View AN2728_8304094.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

april 2008 rev 1 1/20 20 AN2728 application note st1s12 small synchronous buck converter introduction the st1s12 family of synchronous step-down dc-dc converters optimized for powering low-voltage digital cores in hdd applications is generally used to replace the high-current linear solution when the power dissipation may cause high heating of the application environment. it provides up to 0.7 a over an input voltage range of 2.5 v to 5.5 v. a high switching frequency (1.7 mhz) allows the use of tiny surface-mount components. a resistor divider to set the output voltage value, an inductor, and two capacitors are required for the adjustable version. only an inductor and 2 capacitors are needed for the 1.2 v and 1.8 v fixed version. a low output ripple is guaranteed by the current mode pwm topology and by the use of low esr surface-mount ceramic capacitors. the device is thermal protected and current limited to prevent damages due to accidental short-circuit. this family of products is available in the tsot23-5l package. figure 1. st1s12 - simplified schematic + - g m + - driver osc r sense v in sw fb/v o mosfet comp driver control logic + - soft start ref1 gnd dmd i_sen v c v sum dmd v rst v set v drv_p v drv_n uvlo shut down en www.st.com
contents AN2728 2/20 contents 1 st1s12 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 enable function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 current limit and short-circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 selecting components for your applications . . . . . . . . . . . . . . . . . . . . . 7 2.1 output voltage selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3 output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4 inductor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.5 layout considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 thermal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 demonstration board usage recommendation . . . . . . . . . . . . . . . . . . . 13 4.1 external component selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.2 capacitors selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.3 inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5 bill of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 6 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7 revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
AN2728 list of figures 3/20 list of figures figure 1. st1s12 - simplified schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 figure 2. inductor current at no load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 figure 3. inductor current at medium load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 figure 4. inrush current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 figure 5. enable voltage vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 figure 6. short-circuit protection simplified schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 figure 7. typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 figure 8. drop vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 figure 9. feedback voltage vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 figure 10. layout considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 figure 11. st1s12 demonstration board layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3 figure 12. demonstration board layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 figure 13. demonstration board schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 figure 14. efficiency vs. output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 figure 15. efficiency vs. output voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 figure 16. efficiency vs. inductor at v o = 1.8 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 figure 17. efficiency vs. inductor at v o = 3.3 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 figure 18. efficiency vs. input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 figure 19. tsot23-5l footprint dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
