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_______________general description the max1658/max1659 linear regulators maximize bat- tery life by combining ultra-low supply currents and low dropout voltages. they feature dual mode operation, which presets the output to 3.3v (max1658) or 5v (max1659), or permits it to be adjusted between 1.25v and 16v. the regulator supplies up to 350ma, with a typical dropout of 650mv for the max1658 and 490mv for the max1659. with their p-channel mosfet pass transistor, these devices maintain a low quiescent cur- rent from zero output current to the full 350ma, even in dropout. they support input voltages ranging from 2.7v to 16.5v. the max1658/max1659 feature a 1? shutdown mode, reverse battery protection, short-circuit protection, and thermal shutdown. they are available in a special high- power (1.2w), 8-pin so package designed specifically for compact applications. ________________________applications digital cordless phones pcs phones cellular phones pcmcia cards modems hand-held instruments palmtop computers electronic planners ____________________________features ? wide input voltage range: 2.7v to 16.5v ? low, 490mv dropout at 350ma output current (max1659) ? 30? supply current ? 1? max shutdown current ? high-power (1.2w) 8-pin so package ? dual mode operation output: fixed 3.3v (max1658) fixed 5.0v (max1659) or adjustable (1.25v to 16v) ? thermal overload protection ? current-limit protection ? reverse battery protection max1658/max1659 350ma, 16.5v input, low-dropout linear regulators ________________________________________________________________ maxim integrated products 1 in out out 1 2 8 7 gnd in shdn in set so top view 3 4 6 5 max1658 max1659 __________________pin configuration max1658 max1659 in shdn off on input up to 16.5v output 3.3v or 5v, or adj. (down to 1.25v); up to 350ma gnd set out __________typical operating circuit 19-1263; rev 0; 7/97 part max1658 c/d max1659 c/d 0? to +70? 0? to +70? temp. range pin-package dice* dice* ______________ordering information dual mode is a trademark of maxim integrated products. max1658esa -40? to +85? 8 so max1659esa -40? to +85? 8 so * dice are tested at t a = +25?, dc parameters only. for free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. for small orders, phone 408-737-7600 ext. 3468.
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = 5v (max1658), v in = 6v (max1659); c out = 10 f; shdn = in; t a = t min to t max ; unless otherwise noted. typical values are at t a = +25 c.) (note 2) 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 to gnd ................................................................ -17v to +17v continuous output current ............................................... 500ma output short-circuit duration ............................................ infinite set, shdn to gnd ................................................. -17v to +17v out to gnd ................................................ -0.3v to (vin + 0.3v) continuous power dissipation (note 1) so (derate 14.5mw/ c above +70 c) ............................. 1.2w operating temperature range max1658esa/max1659esa ............................ -40 c to +85 c junction temperature ...................................................... +150 c storage temperature range ............................. -65 c to +160 c lead temperature range (soldering, 10sec) .................. +300 c set = gnd, 0ma < i load < 350ma v out = 5.0v shdn 0.4v set = out shdn = gnd or shdn = in 2.7v v in 16.5v 2.7v v in 16.5v max1658, v in = 5v to 16.5v i out = 350ma 10hz to 100khz (note 3) i out = 0ma to 350ma conditions s 120 t start shutdown exit time a 0.1 1 i q shdn shutdown supply current a 0.1 i shdn shutdown input bias current v 2.0 v inh shd n logic-high input threshold v 0.4 v inl shdn logic-low input mvp-p 2.5 e n output noise %v out 0 v osh startup overshoot %/ma 0.003 ? v ldr load regulation v 4.85 5.00 5.15 3.20 3.30 3.40 v out v 2.7 16.5 v in input voltage range output voltage 0.03 mv 490 875 ? v do dropout voltage (note 4) 650 1500 2 v 1.25 16 regulated output voltage range ma 350 i out(max) maximum output current ma 900 i lim current limit a 30 60 i q supply current units min typ max symbol parameter max1659, v in = 6v to 16.5v %/v 0.05 ? v lnr line regulation max1658, 5v v in 16.5v max1659, 6v v in 16.5v i out = 1ma max1658 max1659 shutdown note 1: see operating region and power dissipation section.
