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product structure silicon monolithic integrated circuit this product has no designed protection against radioactive ra ys . 1/ 16 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 tsz22111 ? 14 ? 001 www.rohm.com tsz02201-0j2j0a900980-1-2 termination regulators for ddr-sdrams bd3538f bd3538hfn general description bd3538f/hfn is a termination regulator that complies with jedec requirements for ddr -sdram. this linear power supply uses a built-in n-channel mosfet and high-speed op-amps specially designed to provide excellent transient response. it has a sink/source current capability of up to 1a and has a power supply bias requirements of 3.3v to 5.0v for driving the n-channel mosfet. by employing an independent reference voltage input (vddq) and a feedback pin (vtts), this termination regulator provides excellent output voltage accuracy and load regulation as required by jedec standards. additionally, bd3538 has a reference power supply output (vref) for ddr-sdram or a memory controller. unlike the vtt output that goes to hi - z state, the vref output is kept unchanged when en input is changed to low, making this ic suitable for ddr -sdram under self refresh state. features ? incorporates a push-pull power supply for termination (vtt) ? in corporates a reference voltage circuit (vref) ? incorporates an enabler ? incorporates an undervoltage lockout (uvlo) ? incorporates a thermal shutdown protector (tsd) ? compatible with dual channel (ddr- ii) applications power supply for ddr i / ii - sdram ke y specifications ? termination input voltage range: 1.0v to 5.5v ? vcc input voltage range: 2.7v to 5.5v ? vddq reference voltage range: 1.0v to 2.75v ? output voltage: 1/2 x v vddq v(typ) ? output current: 1 .0 a (max) ? high side fet o-resistance: 0.4 (typ) ? low side fet on -resistance: 0.4 (typ) ? standby current: 0.5ma (typ) ? operating temperature range: - 40 c to + 10 5c packages w(typ) x d(typ) x h(max) typical application circuit , block diagram sop8 5.00mm x 6.20mm x 1.71mm h so n8 2.90mm x 3.00mm x 0.60mm vcc vcc vddq vddq vtt_in vcc vcc vcc soft uvlo tsd reference block thermal protection enable en gnd vref vtts vddq ? x vtt vtt vtt_in uvlo tsd en uvlo tsd en uvlo vcc tsd en uvlo en 1 2 4 3 8 7 5 6 datashee t datashee t downloaded from: http:///
2/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn pin configuration pin descriptions pin no. pin name pin function 1 gnd gnd pin 2 en enable input pin 3 vtts detector pin for termination voltage 4 vref reference voltage output pin 5 vddq reference voltage input pin 6 vcc vcc pin 7 vtt_in termination input pin 8 vtt termination output pin bottom fin (note 1) substraight (conntct to gnd) (note 1) only bd3538hfn description of blocks 1. vcc the vcc pin is for the independent power supply input that operates the internal circuit of the ic. it is the voltage at this pin that drives the ics amplifier circuits. the vcc input ranges from 3.3v to 5.5v and maximum current consumption is 4ma. a bypass capacitor of 1 f or so shoul d be connected to this pin when using the ic in an application circuit. 2. vddq this is the power supply input pin for an internal voltage divider network. the voltage at vddq is halved by two 50 k? internal voltage-divider resistors and the resulting volta ge serves as reference for the vtt output. since vtt = 1/2vddq, the jedec requirement for ddr-sdram can be satisfied by supp lying the correct voltage to vddq. noise input should be avoided at the vddq pin as it is also included by the voltage-divider at the output. an rc fil ter consisting of a resistor and a capacitor (220 ? and 2.2 f, for instance) may be used to reduce the noise input but make sure that it will not significant ly effect t he voltage-divid ers output. 3. vtt_in vtt_in is a power supply input pin for vtt output. voltage in the range between 1.0v to 5.5v , but consideration must be given to the current limit dictated by the on-resistance of the ic and to the change in allowable loss due to input/output voltage difference. generally, the following voltages are supplied: ? ddr i v vtt_in =2.5v ? ddrii v vtt_in =1.8v take note that a high impedance voltage input at vtt_in may result in oscillation or degradation in ripple rejec tion, so connecting 10f capacitor with minimal change in capac itance to vtt_in terminal is recommended. however, this impedance may depend on the characteristics of the power s upply input and the impedance of the pc board wiring, which must be carefully checked before