microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 1 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products description the lx8818 is a single channel positive-voltage linear regulator. the regulator output is configured as fixed (3.3v or 2.5v) or adjustable, featuring low-dropout and high accuracy. the lx8818 regulator is stable with ceramic or tantalum low-value capacitors, typically 2.2 f on the outputs, allowing designers flexibility in external component selection. the lx8818 provides designers with a flexible power management solution. the regulator design is optimized for system efficiency by consuming minimal ground current and directing quiescent current to the load. the lx8818 features on-chip trimming of the internal voltage enabling precise output voltages, typically 1% of it?s specified value, while the bipolar outpu t transistor has a low dropout voltage even at full output current (v do < 1.2v typ. @ 1a). output voltage overshoot is minimized when v in is applied, typically v out overshoot < 2% for v in 1v/us ramp. thermal and short circuit curren t protection are integrated on-chip. microsemi?s d-pak or micro powe r p ackage enables maximum powe r dissipation and ease of assembly using surface mount technology. important: for the most current data, consult microsemi ?s website: http://www.microsemi.com key features accurate output voltage typical dropout of 1.2v at 1a and 1.1v at 500ma independent thermal and current limit protection low profile 3 lead smt power package low tolerance load regulation (0.4%) wide dc supply voltage of 4.3v to 10v loop stability independent of output capacitor type applicati ons/benefits 5v to 3.3v/2.5v regulators hard disk drives, cd-roms adsl and cable modems battery charging circuits instrumentation pc peripherals application circuits v out gnd v in lx8818-0x 4.7f 4.7f v in = 5v 3.3v @ 1.0a fixed output adj v out gnd v in lx8818-0x 4.7f v in = 5v 1 2 1 1 * 1 r i r r v v adj ref + ? ? ? ? ? ? ? + = 4.7f 1.8v* @ 1.0a r1 499 r2 1150 adjustable output package order info t j ( c) o utput v lm plastic mlp 6-pin mlp part marking dt plastic to-252 3-pin 0 to 125 3.3v lx8818-02clm 8-02 LX8818-01CDT consult factory for 2.5v and adjustable versions note: available in tape & reel. append the letter ?t? to the part number. (i.e. LX8818-01CDTt) l l x x 8 8 8 8 1 1 8 8
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 2 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products absolute maximum ratings thermal data dt plastic d-pak 3-pin t hermal r esistance -j unction to t ab , jt 6c/w t hermal r esistance -j unction to a mbient , j a (t ypical , depending on mounting / pcb layout ) 25-35c/w lm plastic mlp 6-pin t hermal r esistance -j unction to t ab , jt 8c/w t hermal r esistance -j unction to a mbient , j a (t ypical , depending on mounting / pcb layout ) 29-35c/w junction temperature calculation: t j = t a + (p d x ja ). the ja numbers are guidelines for the therma l performance of the device/pc-board system. all of the above assume no ambient airflow. ja can vary significantly depending on mounting technique. (see application notes section: thermal considerations) package pin out v in v out gnd tab is gnd dt p ackage (top view) v in gnd v out 1 2 3 4 5 6 * * adj n/c n/c lm p ackage (top view) * must be connected to gnd or left floating (see pg 8 for details) n/c = not internally connected functional pin description p in n ame d escription v in positive unregulated supply input fo r the regulator. bypass to gnd with at least 2.2f of low esr and esl capacitance. adj adjustable version only. the output voltage can be se t by two external resistors with the following relationship: v out = v ref * (1+ (r 1 /r 2 )) + (i adj * r 1 ) where r 1 is the resistor connected between v out and adj, and r 2 is the resistor connected between adj and gnd (see figure 2 on page 7). gnd common terminal for ground reference. the input and output bypass capacitors should be connected to this pin. in addition the tab on the ?dt? pack age is also used for heat sinking the device. v out regulator output. it is recommended to bypass to gnd with at least 2. 2uf. size your out put capacitor to meet the transient loading requirement. if you have a very dynamic load, a lower esr capacitor will improve the response to these load steps. input voltage (v in ) .................................................................................................... 13.5v load current (intern ally limited) .................................................................................. 1a power dissipati on ................................................................................... internal ly limited short-circuit protec tion ........................................................................................inde finite operating junction temperature................................................................................ 150 c lead temperature (sol dering 180 s econds) ............................................................... 235 c n ote: exceeding these ratings could cause damage to th e device. all voltages are with respect to ground. currents are positive into, ne gative out of specified terminal. p p a a c c k k a a g g e e d d a a t t a a
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 3 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products recommended max operating conditions lx8818-0x parameter symbol min typ max units input voltage v in 4.5 10 v output voltage (adjustable) v out 5.5 v load current (with adequate heat sinking) i l 1000 ma operating junction temperature t j 125 c electrical characteristics unless otherwise specified, the following specificati ons apply over the operat ing ambient temperature 0 c t a 125 c except where otherwise noted and the following test conditions: v in = 5v, i out = 10ma, c 1 = 10 f (tantalum), c 2 = 4.7 f (tant.), & t j = t a using low duty cycling methods. lx8818-0x parameter symbol test conditions min typ max units ` fixed output (3.3v) output voltage v out 5ma < i out < 1a, 4.75v < v in < 7v 3.250 3.300 3.353 v line regulation ? v out (v in ) 4.75v < v in < 10v, i out = 5ma .0042 .0065 v/v(vin) load regulation ? v out (i out ) 5ma < i out < 1a, v in = 4.75v 4 7 mv i load = 1a, ? v out = -1% 1.25 1.33 v dropout voltage (pwr) ? v i load = 0.5a, ? v out = -1% 1.12 1.18 v current limit i out (max) 1.0 1.32 a minimum load current i l note 1 0 0 ma ` fixed output (2.5v) output voltage v out 5ma < i out < 1a, 4.75v < v in < 7v 2.469 2.500 2.539 v line regulation ? v out (v in ) 4.75v < v in < 10v, i out = 5ma .0042 .0065 v/v(vin) load regulation ? v out (i out ) 5ma < i out < 1a, v in = 4.75v 4 6 mv dropout voltage (pwr) ? v i load = 1a, ? v out = -1% 1.25 1.30 v i load = 0.5a, ? v out = -1% 1.12 1.15 current limit i out (max) 1.0 1.32 a minimum load current i l note 1 0 0 ma ` adjustable output reference voltage v ref 5ma < i out < 1a, 4.75v < v in < 7v 1.234 1.250 1.266 v line regulation ? v out (v in ) 4.5v < v in < 10v, i out = 5ma .06 .075 %/v out load regulation ? v out (i out ) 5ma < i out < 1a, v in = 4.75v .14 0.2 %/v out i load = 1a, ? v out = -1% 1.25 1.30 v i load = 0.5a, ? v out = -1% 1.12 1.15 dropout voltage (pwr) ? v i load = 5ma, ? v out = -1% 1.0 1.02 current limit i out (max) 1.0 1.32 a minimum load current i l note 1 0 5 ma adjust pin bias current i adj 0.05 0.5 a note 1: minimum load current is defined as the am ount of output current required to maintain regulation . e e l l e e c c t t r r i i c c a a l l s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 4 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products electrical characteristics unless otherwise specified, the following specificati ons apply over the operat ing ambient temperature 0 c t a 125 c except where otherwise noted and the following test conditions: v in = 5v, i out = 10ma, c 1 = 10 f (tantalum), c 2 = 4.7 f (tant.), & t j = t a using low duty cycling methods. lx8818-0x parameter symbol test conditions min typ max units ` entire regulator quiescent current i q v in < 7v 2.56 3.5 ma ripple rejection psrr f=120hz, v in = 5v 60 75 db rms output noise (% of v out ) v out (rms) 10hz < f < 10khz 