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. general description the max8860 low-noise, low-dropout linear regulator operates from a 2.5v to 6.5v input and is guaranteed to deliver 300ma. typical output noise for this device is 60? rms , and typical dropout is 105mv at 200ma. in addition to the six available preset output voltages (1.8v, 2.5v, 2.77v, 2.82v, 3v, and 3.3v), the dual mode feature allows the device to be configured as an adjustable output regulator from 1.25v to 6.5v. designed with an internal p-channel mosfet pass tran- sistor, the max8860 has a low 120? supply current. an output fault-detection circuit indicates loss of regulation. other features include a 10na, logic-controlled shut- down mode, short-circuit and thermal-shutdown protec- tion, and reverse battery protection. the max8860 is available in a miniature 8-pin ?ax package. applications wireless handsets dsp core power pcmcia cards hand-held instruments palmtop computers electronic planners features high output current (300ma) low output voltage noise: 60v rms low 105mv dropout at 200ma output low 120a no-load supply current thermal overload and short-circuit protection reverse battery protection 10na logic-controlled shutdown fault indicator small, space-saving max package (1.1mm max height) small 2.2f output capacitor saves space and cost max8860 low-dropout, 300ma linear regulator in max ________________________________________________________________ maxim integrated products 1 1 2 3 4 8 7 6 5 fault shdn cc set out gnd in out max8860 max top view max8860 out out cc set fault gnd in shdn c1 2.2 f c2 2.2 f c3 33nf output up to 300ma input +2.5v to +6.5v fault- detect output r1 100k ? typical operating circuit 19-1422; rev 2; 1/01 max8860eua18 max8860eua28 -40? to +85? -40? to +85? 8 ?ax 8 ?ax pin configuration ordering information dual mode is a trademark of maxim integrated products. max8860eua33 -40? to +85? 8 ?ax part temp range pin- package +1.80 +2.82 +3.30 v out (v) +2.77 max8860eua27 -40? to +85? 8 ?ax +2.50 max8860eua25 -40? to +85? 8 ?ax max8860eua30 -40? to +85? +3.00 8 ?ax
max8860 low-dropout, 300ma linear regulator in max 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = 3.6v, c cc = 33nf, t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. in, shdn to gnd .......................................................-7v to +7v shdn to in ...............................................................-7v to +0.3v set, cc, fault to gnd ..........................................-0.3v to +7v out to gnd .............................................. -0.3v to (v in + 0.3v) fault sink current ...........................................................20ma continuous output current ..............................................330ma output short-circuit duration ....................................continuous continuous power dissipation (t a = +70?) 8-pin ?ax (derate 4.1mw/? above +70?) ............330mw thermal resistance ( ja ) 8-pin ?ax ............................................................+244?/w operating temperature range max8860eua_ _ ...........................................-40? to +85? junction temperature ......................................................+150? storage temperature range ............................-65? to +150? lead temperature (soldering, 10sec) ............................+300? i out = 100? to 300ma v in = 2.5v to 6.5v, set = out, i out = 1ma i out = 300ma i out = 200ma i out = 1ma dc average current rating v out = 0, shdn = gnd set = gnd conditions %/ma 0.0006 load regulation 0.0001 %/v -0.1 0.01 0.1 line regulation mv 155 dropout voltage (note 4) 105 220 0.6 ? 0.05 shutdown supply current 0.01 1 ? 