use. 4. vref bd3538 provides a constant voltage, vref, which is independ ent from the vtt output and can serve as a reference input for memory controllers and drams. the voltage level o f vref is kept constant even if the en pin is at low level, making the use of this ic compatible with self refresh state of dram. in order to stabilize the output voltage, connecting th e correct combination of capacitor and resistor to vref is ne cessary. for this purpose, a combination of 1.0f to 2.2f cera mic capacitor, characterized by minimal variation in capacitance and a 0.5 to 2.2 phase compensating resistor is recommended. the maximum current capability of the vref pin is 20ma but for an application which consumes a small amount of vref current, using a capacitance of 1 f or less will do. 5. vtts vtts is a sense pin for the load regulation of the vtt output voltage. i n case the wire connecting vtt pin and the load is too long, connecting vtts pin to the part of the wire nearer to the load may improve load regulation. 6. vtt this is the output for the ddr memory termination voltage and it has a sink/source cu rrent capability of 1.0a . vtt voltage tracks the voltage at vddq pin divided in half. the output is turned to off when en pin is low or when either the vcc uvlo or the thermal shutdown protection function is activated . always connect a capacitor to vtt pin for loop gain and phase compensation and for reduction in output voltage variation in the event of sudden load change. be careful in choosing the capacitor as sufficient capacitance ma y cause oscillation and high esr (equivalent series resistance) may res ult in increase d output voltage variation during a sudden change in load. a 220f or so ceramic capacito r is recommended, though ambient temperature and other conditions should also be considered. vtt_in vddq gnd en vtts vref vtt vcc 1 2 3 4 5 6 7 8 top view downloaded from: http:///
3/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn description of blocks - continued 7. en a high input of 2.3v or higher to en turns on the vtt output. a low input of 0.8v or less, on the other hand, turns vtt to a hi- z state. with a low en input, however, the vref output remains on, provided that suff i ci ent vcc and vddq voltages have been established. absolute maximum ratings parameter symbol rating unit bd3538f bd3538hfn input voltage v cc 7 (note 2) (note 3) 7 (note 2) (note 3) v enable input voltage v en 7 (note 2) (note 3) 7 (note 2) (note 3) v termination input voltage v vtt_ in 7 (note 2) (note 3) 7 (note 2) (note 3) v vddq reference voltage v vddq 7 (note 2) (note 3) 7 (note 2) (note 3) v output current i v tt 1 1 a power dissipation1 pd 1 0.56 (note 4) 0.63 (note 6) w power dissipation2 pd 2 0.69 (note 5) 1. 35 (note 7) w power dissipation3 pd 3 - 1. 75 (note 8) w operating temperature range topr - 40 to + 105 - 40 to + 105 c storage temperature range tstg -55 to +1 50 -55 to +1 50 c maximum junction temperature tjmax +150 +150 c (note 2) should not exceed pd. (note 3) instantaneous surge voltage, back electromotive force and voltag e under less than 10% duty cycle. (note 4) derate by 4.48mw /c for ta over 25c (with no heat sink). (note 5) derate by 5.52mw /c for ta over 25c (when mounted on a board 70mm x 70mm x 1.6mm glass-epoxypcb ). (note 6) derate by 5.04mw/ c for ta over 25 c (when mounted on a 70mm x 70mm x 1.6mm glass-epoxy board, 1-layer) on less than 0.2% (percentage occupied by copper foil. (note 7) derate by 10.8mw/ c for ta over 25 c (when mounted on a 70mm x 70mm x 1.6mm glass-epoxy board, 1-layer) on less than 7.0% (percentage occupied by copper foil. (note 8) derate by 14.0mw/ c for ta over 25 c (when mounted on a 70mm x 70mm x 1.6mm glass-epoxy board, 1-layer) on less than 65.0% (percentage occupied by copper foil. caution: operating the ic over the absolute maximum ratings may damage the ic. in addition, it is impossible to predict all destructive situations su ch as short-circuit modes, open circuit modes, etc. therefore, it is important to c onsider circuit protection measures, like adding a fuse, in case the ic is op erated in a special mode exceeding the absolute maximum ratings. recommended operating ratings (ta=25 c ) parameter symbol rating unit min max input voltage v cc 2.7 5.5 v termination input voltage v vtt_ in 1.0 5.5 v vddq reference voltage v vddq 1.0 2.75 v enable input voltage v en -0.3 +5.5 v downloaded from: http:///
4/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn electrical characteristics (unless otherwise noted, ta=25 c v cc =3.3v v en =3v v vddq =1.8v v vtt_ in =1.8v) parameter symbol limit unit conditions min typ ma x standby current i st - 0.5 1.0 ma v en =0v bias current i cc - 2 4 ma v en =3v [enable] high level enable input voltage v enhigh 2.3 - 5.5 v low level enable input voltage v enlow -0.3 - +0.8 v enable pin input current i en - 7 10 a v en =3v [terminatio n] termination output voltage 1 v vtt1 v vref - 30m v vref v vref +30 m v i v tt =-1.0a to +1.0a ta=0 c to 105 c (note 9) termination output voltage 2 v vtt2 v vref - 30m v vref v vref +30 m v v cc =5v, v vddq =2.5v v vtt_ in =2.5v i v tt =-1.0a to +1.0a ta=0 c to 105 c (note 9) so urce current i v tt+ 1.0 - - a sink current i v tt - - - -1.0 a load regulation ? v vtt - - 50 mv i v tt =-1.0a to +1.0a line regulation reg.l - 20 40 mv upper side on-resistance 1 r hron1 - 0.45 0.9 lower side on-resistance 1 r lron1 - 0.45 0.9 upper side on-resistance 2 r hron2 - 0.4 0.8 v cc =5v, v vddq =2.5v v vtt_ in =2.5v lower side on-resistance 2 r lron2 - 0.4 0.8 v cc =5v, v vddq =2.5v v vtt_ in =2.5v [reference voltage input] input impedance z vddq 70 100 130 k output voltage 1 v vref1 1/2 x v vddq - 18m 1/2 x v vddq 1/2 x v vddq +18m v i ref =-5ma to +5ma ta=0 c to 105 c (note 9) ou tput voltage 2 v vref2 1/2 x v vddq - 40m 1/2 x v vddq 1/2 x v vddq +40m v i ref =-10ma to +10ma ta=0 c to 105 c (note 9) output voltage 3 v vref3 1/2 x v vddq - 25m 1/2 x v vddq 1/2 x v vddq +25m v v cc =5v, v vddq =2.5v v vtt_ in =2.5v i vref =-5ma to +5ma ta=0 c to 105 c (note 9) output voltage 4 v vref4 1/2 x v vddq - 40m 1/2 x v vddq 1/2 x v vddq +40m v v cc =5v, v vddq =2.5v v vtt_ in =2.5v i v tt =-10ma to +10ma ta=0 c to 105 c (note 9) [uvlo] threshold voltage v uvlo 2.40 2.55 2.70 v vcc : sweep up hysteresis voltage ? v uvlo 100 160 220 mv vcc : sweep down (note 9) no tested on outgoing inspection downloaded from: http:///
5/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn v vtt (2 0mv/div) i v tt (1a/div) 10sec/div v vtt (20mv/div) i v tt (1a/div) 10sec/div v vtt (2 0mv/div) i v tt (1a/div) 10sec/div v vtt (20mv/div) i v tt (1a/div) 10sec/div typical waveforms figure 1. ddr 1 (-1a +1a) figure 2. ddr1 (+1a -1a) figure 3. ddr2 (-1a +1a) figure 4. ddr2 (+1a -1a) downloaded from: http:///
6/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn typical waveforms - continued figure 5. input sequence 1 figure 6. input sequence 2 figure 7. input sequence 3 figure 8. start up wave form vcc en vddq vtt_in vtt vcc en vddq vtt_in vtt vcc en vddq vtt_in vtt vtt_in vref vtt itt_in (1a/div) downloaded from: http:///
7/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn typical performance curves figure 11. terminal output voltage vs output current (ddr1) 1.240 1.245 1.250 1.255 1.260 -2 -1 0 1 2 itt(a) vtt(v) terminal output voltage : v vtt (v) output current : i v tt (a) figure 10. output voltage vs i vref (ddr2) output voltage : v vref (v) i vref (ma) figure 9. output voltage vs i vref (ddr1) 1.248 1.249 1.250 1.251 1.252 - 10 -5 0 5 10 output voltage : v vref (v) i vref (ma) figure 12. terminal output voltage vs output current (ddr2) 0.880 0.885 0.890 0.895 0.900 0.905 0.910 0.915 0.920 -2 -1 0 1 2 terminal output voltage : v vtt (v) output current : i v tt (a) downloaded from: http:///
8/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn application information 1. evaluation board bd3538 evaluation board circuit bd3538 evaluation board application components part no value company parts name u1 - rohm bd3538 r 4 220 rohm mcr03 j2 0 - - c 2 10f murata grm21 series c 3 1f murata grm18 series c 5 10f murata grm21 series c 7 220f sanyo 2r5tpe220mf c 9 2.2f murata grm18 series c 5 gnd bd3538 vref en vcc vddq vtt_in vtts vtt gnd v cc sw1 j2 r 4 c 9 c 3 c 7 c 2 2 7 5 6 1 8 3 4 u1 vtt_in vcc vtt vref vddq en vtts g nd downloaded from: http:///
9/ 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn 2. power dissipation heat loss in thermal design, consider the temperature range wherein th e ic is guaranteed to operate and apply appropriate margins. the temperature conditions that need to be conside red are listed below: (1) ambient temperature ta: 100c or lower (2) chip junction temperature tj: 150c or lower the chip junction temperature tj can be considered as follows. see below diagrams for ja. since the package has fin at the bottoms of ic, package powe r is considerably affected by the area of the copper foil where fin is connected. in order to release heat, please make the board area large enough or add many through-holes to the inner layer pattern . most of heat loss in bd3538 occurs at the output n-channel fet . the power lost is determined by multiplying the voltage between in and out by the output current. since this ic is packaged for a high power applications. its thermal derating characteristics significantly depend on the pc board. so when designing, the size of the pc board to be used should be carefully considered. ? ? ? ? ? ? ? ? ? ? ave i v v voltage output v voltage input wn dissipatio power out vddq vtt in vtt ? ? ? ? 21 _ if v v tt _in = 1.8 volts, v v ddq =1.8 volts, and i out (ave)=0.5 a, for instance, the power dissipation is determined a s follows: ? ? ? ? ? ? ? ? ? ? ? ? w 4.0 a5.0 v9.0 v8.1 w n dissipatio power ? ? ? ? sop8 hson8 (1) 70mm x 70mm x 1.6mm glass-epoxy pcb j -c=181c/w (2) with no heat sink j -a=222c/w 0.0 0.5 1.0 1.5 2.0 0 25 50 75 100 125 150 ambient temperatureta() power dissipation pd w) (3) 0.63w (2) 1.3 5w (1) 1.75w (1) 1 layer (copper foil density : 65% ja=71.4c/w (2) 1 layer (copper foil density : 7%) ja=92.4c/w (3) 1 layer (copper foil density : 0.2%) ja=198.4c/w ambient temperature : ta (c) power dissipation : pd (w) 0 100 200 300 400 500 600 700 800 0 25 50 75 100 125 150 ambient temperatureta() power dissipation pd mw) (2) 0. 56w (1) 0. 69w 1 00 c ambient temperature : ta (c) power dissipation : pd (w) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 downloaded from: http:///
10 / 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn operational notes 1. reverse connection of power supply connecting the power supply in reverse polarity can damage the ic. take precautions against reverse polarity when connecting the power supply, such as mounting an extern al diode between the power supply and the ic s power supply pin s. 2. power supply lines design the pcb layout pattern to provide low impedance sup ply lines. separate the ground and supply lines of the digital and analog blocks to prevent noise in the grou nd and supply lines of the digital block from affecting the analog block. furthermore, connect a capacitor to ground at all pow er supply pins . consider the effect of temperature and aging on the capacitance value when using electrolytic capa citors. 3. ground voltage ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. 4. ground wiring pattern when using both small-signal and large-current ground traces , the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small- signal ground caused by large currents. also ensure that the ground traces of external components do not cause variations on the ground voltage. the ground lines must be as short and thick as possible to reduce line impedance. 5. thermal consideration should by any chance the power dissipation rating be exc eeded the rise in temperature of the chip may result in deterioration of the properties of the chip. in case of exceeding th is absolute maximum rating, increase the board size and copper area to prevent exceeding the pd rating. 6. recommended operating conditions these conditions represent a range within which the expe cted characteristics of the ic can be approximately obtained . the electrical characteristics are guaranteed under the condi tions of each parameter. 7. inrush current when power is first supplied to the ic, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the ic has more than one powe r supply. therefore, give special consideration to power co upling capacitance, power wiring, width of ground wiring, and routing of connections. 8. operation under strong electromagnetic field operating the ic in the presence of a strong electromagnetic field ma y cause the ic to malfunction. 9. testing on application boards when testing the ic on an application board, connecting a capacitor directly to a low-impedance output pin may subject the ic to stress. always discharge capacitors comple tely after each process or step. the ics power supply should always be turned off completely before connecting or removing it from the test setup during the inspection process. to prevent damage from static discharge, ground the ic during assembly and use similar precautions during transport and storage. 10. inter-pin short and mounting errors en sure that the direction and position are correct when mounting the ic on the pcb. incorrect mounting may result in damaging the ic. avoid nearby pins being shorted to each other especially to ground, power supply and output pin . inter-pin shorts could be due to many reasons such as me tal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins du ring assembly to name a few. 11. unused input pins input pins of an ic are often connected to the gate of a mos tran sistor. the gate has extremely high impedance and extremely low capacitance. if left unconnected, the elec tric field from the outside can easily charge it. the smal l charge acquired in this way is enough to produce a signi ficant effect on the conduction through the transistor and cause unexpected operation of the ic. so unless otherwise spec ified, unused input pins should be connected to the power supply or ground line. downloaded from: http:///