0.003 %/v thermal shutdown t jsd 5ma < i out < 1a, v in = 4.75v 135 140 c note 1: minimum load current is defined as the am ount of output current required to maintain regulation. e e l l e e c c t t r r i i c c a a l l s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 5 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products block diagram bias 1.25v v ref v in c 1 10 f note: application circuit above using ceramic capacitors. + - v out c 2 4.7 f gnd figure 1 ? fixed output bias 1.25v v ref v in c 1 10 f 2 1 adj 2 1 ref out //r r i r r 1 v v + ? ? ? ? ? ? + = note: application circuit above using ceramic capacitors. + - v out c 2 4.7 f gnd r 2 r 1 adj figure 2 ? adjustable output (r1/r2 can be selected to satisfy the minimum load requirements) b b l l o o c c k k d d i i a a g g r r a a m m
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 6 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products characteristic curves output voltage temperature stability vout vs temp 3.27 3.275 3.28 3.285 3.29 3.295 3.3 3.305 3.31 3.315 3.32 -75 -50 -25 0 25 50 75 100 125 150 temp, c vout step load stability 50.0mv~ ch2 500ma ? ch4 b w 10.0s m ch4 610ma a 4 t t 11.80% 2 ch2: vout, ch4: istep, ci n = cout = 10f ceramic, load current, dc = 5mavdroop=150mv supply voltage, fast turn on (trise = 10us) 1.00v ch2 2.00v ch1 100s m ch1 3.64v a 2 t t 288.8s 1 ch1: vin, ch2: vout, cin = cout = 10f ceramic, load current, dc = 5ma short circuit and recovery ch1: vout, ch4: istep, cin = cout = 10f ceramic 500ma ? ch4 2.00v ch1 4.00 s m ch1 3.92v a 4 1 ch1: vout, ch4: iout, cin = cout = 10f ceramic c c h h a a r r t t s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 7 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products application information description the lx8818 is part of a family of ldo (low drop-out) linear regulators in the to-252 or mo229 packages which offer maximum power dissipation in a low profile surface mount technology. the family includes either fixed or adju stable output vers ions. the output can supply up to one amp with a regul ator design optimized for system efficiency by consuming mini mal ground current and directing quiescent current to the load. input capacitor to improve load transient response and noise rejection an input bypass capacitor of at least 10uf is requi red. generally we recommend a 10uf ceramic or tant alum or 22uf electr olytic capacitor. output capacitor the regulator requires an output capacitor connected between v out to gnd to stabilize th e internal co ntrol loop. many types of capacitors are available, with different capacitance values tolerances, temperature coefficients and equivalent series resistance. we recommend a minimum of 4.7uf. to ensure good transient response from the power supply system under rapidly cha nging current load conditions, designers generally use additional output capacitors connected in parallel. such an arrangement serves to minimize the effects of the parasitic resistance (esr) and inductance (esl) that are present in all capacitors. the regulator has been tested stable with capacitor esr?s in the range of 0.05 to 2 ohms. we have found it best to use the same type of capacitor for both input and output bypass. adjustable output voltage the lx8818 develops a 1.25v refere nce voltage between the adjust terminal and gnd (see figure 2). by placing a resistor, r2, between these two terminals, a constant curre nt is caused to flow through r1 and down through r2 to set the ov erall output voltage.. because i adj is very small and constant when compar ed with the current through r2, it represents a small error a nd can usually be ignored. lx8818-0x r1 r2 v in adj v out figure 2 - basic adjustable regulator v ref 1 2 1 1 r adj i r r ref v out v + ? ? ? ? ? ? ? ? + = i adj 1a minimum load requirement the lx8818 has a minimum load requirement for proper output regulation. this minimum current is specified at 0ma for the fixed output and 5ma for the adjustable output. temperature protection the thermal protection shuts the lx8818 down when the junction temperature exceeds 140 0 