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downloaded from elcodis.com electronic components distributor rt9027a/b 1 ds9027a/b-01 october 2008 www.richtek.com pin configurations ordering information (top view) sop-8 note : richtek pb-free and green 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. linear fan driver general description the rt9027a/b is a high performance positive voltage regulator designed for very low dropout voltage up to 0.5 amps. the v set voltage must be larger than 1v to guarantee that v out is 1.6 times of v set . when v set is less than 1v, the ic will be shutdown. the fon pin turns v out to fully- on when fon is given low. for RT9027B (en version), fon pin is equivalent to en pin. the rt9027a/b provides excellent regulation over variations in line, load and temperature. the rt9027a/b is available in the sop-8 package. package type s : sop-8 rt9027 operating temperature range p : pb free with commercial standard g : green (halogen free with commer- cial standard) a : fon function b : en function features z z z z z v out follows 1.6 times of v set z z z z z 150mv dropout @ 0.5a z z z z z over current and over temperature protection z z z z z fon pin turns v out fully on z z z z z rohs compliant and 100% lead (pb)-free applications z notebook computer fan driver z battery powered system z motherboard z peripheral card gnd vin vset vout gnd gnd gnd 2 3 4 5 8 7 6 fon gnd en vin vset vout gnd gnd gnd 2 3 4 5 8 7 6 rt9027a RT9027B typical application circuit vin vset vout gnd rt9027a/b v out 2.2uf 2.2uf v in c out c in v set fon/en fon/en 1 2 3 4 5 to 8 free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 2 ds9027a/b-01 october 2008 www.richtek.com functional pin description pin no. pin name pin function fon internal pulled high. for rt9027a, the ic will be fully turned on when this pin?s voltage is below 0.4v. 1 en internal pulled high. for RT9027B, the ic will be shutdown when this pin?s voltage is below 0.4v. 2 vin input voltage pin. 3 vout output voltage pin. 4 vset this pin is used for output voltage setting. it is necessary to make this pin higher than 1v to guarantee v out to be 1.6 times of vset. the ic will be shutdown when this pin volt age is below 1v. 5 to 8 gnd ground. function block diagram + - ocp v set por (enable) v in por bias+thermal shutdown ea 0.6 logic vin vset vout gnd fon/en 1 free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 3 ds9027a/b-01 october 2008 www.richtek.com absolute maximum ratings (note 1) z supply input voltage, v in ------------------------------------------------------------------------------------------------ 6v z en, fon, vset voltage ------------------------------------------------------------------------------------------------ 6v z power dissipation, p d @ t a = 25 c sop-8 ------------------------------------------------------------------------------------------------------------------------ 1.053w z package thermal resistance (note 4) sop-8, ja ------------------------------------------------------------------------------------------------------------------ 95 c/w z lead temperature (soldering, 10 sec.) ------------------------------------------------------------------------------- 260 c z junction temperature ----------------------------------------------------------------------------------------------------- 150 c z storage temperature range -------------------------------------------------------------------------------------------- ? 65 c to 150 c z esd susceptibility (note 2) hbm -------------------------------------------------------------------------------------------------------------------------- 2k v mm ---------------------------------------------------------------------------------------------------------------------------- 2 00v recommended operating conditions (note 3) z supply input voltage, v in ------------------------------------------------------------------------------------------------ 4.5v to 5.5v z junction temperature range -------------------------------------------------------------------------------------------- ? 40 c to 125 c z ambient temperature range -------------------------------------------------------------------------------------------- ? 40 c to 85 c electrical characteristics (v set = 2v, v in = 5v, i out = 0.5a, c in = c out = 2.2uf, t a = 25 c, unless otherwise specified) to be continued parameter symbol test conditions min typ max units input voltage input voltage range v in 4.5 -- 5.5 v quiescent current i q i out = 0a -- 300 -- ua rt9027a v set = 0v -- 10 --- shutdown current RT9027B i shdn v en = 0v -- 10 -- ua output voltage v ou t /v set 1.552 1.6 1.648 v line regulation v line -- 0.2 0.5 load regulation v load -- 0.2 0.8 % r on i out = 0.5a, v in = 5v, v set = 3.3v -- 0.15 0.3 current limit i lim 1.6 2 3.5 a short current i sc -- 1.1 -- a v in uvlo threshold rising -- 2.5 -- v in uvlo hysteresis -- 0.7 -- v v set uvlo threshold rising -- 0.8 -- v set uvlo hysteresis -- 0.1 -- v free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 4 ds9027a/b-01 october 2008 www.richtek.com 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. devices are esd sensitive. handling precaution is recommended. note 3. the device is not guaranteed to function outside its operating conditions. note 4. ja is measured in the natural convection at t a = 25 c on a high effective four layers thermal conductivity test board of jedec 51-7 thermal measurement standard. parameter symbol test conditions