11 / 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn operational notes C continued 12. regarding the input pin of the ic this monolithic ic contains p+ isolation and p substrate l ayers between adjacent elements in order to keep them isolated. p-n junctions are formed at the intersection of t he p layers with the n layers of other elements, creating a parasitic diode or transistor. for example (refer to figure below): when gnd > pin a and gnd > pin b, the p-n junction operates as a paras itic diode. when gnd > pin b, the p-n junction operates as a parasitic transistor. parasitic diodes inevitably occur in the structure of the ic. the operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physic al damage. therefore, conditions that cause these diodes to operate, such as applying a voltage lower than the gnd vo ltage to an input pin (and thus to the p substrate) should be avoided. figure 13. example of monolithic ic structure 13. thermal shutdown circuit(tsd) this ic has a built-in thermal shutdown circuit that prevent s heat damage to the ic. normal operation should always be within the ics power di ssipation rating. if however the rating is exceeded for a con tinued period, the junction temperature (tj) will exceed 175 c which will activate the tsd circuit that will turn off al l output pins. when the tj falls below the tsd threshold, the circuits are automatically restor ed to normal operation. note that the tsd circuit operates in a situation that exceeds th e absolute maximum ratings and therefore, under no circumstances, should the tsd circuit be used in a set des ign or for any purpose other than protecting the ic from heat damage. 14. capacitor across output and gnd if a large capacitor is connected between the output pin an d ground pin, current from the charged capacitor can flow into the output pin and may destroy the ic when the vcc or in pi n is shorted to ground or pulled down to 0v. use a capacitor smaller than 10 00 f between output and ground. 15. output capacitor resistor do not fail to connect a output capacitor to vref output terminal fo r stabilization of output voltage. the capacitor connected to vref output terminal works as a loop gain pha se compensator. insufficient capacitance may cause an oscillation. it is recommended to use a low temperature coe fficient 1-10 f ceramic capacitor, though it depends on ambient temperature and load conditions. it is therefore re quested to carefully check under the actual temperature and load conditions to be applied. 16. output capacitor do not fail to connect a capacitor to vtt output pin for stabil ization of output voltage. this output capacitor works as a loop gain phase compensator and an output voltage varia tion reducer in the event of sudden change in load. insufficient capacitance may cause an oscillation. and i f the equivalent series resistance (esr) of this capacitor is high, the variation in output voltage increases in the e vent of sudden change in load. it is recommended to u se a 220 f functional polymer capacitor, though it depends on ambient temperature and load conditions. using a lo w esr ceramic capacitor may reduce a loop gain phase margin and cause an oscillation, which may be improved by connecting a resistor in series with the capacitor. it is t herefore requested to carefully check under the actual temperature and load conditions to be applied. n n p + p n n p + p substrate gnd n p + n n p + n p p substrate gnd gnd parasitic elements pin a pin a pin b pin b b c e parasitic elements gnd parasitic elements c be transistor (npn) resistor n region close-by parasitic elements downloaded from: http:///
