TS2509 3a / 500khz pwm buck converter 1 / 9 version: a09 sop - 8 general description TS2509 consists of step - down switching regulator with pwm control. these devise include a reference voltage source, oscillation circuit, error amplifier, internal pmos and etc. TS2509 provides low - ripple power, high ef ficiency, and excellent transient characteristics. the pwm control circuit is able to the duty ratio linearly form 0 up to 100%. this converter also contains an error amplifier circuit as well as a soft - start circuit that prevents overshoot at startup. an enable function, an over current protect function and short circuit protect function are built inside, and when ocp or scp happens, the operation frequency will be reduced. also, an internal compensation block is built in to minimum external component coun t. with the addition of an internal p - channel power mos, a coil, capacitors, and a diode connected externally, these ics can function as step - down switching regulators. they serve as ideal power supply units for portable devices when coupled with the sop - 8 l package, providing such outstanding features as low current consumption. since this converter can accommodate an input voltage up to 23v, it is also suitable for the operation via an ac adapter. orderin g information part no. package packing TS2509cs rl sop - 8 2.5kpcs / 13 reel features input voltage: 3.6v~23v output voltage: 0.8v~vc c duty ratio: 0%~100% pwm control oscillation frequency: 500khz typ. soft - start (ss), current limit (cl), enable function thermal shutdown function short circuit protect (scp) external sw p - channel mosfet low esr output capacitor (mlcc application) application simple high - efficiency step down regulator on - card switching regulators absolute maximum rating parameter symbol rating unit vcc pin voltage v cc v ss - 0.3 to v ss + 2 5 v feedback pin voltage v fb v ss - 0.3 to v cc v on/off pin voltage v en v ss - 0.3 to v cc + 0.3 v switch pin voltage v sw v ss - 0.3 to v cc + 0.3 v power dissipation p d internally limited mw storage temperature range t st g - 40 to +150 operating temperature range t op - 20 to +125 operating supply voltage v op +3.6 to +2 3 v thermal resistance from junction to case jc 40 /w thermal resistance from junction to ambient ja 70 /w pin definition : 1. fb 8 . vss 2. en 7 . vss 3. comp 6 . sw 4. vcc 5 . sw
TS2509 3a / 500khz pwm buck converter 2 / 9 version: a09 electrical specifications ( v i n =12v, ta=25 o c unless otherwise noted ) characteristics symbol conditions min typ max units feedback voltage v fb i out =0.1a 0.784 0.800 0.816 v quiescent current i q v fb =1.2v force driver off -- 3 5 ma feedback bias current i fb i out =0.1a -- 0.1 0 .5 ua shutdown supply current i sd v en =0v -- 2 10 ua current limit i sw 4 -- -- a line regulation ? v out /v out v cc = 5v~2 3 v, i out =0.2a -- 0.6 1.2 % load regulation ? v out /v out i out = 0.1 to 3 a -- 0. 2 0. 4 % oscillation frequency f osc sw pin 40 0 50 0 6 00 khz v sh high (regulator on) 2.0 -- -- en pin logic input threshold voltage v sl low (regul ator off) -- -- 0.8 v i sh v en =2.5v (on) -- 20 -- ua en pin input current i sl v en =0.3v (off) -- - 10 -- ua soft - start time t ss 0.3 4 8 ms v cc = 5v , v fb = 0v -- 90 140 internal mosfet r dson v cc = 12 v , v fb = 0 v -- 60 90 m i out = 2 a -- 9 1 -- efficiency e ffi v out = 5v i out = 3 a -- 9 0 -- % thermal shutdown temp. t sd -- 125 -- ? block diagram pin assignment name description fb feedback pin en h : normal operation (step - down) l : step - down operation stopped (all circuit deactivated) comp compensation pin sw switch pin. connect external inductor/diode here vcc ic power supply pin vss gnd pin
TS2509 3a / 500khz pwm buck converter 3 / 9 version: a09 application circuit mlcc compensation capacitor selection (mlcc) vin v out l1 r3 c7 c1 7~23v 5.0/3.3/2.5v 15uh 2.2k 330pf 1nf 7~20v 1.8/1.5v 10uh 2k 330pf 1nf 9~20v 1.2v 10uh 2k 330pf 820pf 9~18v 1.1v 10uh 2k 560pf 820pf 9~18v 1.0v 10uh 2k 560pf 680pf 4~10v 3.3/2.5v 15uh 6.8k 330pf 1nf 4~10v 1.8/1.5/1.2/ 1.1/1.0v 10uh 4.7k 330pf 1nf el cap compensation capacitor selection (el cap ) vin v out l1 r3 c7 c1 7 - 20v 5.0/3.3/2.5/1.8v coil 3.9k 10nf 1nf 7 - 20v 1.8/1.5v coil 2k 10nf 1nf 5 - 7v 3.3/2.5/1.8/1.5/1.2v coil 2k 10nf 1nf 5 - 20v 3.3/2.5/1.8/1.5/1.2v smd 0.82k 10nf 1nf
TS2509 3a / 500khz pwm buck converter 4 / 9 version: a09 function descriptions pwm control the TS2509 consists of dc/dc converters that employ a pulse - width modulation (pwm) system. in converters of the TS2509 , the pulse width varies in a range from 0 to 100%, according to the load current. the ri pple voltage produced by the switching can easily be removed through a filter because the switching frequency remains constant. therefore, these converters provide a low - ripple power over broad ranges of input voltage and load current. setting the output voltage application circuit item shows the basic application circuit with ts250 9 adjustable output version. the external resistor sets the output voltage according to the following equation: (el cap) resistor select for output voltage setting (mlcc) resistor select for output voltage setting v out r2 r1 v out r2 r1 5v 1.3k 6.8k 5v 7.5k 39k 3.3v 1.5k 4.7k 3.3v 15k 47k 2.5v 2.2k 4.7k 2.5v 22k 47k 1.8v 2 k 2.5 k 1.8v 27k 33k 1.5v 2.2k 2k 1.5v 30k 27k 1 .2v 3 k 1 .5 k 1.2v 30k 15k 1v 10 k 2 .5k 1v 56k 13k inductor selection for most designs, the operate with inductors of 10 h to 22 h. the inductor value can be derived from the following equation: l1 recommend va lue (v in =12v, i out =3a) v out 1.8v 2.5v 3.3v 5v l1 value 10~15uh 10~15 uh 15~22 uh 15~ 22uh where is inductor ripple current. large value inductors lower ripple current and small value inductors result in high ripple currents. choose inductor ripple current approximately 15% of the maximum load current 3a, il=0.4a. the dc current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (3a+0.2a). input capacitor selection (el cap) th is capacitor should be located close to the ic using short leads and the voltage rating should be approximately 1.5 times the maximum input voltage. the rms current rating requirement for the input capacitor of a buck regulator is approximately 1 2 the dc load current. a low esr input capacitor sized for maximum rms current must be used. a 220 f low esr capacitor for most applications is sufficient. ( mlcc ) a 22 f mlcc or two 10uf mlcc capacitors for most applications is sufficient.
