rt9043 1 ds9043-02 april 2011 www.richtek.com ordering information marking information for marking information, contact our sales representative directly or through a richtek distributor located in your area. high psrr, low dropout, 400ma adjustable ldo regulator general description the rt9043 is a high-performance, 400ma ldo regulator, offering high psrr and low dropout. the quiescent current is as low as 35 a, further prolonging the battery life. the rt9043 also works with low-esr ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. the rt9043 consumes typical 0.7 a in shutdown mode. the other features include low dropout voltage, high output accuracy, current limit protection, and enable/shutdown control. the rt9043 is available in the sot-23-5 package. features z z z z z adjustable output voltage z z z z z enable/shutdown control z z z z z wide operating voltage range : 2.2v to 5.5v z z z z z low dropout : 230mv at 400ma z z z z z low-noise for rf application z z z z z ultra-fast response in line/load transient z z z z z current limit protection z z z z z high power supply rejection ratio z z z z z output only 1 f capacitor required for stability z z z z z rohs compliant and halogen free applications z mega sim card z cdma/gsm cellular handsets z portable information appliances z laptop, palmtops, notebook computers z hand-held instruments z mini pci & pci-express cards z pcmcia & new cards note : richtek products are : ` rohs compliant and compatible with the current require- ments of ipc/jedec j-std-020. ` suitable for use in snpb or pb-free soldering processes. typical application circuit pin configurations (top view) sot-23-5 vin gnd en vout fb 4 23 5 vin gnd vout rt9043 c out 1f 1f fb en c in v in v out chip enable r1 r2 r3 10k 15 4 2 3 rt9043 package type b : sot-23-5 lead plating system g : green (halogen free and pb free) -
rt9043 2 ds9043-02 april 2011 www.richtek.com absolute maximum ratings (note 1) z supply input voltage, v in ------------------------------------------------------------------------------------------------ 6v z en input voltage ----------------------------------------------------------------------------------------------------------- 6v z power dissipation, p d @ t a = 25 c sot-23-5 -------------------------------------------------------------------------------------------------------------------- 0.4w z package thermal resistance (note 2) sot-23-5, ja --------------------------------------------------------------------------------------------------------------- 250 c/w z lead temperature (soldering, 10 se c.) ------------------------------------------------------------------------------- 260 c z junction temperature ----------------------------------------------------------------------------------------------------- 150 c z storage temperature range -------------------------------------------------------------------------------------------- ? 65 c to 150 c z esd susceptibility (note 3) hbm -------------------------------------------------------------------------------------------------------------------------- 2k v mm ---------------------------------------------------------------------------------------------------------------------------- 2 00v recommended operating conditions (note 4) z junction temperature range -------------------------------------------------------------------------------------------- ? 40 c to 125 c z ambient temperature range -------------------------------------------------------------------------------------------- ? 40 c to 85 c functional pin description pin no. pin name pin function 1 vin voltage input. 2 gnd ground. 3 en chip enable (active high). 4 fb output voltage feedback. 5 vout voltage output. function block diagram + - por otp en vin vout gnd mosfet driver current limit v ref fb
rt9043 3 ds9043-02 april 2011 www.richtek.com electrical characteristics parameter symbol test conditions min typ max unit input voltage range v in 2.2 -- 5.5 v reference voltage v ref 1.188 1.200 1.212 v quiescent current i q i out = 0ma -- 35 50 a shutdown current i shdn v en = 0v -- 0.7 1.5 a current limit i lim r load = 0 , 2.2v v in < 5.5v 400 650 -- ma dropout voltage v drop i out = 400ma -- 230 350 mv load regulation v load 1ma < i out < 400ma 2.2v v in < 5.5v -- -- 1 % line regulation v line v in = (v ou t + 0.5v) to 5.5v, i out = 1ma -- 0. 01 0.2 %/v logic-low voltage v il 0 -- 0.6 en threshold logic-high voltage v ih 1.6 -- 5.5 v en pin current i en -- 0.1 1 a fb pin current i fb -- 0.1 1 a f = 1khz, i out = 10ma -- 67 -- db power supply rejection ratio psrr f = 10khz, i out = 10ma -- 56 -- db output noise voltage v on v out = 1.5v, c out = 1 f, i out = 0ma -- 30 -- v rms thermal shutdown temperature t sd -- 160 -- c thermal shutdown recovery temperature -- 110 -- c (v in = 3.7v, c in = c out = 1 f, i out = 20ma, t a = 25 c, unless otherwise specified) note 1. stresses listed as the above ? absolute maximum ratings ? may cause permanent damage to the device. these are for stress ratings. functional operation of the device 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 remain possibility to affect device reliability. note 2. ja is measured in the natural convection at t a = 25 c on a low effective thermal conductivity test board of jedec 51-3 thermal measurement standard. note 3. devices are esd sensitive. handling precaution is recommended. note 4. the device is not guaranteed to function outside its operating conditions.