st1s12 description AN2728 4/20 1 st1s12 description the st1s12 is an adjustable current mode pwm synchronous step-down dc-dc converter with an internal 0.7 a power switch. it is a co mplete 0.7 a switching regulator with internal compensation which eliminates the need for additional components. the device operates with typically 1.7 mhz fixed frequency, and in order to guarantee the lowest switching ripple, operates in pulse width modulation (pwm) mode even at low-load condition. ( figure 2 and figure 3 ) to clamp the error amplifier reference voltage, a soft - start control block generating a voltage ramp is implemented. when swit ching on the power supply, it allows controlling the inrush current value ( figure 4 ). figure 2. inductor current at no load figure 3. inductor current at medium load v en =v in =5 v, v out =1.8 v, no load, ch1=sw, ch2=v out , ch4=i l v en =v in =5 v, v out =1.8 v, r load =4.7 ? , ch1=sw, ch2=v out , ch4=i l i l sw v out (ac) i l sw vout (ac) figure 4. inrush current i in sw en v out v en =v in =5 v, v out =1.8 v, r load =15 ? , ch1=sw, ch2=v out , ch3=en, ch4=i in
AN2728 st1s12 description 5/20 other protection circuits in the device are the thermal shutdown block which turns off the regulator when the junction temperature exceeds 150 c (typ.) and the cycle-by-cycle current limiting that provides protection against shorted outputs. the few components required for operation of the device are an inductor, two capacitors, and a resistor divider. the inductor chosen must be capable of withstanding peak current level without saturating. the value of the inducto r should be selected keeping in mind that a large inductor value increases the efficiency at low output current and reduces output voltage ripple, while a smaller inductor can be chosen when it is important to reduce the package size and the total application cost. the st1s12 has been designed to work properly with x5r or x7r smd ceramic capacitors both at the input and at the output. these types of capacitors, thanks to their very low series resistance (esr), minimize the output voltage ripple. other low esr capacitors can be used according to the need of the application without compromising the right functioning of the device. finally, if the input voltage falls close to the output voltage, the st1s12 can run at 100 % duty cycle, in this mode the pmos switch is continuously maintained on. in this case the output voltage value is the input voltage minus the voltage drop across the pmos switch and the resistance of the inductor. the minimum input voltage to guarantee the right output voltage is: where dcr l is dc resistance of the inductor and r ds(on)_p is the resistance of the pmos. due to the high switching frequency and peak current, it is important to optimize the application environment such as reducing the length of the pcb traces and placing all external components near the device. 1.1 enable function the st1s12 features an enable function (pin 1). when the en voltage is higher than 1.5 v the device is on and if it is lower than 0.5 v the device is off, figure 5 shows the enable voltage vs temperature. in shutdown mode consumption is lower than 1 a. the en pin does not have an internal pull-up, which means that the enable pin cannot be left floating. if the enable function is not used, the en pin must be connected to v in. v in_min = i out_max x (r ds(on)_p + dcr l ) + v out figure 5. enable voltage vs. temperature 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 -75 -50 -25 0 25 50 75 100 125 150 175 t [c] v en [v] on off v in = 5.5 v, i out = 10 ma 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 -75 -50 -25 0 25 50 75 100 125 150 175 t [c] v en [v] on off v in = 5.5 v, i out = 10 ma
st1s12 description AN2728 6/20 1.2 current limit and short-circuit protection in overcurrent protection mode, when the peak current reaches the current limit, the device reduces t on down to its minimum value. in these conditions, the duty cycle is strongly reduced and, in most applications, this is enough to limit the current to i lim . in case of heavy short-circuit when the feedback voltage is lower than 0.1 v (typ.), the loop switches to short mode automatically. in this condition the voltage v sum =i sen * r sen is compared with 0.4 v (typ.) to clamp the upper limit of the inductor current. in this condition the maximum output limitation current is reduced to 300 ma instead of 1 a. at the same time the dmd circuit clamps the lower boundary of the inductor current. one rs flip-flop is being used to control the pmos and nmos switches. when the feedback voltage is higher than 0.1 v (typ.) voltage, the device returns to normal closed-loop switching operation ( figure 6 ). figure 6. short-circuit protection simplified schematic q r s dmd com 0.1v com v in v out c2 + - - + + - r1 r2 l1 v sum =i sen *r sen v fb gnd gnd v ref1 v c gnd q r s dmd com 0.1v com v in v out c2 + - - + + - r1 r2 l1 v sum =i sen *r sen v fb gnd gnd v ref1 v c gnd