165 supply current 120 270 3.24 3.3 3.35 v 2.5 6.5 input voltage (note 2) ma 330 770 output current limit ma 300 maximum output current 1.230 1.248 1.267 units min typ max parameter v 1.25 6.5 adjustable output voltage range (note 3) t a = +25? max8860eua33 t a = -40? to +85? 3.21 3.38 t a = +25? max8860eua30 t a = -40? to +85? 2.92 3.08 2.95 3.00 3.05 t a = +25? max8860eua28 t a = -40? to +85? 2.75 2.90 2.78 2.82 2.87 i out = 0 i out = 300ma t a = +25? t a = +85? set = out set = gnd set threshold voltage v set = out, v in = 2.5v to 6.5v, i out = 1ma 1.220 1.275 t a = +25? t a = -40? to +85? 100? < i out < 300ma, v in = v out 1v, set = gnd t a = +25? max8860eua25 t a = +25? max8860eua27 t a = -40? to +85? t a = -40? to +85? 2.70 2.84 2.43 2.57 2.73 2.77 2.81 2.46 2.50 2.54 t a = +25? v output voltage max8860eua18 t a = -40? to +85? 1.755 1.845 1.77 1.80 1.83
max8860 low-dropout, 300ma linear regulator in max _______________________________________________________________________________________ 3 electrical characteristics (continued) (v in = 3.6v, c cc = 33nf, t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) note 1: specifications to -40? are guaranteed by design and not production tested. note 2: guaranteed by line-regulation test. note 3: adjustable mode only. note 4: the dropout voltage is defined as v in - v out when v out is 100mv below the value of v out for v in = v out 2v. since the minimum input voltage is 2.5v, this is applicable only for voltages of 2.5v or higher. note 5: the fault detection voltage is the difference from input to output voltage. maintain the input above this level to ensure good line and load regulation. c out = 10?, v out to 90% of final value v in = 2.5v, i sink = 2ma shdn = gnd or in v set = 1.3v conditions ? 120 start-up time ? 20 thermal shutdown hysteresis ? 170 thermal shutdown temperature na 0.01 100 0.01 100 v 0.25 fault output low voltage na 0.5 shdn input bias current 0.01 2.5 na 0.5 set input leakage current (note 3) units min typ max parameter t a = +25? t a = +85? 60 65 t a = +25? t a = +85? set = gnd, i out = 200ma mv 130 280 fault detection voltage (note 5) typical operating characteristics (v in = v out + 0.5v, c in = c out = 2.2?, c cc = 33nf, t a = +25?, unless otherwise noted.) -0.4 -0.2 0 0.2 0.4 normalized output voltage vs. load current max8860 toc01 load current (ma) output voltage (%) 0 150 200 50 100 250 300 v out normalized at i out = 0 -0.3 -0.1 -0.2 0 0.2 0.1 0.3 normalized output voltage vs. temperature max8860 toc02 temperature ( c) output voltage (%) -40 20 40 -20 0 60 80 i out = 0 i out = 100ma i out = 200ma v out normalized at +25?, i out = 0 0 40 120 100 80 60 20 160 140 200 180 0 100 50 150 200 250 300 supply current vs. load current max8860 toc03 load current (ma) supply current ( a) t a = +85 c t a = +25 c t a = -40 c v fault = 3.6v 0.5 fault output off-leakage current t a = +25? t a = +85? v il , 2.5v v in 5.5v v ih , 2.5v v in 5.5v v 0.4 v 2.0 shdn input threshold c out = 2.2? c out = 10? i out = 10ma, 10hz < f < 100khz c out = 100? 10hz < f < 100khz, c out = 10? ? rms 190 55 output voltage noise nv hz output voltage noise density
max8860 low-dropout, 300ma linear regulator in max 4 _______________________________________________________________________________________ typical operating characteristics (continued) (v in = v out + 0.5v, c in = c out = 2.2?, c cc = 33nf, t a = +25?, unless otherwise noted.) 