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general description the max1836/max1837 high-efficiency step-down converters provide a preset 3.3v or 5v output voltage from supply voltages as high as 24v. using external feedback resistors, the output voltage may be adjusted from 1.25v to v in . an internal current-limited switching mosfet delivers load currents up to 125ma (max1836) or 250ma (max1837). the unique current-limited control scheme, operating with duty cycles up to 100%, minimizes the dropout voltage (120mv at 100ma). additionally, this control scheme reduces supply current under light loads to 12?. high switching frequencies allow the use of tiny surface-mount inductors and output capacitors. the max1836/max1837 step-down converters with internal switching mosfets are available in 6-pin sot23 and 3mm x 3mm tdfn packages, making them ideal for low-cost, low-power, space-sensitive applica- tions. for increased output drive capability, use the max1776 step-down converter that uses an internal 24v switch to deliver up to 500ma. for even higher cur- rents, use the max1626/ max1627 step-down con- trollers that drive an external p-channel mosfet to deliver up to 20w. applications 9v battery systems notebook computers distributed power systems backup supplies 4ma to 20ma loop power supplies industrial control supplies handheld devices ____________________________features ? 4.5v to 24v input voltage range ? preset 3.3v or 5v output ? adjustable output from 1.25v to v in ? output currents up to 125ma (max1836) or 250ma (max1837) ? efficiency over 90% ? 12? quiescent current ? 3? shutdown current ? 100% maximum duty cycle for low dropout ? small 6-pin sot23 and tdfn packages max1836/max1837 24v internal switch, 100% duty cycle, step-down converters ________________________________________________________________ maxim integrated products 1 19-1919; rev 3; 7/06 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. max1836 max1837 in gnd lx shdn fb out note: high-current paths shown with bold lines. output 3.3v or 5v input 4.5v to 24v typical operating circuit gnd lx in 16 out 5 shdn fb max1836 max1837 max1836 max1837 sot23 tdfn top view 2 3 gnd in 1 fb 2 3 4 lx 6 out 5 shdn 4 pin configurations part temp range pin- package top mark max1836 ett33-t -40 c to +85 c 6 tdfn-ep* ajg max1836ett50-t -40 c to +85 c 6 tdfn-ep* aje max1836eut33-t -40 c to +85 c 6 sot23-6 aany max1836eut50-t -40 c to +85 c 6 sot23-6 aanw max1837 ett33-t -40 c to +85 c 6 tdfn-ep* ajh MAX1837ETT50-T -40 c to +85 c 6 tdfn-ep* ajf max1837eut33-t -40 c to +85 c 6 sot23-6 aanz max1837eut50-t -40 c to +85 c 6 sot23-6 aanx ordering information selector guide appears at end of data sheet. * ep = exposed pad.
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 2 _______________________________________________________________________________________ absolute maximum ratings 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 ...................................................-0.3v to +25v lx to gnd.......................................................-2v to (v in + 0.3v) out, fb to gnd.......................................................-0.3v to +6v continuous power dissipation (t a = +70?) (note 1) 6-pin sot23 (derate 8.7mw/? above +70?)............696mw 6-pin tdfn (derate 24.4mw/? above +70?) .........1951mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? note 1: thermal properties are specified with product mounted on pc board with 1in 2 of copper area and still air. parameter symbol conditions min typ max units input supply range v in 4.5 24 v v in rising 3.55 4.0 4.4 input undervoltage lockout threshold v uvlo v in falling 3.45 3.9 4.3 v input supply current i in 12 25 ? input supply current in dropout i in ( d rop ) v in = 5v 18 ? input shutdown current shdn = gnd 3 7 ? max183_eut50, max183_ett50 4.80 5.00 5.20 output voltage (preset mode) v out fb = gnd, i load = 0 to 125ma (max1836) or 250ma (max1837) max183_eut33, max183_ett33 3.168 3.30 3.432 v output voltage range (adjustable mode) v out (note 2) 1.25 v in v feedback set voltage (adjustable mode) v fb 1.200 1.25 1.300 v out bias current v out = 5v 2.5 7.4 ? fb bias current i fb v fb = 0 or 1.25v, t a = +25? -25 +25 na fb dual mode tm threshold v fb rising or falling 50 100 150 mv lx switch minimum off-time t off ( m in ) 0.2 0.4 0.6 ? lx switch maximum on-time t on ( m ax ) v fb = 1.3v 7 10 13 s lx switch on-resistance r lx v in = 6v 1.1 2 ? max1836 250 312 450 lx current limit i lim max1837 500 625 850 ma lx zero-crossing threshold -75 +75 mv electrical characteristics (circuits of figures 1 (max1836) and 2 (max1837), v in = 12v, shdn = in, t a = 0? to +85? . typical values are at t a = +25?, unless otherwise noted.) dual mode is a trademark of maxim integrated products, inc.
