lx8941 p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 1 www. microsemi . com adjustable low dropout regulator tm ? copyright ? 2001 rev. 1.0, 2011-02-04 description the microsemi lx8941 is an adjustable, low dropout regulator rated for more than 1a of output current. it can regulate with as low as 0.8v headroom between the input and output voltages, at 1a output current, thus minimizing power dissipation. in addition, it can be used in applications where worst case supplies require a low input / output differential to maintain regulation. this feature makes it ideal for some processor applications that require 4v operation from a 5v supply. in addition, the lx8941 provides an on / off switch that reduces the ic quiescent current when activat ed, making it ideal for battery operated applications. important: for the most current data, consult microsemi ?s website: http://www.microsemi.com key features ? 2% internally trimmed output ? output current in excess of 1a ? input ? output differential less than 0.8v @ 1a ? reverse battery protection ? short circuit protection ? internal thermal overload protection ? available in 5-lead plastic to-220 & surface-mount to-263 product highlight in out adj part lx8941 10 f r1 412 r2 187 22f 4v on off 5v 600 500 400 300 200 100 0 100 500 1000 125c 25c -40c dropout voltage - (mv) output current (ma) dropout voltage vs. output current vs. temperature package order info t a ( c) plastic to-220 5 pin plastic to-263 5 pin p dd rohs compliant / pb-free transition dc: 0543 rohs compliant / pb-free transition dc: 0535 0 to 70 lx8941cp lx8941cdd note: available in tape & reel. append the letters ?tr? to the part number. (i.e. lx8941cdd-tr) l l x x 8 8 9 9 4 4 1 1
lx8941 p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 2 www. microsemi . com adjustable low dropout regulator tm ? copyright ? 2001 rev. 1.0, 2011-02-04 absolute maximum ratings input voltage (v in ) ....................................................................................................... 26v operating temper ature ra nge ................................................................................... 150 c storage temperat ure rang e ........................................................................ -65 c to 150 c lead temperature (sol dering 10 s econds) ................................................................. 300 c package peak temp. for solder reflow ( 40 seconds maximum exposure) .... 260c (+0 -5) note: exceeding these ratings could cause damage to the device. all voltages are with respect to ground. currents are positive into, negative out of specified terminal . package pin out 1 2 3 tab is gnd 4 5 gnd on/of f adj v o v in p p ackage (top view) 1 v in gnd on/off 2 3 tab is gnd 4 5 adj v o dd p ackage (top view) rohs / pb-free 100% matte tin lead finish thermal data p plastic to-220 5-pin thermal resistance - junction to t ab , jt 4.5 c/w thermal resistance - junction to a mbient , j a 60 c/w dd plastic to-263 5-pin thermal resistance - junction to c ase , jc 4.5 c/w thermal resistance - junction to a mbient , j a 60 c/w junction temperature calculation: t j = t a + (p d x ja ). the ja numbers are guidelines for the thermal performan ce of the device/pc-board system. all of the above assume no ambient airflow. recommended operating conditions parameter symbol lx8941 units min typ max input voltage v in 3.8 26 v load current (with adequate heat sinking) i l 5 1000 ma input capacitor (v in to gnd) 0.1 f output capacitor with esr of min 0.1 ? , 10 ? max*., (v o to gnd) 10 f * at low output current levels the range of acceptable esr values may be narrower, and should be evaluated to insure stability p p a a c c k k a a g g e e d d a a t t a a
lx8941 p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 3 www. microsemi . com adjustable low dropout regulator tm ? copyright ? 2001 rev. 1.0, 2011-02-04 electrical characteristics unless otherwise specified, the following characteristics apply over the operating ambient temperature of 0 c to 125c for the lx8941cp & lx8941cdd; v in = 10v, i o = 1a, c out = 22f and are for dc characteristics only. lo w duty cycle pulse test ing techniques are used which maintain junction and case temperatures equal to the ambient temperature. note 2: the out put voltage range is 4v to 25v and is determined by the two external resist ors, r1 and r2. see product highlight. parameter symbol test conditions lx8941 units min typ max adj pin voltage (note 2) v a dj i o = 0a, t a = 25c 1.225 1.25 1.275 v line regulation ? v oi v o + 2v < v in < 26v, i o = 5ma 1 50 mv load regulation ? v ol 50ma < i o < 1a, v o = v a dj 10 50 mv dropout voltage ? v i o = 100ma 150 300 mv i o = 500ma 275 500 mv i o = 1a 400 800 mv quiescent current i q i o = < 5ma, 7 < v in < 26v 3 15 ma i o = 500ma 30 50 ma i o = 1000ma 115 180 ma adjust pin current i a dj v in = 10v, i o = 1a 2 20 a current limit i cl v in = 26v 1 1.2 a output noise voltage (note 3) v o rms 10hz ? 100khz, io = 5ma 150 v rms long term stability (note 3) 20 mv / 1000hr ripple rejection (note 3) r r f o = 120hz, 1v rms , i o = 100ma 66 db ` enable logic section on threshold voltage 2 v on threshold current 0.1 50 a off threshold voltage 0.8 v off threshold current -10 -0.3 a note 3: these parameters although guar anteed, are not tested in production. simplified block diagram + - thermal shutdown on / off circuit c1* 0.1f c2 10f on off input voltage output voltage v in on / off v o adj gnd lx8941 figure 1 ? simplified block diagram e e l l e e c c t t r r i i c c a a l l s s
lx8941 p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 4 www. microsemi . com adjustable low dropout regulator tm ? copyright ? 2001 rev. 1.0, 2011-02-04 package dimensions dd 5-pin plastic to-263 a b k i f h c d 0 -8 m n j seating plane e g dim m illimeters i nches min max min max a 10.03 10.67 0.395 0.420 b 8.51 9.17 0.335 0.361 c 4.19 4.59 0.165 0.181 d 1.14 1.40 0.045 0.055 e 0.330 0.51 0.013 0.020 f 0.74 0.89 0.029 0.035 g 1.57 1.83 0.062 0.072 h 2.29 2.79 0.090 0.110 i ? 1.65 ? 0.065 j 0 0.25 0 0.010 k 14.60 15.87 0.575 0.625 m 7 7 n 3 3 p 5-pin plastic to-220 a g f b d c j r k n s t 15 note: 1. dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006?) on any side. lead dimension shall not include solder coverage. dim m illimeters i nches min max min max a 14.23 16.51 0.560 0.650 b 9.66 10.66 0.380 0.420 c 3.56 4.82 0.140 0.190 d 0.46 0.89 0.018 0.035 f 3.56 4.06 0.140 0.160 g 3.40 0.134 j 0.31 1.14 0.012 0.045 k 12.70 14.73 0.500 0.580 n 6.80 typ 0.268 typ r 2.04 2.92 0.080 0.115 s 1.14 1.39 0.045 0.055 t 5.85 6.85 0.230 0.270 m m e e c c h h a a n n i i c c a a l l s s
lx8941 p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 5 www. microsemi . com adjustable low dropout regulator tm ? copyright ? 2001 rev. 1.0, 2011-02-04 notes production data ? information contained in this document is proprietary to microsemi and is current as of publication date. this document may not be modified in any way without the express written consent of microsemi. product processing does not necessarily include testing of all parameters. microsemi reserves the right to change the configuration and performance of the product and to discontinue product at any time. n n o o t t e e s s
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