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this is information on a product in full production. april 2013 docid022607 rev 2 1/22 22 STOD1317B 170 ma 13 v, high efficiency boost converter + ldo datasheet - production data features ? operating input voltage range from 2.6 v to 4.8 v ? 1% output voltage tolerance ? low output ripple ? true-shutdown ? short-circuit protection ? digital low power function ? very high efficiency at light load thanks to pulse skipping operation ? very fast line and load transients ? 1.2 mhz switching frequency ? 1 a max. quiescent current ? dfn12l (3 x 3 x 0.8 mm) applications ? single rail amoled display ? cellular phones ? battery powered equipment description the STOD1317B is a fixed frequency, high efficiency, boost dc-dc converter with cascaded ldo able to provide output voltages ranging from 6 v to 13 v starting with an input voltage from 2.6 v to 4.8 v. the device is designed to supply loads that are very sensitiv e to output ripple such as amoled display panels. a dedicated ldo is able to suppress any ripple and noise coming out from the dc-dc converter. the ldo works with a constant drop in order to maintain high efficiency in the whole operating range. the low r dson n- channel and p-channel mosfet switches are integrated and contribut e to achieving high efficiency. the true-shutdown feature allows physical disconnection of the battery from the load when the device is in shutdown mode. the control technique is able to maintain efficiency higher than 85% at light loads and higher than 80% at full load. the device includes soft-start control, inrush current limiter, thermal shutdown and inductor peak current limit. the STOD1317B is packaged in dfn12l (3 x 3 x 0.8 mm) height. dfn12l (3 x 3 mm) table 1. device summary order code marking package packaging STOD1317Btpur 1317b dfn12l (3 x 3 mm) 3000 parts per reel www.st.com
contents STOD1317B 2/22 docid022607 rev 2 contents 1 schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 typical performance characteris tics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1 boost multiple mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 6.1.1 pulse skipping operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1.2 discontinuous conduction mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1.3 continuous conduction mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.2 enable pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.3 soft-start and inrush current limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.4 undervoltage lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.5 overtemperature protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.6 digital low power function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 7 application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1 external passive components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1.1 inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1.2 input and output capacitor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.2 recommended pcb layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 8 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 9 revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
docid022607 rev 2 3/22 STOD1317B schematic 1 schematic figure 1. application schematic note: all the above components refer to a typical app lication. operation of the device is not limited to the choice of these external components. table 2. typical external components comp. manufacturer part number value ratings size c in murata taiyo yuden tdk grm219r61a106ke44 lmk212bj106kd-t c1608x5r0j106 10f 10%, x5r, 10v 10%, x5r, 10v 10%, x5r, 6.3v 0805 0805 0603 c mid murata tdk grm219r61c475ke15 c2012x5r1c475 4.7f 10%, x5r, 16v 10%, x5r, 16v 0805 0805 c out murata tdk grm219r61c475ke15 c2012x5r1c475 4.7f 10%, x5r, 16v 10%, x5r, 16v 0805 0805 l (1) coilcraft tdk dastek lps4012-472ml vls252012t-4r7mr81 pnl3008-4r7m 4.7h 20%, curr. 1.7a, resist. 0.175 ? 20%, curr. 1.3a, resist. 0.338 ? 20%, curr. 0.9a, resist. 0.280 ? 4.0 x 4.0 x 1.2 2.5 x 2.0 x 1.2 3.1 x 3.1 x 0.8 r1 k ? 0402 r2 k ? 0402 1. inductor used for the typical application conditions. inductance values ranging from 3.3 h to 6.8 h can be used together with the STOD1317B. a minimum saturation current of 1.2 a must be ensured to support 170 ma at 2.6 v in full range.
