 25 c t j = ? 40 dropout voltage 0 100 200 300 400 500 0 0.3 0.6 0.9 1.2 1.5 load current (a) dropout voltage (mv)
RT9183 preliminary www.richtek.com ds9183-00 july 2003 8 (o c) en pin shutdown threshold vs. temperatur e 0.7 0.8 0.9 1 1.1 -50 -25 0 25 50 75 100 125 temperature shutdown threshold voltage (v) 1 RT9183l-33cm5 -40 v out off to on v out on to off RT9183h-18cs en pin shutdown response time (500s/div) c in = c out = 10f (ceramic, y5v) en voltage (v) o utput voltage (v) 2 1 0 5 0 i load = 100m a v in = 5v t a = 25 ? c
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 9 application information like any low-dropout regulator, the RT9183 series requires input and output decoupling capacitors. these capacitors must be correctly selected for good performance (see capacitor characteristics section). please note that linear regulators with a low dropout voltage have high internal loop gains which require care in guarding against oscillation caused by insufficient decoupling capacitance. input capacitor an input capacitance of ? 10 f is required between the device input pin and ground dire ctly (the amount of the capacitance may be increased without limit). the input capacitor must be located less than 1 cm from the device to assure input stability (see pcb layout section). a lower esr capacitor allows the use of less capacitance, while higher esr type (like aluminum electrolytic) require more capacitance. capacitor types (aluminum, ceramic and tantalum) can be mixed in parallel, but the total equivalent input capacitance/esr must be defined as above to stable operation. there are no requirements for the esr on the input capacitor, but tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance will be ? 10 f over the entire operating temperature range. output capacitor the RT9183 is designed specifically to work with very small ceramic output capacitors. the recommended minimum capacitance (temperature characteristics x7r or x5r) is 10 f to 47 f range with 10m ? to 25m ? range ceramic capacitor between ldo output and gnd for transient stability, but it may be increased without limit. higher capacitance values help to improve transient. the output capacitor?s esr is critical because it forms a zero to provide phase lead which is required for loop stability. (when using the y5v dielectric, the minimum value of the input/output capacitance that can be used for stable over full operating temperature range is 33 f .) no load stability the device will remain stable and in regulation with no external load. this is sp ecially important in cmos ram keep-alive applications. input-output (dropout) voltage a regulator?s minimum input-to-output voltage differential (dropout voltage) determines the lowest usable supply voltage. in battery-powered systems, this determines the useful end-of-life battery voltage. because the device uses a pmos, its dropout voltage is a function of drain-to-source on-resistance, r ds(on) , multiplied by the load current: v dropout = v in ? v out = r ds(on) i out current limit the RT9183 monitors and controls the pmos ? gate voltage, minimum limiting the output current to 2a. the output can be shorted to ground for an indefinite period of time without damaging the part. short-circuit protection the device is short circuit protected and in the event of a peak over-current condition, the short-circuit control loop will rapidly drive the output pmos pass element off. once the power pass element shuts down, the control loop will rapidly cycle the output on and off until the average power dissipation causes the thermal shutdown circuit to respond to servo the on/off cycling to a lower frequency. please refer to the section on thermal information for power dissipation calculations. capacitor characteristics it is important to note that capacitance tolerance and variation with temperature must be taken into consideration when selecting a capacitor so that the minimum required amount of capacitance is provided over the full operating temperature range. in general, a good tantalum capacitor will show very little capacitance variation with temperature, but a ceramic may not be as good (depending on dielectric type).