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters _______________________________________________________________________________________ 3 parameter symbol conditions min typ max units zero-crossing timeout lx does not rise above the threshold 30 s lx switch leakage current v in = 18v, lx = gnd, t a = +25 c1a dropout voltage v dropout i out = 100ma, v in = 5v 120 mv line regulation v in = 5v to 24v 0.05 % load regulation i out = 0 to 125ma (max1836) or 250ma (max1837) 0.3 % shutdown input threshold v shdn v in = 4.5v to 24v (note 3) 0.8 2.4 v shutdown leakage current i shdn v shdn = 0 or 24v -1 +1 ? thermal shutdown 10 c hysteresis (typ) 160 c electrical characteristics (continued) (circuits of figures 1 (max1836) and 2 (max1837), v in = 12v, shdn = in, t a = 0? to +85? . typical values are at t a = +25?, unless otherwise noted.) parameter symbol conditions min typ max units input supply range v in 4.5 24 v v in rising 3.55 4.4 input undervoltage lockout threshold v uvlo v in falling 3.45 4.3 v input supply current i in 25 ? input shutdown current shdn = gnd 7 a max183_eut50, max183_ett50 4.80 5.20 output voltage (preset mode) v out fb = gnd, i load = 0 to 125ma (max1836) or 250ma (max1837) max183_eut33, max183_ett33 3.168 3.432 v output voltage range (adjustable mode) v out (note 2) 1.25 v in v feedback set voltage (adjustable mode) v fb 1.200 1.300 v out bias current v out = 5v 7.4 ? fb dual mode threshold v fb rising or falling 50 150 mv lx switch minimum off-time t off ( m in ) 0.2 0.6 ? lx switch maximum on-time t on ( m ax ) v fb = 1.3v 7 13 s lx switch on-resistance r lx v in = 6v 2 ? max1836 250 450 lx current limit i lim max1837 500 900 ma electrical characteristics (circuits of figures 1 (max1836) and 2 (max1837), v in = 12v, shdn = in, t a = -40? to +85? , unless otherwise noted.) (note 4)
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 4 _______________________________________________________________________________________ typical operating characteristics (circuits of figures 1 (max1836) and 2 (max1837), v in = 12v, shdn = in, t a = +25?.) 3.27 3.29 3.28 3.31 3.30 3.32 3.33 0 100 50 150 200 max1836eut33 output voltage vs. load current max1836/7 toc01 load current (ma) output voltage (v) v in = 5v v in = 9v to 12v figure 1 100 95 90 85 80 70 0.1 10 100 1 1000 max1836eut33 efficiency vs. load current max1836/7 toc02 load current (ma) efficiency (%) 75 v in = 9v v in = 12v v in = 5v figure 1 v out = 3.3v 3.27 3.29 3.28 3.31 3.30 3.32 3.33 0 150 200 50 100 250 300 350 max1837eut33 output voltage vs. load current max1836/7 toc03 load current (ma) output voltage (v) v in = 9v v in = 5v v in = 12v figure 2 100 95 90 85 80 70 0.1 10 100 1 1000 max1837eut33 efficiency vs. load current max1836/7 toc04 load current (ma) efficiency (%) 75 v in = 9v v in = 12v v in = 5v figure 2 v out = 3.3v 0 40 20 100 80 60 160 140 120 180 0 100 150 50 200 250 300 350 max1837eut33 switching frequency vs. load current max1836/7 toc05 load current (ma) frequency (khz) v in = 9v v in = 5v v in = 12v figure 2 v out = 3.3v 3.27 3.29 3.28 3.31 3.30 3.32 3.33 0 4 8 12162024 max1837eut33 output voltage vs. input voltage max1836/7 toc06 input voltage (v) output voltage (v) i out = 10ma i out = 200ma figure 2 v out = 3.3v l1 = 47 h note 2: when using the shutdown input, the maximum output voltage allowed with external feedback is 5.5v. if the output voltage is set above 5.5v, connect shutdown to the input. note 3: shutdown input minimum slew rate (rising or falling) is 10v/ms. note 4: specifications to -40? are guaranteed by design, not production tested. parameter symbol conditions min typ max units lx zero-crossing threshold -75 +75 mv shutdown input threshold v shdn v in = 4.5v to 24v (note 3) 0.8 2.4 v shutdown leakage current i shdn v shdn = 0 or 24v -1 +1 ? electrical characteristics (continued) (circuits of figures 1 (max1836) and 2 (max1837), v in = 12v, shdn = in, t a = -40? to +85? , unless otherwise noted.) (note 4)
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters _______________________________________________________________________________________ 5 70 80 75 90 85 95 100 0 4 8 12162024 max1837eut33 efficiency vs. input voltage max1836/7 toc07 input voltage (v) efficiency (%) i out = 10ma i out = 200ma figure 2 v out = 3.3v l1 = 47 h 100 1 0812 10 input voltage (v) frequency (khz) 4 max1837eut33 switching frequency vs. input voltage 16 24 20 max1836/7 toc08 i out = 200ma i out = 10ma figure 2 v out = 3.3v l1 = 47 h 0 200 600 400 800 1000 0 4 8 12162024 max1837eut33 peak inductor current vs. input voltage max1836/7 toc09 input voltage (v) peak inductor current (ma) i out = 10ma i out = 200ma figure 2 v out = 3.3v l1 = 47 h limited by t on(min) limited by i lim 4.96 4.98 5.00 5.02 5.04 0 100 50 150 200 250 300 max1837eut50 output voltage vs. load current max1836/7 toc10 load current (ma) output voltage (v) v in = 12v to 24v v in = 7v v in = 9v figure 6 100 95 90 85 80 70 0.1 10 100 11000 max1837eut50 efficiency vs. load current max1836/7 toc11 load current (ma) efficiency (%) 75 v in = 9v v in = 24v v in = 18v v in = 7v figure 6 v out = 5v v in = 12v 200 250 300 350 400 0 100 200 300 max1837eut50 dropout voltage vs. load current max1836/7 toc12 load current (ma) dropout voltage (mv) 0 50 100 150 figure 6 v out = 5v 10 11 12 13 14 15 0 4 8 12 16 20 24 no-load supply current vs. input voltage max1836/7 toc13 input voltage (v) supply current ( a) typical operating characteristics (continued) (circuits of figures 1 (max1836) and 2 (max1837), v in = 12v, shdn = in, t a = +25?.)