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators _______________________________________________________________________________________ 3 electrical characteristics (continued) (v in = 5v (max1658), v in = 6v (max1659); c out = 10 f; shdn = in; t a = t min to t max ; unless otherwise noted. typical values are at t a = +25 c.) (note 2) note 2: specifications to -40 c are guaranteed by design, not production tested. note 3: adjustable configuration only. v in = 16.5v. 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. t a = +85 c (note 3) t a = +25 c (note 3) i out = 10 a (note 3) conditions a 0.1 i set set input leakage current 0.01 0.025 v 1.174 1.210 1.246 v set set reference voltage units min typ max symbol parameter c 165 t sd thermal shutdown temperature c 10 ? t sd thermal shutdown hysteresis __________________________________________ t ypical operating characteristics (v in = 5v (max1658), v in = 6v (max1659); shdn = in; set = gnd; c in = 0.1 f; c out = 10 f tantalum; t a = +25 c; unless otherwise noted.) -10 -90 10 1000 10k 100 100k max1658 power-supply rejection ratio vs. frequency -70 -80 max1658 toc01 frequency (hz) psrr (db) -60 -40 -50 -30 -20 v in = 5.2v to 5.4v v out = 3.3v -8 -72 10 1000 10k 100 100k max1659 power-supply rejection ratio vs. frequency -56 -64 max1658 toc03 frequency (hz) pssr (db) -48 -32 -40 -24 -16 v in = 6.15v to 6.4v v out = 5v set input thermal protection
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators 4 _______________________________________________________________________________________ ____________________________ t ypical operating characteristics (continued) (v in = 5v (max1658), v in = 6v (max1659); shdn = in; set = gnd; c in = 0.1 f; c out = 10 f tantalum; t a = +25 c; unless otherwise noted.) 0.990 0.994 0.992 0.996 0.998 1.000 0 100 200 300 400 normalized output voltage vs. load current max1658/59 toc05 output current (ma) output voltage v nominal /v out (v) 3.3v output 5v output 0 20 40 60 80 0 3 6 9 15 12 18 max1658 supply current vs. input voltage max1658/59 toc06 input voltage (v) supply current ( m a) i l = 100ma i l = 0ma v out = 3.3v 0 500 1000 1500 2000 0 3 6 9 12 15 dropout voltage vs. output voltage max1658/59 toc07 output voltage (v) dropout voltage (mv) i l = 350ma b a max1659 line-transient response max1658/59toc10 a: input voltage (1v/div), v in = 7v (high), v in = 6v (low) b: output voltage (100mv/div) 100 m s/div v out = 5.0v 0 200 400 600 100 300 500 700 800 0 100 200 300 400 dropout voltage vs. load current max1658/59 toc08 load current (ma) dropout voltage (mv) v out = 5.0v v out = 3.3v 0 40 80 100 20 60 120 140 0 100 200 300 400 50 150 250 350 quiescent current vs. load current max1658/59 toc09 load current (ma) quiescent current ( m a) b a 100 m s/div max1658 line-transient response max1658/59toc11 a: input voltage (1v/div), v in = 6v (high), v in = 5v (low) b: output voltage (100mv/div) v out = 3.3v b a v out = 5v max1659 load-transient response max1658/59toc12 a: output voltage (100mv/div) b: i out = 300ma (high), i out = 40ma (low) 200 m s/div b a v out = 3.3v max1658 load-transient response max1658/59toc13 a: output voltage (100mv/div) b: i out = 300ma (high), i out = 40ma (low) 200 m s/div
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators _______________________________________________________________________________________ 5 ____________________________ t ypical operating characteristics (continued) (v in = 5v (max1658), v in = 6v (max1659); shdn = in; set = gnd; c in = 0.1 f; c out = 10 f tantalum; t a = +25 c; unless otherwise noted.) b a 0v 3.3v 100 m s/div max1658 overshoot and time exiting shutdown max1658/59toc14 a: output voltage (1v/div) b: shdn pin voltage (2v/div) b a 0v 5v 100 m s/div max1659 overshoot and time exiting shutdown max1658/59toc15 a: output voltage (2v/div) b: shdn pin voltage (2v/div) 10ms/div 10hz to 100khz noise, v out = 5v (1mv/div), i out = 165ma output noise ______________________________________________________________ pin description ground gnd 8 regulated output voltage. fixed or adjustable from 1.25v to 16v. sources up to 350ma. for stable opera - tion, bypass with a 10 f, low-esr (<0.2 ) capacitor from out to gnd. for improved load-transient response, use a larger low-esr capacitor. out 4, 5 unregulated input supply voltage, 2.7v to 16.5v input range. the in pins also serve as heatsinks. connect to a copper plane to achieve maximum thermal dissipation. in 3, 6, 7 pin shutdown input. when shdn is low, the device turns off and typically draws 0.1 a of supply current. shdn 2 output voltage input. connecting set to ground selects the factory-preset 3.3v (max1658) or 5v (max1659) output voltage. for an adjustable output voltage, connect set to a resistive voltage divider from out to gnd. set 1 function name 10 4 10 3 10 2 10 10 50k output noise density vs. frequency max1658 toc02 frequency (hz) output noise density (nv rms / ? hz) v out = 5v i out = 165ma