12 / 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn operational notes C continued 17. input capacitors these input capacitors are used to reduce the output impeda nce of power supply to be connected to the input terminals (vcc and vtt_in). increase in the power supp ly output impedance may result in oscillation or de gradation in ripple rejecting characteristics. it is recommended to u se a low temperature coefficient 1f (for vcc) and 10f (for vtt_in) capacitor, but it depends on the characteristics of the p ower supply input, and the capacitance and impedance of the pc board wiring pattern. it is therefore r equested to carefully check under the actual temperature and load conditions to be applied. 18. input terminals (vcc, vddq, vtt_in and en) vcc, vddq, vtt_in and en terminals of this ic are made up independent o ne another. to vcc terminal, the uvl o function is provided for malfunction protection. irrespective of the input order of the inputs terminals, vtt output is activated to provide the output voltage when uvlo and en vol tages reach the threshold voltage while vref output is activated when uvlo voltage reaches the threshold. if vddq and vtt_in t erminals have equal potential and common impedance, any change in current at vtt_in terminal may re sult in variation of vtt_in voltage, which affects vddq terminal and may cause variation in the output voltage. it i s therefore required to perform wiring in such manner that vddq and vtt_in terminals may not have common impedance. if i mpossible, take appropriate corrective measures including suitable cr filter to be inserted between vddq and vtt_in terminal s. 19. vtts terminal this terminal used to improve load regulation of vtt outp ut. connection with vtt terminal must be done not to have common impedance with high current line, which may offer better lo ad regulation of vtt output. 20. operating range within the operating range, the operation and function of the circuits are generally guaranteed at an ambient temperature within the range specified. the values specif ied for electrical characteristics may not be guaranteed, bu t drastic change may not occur to such characteristics within the operating range. 21. built-in thermal shutdown protection circuit thermal shutdown protection circuit is built- in to prevent thermal breakdown. turns vtt output to off when the thermal shutdown protection circuit activates. this thermal s hutdown protection circuit is originally intended to protec t the ic itself. it is therefore requested to conduct a thermal design not to exceed the temperature under which the thermal shutdown protection circuit can work. 22. in the event that load containing a large inductance component is connected to the output terminal, and generation of back-emf at th e start-up and when output is turned off is assumed, it is recommende d to insert a protection diode. 23. application circuit although we can recommend the application circuits containe d herein with a relatively high degree of confidence, we ask that you verify all characteristics and specif ications of the circuit as well as its performance under actual conditions. please note that we cannot be held responsible for problems that may arise due to patent infringements or noncompliance with any and all a pplicable laws and regulations. output pin (example) downloaded from: http:///
13 / 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn ordering information b d 3 5 3 8 x x x x x part number package f : sop8 hfn : hson8 packaging and forming specification e2 : embossed tape and reel (sop8) tr : embossed tape and reel(hson8) marking diagrams sop8 (top view) d 3 5 3 8 part number marking lot number 1pin mark hson8 (top view) 538 part number marking lot number 1pin mark bd3 downloaded from: http:///
14 / 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn physical dimension, tape and reel information package name sop8 (unit : mm) pkg : sop8 drawing no. : ex112-5001-1 (max 5.35 (include.burr)) downloaded from: http:///
15 / 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn physical dimension, tape and reel information - continued package name hson8 downloaded from: http:///
16 / 16 tsz02201-0j2j0a900980-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 www.rohm.com tsz22111 ? 15 ? 001 bd3538f bd3538hfn revision history date revision changes 02.nov.2015 001 new release downloaded from: http:///