c. exposure to absolute maximum rated conditions for extended periods ma y affect device reliability (see thermal considerations below). current limit protection the lx8818 includes over current protection. when the output load current exceeds typically 1.4a, the circuit forces the regulator output to decrease. thermal considerations thermal shutdown protects the integrated circuit from thermal overload caused from a rise in j unction temperature during power dissipation. this means of protection is intended for fault protection only and not as a means of curr ent or power limiting during normal application usage. proper thermal ev aluation should be done to ensure that the junction temperature dose not exceed it?s maximum rating. operating at the maximum t j of 150c can impact reliability . due to variation in individual device electrical characteristics and thermal resistance , the built in thermal overload protection may be activated at power levels slightly above or belo w the rated dissipation. also peak output power should be consider ed for each individual output. power dissipation for regulator can be calculated using the following equation: p d = (v in(max) -v out ) * i out (note: power dissipation resulting from qu iescent (ground) current is negligible) for the d-pak package, thermal resistance, tab-amb is 25-45 0 c/w depending on mounting technique when mounted on a fr4 copper clad pcb. junction temperature of the integrated circuit can be calculated using: t junction = t junction-tab rise _ + t tab-amb rise + t amb t tab = p d max * jt ; t tab-amb = p d reg * pcb an example: given conditions: t a = 50c, v in = 5.0v, v out = 3.3v, i out = 200ma. calculated values: t j-tab reg = (5v-3.3v) * (200ma) * 6c/w = (440mw) * 6c/w = 2.6c t tab-amb rise = ( 440mw ) * 32c/w = 14.1c t junction = 2.6c + 14.1c + 5 0c = 66.7c it is important to note that although each output of the regulator will produce up to 1a in current, the individual or total power dissipation may limit the useful total current draw. the junction temperature should be calculated for each individual output as well as the combined outputs to insure the maximum junction temperature in not exceeded. a a p p p p l l i i c c a a t t i i o o n n s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 8 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products mechanical drawings lm 6-pin plastic exposed pad jedec mo-229 reference e d2 e2 l2 a a2 top view side view bottom view l b e d d1 e/2 d/2 .08 d2/2 (e-l)/2 e2/2 e3 e3/2 e1 pin 1 identifier m illimeters i nches dim min max min max a 0.80 1.05 0.031 0.041 a2 0.65 0.75 0.025 0.295 b 0.33 0.45 0.012 0.017 d 2.90 3.25 0.114 0.127 d1 2.70 --- 0.106 --- d2 1.78 2.34 0.070 0.092 e 0.85 1.05 0.033 0.041 e 2.90 3.25 0.114 0.127 e1 2.70 --- 0.106 --- e2 1.01 1.57 0.039 0.061 e3 0.17 0.30 0.006 0.012 l 0.20 0.60 0.007 0.024 l2 --- 0.12 --- 0.005 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. m m e e c c h h a a n n i i c c a a l l s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 9 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products mechanical drawings dt 3-pin plastic to-252 w k r x a l u o p n b d c e f g i j m q v h m illimeters i nches dim min max min max a 6.47 6.73 0.255 0.265 b 5.97 6.23 0.235 0.245 c 2.16 2.42 0.085 0.095 d 0.68 0.94 0.027 0.037 e 0.38 0.64 0.015 0.025 f 0.63 0.89 0.025 0.035 g 2.16 2.42 0.085 0.095 h 0.84 1.10 0.033 0.043 i 0.89 1.15 0.035 0.045 j 2.44 2.70 0.096 0.106 k 9.55 9.81 0.376 0.386 l 5.20 5.46 0.205 0.215 m 7.0 7.0 n 0.51 0.77 0.020 0.030 o 0.51 0.77 0.020 0.030 p 4.19 4.45 0.165 0.175 q 0.76 1.02 0.030 0.040 r 0.48 0.74 0.019 0.029 s 0.89 1.15 0.035 0.045 t r0.20 r0.30 r0.008 r0.012 u 0.51 0.77 0.020 0.030 v 45 45 w 1.44 1.70 0.057 0.067 x 0 0.10 0 0.004 m m e e c c h h a a n n i i c c a a l l s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 10 copyright ? 2000 rev. 1.0, 2002-10-01 www. microsemi . com lx8818 1a low dropout re g ulator p roduction data sheet integrated products 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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