0 60 40 20 100 80 180 160 140 120 200 0123456 no load supply current vs. input voltage max8860 toc04 input voltage (v) supply current ( a) t a = +85 c t a = +25 c t a = -40 c 20 60 40 120 100 80 160 0 140 180 0 100 50 150 200 250 300 dropout voltage vs. load current max8860 toc05 load current (ma) dropout voltage (mv) t a = +85 c t a = +25 c t a = -40 c 0 50 150 100 200 250 0 100 50 150 200 250 300 fault detect threshold vs. load current max8860 toc06 load current (ma) fault detect threshold (mv) fault = high fault = low -70 -50 -60 -30 -40 -10 -20 0 0.01 1 0.1 10 100 1000 power-supply rejection ratio vs. frequency max8860 toc07 frequency (khz) psrr (db) 200ma i load 0 load-transient response max8860 toc10 400 s/div v out 20mv/div v in = v out + 200mv 0.1 10 1 100 1000 output noise spectral density max8860 toc08 frequency (khz) noise ( v/ hz) 0.01 0.1 1.0 10 c out = 2.2 f c out = 10 f i load = 10ma v out 500 v/div output noise (10hz to 1mhz) max8860 toc09 1ms/div i load = 200ma +4.3v line-transient response max8860 toc12 500 s/div v out 2mv/div v in +3.3v i load = 200ma
max8860 low-dropout, 300ma linear regulator in max _______________________________________________________________________________________ 5 typical operating characteristics (continued) (v in = v out + 0.5v, c in = c out = 2.2?, c cc = 33nf, t a = +25?, unless otherwise noted.) name function 1, 4 out regulator output. bypass with 2.2?, low-esr capacitor to gnd for stable operation. pin pin description 4v 2v 0 4v 3v 2v 1v 0 power-up response max8860 toc13 5ms/div fault v out v in 4v 2v 0 4v 3v 2v 1v 0 power-down response max8860 toc14 2ms/div v out v in fault 4v 2v 0 3v 2v 1v 0 shutdown/power-up max8860 toc15 400 s/div v out shdn 2 in supply input. connect to power source (2.5v to 6.5v). bypass with 2.2? capacitor to gnd. 3 gnd ground 5 set output voltage set. connect to gnd for internally set threshold. connect to resistor-divider for adjustable output voltages. see the output voltage selection section for more information. 6 cc compensation capacitor. connect a 0.033? capacitor from cc to gnd. 7 shdn shutdown input. connect to in for normal operation. drive shdn low to turn off the regulator. 8 fault fault output. a high-impedance, open-drain output. when the max8860 is out of regulation, fault goes low. in shutdown, the fault pin is high impedance. connect to gnd if unused. detailed description the max8860 is a low-dropout, low-quiescent-current linear regulator designed primarily for battery-powered applications. it supplies an adjustable 1.25v to 6.5v output voltage or a fixed-voltage output of 1.8v (max8860eua18), 2.5v (max8860eua25), 2.77v (max8860eua27), 2.82v (max8860eua28), 3.0v (max8860eua30), or 3.3v (max8860eua33) for load currents up to 300ma. the devices with 2.77v and 2.82v nominal outputs are designed to guarantee mini- mum output voltages of 2.70v and 2.75v, respectively. the device consists of a 1.25v reference, error amplifi- er, mosfet driver, p-channel pass transistor, dual mode comparator, fault detector, and internal-feedback voltage divider (figure 1). the 1.25v bandgap reference is connected to the error amplifier? inverting input. the error amplifier compares this reference to the selected feedback voltage and amplifies the difference. the mosfet driver reads the error signal and applies the appropriate drive to the p- channel pass transistor. if the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled lower, allowing more current to pass and increasing the output voltage. if the feedback voltage is higher than the reference voltage, the pass-transistor gate is driven higher, allowing less current to pass to the output. the output voltage is fed back through either an internal resistor voltage divider connected to out, or an external resistor network connected to set. the dual mode comparator examines v set and selects the feedback path. if v set is below 60mv, internal feedback is used and the output voltage is regulated to the preset output voltage. additional blocks include an output current limiter, reverse battery protection, a ther- mal sensor, a fault detector, and shutdown logic.