schematic STOD1317B 4/22 docid022607 rev 2 figure 2. block schematic vin ring killer ovp pwm logic control & driver ocp osc comp ea + +- shut down otp soft start vref +- +- ota vout m1 m3 s vo_set fb dmd s s m2 m0 scp s vmid lx pgnd gnd pgnd en nc
docid022607 rev 2 5/22 STOD1317B pin configuration 2 pin configuration figure 3. pin configuration (top view) table 3. pin description pin name pin number description vmid 1 step-up output voltage vout 2 ldo output voltage vo_set 3 ldo output voltage set gnd 4 analog ground fb 5 feedback voltage en 6 enable pin. connect this pin to gnd or a voltage lower than 0.4v to shut down the ic. a voltage higher than 1.2v is required to enable the ic nc 7 not connected vin 8 supply voltage pgnd 9 , 10 power ground lx 11, 12 switch pin. inductor conne ction to the internal switches exposed pad internally connected to pgnd lx lx pgnd pgnd vin nc vmid vout vo_set gnd fb en agnd
maximum ratings STOD1317B 6/22 docid022607 rev 2 3 maximum ratings note: absolute maximum ratings ar e those values beyond which damage to the device may occur. functional operation under these conditions is not implied. table 4. absolute maximum ratings symbol parameter value unit v in supply voltage -0.3 to +7.0 v lx switching node -0.3 to +16 v v out_set ldo output voltage set 16 v v out output voltage -0.3 to +16 v en logic pin -0.3 to 4.6 v fb feedback pin -0.3 to +2.5 v esd machine model 200 v human body model 2000 v t amb operating ambient temperature -40 to 85 c t j maximum operating junction temperature +150 c t stg storage temperature -65 to 150 c table 5. thermal data symbol parameter value unit r thja thermal resistance junction-ambient 49.1 c/w r thjc thermal resistance junction-case (fr-4 pcb) 4.216 c/w
docid022607 rev 2 7/22 STOD1317B electrical characteristics 4 electrical characteristics t j = 25 c, v in = 3.7 v, v out = 10 v, c in = 2 x 10 f, c mid = 2 x 4.7 f, c out = 2 x 4.7 f, l = 4.7 h, v en = 2 v, unless otherwise specified. table 6. electrical characteristics symbol parameter test conditions min. typ. max. unit general section v in operating power input voltage range 2.6 3.7 4.8 v iq shutdown mode shutdown mode, v en =gnd 0.5 1 a no switching v en =v in =3.7v, v fb =1.3v 1 1.5 ma v uvlo undervoltage lockout threshold v in rising 2.4 2.5 v v in falling 2.1 2.2 f sw switching frequency 1 1.2 1.35 mhz i pk switch current limitation 1.6 2 2.4 a output voltage (v out ) v fb feedback voltage t a =25c 1.08 1.2 1.32 v ? v fb accuracy -40c electrical characteristics STOD1317B 8/22 docid022607 rev 2 symbol parameter test conditions min. typ. max. unit dlp function i o_leak leakage current from load v in =3.7v, v en =0, v out =6v (supplied by external power) 0.5 2 a 1. not tested in production. this value is guaranteed by correlation with r dson , peak current limit and operating input voltage. 2. not tested in production. table 6. electrical characteristics (continued)
docid022607 rev 2 9/22 STOD1317B typical performance characteristics 5 typical performance characteristics t j = 25 c, v in = 3.7 v, v out = 10 v, c in = 2 x 10 f, c mid = 2 x 4.7 f, c out = 2 x4.7 f, l = 4.7 h, v en = 2 v, unless otherwise specified. figure 4. quiescent current vs. temperature figure 5. switching frequency vs. temperature figure 6. efficiency vs. output curr ent figure 7. switching frequency vi v in = 3.7 v, i out = 170 ma, t j = 25 c figure 8. soft-start inrush current figure 9. feedback voltage vs. temperature v in = 3.7 v, no load, t j = 25c, ss:1.265 ms , inrush current: 260 ma 1.5 1.75 2 2.25 2.5 2.75 3 -25 0 25 50 75 100 125 quiescent current [ma] temperature [c] 1.25 1.27 1.29 1.31 1.33 1.35 -25 0 25 50 75 100 125 temperature [c] switching frequency [khz] 3.7v 2.9v 4.8v 55 60 65 70 75 80 85 90 0 20 40 60 80 100 120 140 160 180 output current [ma] efficiency [%] vin=4.2v vin=3.7v vin=3.2v vin=2.9v sw vmid vout frequency : 1.285 mhz en v out i in 1.15 1.16 1.17 1.18 1.19 1.2 1.21 1.22 2.3 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 input voltage [v] v fb [v]
typical performance characteristics STOD1317B 10/22 docid022607 rev 2 figure 10. tdma noise immunity v in = 2.6 v to 3.1 v, i out = 20 ma v out v in