AN2728 selecting components for your applications 7/20 2 selecting components for your applications this section provides information to assist in the selection of the most appropriate components for your applications. figure 7 shows the typical application schematic. 2.1 output voltage selection the output voltage can be adjusted from 0.6 v up to input voltage (d max = 100 %) minus the voltage drop across the pmos switch and the dc resistance of the inductor by connecting a resistor divider between the v fb pin and the output, thus allowing remote voltage sensing. figure 7. typical application schematic v in vfb sw gnd v in v out 2 3 en 1 5 4 st1s12_adj l1 r1 c2 r2 c1 gnd off on v in vfb sw gnd v in v out 2 3 en 1 5 4 st1s12_adj l1 r1 c2 r2 c1 gnd off on figure 8. drop vs. temperature 0 0.1 0.2 0.3 0.4 0.5 -75 -50 -25 0 25 50 75 100 125 150 175 t [c] drop [v] v out = 2.7 v, i out = 700 ma, duty cycle = 100% 0 0.1 0.2 0.3 0.4 0.5 -75 -50 -25 0 25 50 75 100 125 150 175 t [c] drop [v] v out = 2.7 v, i out = 700 ma, duty cycle = 100%
selecting components for your applications AN2728 8/20 you must choose the resistor divider according to the following equation: equation 1 with v fb = 0.6 v. figure 9 shows the feedback voltage versus temperature. we suggest using a resistor with values in the range of 10 k ? to 100 k ? . lower values are suitable as well but increase current consumption. for output voltages close to the feedback volt age, we suggest adding a very small capacitor in parallel with r 1 in the range of 10 pf. as an alternative, we suggest increasing the current in the resistor divider by decreasing the r 1 and r 2 value. 2.2 input capacitor the input capacitor must be able to support the maximum input operating voltage and the maximum rms input current. since step-down converters draw current from the input in pulses, the input current is squared and the height of each pulse is equal to the output current. the input capacitor has to absorb switching current that can be as high as the load current divided by two (worst case, with duty cycle of 50 %). for this reason, th e quality of these capaci tors has to be very high to minimize its power dissipation generated by the internal esr, thus improving the system reliability and efficiency. the critical parameter is usually th e rms current rating, which must be higher than the rms input current. the maximum rms input current (flowing through the input capacitor) is: equation 2 where is the expected system efficiency, d is the duty cycle and i out the output dc current. this function reaches its maximum value at d = 0.5 and the equivalent rms current is equal to i out divided by 2 (considering = 1). + = 2 1 fb out r r 1 v v [] + = 2 1 fb out r r 1 v v [] figure 9. feedback voltage vs. temperature 550 570 590 610 630 650 -75 -50 -25 0 25 50 75 100 125 150 175 t [c] v fb [mv] v in = 3.6 v, i out = 10 ma 550 570 590 610 630 650 -75 -50 -25 0 25 50 75 100 125 150 175 t [c] v fb [mv] v in = 3.6 v, i out = 10 ma d d 2 d i i 2 2 out rms + - = d d 2 d i i 2 2 out rms + - =
AN2728 selecting components for your applications 9/20 the maximum and minimum duty cycles are: equation 3 and equation 4 where v f it is the voltage drop across the internal nmos and v sw the voltage drop across the internal pmos. considering the range d min to d max it is possible to determine the maximum i rms flowing through the input capacitor. the use of ceramic capacitors with voltage ratings in the range of 1.5 times the maximum output voltage is recommended. 2.3 output capacitor the output capacitor is very important to satisfy the output voltage ripple requirement. using a small inductor value is useful to reduce the size of the coil, but increases the current ripple. so, in order to reduce the output voltage ripple a low esr capacitor is required. the output voltage ripple (v out_ripple ) is: equation 5 where ? i is the ripple current and f sw is the switching frequency. the use of ceramic capacitors with voltage ratings in the range of 1.5 times the maximum output voltage is recommended. 2.4 inductor the inductor value is very important because it fixes the ripple current flowing through output capacitor. the ripple current is usually fixed at 20-40 % of i out_max , that is 0.14-0.28 a with i out_max = 0.7 a. the inductor value is approximately obtained by the following formula: equation 6 where t on is the on time of the internal switch, given by d x t. sw inmin f out max v v v v d - + = sw inmin f out max v v v v d - + = sw inmax f out max v v v v d - + = sw inmax f out max v v v v d - + = + ? i = sw out ripple out f c esr 8 1 v _ [] + ? i = sw out ripple out f c esr 8 1 v _ [] on out in t v v l ? i - = on out in t v v l ? i - =