max8860 low-dropout, 300ma linear regulator in max 6 _______________________________________________________________________________________ internal p-channel pass transistor the max8860 features a 0.5 ? typical p-channel mosfet pass transistor. this provides several advan- tages over similar designs using pnp pass transistors, including longer battery life. pnp-based regulators waste considerable amounts of current in dropout when the pass transistor saturates. they also use high base- drive currents under large loads. the p-channel mosfet requires no base-drive current, which reduces quiescent current considerably. the max8860 con- sumes less than 165? of quiescent current whether in dropout, light-load, or heavy-load applications (see the typical operating characteristics ). output voltage selection the max8860 features dual mode operation: it operates in either a preset voltage mode or an adjustable mode. in preset voltage mode, internal, trimmed feedback resistors set the output voltage to an adjustable 1.25v to 6.5v output voltage or a fixed-voltage output of 1.8v (max8860eua18), 2.5v (max8860eua25), 2.77v (max8860eua27), 2.82v (max8860eua28), 3v (max8860eua30), or 3.3v (max8860eua33). select this mode by connecting set to ground. in adjustable mode, select an output between 1.25v and 6.5v using two external resistors connected as a voltage divider to set (figure 2). calculate the output voltage with the fol- lowing equation: where v set = 1.25v. to simplify resistor selection, use the following equation: r1 r2 v v 1 out set =? ? ? ? ? ? ? vv r r out set =+ ? ? ? ? ? ? 1 1 2 shutdown logic error amp 1.25v ref p out cc set fault dual-mode comparator 60mv gnd in shdn max8860 thermal sensor fault detect reverse battery protection mos driver with i limit figure 1. functional diagram figure 2. adjustable output using external feedback resistors max8860 out set fault gnd in shdn cc c out 2.2 f c in 2.2 f 33nf battery output voltage r1 r2 100k ?
max8860 low-dropout, 300ma linear regulator in max _______________________________________________________________________________________ 7 choose r2 = 100k ? to optimize power consumption, accuracy, and high-frequency power-supply rejection. ensure that the total current through the external resis- tive feedback and load resistors is not less than 10?. since the v set tolerance is typically less than ?0mv, set the output using fixed resistors instead of trim pots. in preset voltage mode, connect set to gnd. keep impedances between set and ground to less than 100k ? . otherwise, spurious conditions can cause v set to exceed the 60mv dual mode threshold. shutdown drive shdn low to place the max8860 in shutdown mode. in shutdown mode, the pass transistor, control circuit, reference, and all biases are turned off, reduc- ing the supply current to typically 10na. connect shdn to in for normal operation. current limit the max8860 includes short-circuit protection. it includes a current limiter that controls the pass transistor? gate voltage to limit the output current to about 770ma. for design purposes, the minimum current limit is 330ma. thermal overload protection thermal overload protection limits total power dissipa- tion in the max8860. when the junction temperature (t j ) exceeds +170?, the thermal sensor sends a sig- nal to the shutdown logic, turning off the pass transistor and allowing the ic to cool. the pass transistor turns on again after the ic? junction temperature typically cools by 20?, resulting in a pulsed output during continuous thermal overload conditions. thermal overload protection is designed to protect the max8860 against fault conditions. stressing the device with high-load currents and high input-output differen- tial voltages (which result in die temperatures above +125?) may cause a momentary overshoot (2% to 8% for 200ms) when the load is completely removed. remedy this by raising the minimum load current from 0 (+125?) to 100? (+150?). this is accomplished with an external load resistor. for continuous operation, do not exceed the absolute maximum junction tempera- ture rating of +150?. operating region and power dissipation maximum power dissipation of the max8860 depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. the power dis- sipated by the device is: p = i out (v in - v out ) the maximum power dissipation is: p max = (t jmax - t a ) / ja where: t jmax = +150? t a is the ambient temperature ja = 244?