docid022607 rev 2 11/22 STOD1317B detailed description 6 detailed description the STOD1317B is a high efficiency dc-dc c onverter which integrates a step-up and ldo power stage suitable for supplying amoled panels. thanks to the high level of integration it needs only 6 external components to operate an d it achieves very high efficiency using a synchronous rectification technique. the controller uses an av erage current mode technique in order to obtain good stability and precise voltage regulation in all possible cond itions of input voltage, output voltage and output current. in addition, the peak inductor cu rrent is monitored in order to avoid saturation of the coils. the STOD1317B implements a power saving technique in order to maintain high efficiency at very light load and it switches to pwm operation as the load increases in order to guarantee the best dynamic perfo rmances and low noise operation. in order to guarantee very low ripple on the outp ut voltage, the step-up output is filtered by the ldo. there are two control loops; the ldo control loop regulates v out in order to provide the right voltage to the output, while the boost control loop is in ternally set to provide and output voltage 380 mv higher than v out in order to maintain th e ldo in regulation at the minimum possible drop. the STOD1317B avoids battery leakage thanks to the true-shutdown feature and it is self protected from overtemperature and short-circuit on the v out pin. undervoltage lockout and soft-start guarantee proper operation during startup. 6.1 boost multiple mode of operation the boost dc-dc operates in three different modes: pulse skipping (ps), discontinuous conduction mode (dcm) and continuous conduct ion mode (ccm). it switches automatically between the three modes according to input voltage, output current and output voltage conditions. 6.1.1 pulse skipping operation the STOD1317B works in pulse skipping mode w hen the load current is below some tens of ma. the load current level at which this way of operation occurs depends on the input and output voltage. 6.1.2 discontinuous conduction mode when the load increases above some tens of ma, the STOD1317B enters dcm operation. in order to obtain this type of operation the controller must avoid the inductor current going negative. the discontinuous mode detector (dmd) block senses the voltage across the synchronous rectifier and turns off the switch when the voltage crosses a defined threshold which, in turn, represents a certain current in the inductor. this current can vary according to the slope of the inductor current which depends on input voltage, inductance value, and output voltage. 6.1.3 continuous conduction mode at medium/high output loads the STOD1317B enters full ccm at constant switching frequency mode.
detailed description STOD1317B 12/22 docid022607 rev 2 6.2 enable pin the device operates when the en pin is set high . if the en pin is set low, the device stops switching, all the internal blocks are turned of f. in this condition the current drawn from v in is below 1 a in the whole temperature range. in addition, the internal switches are in off state so the load is electrically disconnected from the input, this avoids unwanted current leakage from the input to the load. 6.3 soft-start and in rush current limiting after the en pin is pulled high, or after a suitable voltage is applied to v in and en, the device initiates the startup phase. as a first step, the c mid capacitor is charged, the p1 switch implements a current limiting technique in order to keep the charge current below 400 ma. this avoids battery overloading during startup. after v mid reaches the v in voltage level, the p1 switch is fully turned on and the soft-start procedure for the step-up is started. v out starts to softly increa se until it reaches the regulation value. 6.4 undervoltage lockout the undervoltage lockout function avoids im proper operation of the STOD1317B when the input voltage is not high enough. when the i nput voltage is below the uvlo threshold the device is in shutdown mode. the hysteresis of 100 mv avoids unstable operation when the input voltage is close to the uvlo threshold. 6.5 overtemperature protection an internal temperature sensor continuously monitors the ic junction temperature. if the ic temperature exceeds 150 c, typical, the de vice stops operating. as soon as the temperature falls below 135 c, typi cal, normal operation is restored. 6.6 digital low power function the digital low power (dlp) function allows physical disconnection of the load from the device.