selecting components for your applications AN2728 10/20 the peak current through the inductor is given by: equation 7 it can be observed that if the inductor value decreases, the peak current (that has to be lower than the current limit of the device) increases. so, for fixed peak current protection, higher value of the inductor permits a higher value of the output current. 2.5 layout considerations due to the high switching frequency and peak current, the layout is an important design step for all switching power supplies. if the layout is not carefully done, important parameters such as efficiency and output voltage ripple could be compromised. short, wide traces must be implemented for main current and for power ground paths as shown in bold in figure 10 . the input capacitor must be placed as close as possible to the device pins as well as the inductor and output capacitor. a common ground node minimizes ground noise, as shown in figure 10 . 2 i i out pk ? i + = 2 i i out pk ? i + = figure 10. layout considerations v in v fb sw gnd v in v out 2 3 en 1 5 4 st1s12_adj l1 r 1 c2 r 2 c1 gnd v in v fb sw gnd v in v out 2 3 en 1 5 4 st1s12_adj l1 r 1 c2 r 2 c1 gnd
AN2728 thermal considerations 11/20 3 thermal considerations the dissipated power of the device is determined by three different factors: switch losses due to the non-negligible r ds(on) . these are equal to: equation 8 and equation 9 where d is the duty cycle of the application. note: the duty cycle is theoretically given by the ratio between v out and v in , but in practice it is significantly higher than this value in order to compensate for the losses of the overall application. due to this reason, the switching losses related to the r ds(on) increase compared to an ideal case. on and off switching losses. these are given by the following relation: equation 10 where t on and t off are the overlap times of the voltage across the power switch and the current flowing into it during the turn-on and turnoff phases. t sw is the equivalent switching time. quiescent current losses: equation 11 where i q is the quiescent current. the overall losses are: equation 12 when the device operates at v out close to v in (high duty cycle) the power dissipated can be approximated by: equation 13 d i r p 2 out ds(on)_p on_p = d i r p 2 out ds(on)_p on_p = d) 1 ( i r p 2 out ds(on)_n on_n - = d) 1 ( i r p 2 out ds(on)_n on_n - = sw sw out in sw off on out in sw f t i v f 2 ) t (t i v p = + = sw sw out in sw off on out in sw f t i v f 2 ) t (t i v p = + = p q = v in x i q q in sw sw out in 2 out ds(on)_n 2 out ds(on)_p tot i v f t i v d) 1 ( i r d i r p + + - + = q in sw sw out in 2 out ds(on)_n 2 out ds(on)_p tot i v f t i v d) 1 ( i r d i r p + + - + = q in 2 out ds(on)_p tot i v i r p x + x = q in 2 out ds(on)_p tot i v i r p x + x =
thermal considerations AN2728 12/20 the junction temperature of device is: equation 14 where t a is the ambient temperature and r thja is the junction-to-ambient thermal resistance. t j = t a + r thja x p tot
AN2728 demonstration board usage recommendation 13/20 4 demonstration board usage recommendation the demonstration board shown in figure 11 is provided with kelv in connection, which means that two lines are available for each pin. one used for supplying or sinking current (v out_f and v in_f ) and the other (v out_s and v in_s ) used to perform the needed measurement. the board has one enable pin available which is located on the right side of the board. this pin can be used to supply the enable pin with a external voltage higher than 1.5 v to turn on or lower than 0.5 v to turn off the device. figure 11. st1s12 demonstration board layout figure 12. demonstration board layers bottom layer top layer
demonstration board usage recommendation AN2728 14/20 4.1 external component selection figure 13 shows the demonstration board schematic. the r en is used to pull up the en pin to v in . we suggest using a resistor with a value in the range of 500 k ? to 1 m ? in order to reduce current consumption. in order to obtain the needed output voltage, the resistor divider must be selected in accordance with the following formula: equation 15 with v fb = 0.6 v. the resistors given in ta b l e 1 are good choices in terms of current consumption. 4.2 capacitors selection it is possible to use any x5r or x7r ceramic capacitor: - c in = 4.7 f (ceramic) or higher - c out = 10 f (ceramic) or higher figure 13. demonstration board schematic vfb sw gnd v in v out 2 3 en 1 5 4 st1s12_adj l r1 c out r2 gnd v in c in ren vfb sw gnd v in v out 2 3 en 1 5 4 st1s12_adj l r1 c out r2 gnd v in c in ren table 1. recommended resistor divider v out r 1 r 2 1.2 v 68 k ? 68 k ? 3.3 v 68 k ? 15 k ? + = 2 1 fb out r r 1 v v [] + = 2 1 fb out r r 1 v v []