/w the max8860? pins perform the dual function of provid- ing an electrical connection as well as channeling heat away from the die. use wide circuit-board traces and large, solid copper polygons to improve power dissipa- tion. using multiple vias to buried ground planes further enhances thermal conductivity. reverse battery protection the max8860 has a unique protection scheme that lim- its the reverse supply current to less than 1ma when either v in or v shdn falls below gnd. the circuitry monitors the polarity of these two pins, disconnecting the internal circuitry and parasitic diodes when the applied voltage is reversed. this feature prevents the device from overheating and damaging an improperly installed battery. integrator circuitry the max8860 uses an external 33nf compensation capacitor for minimizing load- and line-regulation errors and for lowering output noise. when the output voltage shifts due to varying load current or input voltage, the integrator capacitor voltage is raised or lowered to compensate for the systematic offset at the error ampli- fier. compensation is limited to ?% to minimize tran- sient overshoot when the device goes out of dropout, current limit, or thermal shutdown. fault-detection circuitry when the output voltage goes out of regulation?uch as during dropout, current limit, or thermal shutdown fault goes low. in addition, the fault-detection circuitry detects when the input-to-output voltage differential is insufficient to ensure good load and line regulation at the output. when the input-to-output voltage differential is less than 130mv for a load current of 200ma, fault also goes low. the differential threshold is designed to be always higher than and track with the dropout volt- age, and to scale proportionally with load current (see fault detect threshold vs. load current graph in the typical operating characteristics ). the fault pin is an open-drain n-channel mosfet. to create a voltage level output, connect a pull-up resistor from fault to out. to minimize current consumption, make this resistor as large as practical. a 100k ? resistor works well for most applications.
max8860 low-dropout, 300ma linear regulator in max maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2001 maxim integrated products printed usa is a registered trademark of maxim integrated products. v in > +5.5v minimum load current requirements when operating the max8860 with an input voltage above 5.5v, a minimum load current of 50? is required to maintain regulation in preset voltage mode. when setting the output with external resistors, ensure that the minimum current through the external feedback resis- tors and load is at least 60?. this applies only when the input voltage exceeds 5.5v. for input voltages less than 5.5v, the max8860 maintains regulation and sta- bility without external loading. applications information capacitor selection and regulator stability typically, use a 2.2? capacitor on the input and a 2.2? capacitor on the output of the max8860. capacitor type is not critical, as long as it has an esr less than 0.5 ? . larger capacitor values and lower esr provide better supply-noise rejection and transient response. use higher-value capacitors (10?) if large, fast input or load transients are anticipated or if the device is located several inches from the power source. for stable operation over the full temperature range, with load currents up to 300ma, a minimum output- capacitor value of 2.2? is recommended. there is no upper limit to capacitor size. the circuit used to gener- ate the typical operating characteristics data used 2.2?, x7r, 16v (1206) ceramic capacitors. these capacitors typically have an esr of 50m ? . power-supply rejection and operation from sources other than batteries the max8860 is designed to deliver low dropout volt- age and low quiescent current in battery-powered sys- tems. power-supply rejection is 67db at low frequencies and rolls off above 100khz. at high frequencies, the out- put capacitor is the major contributor to the rejection of power-supply noise (see the power-supply rejection ratio vs. frequency graph in the typical operating characteristics ). when operating from sources other than batteries, improve supply-noise rejection and transient response by increasing the values of the input and output capaci- tors, and by using passive filtering techniques (see the supply and load-transient responses in the typical operating characteristics ). load-transient considerations the max8860 load-transient response graph (see the typical operating characteristics ) shows the output response due to changing load current. reduce over- shoot by increasing the output capacitor? value and decreasing its esr. input-output (dropout) voltage a regulator? minimum input-output voltage differential (or dropout voltage) determines the lowest usable sup- ply voltage. in battery-powered systems, this deter- mines the useful end-of-life battery voltage. because the max8860 uses a p-channel mosfet pass transis- tor, its dropout voltage is a function of r ds(on) (typical- ly 0.5 ? ) multiplied by the load current (see the electrical characteristics table). chip information transistor count: 148
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