datasheet d a t a s h e e t notice-pga-e rev.00 2 ? 2015 rohm co., ltd. all rights reserved. notice precaution on using rohm products 1. our products are designed and manufac tured for application in ordinary elec tronic equipments (such as av equipment, oa equipment, telecommunication equipment, home electroni c appliances, amusement equipment, etc.). if you intend to use our products in devices requiring ex tremely high reliability (such as medical equipment (note 1) , transport equipment, traffic equipment, aircraft/spacecra ft, nuclear power controllers, fuel c ontrollers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property (?specific applications?), please consult with the rohm sale s representative in advance. unless otherwise agreed in writing by rohm in advance, rohm shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ro hm?s products for specific applications. (note1) medical equipment classification of the specific applications japan usa eu china class class class b class class ? class 2. rohm designs and manufactures its products subject to strict quality control system. however, semiconductor products can fail or malfunction at a certain rate. please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe desi gn against the physical injury, damage to any property, which a failure or malfunction of our products may cause. the following are examples of safety measures: [a] installation of protection circuits or other protective devices to improve system safety [b] installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. our products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditio ns, as exemplified below. accordin gly, rohm shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of an y rohm?s products under any special or extraordinary environments or conditions. if you intend to use our products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] use of our products in any types of liquid, incl uding water, oils, chemicals, and organic solvents [b] use of our products outdoors or in places where the products are exposed to direct sunlight or dust [c] use of our products in places where the products ar e exposed to sea wind or corrosive gases, including cl 2 , h 2 s, nh 3 , so 2 , and no 2 [d] use of our products in places where the products are exposed to static electricity or electromagnetic waves [e] use of our products in proximity to heat-producing components, plastic cords, or other flammable items [f] sealing or coating our products with resin or other coating materials [g] use of our products without cleaning residue of flux (ev en if you use no-clean type fluxes, cleaning residue of flux is recommended); or washing our products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] use of the products in places subject to dew condensation 4. the products are not subjec t to radiation-proof design. 5. please verify and confirm characteristics of the final or mounted products in using the products. 6. in particular, if a transient load (a large amount of load applied in a short per iod of time, such as pulse. is applied, confirmation of performance characteristics after on-boar d mounting is strongly recomm ended. avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading c ondition may negatively affect product performance and reliability. 7. de-rate power dissipation depending on ambient temperature. when used in sealed area, c onfirm that it is the use in the range that does not exceed t he maximum junction temperature. 8. confirm that operation temperat ure is within the specified range described in the product specification. 9. rohm shall not be in any way responsible or liable for fa ilure induced under deviant condi tion from what is defined in this document. precaution for mounting / circuit board design 1. when a highly active halogenous (chlori ne, bromine, etc.) flux is used, the resi due of flux may negatively affect product performance and reliability. 2. in principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must be used on a through hole mount products. if the flow sol dering method is preferred on a surface-mount products, please consult with the rohm representative in advance. for details, please refer to rohm mounting specification downloaded from: http:///
datasheet d a t a s h e e t notice-pga-e rev.00 2 ? 2015 rohm co., ltd. all rights reserved. precautions regarding application examples and external circuits 1. if change is made to the constant of an external circuit, pl ease allow a sufficient margin considering variations of the characteristics of the products and external components, including transient characteri stics, as well as static characteristics. 2. you agree that application notes, re ference designs, and associated data and in formation contained in this document are presented only as guidance for products use. theref ore, in case you use such information, you are solely responsible for it and you must exercise your own indepen dent verification and judgment in the use of such information contained in this document. rohm shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. precaution for electrostatic this product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. please take proper caution in your manufacturing process and storage so that voltage exceeding t he products maximum rating will not be applied to products. please take special care under dry condit ion (e.g. grounding of human body / equipment / solder iron, isolation from charged objects, se tting of ionizer, friction prevention and temperature / humidity control). precaution for storage / transportation 1. product performance and soldered connections may deteriora te if the products are stor ed in the places where: [a] the products are exposed to sea winds or corros ive gases, including cl2, h2s, nh3, so2, and no2 [b] the temperature or humidity exceeds those recommended by rohm [c] the products are exposed to di rect sunshine or condensation [d] the products are exposed to high electrostatic 2. even under rohm recommended storage c ondition, solderability of products out of recommended storage time period may be degraded. it is strongly recommended to confirm sol derability before using products of which storage time is exceeding the recommended storage time period. 3. store / transport cartons in the co rrect direction, which is indicated on a carton with a symbol. otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. use products within the specified time after opening a humidity barrier bag. baking is required before using products of which storage time is exceeding the recommended storage time period. precaution for product label qr code printed on rohm products label is for rohm?s internal use only. precaution for disposition when disposing products please dispose them proper ly using an authorized industry waste company. precaution for foreign exchange and foreign trade act since concerned goods might be fallen under listed items of export control prescribed by foreign exchange and foreign trade act, please consult with rohm in case of export. precaution regarding intellectual property rights 1. all information and data including but not limited to application example contained in this document is for reference only. rohm does not warrant that foregoi ng information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. 2. rohm shall not have any obligations where the claims, actions or demands arising from the co mbination of the products with other articles such as components, circuits, systems or external equipment (including software). 3. no license, expressly or implied, is granted hereby under any intellectual property rights or other rights of rohm or any third parties with respect to the products or the informati on contained in this document. pr ovided, however, that rohm will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to manufacture or sell products containing the produc ts, subject to the terms and conditions herein. other precaution 1. this document may not be reprinted or reproduced, in whol e or in part, without prior written consent of rohm. 2. the products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of rohm. 3. in no event shall you use in any wa y whatsoever the products and the related technical information contained in the products or this document for any military purposes, incl uding but not limited to, the development of mass-destruction weapons. 4. the proper names of companies or products described in this document are trademarks or registered trademarks of rohm, its affiliated companies or third parties. downloaded from: http:///
datasheet datasheet notice ? we rev.001 ? 201 5 rohm co., ltd. all rights reserved. general precaution 1. before you use our pro ducts, you are requested to care fully read this document and fully understand its contents. rohm shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny rohms products against warning, caution or note contained in this document. 2. all information contained in this docume nt is current as of the issuing date and subj ec t to change without any prior notice. before purchasing or using rohms products, please confirm the la test information with a rohm sale s representative. 3. the information contained in this doc ument is provi ded on an as is basis and rohm does not warrant that all information contained in this document is accurate an d/or error-free. rohm shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. downloaded from: http:///

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