AN2728 demonstration board usage recommendation 15/20 it is possible to put several capacitors in parallel in order to reduce the equivalent series resistance and improve the ripple present in the output voltage. 4.3 inductor selection due to the high switching frequency (1.5 mhz) it is possible to use very small inductor values. in this board the device was tested with inductors in the range of 1 h to 10 h, with very good efficiency performances (see figure 14 and 15 ). as the device is able to provide an operative output current of 0.7 a, the use of inductors capable of managing at least 1.5 a is strongly recommended. figure 14. efficiency vs. output current figure 15. efficiency vs. output voltage 0 10 20 30 40 50 60 70 80 90 100 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 i ou t [a] efficiency [%] v out = 0.6 v v out = 1.2 v v out = 2.5 v v out = 3.3 v v in = 5 v, c in = 4.7 f, c out = 10 f, l = 2.2 h 0 10 20 30 40 50 60 70 80 90 100 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 i ou t [a] efficiency [%] v out = 0.6 v v out = 1.2 v v out = 2.5 v v out = 3.3 v v in = 5 v, c in = 4.7 f, c out = 10 f, l = 2.2 h 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 3.5 4 v ou t [v] efficiency [%] i out = 50 ma i out = 250 ma i out = 500 ma v in = 5 v, c in = 4.7 f, c out = 10 f, l = 2.2 h 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 3.5 4 v ou t [v] efficiency [%] i out = 50 ma i out = 250 ma i out = 500 ma v in = 5 v, c in = 4.7 f, c out = 10 f, l = 2.2 h
demonstration board usage recommendation AN2728 16/20 figure 16. efficiency vs. inductor at v o = 1.8 v figure 17. efficiency vs. inductor at v o = 3.3 v figure 18. efficiency vs. input voltage 0 10 20 30 40 50 60 70 80 90 100 024681012 l [ h] efficiency [%] i out =50ma i out =100ma i out =250ma i out =500ma i out =700ma v in = 3.6 v, v out = 1.8 v, c in = 4.7 f, c out = 10 f 0 10 20 30 40 50 60 70 80 90 100 024681012 l [ h] efficiency [%] i out =50ma i out =100ma i out =250ma i out =500ma i out =700ma v in = 3.6 v, v out = 1.8 v, c in = 4.7 f, c out = 10 f 0 10 20 30 40 50 60 70 80 90 100 024681012 l [ h] efficiency [%] i out =50ma i out =100ma i out =300ma i out =500ma i out =700ma v in = 5 v, v out = 3.3 v, c in = 4.7 f, c out = 10 f 0 10 20 30 40 50 60 70 80 90 100 024681012 l [ h] efficiency [%] i out =50ma i out =100ma i out =300ma i out =500ma i out =700ma v in = 5 v, v out = 3.3 v, c in = 4.7 f, c out = 10 f 0 10 20 30 40 50 60 70 80 90 100 33.544.555.56 v in [v] efficiency [%] i out =50ma i out =100ma i out =250ma v out = 3.3 v, c in = 4.7 f, c out = 10 f, l = 2.2 h 0 10 20 30 40 50 60 70 80 90 100 33.544.555.56 v in [v] efficiency [%] i out =50ma i out =100ma i out =250ma v out = 3.3 v, c in = 4.7 f, c out = 10 f, l = 2.2 h
AN2728 bill of materials 17/20 5 bill of materials table 2. bill of materials with most common components name value material manufacturer p/n c in 4.7f ceramic murata grm21br61e475ka12b c out 10f ceramic murata grm21br61a106ke19l murata grm31cr61e106ka12b l 2.2h coilcraft lps4018-222mlb coiltronics dr73-2r2 ren 1m ?
recommended footprint AN2728 18/20 6 recommended footprint figure 19. tsot23-5l footprint dimensions table 3. footprint data values dim. mm. in. a3.500.138 b1.100.043 c0.600.024 d0.950.037 e1.200.047 f2.300.090
AN2728 revision history 19/20 7 revision history table 4. document revision history date revision changes 22-apr-2008 1 initial release.
AN2728 20/20 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. unless expressly approved in writing by an authorized st representative, st products are not recommended, authorized or warranted for use in milita ry, air craft, space, life saving, or life sustaining applications, nor in products or systems where failure or malfunction may result in personal injury, death, or severe property or environmental damage. st products which are not specified as "automotive grade" may only be used in automotive applications at user?s own risk. 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. ? 2008 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 - singapore - spain - sweden - switzerland - united kingdom - united states of america www.st.com

▲Up To Search▲

Price & Availability of AN2728

	To Download AN2728 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .