general description the max8840/max8841/max8842 ultra-low-noise, low- dropout (ldo) linear regulators are designed to deliver up to 150ma continuous output current. these regula- tors achieve a low 120mv dropout for 120ma load cur- rent. the max8840 uses an advanced architecture to achieve ultra-low output voltage noise of 11? rms and psrr of 54db at 100khz. the max8841 does not require a bypass capacitor, hence achieving the smallest pc board area. the max8842 output voltage can be adjusted with an exter- nal divider. the max8840/max8841 are preset to a variety of volt- ages in the 1.5v to 4.5v range. designed with a p-channel mosfet series pass transistor, the max8840/max8841/ max8842 maintain very low ground current (40?). the regulators are designed and optimized to work with low-value, low-cost ceramic capacitors. the max8840 requires only 1? (typ) of output capacitance for stability with any load. when disabled, current consumption drops to below 1?. the max8840/max8841/max8842 are available in a tiny 1mm x 1.5mm x 0.8mm ?fn. applications cellular and cordless phones pda and palmtop computers base stations bluetooth portable radios and accessories wireless lans digital cameras personal stereos portable and battery-powered equipment features ? space-saving 1.0mm x 1.5mm x 0.8mm dfn ? 11v rms output noise at 100hz to 100khz bandwidth (max8840) ? 78db psrr at 1khz (max8840) ? 120mv dropout at 120ma load ? stable with 1f ceramic capacitor for any load ? guaranteed 150ma output ? only need input and output capacitors (max8841) ? output voltages: 1.5v, 1.8v, 2.5v, 2.6v, 2.7v, 2.8v, 2.85v, 3v, 3.3v, 4.5v (max8840/max8841) and adjustable (max8842) ? low 40a ground current ? excellent load/line transient ? overcurrent and thermal protection max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn ________________________________________________________________ maxim integrated products 1 dfn (1.5mm x 1.0mm) top view gnd bp (max8840) n.c. (max8841) fb (max8842) shdn 1 2 3 6 4 out 5 n.c. in max8840 max8841 max8842 pin configuration ordering information max8840 output preset 1 5v to 4 5v in input 2v to 6v off shdn c bp 10nf c out 1f c in 1f out on bp gnd typical operating circuits 19-0629; rev 0; 10/06 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. *xy is the output voltage code (see the output voltage selector guide). other versions between 1.5v and 4.5v are available in 100mv increments. contact factory for other versions. **future product?ontact factory for availability. +denotes lead-free package. part* temp range pin-package max8840 eltxy+t -40? to +85? 6 ?fn-6 1.5mm x 1.0mm max8841 eltxy+t** -40? to +85? 6 ?fn-6 1.5mm x 1.0mm max8842 elt+t** -40? to +85? 6 ?fn-6 1.5mm x 1.0mm typical operating circuits continued at end of data sheet. output voltage selector guide appears at end of data sheet.
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = v out + 0.5v, t a = -40? to +85?, unless otherwise noted. c in = 1?, c out = 1?, c bp = 10nf. typical values are at +25?; the max8842 is tested with 2.45v output, unless otherwise noted.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. in to gnd .................................................................-0.3v to +7v output short-circuit duration ............................................infinite out, shdn to gnd ......................................-0.3v to (in + 0.3v) fb, bp, n.c. to gnd..................................-0.3v to (out + 0.3v) continuous power dissipation (t a = +70?) 6-pin ?fn (derate 2.1mw/? above +70?) .............0.168w ja ..................................................................................477?/w operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65 c to +150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units input voltage range v in 26v i out = 1ma, t a = +25? -1 +1 i out = 100? to 80ma, t a = +25? -2 +2 output voltage accuracy i out = 100? to 80ma -3 +3 % maximum output current i out 150 ma current limit i lim out = 90% of nominal value 150 200 300 ma v out 3v, i out = 80ma 80 170 v out 3v, i out = 120ma 120 2.5v v out < 3v, i out = 80ma 90 200 2.5v v out < 3v, i out = 120ma 135 2v v out < 2.5v, i out = 80ma 120 250 dropout voltage (note 2) 2v v out < 2.5v, i out = 120ma 180 mv i out = 0.05ma 40 90 ground current i q v in = v out(nom) - 0.1v, i out = 0ma 220 500 ? line regulation v lnr v in = (v out + 0.5v) to 6v, i out = 0.1ma 0.001 %/v load regulation v ldr i out = 1ma to 80ma 0.003 %/ma t a = +25? 0.003 1 shutdown supply current i shdn shdn = 0v t a = +85? 0.05 ? max8840 78 f = 1khz, i out = 10ma max8841/max8842 72 max8840 75 f = 10khz, i out = 10ma max8841/max8842 65 max8840 54 ripple rejection psrr f = 100khz, i out = 10ma max8841/ max8842 46 db
