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3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 1 http://www.sanken-ele.co.jp general descriptions the nr 885 e is synchronous buck regulator ics integrates high-side and low-side power mosfets . with the current mode control, ultra low esr capacitors such as ceramic capacitors can be used. the ics have protection functions such as o ve r-current protection (ocp) , under-voltage lockout (uvlo) and thermal shutdown (tsd) . an adjustable soft-start by an external capacitor prevents the excessive inrush current at turn- on the regulator. the ics integrate phase compensation circuit which reduces the number of external components and simplifies the design of customer application. the on/off pin (en pin) turns the regulator on or off and helps to achieve low power consumption requirements. the nr 885 e is available in a n 8-pin soic package with an exposed thermal pad on the back side. features & benefits ? current mode pwm control ? up to 95% efficiency ? stable with low esr ceramic output capacitors ? built-in protection function over current protection (ocp) thermal shutdown (tsd) under voltage lockout (uvlo) ? built-in phase compensation ? adjustable soft-start with an external capacitor ? turn on/off the regulator function package ? exposed soic 8 thermally enhanced 8-pin package electrical characteristics ? 3a output current ? operating input range v in = 4.5v 18v ? output adjustable v o = 0.8v 14v ? fixed 350khz frequency applications ? lcd tv / blu-ray / set top box ? green electronic products ? other power supply basic connection of NR885E k c1, c2: 10 f / 25v r1: 100k l1: 10 h c4, c5: 22 f / 16v r3: 22 c9: 0.1 f r4: 8.2 k , r5: 4.3k (vo=3.3v) c3 : 0.1 f r6: 3.9k NR885E downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 2 http://www.sanken-ele.co.jp series lineup product no. f sw v in v o i o NR885E 350khz 4.5v to 18v (1) 0.8v to 14v (2) 3a (1) the minimum input voltage shall be either of 4.5v or v o +3v, whichever is higher. (2) the i/o condition limited by the minimum on-time (t on( min) ). absolute maximum ratings parameter symbol ratings units condition dc input voltage v in 20 v power dissipation (3) p d 1.76 w glass-epoxy board mounting in a 3030mm. (copper area in a 2525mm) max t j = 150 c junction temperature (4) t j ? 40 to 150 c storage temperature t s ? 40 to 150 c thermal resistance (junction- pin no. 4) jp 26 c /w thermal resistance (junction-ambient air) ja 71 c /w glass-epoxy board mounting in a 3030mm. (copper area in a 2525mm) (3) limited by thermal shutdown. (4) the temperature detection of thermal shutdown is about 160c recommended operating conditions parameter symbol ratings units condition min max dc input voltage (5) v in vo+3 18 v dc output current (6) (7) io 0 3.0 a output voltage vo 0.8 14 v ambient operating temperature (7) top ? 40 85 c (5) the minimum value of input voltage is taken as the larger one of either 4.5v or v o +3v. in the case of v in =v o +1 v o +3v , it is set to i o = max. 2a (6) recommended circuit refers to typical application circuit. (7) to be used within the allowable package power dissi pation characteristics. downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 3 http://www.sanken-ele.co.jp electrical characteristics ta = 25c parameter symbol ratings units test conditions m i n t y p m a x reference voltage v ref 0.784 0.800 0.816 v v in = 12v i o = 1.0a output voltage temperature coefficient S v ref / S t D 0.05 D mv/c v in = 12v, i o = 1.0a ? 40 c to +85 c switching frequency f sw 280 350 420 khz v in =12v, v o =3.3v, i o =1a line regulation (8) v line D 50 D mv v in = 6.3v 18v, v o = 3.3v, i o = 1a load regulation (8) v load D 50 D mv v in = 12v, v o = 3.3v, i o = 0.1a 3.0a over current protection threshold i s 3.1 D 6.0 a v in = 12v, v o = 3.3v supply current i in D 6 D ma v in = 12v v en =10k pull up to v in shutdown supply current i in(off) 0 D 10 a v in =12v, i o =0a, v en =0v ss pin source current at low level voltage i en/ss 6 10 14 a v ss =0v, v in =12v high level voltage v ssh D 3.0 D v v in =12v en pin sink current i en 50 100 a v en = 10v threshold voltage v c/eh 0.7 1.4 2.1 v v in =12v max on -duty (8) d max D 90 D % minimum on -time (8) (9) t on( min) D 150 D nsec thermal shutdown threshold temperature (8) ts d 151 165 D c thermal shutdown restart hysteresis of temperature (8) tsd_hys D 20 D c (8) guaranteed by design, not tested. (9) the i/o characteristic are limited by the t on( min) . downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 4 http://www.sanken-ele.co.jp typical performance characteristics NR885E typical performance characteristics efficiency v=1.8v 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 3.5 io(a) eff(%) v in =5 v 6v 8v 10v 12v 15v v o =1.8v output current : i o [a] v o = 1 2 v 0 10 20 30 40 50 60 70 80 90 100 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 3 . 5 ? [ a ] e f f i c i e n c y [ % ] v in = 14 v 15 v 18 v v o =12v output current : i o [a] efficiency [%] nr880k es1 hsop8 s1 rt(vo=3.3v) 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 3.5 io(a) eff(%) v in =6v 8v 10v 12v 15v 18v v o =3.3v output current : i o [a] efficiency [%] v o = 5 v 0 10 20 30 40 50 60 70 80 90 100 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 3 . 5 ? [ a ] e f f i c i e n c y [ % ] v in =8v 10 v 12 v 15 v 18 v v o =5v efficiency [%] output current : i o [a] efficiency [%] downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 5 http://www.sanken-ele.co.jp NR885E typical performance characteristics v o = 3 . 3 v 0 . 0 0 0 . 5 0 1 . 0 0 1 . 5 0 2 . 0 0 2 . 5 0 3 . 0 0 3 . 5 0 0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 3 . 5 4 . 0 4 . 5 5 . 0 [ a ] R v [ v ] n r 8 8 0 k e s 1 d i p 2 8 s 1 i q o f f v s v i n a t r t 0 1 2 3 4 5 6 7 8 9 10 0 2 4 6 8 10 12 14 16 18 20 v i n ( v ) i q o f f ( a) e n : o p e n nr880k es1 hsop8 s1 rt(vo=3.3v) 3.25 3.27 3.29 3.31 3.33 3.35 0 0.5 1 1.5 2 2.5 3 3.5 io(a) vo(v) over current protection output startup output voltage [v] shutdown supply current : i in(off) v in = 8v 10v 12v 15v 18v v in = 6v 8v 10v 12v 15v 18v i o = 0 a 0 1 2 3 4 5 6 7 0 2 4 6 8 10 12 14 16 18 R v i [ v ] o ? r q [ a ] supply current : i in i o = 0a 0.5a 1a 2a 3a input voltage v in [v] output current i o [a] v o =3.3v v en =0v v o =3.3v v o =3.3v, load = constant resistance v o =3.3v output current i o [a] input voltage v in [v] input voltage v in [v] output voltage [v] output voltage [v] current [ a] current [ma] nr880k es1 hsop8 s1 rt(vo=3.3v) 300 310 320 330 340 350 360 370 380 390 400 0 0.5 1 1.5 2 2.5 3 3.5 io(a) kz v in = 6v 8v 10v 12v 15v 18v v o =3.3v switching frequency {khz} output current i o [a] switching frequency: f sw load regulation : v load downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 6 http://www.sanken-ele.co.jp functional block diagram pin assignments & functions pin assignments pin functions pin no. symbol description 1 bs high-side boost input. bs supplies the drive for high-side nch-mosfet switch. connect a capacitor and a resistor between sw to bs. 2 in power input. in supplies the power to the ic as well as the regulator s witches 3 sw power switching output. sw supplies power to the output. connect the lc filter from sw to the output. note that a capacitor is required from sw to bs to supply the power the high -side switch 4 gnd ground connect the exposed pad to pin no.4 5 fb feedback input pin to compare reference voltage. the feedback threshold is 0.8v. to set the output voltage, fb pin is required to connect between resistive vo ltage divider r4 and r6. 6 nc no connection. 7 en enable input. drive en pin high to turn on the regulator, low to turn it off. 8 ss soft-start control input. to set the soft-start period, connect to a capacitor between gnd. downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 7 http://www.sanken-ele.co.jp external components design guide (1)diode d1 ? flywheel diode d1 can be connected to enhance the efficiency. ? the schottky-barrier diode must be used for d1. if other diodes like fast reco very diodes are used, ic may be damaged because of the reverse voltage applied by the recovery voltage or on voltage. (2)choke coil l1 ? if the winding resistance of the choke coil is too high, the efficiency may go down to the extent that it is out of the ratin g. ? as the start current of the over current protection is approximately 4a, attention must be paid to the heating of the choke coil by the magnetic saturation due to overload or short-circulated load. (3)capacitor c1 ( c2 ) , c4 (c5), c7 ? as large ripple currents across c1 (c2) and c4 (c5), capacitors with high frequency and low impedance for smps must be used. especially when the impedance of c4 (c5) is high, the sw itching waveform may not be normal at low temperature. ? c7 is a capacitor for soft start. a soft-start controls the over-shoot of the o utput voltage rising and rush current. (4)resistor r4 , r 5, r6 ? r4 , r5 , r6 are resistor to the output voltage. i adj is required to set to 0.2ma. r4 , r5 , r6 are calculated by the equation (1). ------- (1) in order to have optimum operating condition, each component must be con nected with the minimum distance. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? k0.4 3 10 2.0 8.0 adj i fb v 6r 3 10 2.0 8.0 o v adj i fb v o v 5r 4r P downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 8 http://www.sanken-ele.co.jp allowable package power dissipation notes 1) glass-epoxy board mounting in a 3030mm 2) copper area : 2525mm 3) the power dissipation is calculated at the junction temperature 125 c 4) losses can be calculated by the following equation. as the efficiency is subject to the input voltage and output current, it shall be obtain ed from the efficiency curve and substituted in percent 5) thermal design for d1 shall be made separately. ? ?? ? ? ?? ? ? ? ? ? 1 x 100 o i o v d p v o: output voltage v in : input voltage i o : output current x : efficiency (%) downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 9 http://www.sanken-ele.co.jp pcb layout example& recommended land pattern (1) each ground of all components is connected as close as possible to the pin no.4 at one point. (2) to help heat dissipation, connect a large copper plane to exposed pad on the back side of the package. the copper plane is required for gnd circuit diagram of demo-board pcb circuit-diagram as for the part number of the demonstration board "circuit-diagram", a circuit board concerned doesn't partly fit each other with the above application circuit example and so on for nr110, nr1 20 and the nr880 series common use. approve it in advance. c9, r9 and c10 aren't used in the nr880 series. a nd, d1, d2, r3, r8,r10, c 11 and c12 are options. front side: component side (double sided board) back side: gnd side (double sided board) NR885E downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 10 http://www.sanken-ele.co.jp notes: real size of the pcb is 60mm 60 mm notes: 1) dimension is in millimeters, dimension in bracket is in inches. 2) drawing is not to scale. recommended land pattern 0.61 (0.024) 1.27 (0.050) 2.35 (0.092) 5.40 (0.213) 3.24 (0.127) 1.60 (0.063) downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 11 http://www.sanken-ele.co.jp package outline exposed soic8 package notes: 1) dimension is in millimeters, dimension in bracket is in inches. 2) drawing is not to scale. 3) pb -free : device composition comply with the rohs directive. package marking top view bottom view front view side view 2.16 0.127 (0.085 0.005) 3.18 0.127 (0.120 0.005) 3.89 (0.153) 3.73 (0.147) 0.508(0.020) 0.330(0.130) 6.918(0.244) 5.893(0.232) 1.27( 0.050) bsc 1.448 0.05 (0.057 0.002) 0.1524(0.006 ) 0.000(0.000) 4.902 0.102 (0.193 0.004) 0.102(0.004) nr 885 e sk ymw part number lot number sanken control number y= last digit of the year (0 - 9) m= month (1-9, o, n, or d) w= week code (1- 3) xxxx downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 12 http://www.sanken-ele.co.jp operating precautions reliability can be affected adversely by improper storage environments and handling methods. please observe the following cautions. cautions for storage ? ensure that storage conditions comply with the standard temperature (5 to 35 c ) and the standard relative humidity (around 40 to 75%) ; avoid storage locations that experience extreme changes in temperature or h umidity. ? avoid locations where dust or harmful gases are present and avoid direct sunligh t. ? reinspect for rust on leads and solderability of products that have been stored for a long time. cautions for testing and handling ? when tests are carried out during inspection testing and other standard test periods, protect the products from power surges from the testing products, shorts between the product pins, a nd wrong connections. in addition, avoid tests exceeded ratings soldering when soldering the products, please be sure to minimize the working time, within the following limits. ? reflow preheat ; 180 c / 9 030 s heat ; 250 c / 101s (260 c peak ,2times) ? soldering iron ; 38010c / 3 .5 0.5s (1time) electrostatic discharge ? when handling the products, the operator must be grounded. grounded wrist straps worn should have at least 1m of resistance from the operator to ground to prevent shock hazard, and it should be placed near the operator. ? workbenches where the products are handled should be grounded and be p rovided with conductive table and floor mats. ? when using measuring equipment such as a curve tracer, the equipment shou ld be grounded. ? when soldering the products, the head of a soldering irons or the sold er bath must be grounded in order to prevent leak voltages generated by them from being applied to the products. ? the products should always be stored and transported in sanken shipping containers or conductive containers, or be wrapped in aluminum foil. downloaded from: http:///
3a , 18 v, 350khz , synchronous buck regulator NR885E sanken electric co., ltd. dec ./ 02 /2014 rev.1.1 13 http://www.sanken-ele.co.jp importants notes ? the contents in this document are subject to changes, for improvement an d other purposes, without notice. make sure that this is the latest revision of the document before use. ? application and operation examples described in this document are quoted for th e sole purpose of reference for the use of the products herein and sanken can assume no responsibility fo r any infringement of industrial property rights, intellectual property rights or any other rights of sanken or any third party which may result from its use. ? although sanken undertakes to enhance the quality and reliability of it s products, the occurrence of failure and defect of semiconductor products at a certain rate is inevitable. users of sanken products are requested to take, at their own risk, preventative measures including safety design of the equipment or systems against any possible injury, death, fires or damages to the society due to device f ailure or malfunction. ? sanken products listed in this document are designed and intended for the use as components in general purpose electronic equipment or apparatus (home appliances, office equipment, telecommunica tion equipment, measuring equipment, etc.). when considering the use of sanken products in the applications where h igher reliability is required (transportation equipment and its control systems, traffic signal control s ystems or equipment, fire/crime alarm systems, various safety devices, etc.), please contact your nearest sanken sales representative to discuss, prior to the use of the products herein. the use of sanken products without the written consent of sanken in the applications where extremely high reliability is required (aerospace equipment, nuclear power control systems , life support systems, etc.) is strictly prohibited. ? in the case that you use sanken semiconductor products or design yo ur products by using sanken semiconductor products, the reliability largely depends on the degree of derating to be made to the rated values. derating may be interpreted as a case that an operation range is set by derating the load from each rated value or surge voltage or noise is considered for derating in order to assure o r improve the reliability. in general, derating factors include electric stresses such as electric voltage, electric current, electric power etc., environmental stresses such as ambient temperature, humidity etc. and thermal stress caused due to self-heating of semiconductor products. for these stresses, instantaneous values, maximum v alues and minimum values must be taken into consideration. in addition, it should be noted that since power devices or ics including power devices have large self-heating value, the degree of derating of junction temperature affects the reliability significantly. ? when using the products specified herein by either (i) combining other products or materials therewith or (ii) physically, chemically or otherwise processing or treating the products, please duly consider all possible risks that may result from all such uses in advance and proceed therewith at yo ur own responsibility. ? anti radioactive ray design is not considered for the products listed herein. ? sanken assumes no responsibility for any troubles, such as droppin g products caused during transportation out of sanken s distribution network. ? the contents in this document must not be transcribed or copied without sanken s written consent. downloaded from: http:///

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