min typ max units fon function (rt9027a) logic-low voltage -- -- 0.4 v fon threshold logic-high voltage 1.6 -- -- v fon bias pin current v fon = 0 -- 1.5 15 ua en function (RT9027B) logic-low voltage v il -- -- 0.4 v en threshold logic-high voltage v ih 1.6 -- -- v en bias pin current i en v en = 0 -- 10 15 ua over temperature protection thermal shutdown temperature t sd -- 140 -- c thermal shutdown hysteresis -- 30 -- c free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 5 ds9027a/b-01 october 2008 www.richtek.com typical operating characteristics output voltage vs. v set voltage 0 1 2 3 4 5 6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 v set voltage (v) output voltage (v) i out = 0.5a i out = 0a output voltage vs. output current 1.575 1.580 1.585 1.590 1.595 1.600 1.605 1.610 1.615 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 output current (a) output voltage (v) v set = 1v output voltage vs. output current 3.180 3.185 3.190 3.195 3.200 3.205 3.210 3.215 3.220 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 output current (a) output voltage (v) v set = 2v output voltage vs. output current 4.775 4.780 4.785 4.790 4.795 4.800 4.805 4.810 4.815 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 output current (a) output voltage (v) v set = 3v output voltage vs. input voltage 3.190 3.192 3.194 3.196 3.198 3.200 3.202 3.204 3.206 3.208 3.210 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 input voltage (v) output voltage (v) v set = 2v i out = 0.5a i out = 0a output voltage vs. input voltage 1.590 1.591 1.592 1.593 1.594 1.595 1.596 1.597 1.598 1.599 1.600 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 input voltage (v) output voltage (v) v set = 1v i out = 0.5a i out = 0a free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 6 ds9027a/b-01 october 2008 www.richtek.com en threshold vs. temperature 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 -50 -25 0 25 50 75 100 125 temperature en threshold (v) ( c) rising falling vset threshold vs. temperature 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 -50 -25 0 25 50 75 100 125 temperature vset threshold (v) ( c) rising falling v in uvlo threshold vs. temperature 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -50 -25 0 25 50 75 100 125 temperature v in uvlo threshold (v) ( c) rising falling output voltage vs. temperature 1.56 1.57 1.58 1.59 1.60 1.61 1.62 1.63 1.64 -50 -25 0 25 50 75 100 125 temperature output voltage (v) ( c) v set = 1v, i out = 0a output voltage vs. temperature 4.75 4.76 4.77 4.78 4.79 4.80 4.81 4.82 4.83 -50 -25 0 25 50 75 100 125 temperature output voltage (v) ( c) v set = 3v, i out = 0a output voltage vs. temperature 3.16 3.17 3.18 3.19 3.20 3.21 3.22 3.23 3.24 -50 -25 0 25 50 75 100 125 temperature output voltage (v) ( c) v set = 2v, i out = 0a free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 7 ds9027a/b-01 october 2008 www.richtek.com quiescent current vs. temperature 150 170 190 210 230 250 270 290 310 330 350 -50 -25 0 25 50 75 100 125 temperature quiescent current (ua) ( c) v out = 3.2v v out = 1.6v shutdown current vs. input voltage 5 6 7 8 9 10 11 12 13 14 15 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 input voltage (v) shutdown current (ua) v set = 1v v set = 2v en = 0v quiescent current vs. input voltage 200 220 240 260 280 300 320 340 360 380 400 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 input voltage (v) quiescent current (ua) v out = 3.2v v out = 1.6v dropout voltage vs. output current 0 20 40 60 80 100 120 0 50 100 150 200 250 300 350 400 450 500 output current (ma) dropout voltage (mv) 125 c 85 c 25 c -40 c current limit vs. v set voltage 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 v set voltage (v) output current (a ) current limit vs. temperature 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 -50 -25 0 25 50 75 100 125 temperature output current (a ) v set = 1v v set = 2v ( c) free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 8 ds9027a/b-01 october 2008 www.richtek.com shutdown current vs. temperature 5 6 7 8 9 10 11 12 13 14 15 -50 -25 0 25 50 75 100 125 temperature shutdown current (ua) v set = 1v v set = 2v en = 0v ( c) start up for en time (5us/div) v out (1v/div) v en (5v/div) v set = 1v, v in = v en = 5v v out = 1.6v, i out = 500ma i out (0.5a/div) v in (5v/div) start up from vset time (50us/div) v out (1v/div) v set (1v/div) v set = 1v, v in = v en = 5v v out = 1.6v, i out = 500ma i out (0.5a/div) v in (5v/div) short-circuit protection time (1ms/div) v out (2v/div) v set = 2v, v in = v en = 5v v out = 3.2v i out (1a/div) start up from vin time (2.5ms/div) v out (1v/div) v set = 1v, v in = v en = 5v v out = 1.6v, i out = 500ma i out (0.5a/div) v in (5v/div) short-circuit protection time (1ms/div) v out (2v/div) v set = 1v, v in = v en = 5v v out = 1.6v i out (0.5a/div) free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 9 ds9027a/b-01 october 2008 www.richtek.com line transient response v in (v) time (100us/div) 5.5 4.5 v out (10mv/div) v set = 1v, v en = 5v, v out = 1.6v, i out = 500ma line transient response v in (v) time (100us/div) 5.5 4.5 v out (10mv/div) v set = 2v, v en = 5v, v out = 3.2v, i out = 500ma load transient response time (250us/div) v out (10mv/div) i out (0.5a/div) v set = 1v, v in = v en = 5v, v out = 1.6v i out = 50ma to 0.5a load transient response time (250us/div) v out (10mv/div) i out (0.5a/div) v set = 2v, v in = v en = 5v, v out = 3.2v i out = 50ma to 0.5a line transient