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn _______________________________________________________________________________________ 3 electrical characteristics (continued) (v in = v out + 0.5v, t a = -40? to +85?, unless otherwise noted. c in = 1?, c out = 1?, c bp = 10nf. typical values are at +25?; the max8842 is tested with 2.45v output, unless otherwise noted.) (note 1) note 1: limits are 100% tested at +25?. limits over operating temperature range are guaranteed by design. note 2: dropout is defined as v in - v out when v out is 100mv below the value of v out for v in = v out + 0.5v. note 3: time needed for v out to reach 90% of final value. parameter symbol conditions min typ max units max8840 11 f = 100hz to 100khz, i load = 10ma max8841/max8842 230 max8840 13 output noise voltage (rms) f = 100hz to 100khz, i load = 80ma max8841/max8842 230 ? shutdown exit delay r load = 50 (note 3) 300 ? shdn logic-low level v in = 2v to 6v 0.4 v shdn logic-high level v in = 2v to 6v 1.5 v t a = +25? shdn input bias current v in = 6v, shdn = 0v or 6v t a = +85? 0.01 ? t a = +25? 0.006 0.1 fb input bias current (max8842) v in = 6v, v fb = 1.3v t a = +85? 0.01 ? thermal shutdown 160 ? thermal-shutdown hysteresis 10 ? typical operating characteristics (v in = v out + 0.5v, c in = 1?, c out = 1?, c bp = 10nf, t a = +25?, unless otherwise noted.) max8840 output voltage vs. input voltage max8840 toc01 input voltage (v) output voltage (v) 54321 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0.0 06 i out = 150ma i out = 0ma max8840 output voltage accuracy vs. load current max8840 toc02 load current (ma) % deviation (%) 125 100 75 50 25 -0.4 -0 2 0 0 2 0.4 0 6 -0 6 0150 max8840 output voltage accuracy vs. temperature max8840 toc03 temperature (c) % deviation (%) 60 35 10 -15 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0 -1.0 -40 85 i out = 1ma
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn 4 _______________________________________________________________________________________ typical operating characteristics (continued) (v in = v out + 0.5v, c in = 1?, c out = 1?, c bp = 10nf, t a = +25?, unless otherwise noted.) max8440 dropout voltage vs. load current max8840 toc04 input voltage (v) dropout voltage (mv) 125100755025 40 20 80 60 120 100 160 140 200 180 0 0 150 t a = +85c t a = +25c t a = -40c max8840 dropout voltage vs. output voltage max8840 toc05 output (v) dropout voltage (mv) 3.0 2.8 2.6 2.4 2 2 50 100 150 200 250 0 2.0 3.2 i out = 80ma max8840 ground pin current vs. input voltage max8840 toc06 input voltage (v) ground pin current ( a) 4321 150 200 50 100 250 300 350 0 05 i load = 150ma i load = 0ma max8840 ground pin current vs. load current max8840 toc 07 load current (ma) ground pin current ( a) 125100755025 100 50 150 200 250 300 350 0 0 150 v in = 3.8v v in = 5.5v max8840 ground pin current vs. temperature max8840 toc08 temperature (c) ground pin current ( a) 60 35 10 -15 35 40 45 50 30 -40 85 max8840 power-supply rejection ratio vs. frequency max8840 toc09 frequency (khz) psrr (db) 1 10 100 0.1 40 50 60 10 20 30 70 80 90 0 0.01 1000 i load = 10ma c bp = 10nf max8841 power-supply rejection ratio vs. frequency max8840 toc10 frequency (khz) psrr (db) 0.1 1 10 100 40 50 60 10 20 30 70 80 90 0 0 01 1000 i load = 10ma max8840 output noise max8840 toc11 400s/div v in = 3.8v i load = 10ma v noise = 11v rms 20v/div max8840 output noise-spectral density vs. frequency max8840 toc12 frequency (khz) output noise density (nv/ hz) 0.1 1 10 100 1000 100 10,000 10 0 01 1000