rt9043 4 ds9043-02 april 2011 www.richtek.com reference voltage vs. temperature 1.185 1.190 1.195 1.200 1.205 1.210 1.215 -40 -25 -10 5 20 35 50 65 80 95 110 125 temperature reference voltage (v) quiescent current vs. temperature 20 22 24 26 28 30 32 34 36 -40 -25 -10 5 20 35 50 65 80 95 110 125 temperature quiescent current (ua) dropout voltage vs. load current 0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350 400 load current (ma) dropout voltage (mv) en threshold vs. temperature 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 -40-20 0 20406080100 temperature en threshold (v) current limit vs. temperature 450 475 500 525 550 575 600 625 650 675 700 -50 -25 0 25 50 75 100 125 temperature current limit (ma) typical operating characteristics v in = v en = 3.3v, no laod ( c) v in = v en = 3.3v, v out = 2.5v, no laod ( c) t a = ? 40 c t a = 25 c t a = 125 c v in = v en = 3.3v, v out = 2.5v rising ( c) falling v in = 3.3v, no laod v in = 3.3v, v out = 1.8v ( c) current limit vs. input voltage 500 525 550 575 600 625 650 675 700 22.533.544.555.5 input voltage (v) current limit (ma) v out = 1.8v
rt9043 5 ds9043-02 april 2011 www.richtek.com line transient response time (50 s/div) v in (v/div) v out (20mv/div) 5 4 v in = 4v to 5v, v out = 2.5v, i load = 1ma, c out = 1 f/x7r load transient response time (100 s/div) i out (200ma/div) v out (10mv/div) v in = 3.3v, v out = 2.5v, i load = 1ma to 400ma, c in = c out = 1 f/x7r load transient response time (100 s/div) i out (200ma/div) v out (10mv/div) v in = 3.3v, v out = 2.5v, i load = 200ma to 400ma, c in = c out = 1 f/x7r power on from en time (5 s/div) v out (1v/div) v en (5v/div) v in = 3.3v, v out = 2.5v, no load enable/shutdown response time (500 s/div) v in = 5v, v out = 2.5v, i load = 10ma v out (1v/div) v en (5v/div) psrr -80 -70 -60 -50 -40 -30 -20 -10 0 10 100 1000 10000 100000 1000000 frequency (hz) psrr(db) i load = 10ma, c in = c out = 1 f/x7r 1k 10k 100k 1m
rt9043 6 ds9043-02 april 2011 www.richtek.com application information input capacitor selection like any low-dropout linear regulator, the external capacitors used with the rt9043 must be carefully selected for stability and performance. the input capacitance is recommended to be at least 1 f, and can be increased without limit. the input capacitor must be located at a distance of less than 0.5 inch from the input pin of the ic and returned to a clean ground plane. any high-quality ceramic capacitor or tantalum capacitor can be used for the input capacitor. using input capacitor with larger capacitance and lower esr (equivalent series resistance) can obtain better psrr and line transient response. output capacitor selection the output capacitor must meet both the requirements for minimum capacitance and minimum esr value in all applications. the rt9043 is designed specifically to work with low esr ceramic output capacitor to save board space and have better performance. figure 1 shows the allowable esr range for stable operation as a function of load current and output capacitance value. use at least 1 f ceramic output capacitor which esr is within the stable operation range to ensure stability. larger capacitance can reduce noise and improve load transient response, stability, and psrr. the rt9043 can operate with other types of output capacitor due to its wide stable operation range. the output capacitor should be placed less than 0.5 inch from the v out and returned to a clean ground plane. region of stable c out esr vs. load current 0.00 0.01 0.10 1.00 10.00 100.00 0 50 100 150 200 250 300 350 400 load current (ma) region of stable c out esr (ohm) c out = 1 f unstable region stable region unstable region (simulation verity) region of stable c out esr ( ) output voltage setting the output voltage divider r1 and r2 allows to adjust the output voltage for various application as shown in figure 2. v out r9043 fb gnd r1 r2 figure 2. output voltage setting the output voltage is set according to the following equation: out fb r1 vv1 r2 ?? =+ ?? ?? where v fb is the feedback reference voltage (1.2v typical). enable function the rt9043 features enable/shutdown function. the voltage at the en pin determines the enable/shutdown state of the regulator. to ensure the regulator will switch on, the enable control voltage must be greater than 1.6v. the regulator will enter shutdown mode when the voltage at en pin falls below 0.6 volt. if the enable function is not needed, en pin should be pulled high or simply tied to v in to keep the regulator in on state. psrr rt9043 features high power supply rejection ratio (psrr), which is defined as the ratio of output voltage change against input voltage change. out in v psrr 20 log v ?? = ?? ?? a low-dropout regulator with higher psrr can provide better line transient performance. current limit the rt9043 implements an independent current limit circuit, which monitors and controls the pass ele ment?s gate voltage to limit the output current at 650ma (typ.). if the current limit condition lasts for a long time, the regulator temperature may increase high enough to damage the regulator itself. there fore, rt9043 implements current limit function and thermal protection function to prevent figure 1
rt9043 7 ds9043-02 april 2011 www.richtek.com the regulator from damaging when the output is shorted to ground. thermal considerations for continuous operation, do not exceed absolute maximum operation junction temperature. the maximum power dissipation depends on the thermal resistance of ic package, pcb layout, the rate of surroundings airflow and temperature difference between junction to ambient. the maximum power dissipation can be calculated by following formula : p d(max) = ( t j(max) ? t a ) / ja where t j(max) is the maximum operation junction temperature, t a is the ambient temperature and the ja is the junction to ambient thermal resistance. for recommended operating conditions specification of rt9043, the maximum junction temperature is 125 c. the junction to ambient thermal resistance ja is layout dependent. for sot-23-5 packages, the thermal resistance ja is 250 c/w on the standard jedec 51-3 single layer thermal test board. the maximum power dissipation at t a = 25 c can be calculated by following formula : p d(max) = (125 c ? 25 c) / (250 c/w) = 0.4w for sot-23-5 packages the maximum power dissipation depends on operating ambient temperature for fixed t j(max) and thermal resistance ja . for rt9043 packages, the figure 3 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. figure 3. derating curves for rt9043 packages 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0 25 50 75 100 125 ambient temperature (c) maximum power dissipation (w) sot-23-5 single layer pcb
rt9043 8 ds9043-02 april 2011 www.richtek.com information that is provided by richtek technology corporation is believed to be accurate and reliable. richtek reserves the ri ght to make any change in circuit design, specification or other related things if necessary without notice at any time. no third party intellectual property infringemen t of the applications should be guaranteed by users when integrating richtek products into any application. no legal responsibility for any said applications is assumed b y richtek. richtek technology corporation headquarter 5f, no. 20, taiyuen street, chupei city hsinchu, taiwan, r.o.c. tel: (8863)5526789 fax: (8863)5526611 richtek technology corporation taipei office (marketing) 5f, no. 95, minchiuan road, hsintien city taipei county, taiwan, r.o.c. tel: (8862)86672399 fax: (8862)86672377 email: marketing@richtek.com outline dimension a a1 e b b d c h l sot-23-5 surface mount package dimensions in millimeters dimensions in inches symbol min max min max a 0.889 1.295 0.035 0.051 a1 0.000 0.152 0.000 0.006 b 1.397 1.803 0.055 0.071 b 0.356 0.559 0.014 0.022 c 2.591 2.997 0.102 0.118 d 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 h 0.080 0.254 0.003 0.010 l 0.300 0.610 0.012 0.024
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