docid022607 rev 2 13/22 STOD1317B detailed description figure 11. digital low power function operation ? (*) when the power ic is disabled, in order to disconnect leakage current through the feedback node, the s/w function is active. ? (**) a new en transition from low to high and/or device power-up turn off the dlp function and allow ic to work under typical conditions. charge pump sw enable ddvdh(6v) vpnl gpio2 gpio1 en en fb sw disable disable ** disable s/d * d-ic enable/disable refer to next page vddel dcdc leakage pass
application information STOD1317B 14/22 docid022607 rev 2 7 application information 7.1 external passive components 7.1.1 inductor selection the inductor is the key passive component for switching converters. for the step-up converter an inductance bet ween 3.3 h and 6.8 h is recommended. it is very important to select the right inducto r according to the maximum current the inductor can handle in order to avoid saturation. the pe ak current for the step-up can be calculated as: equation 1 where v mid : step-up output voltage, it is fixed internally to v out + 0.38 v; i out : output current; v in : input voltage of the STOD1317B; fs: switching frequency. use the minimum value of 1 mhz for worst case; ? : efficiency of the step-up conv erter (0.80 at maximum load). 7.1.2 input and output capacitor selection it is recommended to use ceramic capacitors with low esr as input and output capacitors in order to filter any disturbance present in the input line and to obtain stable operation of the step-up converter and ldo. a minimum real ca pacitance value of 3 f must be guaranteed for c mid and c out in all conditions. 7.2 recommended pcb layout the STOD1317B is a high frequency power swit ching device so it requires a proper pcb layout in order to obtain the necessary stability and optimize line/load regulation and output voltage ripple. the input capacitor must be as close as possible to the v in pin. in order to minimize the ground noise, a common ground node for power ground (pgnd) and a different one for analog ground (gnd) mu st be used. the exposed pad is connected to pgnd through vias. grounding is fundamental to the operation of dc-dc converters; run separate ground paths for critical parts of the circuit (gnd and power gnd), each connected back to a single ground point. separate ground lines prevent the current and noise of one component from interfering with other components. if using a ground plane, ut ilize ?split? plane techniques to give effective grounding. use multiple vias to decrease the trace impedance to ground. l fs v 2 ) vin v ( vin vin i v i mid min mid min min out mid boost peak ? ? ? ? ? ? ? ? -
docid022607 rev 2 15/22 STOD1317B application information figure 12. ground schematic such isolation is necessary to prevent high-l evel switching currents from returning to the battery, or other power supply, through the same ground-return path as the analog signals. if that happens, the ground path of those sens itive signals is disturbed; the high-level switching currents flowing through the grou nd's resistance and inductance cause the voltage along the return path to vary. in addition to the grounding scheme, proper placement of the regulator's components is important. beginning a new layout, for the reasons above, it is necessary to firstly place the capacitors c in , c out and c mid as close as possible to the related device pins. after that, it is possible to place the indu ctors and the power gnd routing. next, we can trace the gnd connected through vias to the pgnd near to one of the main filter capacitors. the ldo needs a quiet ground signal in order to operate properly. it is important to pay close attention to the r outing of traces from capacitor terminals in a dc-dc converter circuit. large-valued low-esr capacitors are expen sive, and bad routings can cancel their performance. a good routing, on the other hand, can lower the output noise. ripple is directly related to the inductor value, the capacitor esr, the switching frequency, and so forth, but hf noise (spikes) depends on parasitic elements and the switching action. in a bad routing, parasitic inductance associated with trace lengths causes problems: in figure 12 , l1 brings about an increase in noise, and l2 limits the attenuation of an added hf capacitor. the solution is to bring the input trace in on one side of the capacitor pad, and the output trace out on the other side of the pad. this track can be longer. in fact we add here an inductor that creates a second order filter with the cohf cohf via wich dives into the ground plane via wich dives into the power supply plane l2 l1 we add here an impedance that lowers the resonating frequency of cohf do not !! vout cout cohf cout gnd 1/2 l3 1/2 l3 vout do !! vout start from the component pad and not the incoming track # v routing #: the incoming and the outgoing track are not connected to each other but only to the capacitor pad co hf l3 f 100 nf 100nf 100nf 30 nh (1via) 10 nh 1 nh 3 mhz 5 mhz 16 mhz co hf resonating frequency