RT9183 preliminary www.richtek.com ds9183-00 july 2003 10 aluminum electrolytics also typically have large temperature variation of capacitance value. equally important to consider is a capacitor?s esr change with temperature: this is not an issue with ceramics, as their esr is extremely low. however, it is very important in tantalum and aluminum electrolytic capacitors. both show increasing esr at colder temperatures, but the increase in aluminum electrolytic capacitors is so severe they may not be feasible for some applications. ceramic: for values of capacitance in the 10 f to 100f range, ceramics are usually larger and more costly than tantalums but give superior ac performance for by- passing high frequency noise because of very low esr (typically less than 10m ? ). however, some dielectric types do not have good capaci tance characteristics as a function of voltage and temperature. z5u and y5v dielectric ceramics have capacitance that drops severely with applied voltage. a typical z5u or y5v capacitor can lose 60% of its rated capacitance with half of the rated volt age applied to it. the z5u and y5v also exhibit a severe temperature effect, losing more than 50% of nominal capacitance at high and low limits of the temperature range. x7r and x5r dielectric ceramic capacitors are strongly recommended if ceramics are used, as they typically maintain a capacitance range within 20% of nominal over full operating ratings of temperature and voltage. of course, they are typica lly larger and more costly than z5u/y5u types for a given voltage and capacitance. tantalum: solid tantalum capacitors are recommended for use on the output because their typical esr is very close to the ideal value required for loop compensation. they also work well as input capacitors if selected to meet the esr requirements previously listed. tantalums also have good temperature stability: a good quality tantalum will typically show a capacitance value that varies less than 10~15% across the full temperature range of 125c to ? 40c. esr will vary only about 2x going from the high to low temperature limits. the increasing esr at lower temperatures can cause oscillations when marginal quality capacitors are used (if the esr of the capacitor is near the upper limit of the stability range at room temperature). aluminum: this capacitor type offers the most capacitance for the money. the disadvantages are that they are larger in physical size, not widely available in surface mount, and have poor ac performance (especially at higher frequencies) due to higher esr and esl. compared by size, the esr of an aluminum electrolytic is higher than either tantalum or ceramic, and it also varies greatly with temperature. a typical aluminum electrolytic can exhibit an esr increase of as much as 50x when going from 25c down to ? 40c. it should also be noted that many aluminum electrolytics only specify impedance at a frequency of 120hz, which indicates they have poor high frequency performance. only aluminum electrolytics that have an impedance specified at a higher frequency (between 20khz and 100khz) should be used for the device. derating must be applied to the manufacturer?s esr specification, since it is typically only valid at room temperature. any applications using aluminum electrolytics should be thoroughly tested at the lowest ambient operating temperature where esr is maximum.
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 11 thermal considerations the RT9183 series can deliver a current of up to 1.5a over the full operating junction temperature range. however, the maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed 125 c. with all possible conditions, the junction temperature must be within the range specified under operating conditions. power dissipation can be calculated based on the output current and the voltage drop across regulator. p d = (v in ? v out ) i out + v in i gnd the final operating junction temperature for any set of conditions can be estimated by the following thermal equation: p d (max) = ( t j (max) ? t a ) / ja where t j (max) is the maximum junction temperature of the die (125 c) and t a is the maximum ambient temperature. the junction to ambient thermal resistance ( ja ) for sop-8 package at recommended minimum footprint is 42 c/w, 40 c/w for sot-223 package and 25 c/w for to-263 package ( ja is layout dependent). visit our website in which ?recommended footprints for soldering surface mount packages? for detail. pcb layout good board layout practices must be used or instability can be induced because of ground loops and voltage drops. the input and output capacitors must be directly connected to the input, output, and ground pins of the device using traces which have no other currents flowing