response v in (v) time (100us/div) 5.5 4.5 v out (10mv/div) v set = 2v, v en = 5v, v out = 3.2v, i out = 10ma line transient response v in (v) time (100us/div) 5.5 4.5 v out (10mv/div) v set = 1v, v en = 5v, v out = 1.6v, i out = 10ma free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 10 ds9027a/b-01 october 2008 www.richtek.com application information output voltage setting the output voltage of rt9027ab is adjustable from 1.6v to vin by vset voltage. it is set by internal voltage divider resisters shown in function block diagram. the vout voltage level is set as 1.6 times of vset voltage level when vset is higher than 1v. when vset is less than 0.8v, the ic will be shutdown. fully turn on and enable logic function for rt9027a, pin1 named fon features fully turn on function. when the fon pin is in logic low level, the ic goes into fully turn on mode. during this condition, the pass transistor will be fully turned on. the fon pin is pulled to high level internally. for the enable function, it is acceptable to use the vset pin to control the ic. when the vset pin is in logic low level (<0.8v), the ic will be shutdown. for RT9027B, there is an en pin for power on/off control. when the en pin is in logic low level, the ic will be shutdown. during this condition, the pass transistor, error amplifier, and band gap are turned off, reducing the supply current to 10ua typical. the ic goes into operation mode when the en pin is in logic high level condition. the en pin is pulled to high level internally. capacitor selection good bypassing is recommended from input to ground to improve the ac performance. a 2.2uf input ceramic capacitor or greater located as close as possible to the ic is recommended. the rt9027ab is specifically designed to use ceramic output capacitors as low as 2.2uf. the ceramic capacitors offer significant cost and space savings, along with high frequency noise filtering. current limit and short circuit protection the rt9027a contains an independent current limit and short circuit current protection to prevent the ic from damaging in unexpected applications. the current limit monitors and controls the pass transistor ? s gate voltage, limiting the output current to a certain level (2a typ.). when the output voltage is less than 0.4v, the short circuit current protection starts the current fold back function and limits the output current at 0.8a (typ.). thermal-shutdown protection rt9027ab over temperature protection function limits power dissipation to prevent this die from over temperature damage. when the RT9027B operation junction temperature exceeds 140 c, the over temperature protection circuit starts the thermal shutdown function and turns the pass transistor off. the pass transistor turns on again after the junction temperature cools by 30 c. for rt9027a, it lowers its otp trip level to 110 c. it limits ic case temperature under 100 c and provides maximum safety to customer while output short circuit occurring. thermal considerations for continuous operation, do not exceed absolute maximum operation junction temperature 125 c. the power dissipation definition in device is: p d = (v in - v out ) x i out + v in x i q 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 125 c, t a is the ambient temperature and the ja is the junction to ambient thermal resistance. for recommended operating conditions specification of rt9027a/b, where t j(max) is the maximum junction temperature of the die (125 c) and t a is the maximum ambient temperature. since the multiple gnd pins of the sop-8 package are internally shorted and connected to lead frame, it is efficient to dissipate the heat by adding copper area on gnd footprint. figure 1 shows the relation about thermal resistance ja vs. copper area on a standard jedec 51- 7 (4 layer, 2s2p) thermal test board at t a = 25 c. for example, with 10mm x 10mm copper area pcb, we can obtain the lower thermal resistance about 45 c/w. free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 11 ds9027a/b-01 october 2008 www.richtek.com the maximum power dissipation depends on operating ambient temperature for fixed t j(max) and thermal resistance ja . for rt9027ab packages, the figure 2 of de-rating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. figure 2. de-rating curves for rt9027ab package figure 1 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 0 25 50 75 100 125 ambiemt temperature ( ) maximum power dissipation (w) 100mm 2 50mm 2 25mm 2 15mm 2 min. layout ( c) jedec 4-layers pcb 0 10 20 30 40 50 60 70 80 90 100 0 20406080100 copper area (mm2) thermal resistance ja ( /w) ja ( c/w ) the maximum power dissipation at t a = 25 c can be calculated by following formula : p d(max) = (125 c ? 25 c) / 45 c/w = 2.22w for sop-8 package free datasheet http://www.datasheet-pdf.com/
downloaded from elcodis.com electronic components distributor rt9027a/b 12 ds9027a/b-01 october 2008 www.richtek.com 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) 8f, no. 137, lane 235, paochiao road, hsintien city taipei county, taiwan, r.o.c. tel: (8862)89191466 fax: (8862)89191465 email: marketing@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. outline dimension a b j f h m c d i 8-lead sop plastic package 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 0.170 0.254 0.007 0.010 i 0.050 0.254 0.002 0.010 j 5.791 6.200 0.228 0.244 m 0.400 1.270 0.016 0.050 free datasheet http://www.datasheet-pdf.com/

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