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators 6 _______________________________________________________________________________________ max1658 max1659 p p out set in shdn mosfet driver with current limit r2 r1 65mv gnd dual-mode comparator 1.21v reference thermal sensor error amplifier figure 1. functional diagram _______________ detailed description the max1658/max1659 are micropower, low-dropout linear regulators featuring dual mode operation, which allows them to deliver an adjustable (1.25v to 16.5v) or preset (3.3v for the max1658, 5v for max1659) output. they supply up to 350ma while requiring only 120 a of supply current (typically 30 a with no load). the devices include thermal shutdown circuitry, output current limiting, a p-channel pass tran - sistor, a dual mode comparator, and a feedback volt - age divider. figure 1 shows the functional diagram. the 1.21v reference is connected to the amplifier? inverting input. the error amplifier compares this refer - ence with the selected feedback voltage and amplifies the difference. the error signal applies the drive to the p-channel pass transistor. if the feedback voltage is lower than the reference voltage, the transistor? gate is pulled lower, increasing output current. the output voltage is fed back through an internal resistor network or an external user-selected network. the dual mode comparator examines the voltage at the set pin and selects either the internal or external feed - back path. if set is below 65mv, internal feedback sets the max1658? output voltage to 3.3v and the max1659? to 5v. otherwise, external feedback is used for an adjustable output between 1.25v and 16.5v. additional features include internal current limiting, reverse battery protection, thermal-overload protection, and a 1 a shutdown mode.
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators _______________________________________________________________________________________ 7 p-channel pass transistor the max1658/max1659 feature an internal p-channel mosfet pass transistor. using a mosfet provides several advantages over similar pnp designs, including lower dropout voltage and extended battery life. unlike bipolar transistors, mosfets reduce quiescent current, because they require no base current, particularly at heavy loads and in dropout. as a result, the max1658/max1659 operate at a low quiescent current even in dropout. output voltage selection dual mode operation allows the max1658/max1659 to operate at either a preset or a user-adjustable output voltage. the device compares the set pin voltage with an internal 65mv reference. if the voltage is lower than 65mv (typically achieved by grounding set), the device switches to an internal resistor-divider feedback network that sets the output voltage. the max1658? preset output voltage is 3.3v and the max1659? is 5v (figure 2). if the set pin is not below 65mv, the device switches to external feedback and set becomes a feedback input. the feedback network can be configured to produce an output between 16v and the voltage reference (nominally 1.21v). under regulation, the feedback mechanism adjusts the error signal such that the volt - age at the set pin equals the reference voltage. therefore, to achieve the minimum output, connect set directly to out. for other voltages, a resistive voltage- divider network is necessary. figure 3 shows the topol - ogy of a typical circuit operating in adjustable mode. the output voltage is set by the following equation: where v set = 1.21v. solving for r1 yields: the input leakage current of the set input is less than 25na. this allows the use of large resistors in the feed - back network to minimize output current loss without compromising accuracy. r2 can be as high as 500k in most applications. shutdown a logic low on the shdn pin places the max1658/ max1659 in shutdown. this mode deactivates all func - tions, including the pass transistor. the device con - sumes less than 1 a of supply current in shutdown, and its output becomes high impedance. the max1658/max1659 exit shutdown in 100 s. output current limit the max1658/max1659 include current-limiting circuit - ry that monitors and controls the pass transistor and limits output current to around 900ma. the output can be shorted to ground indefinitely without damaging the device. r1 = r2 v v 1 out set - ? ? ? ? v v r r out set = + ? ? ? ? 1 1 2 max1658 (max1659) shdn 2 4, 5 8 1 3, 6, 7 in input voltage on off output voltage 3.3v/350ma (5v/350ma) 10 m f 0.1 m f gnd set out figure 2. preset output configuration max1658 max1659 in 3, 6, 7 4, 5 1 8 2 shdn output voltage c out 10 m f r1 r2 0.1 m f input voltage gnd out set v out = v set ( 1 + r1 ) r2 v set = 1.21v figure 3. adjustable output configuration using external feedback resistors
thermal-overload protection thermal-overload protection limits total power dissipa - tion in the max1658/max1659. when the junction tem - perature exceeds t j = +165 c, the pass transistor deactivates, allowing the ic to cool. once it has cooled by 10 c, the control logic will enable operation. under thermal overload, the output of the device will pulse as the die heats up and then cools to operational levels. prolonged operation under these conditions is not rec - ommended. operating region and power dissipation maximum power dissipation of the max1658/max1659 depends on the thermal resistance of the package and circuit board, the temperature difference between the die and ambient air, and the rate of air flow. the power dissipation by the device is p = i out (v in - v out ). the maximum power dissipation is: where (t j - t a ) is the temperature difference between max1658/max1659 die junction and the surrounding air, q jb is the thermal resistance of the package, and q ba is the thermal resistance through the printed circuit board, copper traces, and other materials to the