through them. the best way to do this is to layout c in and c out near the device with short traces to the v in , v out , and ground pins. the regulator ground pin should be connected to the external circuit ground so that the regulator and its capacitors have a ?single point ground?. it should be noted that stability problems have been seen in applications where ?vias? to an internal ground plane were used at the ground points of the device and the input and output capacitor s. this was caused by varying ground potentials at these nodes resulting from current flowing through the ground plane. using a single point ground technique for the regulator and it?s capacitors fixed the problem. since high current flows through the traces going into v in and coming from v out , kelvin connect the capacitor leads to these pins so there is no voltage drop in series with the input and output capacitors. optimum performance can only be achieved when the device is mounted on a pc board according to the diagram below: sop-8 board layout adjustable operation the adjustable version of the RT9183 has an output voltage range of 0.8v to 4.5v. the output voltage is set by the ratio of two extern al resistors as shown in figure 2. the value of r2 should be less than 80k to maintain regulation. in critical applications, small voltage drop is caused by the resistance (r t ) of pc traces between the ground pin of the device and the return pin of r2 (see figure 4 shown on next page). note that the voltage drop across the external pc tr ace will add to the output voltage of the device. gnd adj gnd gnd v in v out en + + +
RT9183 preliminary www.richtek.com ds9183-00 july 2003 12 optimum regulation will be obtained at the point where the return pin of r2 is connected to the ground pin of the device directly. figure 4. return pin of external resistor connection referring to figure 3 the fixed voltage versions for both sop-8 and to-263-5 packages, the adj pin is the input to the error amplifier and must be tied the ground pin of the device direct ly otherwise it will be in the unstable state if the pin voltage more than 0.1v with respect to the ground pin itself. enable v out vin vout en gnd adj RT9183 v in r 1 r 2 c 2 10 f c 1 10 f (sop-8 & to-263- 5) c 3 0.1 f r t enable v out vin vout en gnd adj RT9183 v in r 1 r 2 c 2 10 f c 1 10 f (sop-8 & to-263- 5) c 3 0.1 f r t
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 13 package information dimensions in millimeters dimensions in inches symbol min max min max a -- 1.803 -- 0.071 a1 0.020 0.100 0.0008 0.0047 b 0.610 0.787 0.024 0.031 b 3.302 3.708 0.130 0.146 c 6.706 7.290 0.264 0.287 d 6.299 6.706 0.248 0.264 d1 2.896 3.150 0.114 0.124 e 2.261 2.362 0.089 0.093 h 0.229 0.330 0.009 0.013 3-lead sot-223 plastic surface mount a a1 b h b d d1 c l e e
RT9183 preliminary www.richtek.com ds9183-00 july 2003 14 dimensions in millimeters dimensions in inches symbol min max min max a 4.801 5.004 0.189 0.197 b 3.810 3.988 0.150 0.157 c 1.346 1.753 0.053 0.069 d 0.330 0.508 0.013 0.020 f 1.194 1.346 0.047 0.053 h 0.178 0.254 0.007 0.010 i 0.102 0.254 0.004 0.010 j 5.791 6.198 0.228 0.244 m 0.406 1.270 0.016 0.050 8?lead sop plastic package a b j f h m c d i
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 15 dimensions in millimeters dimensions in inches symbol min max min max a 4.064 4.826 0.160 0.190 b 1.143 1.676 0.045 0.066 b 0.660 0.914 0.026 0.036 b1 1.143 1.397 0.045 0.055 b2 0.305 0.584 0.012 0.023 c 1.143 1.397 0.045 0.055 d 9.652 10.668 0.380 0.420 e 8.128 9.652 0.320 0.380 e 2.286 2.794 0.090 0.110 l1 14.605 15.875 0.575 0.625 l2 2.286 2.794 0.090 0.110 u 6.223 ref. 0.245 ref. v 7.620 ref. 0.300 ref. 3-lead to- 263 surface mount c b2 a l1 b e e l2 v u d b b1
RT9183 preliminary www.richtek.com ds9183-00 july 2003 16 dimensions in millimeters dimensions in inches symbol min max min max a 4.064 4.826 0.160 0.190 b 1.143 1.676 0.045 0.066 b 0.660 0.914 0.026 0.036 b2 0.305 0.584 0.012 0.023 c 1.143 1.397 0.045 0.055 d 9.652 10.668 0.380 0.420 e 8.128 9.652 0.320 0.380 e 1.524 1.829 0.060 0.072 l1 14.605 15.875 0.575 0.625 l2 2.286 2.794 0.090 0.110 u 6.223 ref. 0.245 ref. v 7.620 ref. 0.300 ref. 5-lead to-263 plastic surface mount package c b2 a b e v u d e l1 b l2
preliminary RT9183 ds9183-00 july 2003 www.richtek.com 17
RT9183 preliminary www.richtek.com ds9183-00 july 2003 18 richtek technology corp. headquarter 5f, no. 20, taiyuen street, chupei city hsinchu, taiwan, r.o.c. tel: (8863)5526789 fax: (8863)5526611 richtek technology corp. taipei office (marketing) 8f-1, no. 137, lane 235, paochiao road, hsintien city taipei county, taiwan, r.o.c. tel: (8862)89191466 fax: (8862)89191465 email: marketing@richtek.com

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