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn _______________________________________________________________________________________ 5 typical operating characteristics (continued) (v in = v out + 0.5v, c in = 1?, c out = 1?, c bp = 10nf, t a = +25?, unless otherwise noted.) max8840 output noise vs. bp capacitance max8840 toc13 bp capacitance (nf) output noise (v) 10 5 10 15 20 25 0 1 100 max8840 load-transient response max8840 toc14 1ms/div v in = 3 5v i load = 0 to 50ma v out 10mv/div max8840 load-transient response near dropout max8840 toc15 1ms/div v in = 3.1v i load = 0 to 50ma v out 10mv/div max8840 line-transient response max8840 toc16 200s/div v in = 3.5v to 4v v out 2mv/div max8840 exiting shutdown waveform max8840 toc17 20s/div v out = 2.85v r load = 47 output voltage 2v/div shutdown voltage max8840 entering shutdown delay max8840 toc18 40s/div c bp = 0.01f output voltage 2v/div shutdown voltage max8840 shutdown exit delay max8840 toc19 20s/div shutdown voltage v out 1v/div v out = 3v c bp = 100nf max8840 region of stable c out esr vs. load current max8840 toc20 load current (ma) c out esr () 100755025 0.1 1 10 100 0.01 0 150125
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn 6 _______________________________________________________________________________________ detailed description the max8840/max8841/max8842 are ultra-low-noise, low-dropout, low-quiescent current linear regulators designed for space-restricted applications. the parts are available with preset output voltages ranging from 1.5v to 4.5v. these devices can supply loads up to 150ma. as shown in the functional diagram, the max8840/max8841 consist of an innovative bandgap core and noise bypass circuit, error amplifier, p-chan- nel pass transistor, and internal feedback voltage- divider. the max8842 allows for adjustable output with an external feedback network. the 1.225v bandgap reference is connected to the error amplifier? inverting input. the error amplifier com- pares this reference with the feedback voltage and amplifies the difference. if the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled low. this allows more current to pass to the output and increases the output voltage. if the feed- back voltage is too high, the pass transistor gate is pulled high, allowing less current to pass to the output. the output voltage is fed back through an internal resis- tor voltage-divider connected to the out pin. an external bypass capacitor connected to bp (max8840) reduces noise at the output. additional blocks include a current limiter, thermal sensor, and shutdown logic. internal p-channel pass transistor the max8840/max8841/max8842 feature a 1 (typ) p-channel mosfet pass transistor. this provides seve- ral advantages over similar designs using a pnp pass transistor, including longer battery life. the p-channel mosfet requires no base drive, which considerably reduces quiescent current. pnp-based regulators waste considerable current in dropout when the pass transis- tor saturates. they also use high base-drive current under heavy loads. the max8840/max8841/max8842 do not suffer from these problems and consume only 40? of quiescent current in light load and 220? in dropout (see the typical operating characteristics ). output voltage selection the max8840/max8841 are supplied with factory-set output voltages from 1.5v to 4.5v, in 100mv increments (see the ordering information ). the max8842 features a user-adjustable output through an external feedback network (see the typical operating circuits). to set the output of the max8842, use the following equation: where r2 is chosen to be less than 240k and v ref = 1.225v. use 1% or better resistors. shutdown the max8840/max8841/max8842 feature a low-power shutdown mode that reduces quiescent current less than 1?. driving shdn low disables the voltage refer- ence, error amplifier, gate-drive circuitry, and pass transistor (see the functional diagram), and the device output enters a high-impedance state. connect shdn to in for normal operation. current limit the max8840/max8841/max8842 include a current limiter, which monitors and controls the pass transis- tor? gate voltage, limiting the output current to 200ma. rrx v v out ref 12 1 = ? ? ? ? ? ? - pin description pin max8840 max8841 max8842 name function 1 1 1 in unregulated input supply 2 2 2 gnd ground 333 shdn shutdown. pull low to disable the regulator. 4 b p noise bypass for low-noise operation. connect a 10nf capacitor from bp to out. it is shorted to out in shutdown mode. 4 fb adjustable output feedback point 5 4, 5 5 n.c. no connection. not internally connected. 666o u t regulated output voltage. bypass with a capacitor to gnd. see the capacitor selection and regulator stability section.