surrounding air. the 8-pin so package for the max1658/max1659 features a special lead frame with a lower thermal resistance and higher allowable power dissipation than a standard so-8. the thermal resis - tance of this package is q jb = 69 c/w, compared with q jb = 170 c/w for an so-8. the in pins of the max1658/max1659 package per - form the dual function of providing an electrical con - nection to in and channeling heat away. connect all in pins to the input voltage using a large pad or power plane on the surface. where this is impossible, connect to a copper plane on an adjacent layer. the pad should meet the dimensions specified in figure 4. figure 4 assumes the ic is soldered directly to the pad, has a +125 c maximum junction temperature and a +25 c ambient air temperature, and has no other heat sources. use larger pad sizes for lower junction tem - peratures, higher ambient temperatures, or conditions where the ic is not soldered directly to a heat-sinking in pad. the max1658/max1659 can regulate currents up to 350ma and operate with input voltages up to 16.5v, but not simultaneously. high output currents can only be sustained when input-output differential voltage is low, as shown in the following equation. maximum power dissipation depends on packaging, board layout, tem - perature, and air flow. the maximum output current is: where p max is derived from the t j = 125 c curve of figure 4. reverse battery protection the max1658/max1659 feature reverse battery protec - tion. under normal operation, a p-channel mosfet connects the substrate of the device to in. when the input voltage falls below ground (implying reverse bat - tery conditions), the p-channel switch turns off and dis - connects the substrate from in, disabling the device. the maximum reverse battery voltage allowed is -17v. shdn also withstands reverse battery conditions and can be connected directly to in with no loss of protec - tion. polarized input bypass capacitors will be damaged under reverse battery conditions. to ensure circuit reli - ability, use a non-polarized capacitor at the input. the max1658/max1659 do not provide reverse current protection. if v out is greater than v in by more than 300mv, reverse current will flow. reverse current pro - tection can be added by connecting a schottky diode in series with in. i p x c t v v x c out max max a in out ( ) = - ( ) - ( ) 125 100 p t t max j a jb ba = - ( ) + ( ) ? ? ? ? ? q q max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators 8 _______________________________________________________________________________________ 1600 1400 1200 1000 800 600 400 0.1 0.65 1 6.5 copper ground pad area 10 (in 2 ) 65 (cm 2 ) power dissipation (mw) t j = +125? t j = +85? single-sided 1oz. copper t a = +25?, still air figure 4. typical maximum power dissipation vs. ground pad area
__________ applications infor mation output capacitor selection and stability to maintain stability, connect a 3 10 f capacitor with less than 200m equivalent series resistance (esr) from out to gnd. larger output capacitors improve load-transient response. currents lower than 350ma make the use of smaller output capacitors possible. table 1 shows the maximum output current typically achieved using various output capacitors. output volt - ages higher than 3.3v require less output capacitance to remain stable. table 1. typical load current capabilities input bypass capacitor the use of a 0.1 f to 10 f input bypass capacitor is recommended. larger capacitors provide better sup - ply-noise rejection and line-transient response, as well as improved performance when the supply has a high ac impedance. polarized input bypass capacitors will be damaged under reverse battery conditions. if reverse input voltages are expected, use a non-polar - ized capacitor at the input. noise and psrr the max1658/max1659 exhibit 2.5mvp-p of noise dur - ing normal operation. this noise level is negligible in most applications. the max1658/max1659 are designed to maintain excellent power-supply rejection (55db) at 50hz/60hz (or 50db at 120hz). these regulators are ideal for wall- cube applications that may contain significant ripple. larger input and output capacitors will further improve the circuit? ac response. see the power-supply rejection ratio vs. frequency graphs in the typical operating characteristics. max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators _______________________________________________________________________________________ 9 output capacitor 0ma to 120ma 2.2 f tantalum load current range 0ma to 250ma 4.7 f tantalum 0ma to 350ma 10 f tantalum ___________________ chip infor mation transistor count: 207
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators 10 ______________________________________________________________________________________ ________________________________________________________ package infor mation soicn.eps
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators ______________________________________________________________________________________ 11 notes
max1658/max1659 350ma, 16.5v input, low-dr opout linear regulators notes 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. 12 ____________________ maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 1997 maxim integrated products printed usa is a registered trademark of maxim integrated products.

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