TS2509 3a / 500khz pwm buck converter 5 / 9 version: a09 function descriptions (continue) output capacitor selection (el cap) the output capacitor is required to filter the output and provide regulator loop stability. the important capacitor parameters are; the 100khz equivalent series resistance (esr), the rms ripples current ratin g, voltage rating, and capacitance value. for the output capacitor, the esr value is the most important parameter. the esr can be calculated from the following formula. v ripple = ?i l x esr = 0.4a x 110m = 44mv an aluminum electrolytic cap acitor's esr value is related to the capacitance and its voltage rating. in most case, higher voltage electrolytic capacitors have lower esr values. most of the time, capacitors with much higher voltage ratings may be needed to provide the low esr values r equired for low output ripple voltage. it is recommended to replace this low esr capacitor by using a 330 f low esr values < 110m ( mlcc ) a 33 f mlcc or three 10uf mlcc capacitors for most applications is sufficient. r ds(on) current limiting the current limit threshold is setting by the internal circuit. v in 4.6v~6v 6v~10v 10v~23v i cl(min ) 3a 3.8a 4.0a i out(ma x) 2.5a 3a 3a lay out guidance when laying out the pc board, the following suggestions should be taken to ensure proper operation of the TS2509. these items are also illustrated graphically in below. 1. the power traces, including the pmos drain & source trace, the schottk y and the c2 trace should be kept short, direct and wide to allow large current flow. 2. connect the c5 to the v cc & en pins of the TS2509 as closely as possible to get good power filter effect. 3. keep the switching node, away from the sensitive f b node. 4. connect ground side of the c2 & d1 as closely as possible. 5. connect pmos source and r3 as closely as possible. 6. do not trace signal line under inductor.
TS2509 3a / 500khz pwm buck converter 6 / 9 version: a09 electrical characteristics curve figure 1. feedback voltage vs. input voltage figure 2.quiescent current vs. input voltage figure 3. frequency vs. input voltage figure 4. frequency vs. temperature figure 5. feedback voltage vs. temperature figure 6. quiescent current vs. temperature
TS2509 3a / 500khz pwm buck converter 7 / 9 version: a09 electrical characteristics curve fi gure 7. efficiency figure 8.output ripple (v in =12v, v out =5v, i out =3a) (v in =12v, v out =5 v, i out =3a) figure 9.power on test wave (v in =12v, v out =5 v, i out =0.2 a) figure 10.power on test wave (v in =12v, v out =5 v, i out = 0.1~ 3a) figure 11. load transient res ponse
TS2509 3a / 500khz pwm buck converter 8 / 9 version: a09 sop - 8 mechanical drawing marking diagram y = year code m = month code ( a =jan, b =feb, c =mar, d =apl, e =may, f =jun, g =jul, h =aug, i =sep, j =oct, k =nov, l =dec) l = lot code sop - 8 dimension millimeters inches dim min max min max. a 4.80 5.00 0.189 0.196 b 3.80 4.00 0.150 0.157 c 1.35 1.75 0.054 0.068 d 0.35 0.49 0.014 0.019 f 0.40 1.25 0.016 0.049 g 1.27bsc 0.05bsc k 0.10 0.25 0.004 0.009 m 0 7 0 7 p 5.80 6.20 0.229 0.244 r 0.25 0.50 0.010 0.019
TS2509 3a / 500khz pwm buck converter 9 / 9 version: a09 notice specifications of the products displayed herein are subject to change without notice. tsc or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies. information contained herein is intended to provide a product descri ption only. no license, express or implied, to any intellectual property rights is granted by this document. except as provided in tsc s terms and conditions of sale for such products, tsc assumes no liability whatsoever, and disclaims any express or impli ed warranty, relating to sale and/or use of tsc products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. the products shown he rein are not designed for use in medical, life - saving, or life - sustaining applications. customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify tsc for any damages resulting from such impr oper use or sale.
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