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn _______________________________________________________________________________________ 7 for design purposes, consider the current limit to be 150ma (min) to 300ma (max). the output can be shorted to ground for an indefinite amount of time without dam- aging the part. thermal-overload protection thermal-overload protection limits total power dissipation in the max8840/max8841/max8842. when the junction temperature exceeds t j = +160?, the thermal sensor signals the shutdown logic, turning off the pass transistor and allowing the ic to cool down. the thermal sensor turns the pass transistor on again after the ic? junction temperature drops by 10?, resulting in a pulsed output during continuous thermal-overload conditions. thermal-overload protection is designed to protect the max8840/max8841/max8842 in the event of a fault condition. for continual operation, do not exceed the absolute maximum junction temperature rating of t j = +150?. operating region and power dissipation the max8840/max8841/max8842 maximum power dissipation depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient, and the rate of airflow. the power dissipation across the device is: p = i out (v in - v out ) the maximum power dissipation is: p max = (t j - t a ) / ( jc + ca ) where t j - t a is the temperature difference between the max8840/max8841/max8842 die junction and the surrounding air, jc is the thermal resistance of the package, and ca is the thermal resistance through the pc board, copper traces, and other materials to the surrounding air. the gnd pin of the max8840/max8841/max8842 per- forms the dual function of providing an electrical con- nection to ground and channeling heat away. connect the gnd pin to ground using a large pad or ground plane. noise reduction for the max8840, an external 0.01? bypass capacitor between bp and out with an innovative noise bypass scheme reduces output noises dramatically, exhibiting 11? rms of output voltage noise with c bp = 0.01? and c out = 1?. startup time is minimized by a power- on circuit that precharges the bypass capacitor. applications information capacitor selection and regulator stability use a 1? capacitor on the max8840/max8841/ max8842 input and a 1? capacitor on the output. larger input capacitor values and lower esrs provide better noise rejection and line-transient response. reduce output noise and improve load-transient response, stability, and power-supply rejection by using large output capacitors. note that some ceramic dielectrics exhibit large capacitance and esr variation with temperature. with dielectrics such as z5u and y5v, it may be necessary to use a 2.2? or larger output capacitor to ensure stability at temperatures below -10?. with x7r or x5r dielectrics, 1? is sufficient at all operating temperatures. a graph of the region of stable c out esr vs. load current is shown in the typical operating characteristics . use a 0.01? bypass capacitor at bp (max8840) for low-output voltage noise. the leakage current going into the bp pin should be less than 10na. increasing the capacitance slightly decreases the output noise. values above 0.1? and below 0.001? are not recommended. noise, psrr, and transient response the max8840/max8841/max8842 are designed to deliver ultra-low noise and high psrr, as well as low dropout and low quiescent currents in battery-powered systems. the max8840 power-supply rejection is 78db at 1khz and 54db at 100khz. the max8841/max8842 psrr is 72db at 1khz and 46db at 100khz (see the power-supply rejection ratio vs. frequency graph in the typical operating characteristics). when operating from sources other than batteries, improved supply-noise rejection and transient response can be achieved by increasing the values of the input and output bypass capacitors, and through passive fil- tering techniques. the typical operating characteristics show the max8840/max8841/max8842 line- and load- transient responses. dropout voltage a regulator? minimum dropout voltage determines the lowest usable supply voltage. in battery-powered sys- tems, this determines the useful end-of-life battery volt- age. because the max8840/max8841/max8842 use a p-channel mosfet pass transistor, their dropout voltage is a function of drain-to-source on-resistance (r ds(on) ) multiplied by the load current (see the typical ope- rating characteristics ).
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn 8 _______________________________________________________________________________________ p out fb*** *max8840 only **max8840/max8841 only ***max8842 only ** ** bp* max8840 max8841 max8842 error amp in shdn gnd shutdown and power-on control thermal sensor mos driver with i limit 1.225v reference and noise bypass functional diagram
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn _______________________________________________________________________________________ 9 chip information transistor count: 284 process: bicmos max8841 output preset 1.5v to 4.5v in input 2v to 6v off shdn c out 1f c in 1f out on gnd typical operating circuits (continued) output voltage selector guide part v out (v) topmark max8840elt16+t 1.6 mn max8840elt18+t 1.8 mo max8840elt19+t 1.9 lx max8840elt25+t 2.5 mp max8840elt26+t 2.6 mk max8840elt27+t 2.7 lu max8840elt28+t 2.8 lv max8840elt29+t 2.85 lw max8840elt30+t 3 lz max8840elt31+t 3.1 ml max8840elt33+t 3.3 mm max8841elt15+t 1.5 mq max8841elt18+t 1.8 mr max8841elt25+t 2.5 ms max8841elt26+t 2.6 mt max8841elt28+t 2.8 mu max8841elt29+t 2.85 mv max8841elt89+t 2.9 mw max8841elt31+t 3.1 mx max8841elt33+t 3.3 my max8841elt45+t 4.5 mz max8842elt+t adjustable na max8842 output adjustable 1 5v to 4 5v in input 2v to 6v off shdn r1 r2 c out 1f c in 1f out on fb gnd ( note: standard output voltage options, shown in bold, are available. contact the factory for other output voltages between 1.5v and 4.5v. minimum order quantity is 15,000 units.)
max8840/max8841/max8842 ultra-low-noise, high psrr, low-dropout, 150ma linear regulators in dfn maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 10 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2006 maxim integrated products is a registered trademark of maxim integrated products, inc. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .) 6l udfn.eps -drawing not to scale- documen con ro no a rova i e rev package outline, 6l udfn, 1.5x1.0x0.8mm 21-0147 2 2 d 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 calendar year legend: marked with bar blank space - no bar required 06-11 payweek 12-17 18-23 24-29 30-35 36-41 42-47 48-51 52-05 table 2 translation table for payweek binary coding table 1 translation table for calendar year code legend: marked with bar blank space - no bar required
|