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 6 _______________________________________________________________________________________ typical operating characteristics (continued) (circuits of figures 1 (max1836) and 2 (max1837), v in = 12v, shdn = in, t a = +25?.) 100 s/div max1837eut50 load transient a: i out = 10ma to 250ma, 200ma/div b: v out = 5v, 20mv/div c: i l , 500ma/div v in = 12v, figure 6 400ma 200ma 5.02v 0 b a c max1836/7 toc14 5.00v 4.98v 750ma 250ma 0 400 s/div max1837eut50 line transient a: v in = 9v to 18v, 10v/div b: v out = 5v, r out = 100 ? , 100mv/div c: i l , 500ma/div figure 6 20v 10v 5.1v 0 b a c max1836/7 toc15 5.0v 4.9v 500ma 0 400 s/div max1837eut50 line transient near dropout a: v in = 5v to 12v, 5v/div b: v out = 5v, r out = 100 ? , 100mv/div c: i l , 500ma/div figure 6 15v 10v 5.1v 5v b a c max1836/7 toc16 5.0v 4.9v 500ma 0 200 s/div max1837eut50 startup waveform a: v shdn = 0 to 2v, 2v/div b: v out = 5v, r out = 100 ? , 2v/div c: i l , 500ma/div v in = 12v, figure 6 2v 0 2v 4v b a c max1836/7 toc17 0 500ma 0
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters _______________________________________________________________________________________ 7 detailed description the max1836/max1837 step-down converters are designed primarily for battery-powered devices, note- book computers, and industrial control applications. a unique current-limited control scheme provides high efficiency over a wide load range. operation up to 100% duty cycle allows the lowest possible dropout voltage, increasing the useable supply voltage range. under no-load, the max1836/max1837 draw only 12?, and in shutdown mode, they draw only 3? to further reduce power consumption and extend battery life. additionally, an internal 24v switching mosfet, internal current sensing, and a high switching frequen- cy minimize pc board space and component cost. current-limited control architecture the max1836/max1837 use a proprietary current-limit- ed control scheme that operates with duty cycles up to 100%. these dc-dc converters pulse as needed to maintain regulation, resulting in a variable switching fre- quency that increases with the load. this eliminates the high supply currents associated with conventional con- stant-frequency pulse-width-modulation (pwm) con- trollers that switch the mosfet unnecessarily. pin name function 1fb dual-mode feedback input. connect to gnd for the preset 3.3v (max183_eut33) or 5.0v (max183_eut50) output. connect to a resistive divider between the output and fb to adjust the output voltage between 1.25v and v in , and connect the out pin to gnd. when setting output voltages above 5.5v, permanently connect shdn to in. 2 gnd ground 3 in input voltage. 4.5v to 24v input range. connected to the internal p-channel power mosfet? source. 4 lx inductor connection. connected to the internal p-channel power mosfet? drain. 5 shdn shutdown input. a logic low shuts down the max1836/max1837 and reduces supply current to 3?. lx is high impedance in shutdown. connect to in for normal operation. when setting output voltages above 5.5v, permanently connect shdn to in. 6 out regulated output voltage high-impedance sense input. internally connected to a resistive divider. connect to the output when using the preset output voltage. connect to gnd when using an external resistive divider to adjust the output voltage. ?p exposed metal pad. connect to gnd. this pad is internally connected to gnd through a soft connect. for proper grounding and good thermal dissipation, connect the exposed pad to gnd. pin description max1836 in gnd lx fb out output 3.3v or 5v input 4.5v or 12v c in 10 f 25v d1 l1 47 h c out 100 f 6.3v c in = taiyo yuden tmk432bj106km l1 = sumida cdrh5d28-470 c out = sanyo poscap 6tpc100m (smaller capacitors can be used for 5v) d1 = nihon ep05q03l note: high-current paths shown with bold lines. shdn figure 1. typical max1836 application circuit max1837 in gnd lx shdn fb out output 3.3v or 5v input 4.5v or 12v c in 10 f 25v d1 l1 22 h c out 150 f 6.3v c in = taiyo yuden tmk432bj106km l1 = sumida cdrh5d28-220 c out = sanyo os-con 6sa150m (smaller capacitors can be used for 5v) d1 = nihon ed05q03l note: high-current paths shown with bold lines. figure 2. typical max1837 application circuit
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 8 _______________________________________________________________________________________ when the output voltage is too low, an error comparator sets a flip-flop, which turns on the internal p-channel mosfet and begins a switching cycle (figure 3). as shown in figure 4, the inductor current ramps up linear- ly, charging the output capacitor and servicing the load. the mosfet turns off when the current limit is reached, or when the maximum on-time is exceeded while the output voltage is in regulation. otherwise, the mosfet remains on, allowing a duty cycle up to 100% to ensure the lowest possible dropout voltage. once the mosfet turns off, the flip-flop resets, diode d1 turns on, and the current through the inductor ramps back down, transferring the stored energy to the output capacitor and load. the mosfet remains off until the 0.5s minimum off-time expires and the inductor cur- rent ramps down to zero, and the output voltage drops back below the set point. 4 s/div circuit of figure 2, v in = 12v a. v lx , 5v/div b. v out = 3.3v, 20mv/div, 200ma load c. inductor current, 500ma/div 10v 0 500ma 3.3v a b c 0 figure 4. discontinuous-conduction operation input 4.5v or 24v c in output 3.3v or 5v d1 l1 c out max1836 max1837 in gnd lx shdn fb out q maximum on-time delay trig q maximum off-time delay trig q r s v sense v set 1.25v 100mv figure 3. functional diagram