application information STOD1317B 16/22 docid022607 rev 2 figure 13. top layer figure 14. bottom layer
docid022607 rev 2 17/22 STOD1317B package mechanical data 8 package mechanical data in order to meet environmental requirements, st offers these devices in different grades of ecopack ? packages, depending on their level of environmental compliance. ecopack ? specifications, grade definitions a nd product status are available at: www.st.com . ecopack ? is an st trademark. table 7. dfn12l (3 x 3 x 0.8 mm.) package mechanical data dim. mm. min. typ. max a 0.70 0.75 0.80 a1 0 0.02 0.05 a3 0.20 b 0.18 0.25 0.30 d 2.85 3 3.15 d2 1.87 2.02 2.12 e 2.85 3 3.15 e2 1.06 1.21 1.31 e0.45 l 0.30 0.40 0.50
package mechanical data STOD1317B 18/22 docid022607 rev 2 figure 15. dfn12l package dimensions 8065043_a
docid022607 rev 2 19/22 STOD1317B package mechanical data dim. mm. inch min. typ max. min. typ. max. a 330 12.992 c 12.8 13.2 0.504 0.519 d 20.2 0.795 n 99 101 3.898 3.976 t 14.4 0.567 ao 3.3 0.130 bo 3.3 0.130 ko 1.1 0.043 po 4 0.157 p 8 0.315 tape & reel qfnxx/dfnxx (3x3) mechanical data
package mechanical data STOD1317B 20/22 docid022607 rev 2 figure 16. dfn12l (3 x 3 mm) footprint recommended data
docid022607 rev 2 21/22 STOD1317B revision history 9 revision history table 8. document revision history date revision changes 19-dec-2011 1 initial release. 11-apr-2013 2 updated: ? package mechanical data table 7 on page 17 and figure 15 on page 18 .
STOD1317B 22/22 docid022607 rev 2 please read carefully: information in this document is provided solely in connection with st products. stmicroelectronics nv and its subsidiaries (?st ?) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described he rein at any time, without notice. all st products are sold pursuant to st?s terms and conditions of sale. purchasers are solely responsible for the choice, selection and use of the st products and services described herein, and st as sumes no liability whatsoever relating to the choice, selection or use of the st products and services described herein. no license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. i f any part of this document refers to any third party products or services it shall not be deemed a license grant by st for the use of such third party products or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoev er of such third party products or services or any intellectual property contained therein. unless otherwise set forth in st?s terms and conditions of sale st disclaims any express or implied warranty with respect to the use and/or sale of st products including without limitation implied warranties of merchantability, fitness for a parti cular purpose (and their equivalents under the laws of any jurisdiction), or infringement of any patent, copyright or other intellectual property right. st products are not authorized for use in weapons. nor are st products designed or authorized for use in: (a) safety critical applications such as life supporting, active implanted devices or systems with product functional safety requirements; (b) aeronautic applications; (c) automotive applications or environments, and/or (d) aerospace applications or environments. where st products are not designed for such use, the purchaser shall use products at purchaser?s sole risk, even if st has been informed in writing of such usage, unless a product is expressly designated by st as being intended for ?automotive, automotive safety or medical? industry domains according to st product design specifications. products formally escc, qml or jan qualified are deemed suitable for use in aerospace by the corresponding governmental agency. resale of st products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by st for the st product or service described herein and shall not create or extend in any manner whatsoev er, any liability of st. st and the st logo are trademarks or registered trademarks of st in various countries. information in this document supersedes and replaces all information previously supplied. the st logo is a registered trademark of stmicroelectronics. all other names are the property of their respective owners. ? 2013 stmicroelectronics - all rights reserved stmicroelectronics group of companies australia - belgium - brazil - canada - china - czech republic - finland - france - germany - hong kong - india - israel - ital y - japan - malaysia - malta - morocco - philippines - singapore - spain - sweden - switzerland - united kingdom - united states of america www.st.com

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