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters _______________________________________________________________________________________ 9 input-output (dropout) voltage a step-down converter?s minimum input-to-output volt- age differential (dropout voltage) determines the lowest useable input supply voltage. in battery-powered sys- tems, this limits the useful end-of-life battery voltage. to maximize battery life, the max1836/max1837 operate with duty cycles up to 100%, which minimizes the input- to-output voltage differential. when the supply voltage approaches the output voltage, the p-channel mosfet remains on continuously to supply the load. dropout voltage is defined as the difference between the input and output voltages when the input is low enough for the output to drop out of regulation. for a step-down converter with 100% duty cycle, the dropout voltage depends on the mosfet drain-to-source on- resistance (r ds(on) ) and inductor series resistance; therefore, it is proportional to the load current: shutdown ( shdn shdn s shdn d shdn shdn n shdn n shdn d s nd s nd s n shdn n s h h nn n s n n nn d dsn nd n nd shdn n hhn hs shn h d ns n n n d
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 10 ______________________________________________________________________________________ the inductor?s saturation current rating must be greater than the peak switching current, which is determined by the switch current limit plus the overshoot due to the 300ns current-sense comparator propagation delay: where the switch current-limit (i lim ) is typically 312ma (max1836) or 625ma (max1837). saturation occurs when the inductor?s magnetic flux density reaches the maximum level the core can support, and the induc- tance starts to fall. inductor series resistance affects both efficiency and dropout voltage (see the input-output voltage section). high series resistance limits the maximum current avail- able at lower input voltages and increases the dropout voltage. for optimum performance, select an inductor with the lowest possible dc resistance that fits in the allotted dimensions. typically, the inductor?s series resis- tance should be significantly less than that of the internal p-channel mosfet?s on-resistance (1.1 typ). inductors with a ferrite core, or equivalent, are recommended. the maximum output current of the max1836/max1837 current-limited converter is limited by the peak inductor current. for the typical application, the maximum out- put current is approximately: output capacitor choose the output capacitor to supply the maximum load current with acceptable voltage ripple. the output ripple has two components: variations in the charge stored in the output capacitor with each lx pulse, and the voltage drop across the capacitor?s equivalent series resistance (esr) caused by the current into and out of the capacitor: the output voltage ripple as a consequence of the esr and output capacitance is: where i peak is the peak inductor current (see the inductor selection section). these equations are suit- able for initial capacitor selection, but final values should be set by testing a prototype or evaluation cir- cuit. as a general rule, a smaller amount of charge delivered in each pulse results in less output ripple. since the amount of charge delivered in each oscillator pulse is determined by the inductor value and input voltage, the voltage ripple increases with larger induc- tance but decreases with lower input voltages. with low-cost aluminum electrolytic capacitors, the esr-induced ripple can be larger than that caused by the current into and out of the capacitor. consequently, high-quality low-esr aluminum-electrolytic, tantalum, polymer, or ceramic filter capacitors are required to minimize output ripple. best results at reasonable cost are typically achieved with an aluminum-electrolytic capacitor in the 100f range, in parallel with a 0.1f ceramic capacitor. input capacitor the input filter capacitor reduces peak currents drawn from the power source and reduces noise and voltage ripple on the input caused by the circuit?s switching. the input capacitor must meet the ripple-current requirement (i rms ) imposed by the switching currents defined by the following equation: for most applications, nontantalum chemistries (ceram- ic, aluminum, polymer, or os-con) are preferred due to their robustness with high inrush currents typical of sys- tems with low-impedance battery inputs. alternatively, two (or more) smaller-value low-esr capacitors can be connected in parallel for lower cost. choose an input capacitor that exhibits <+10?c temperature rise at the rms input current for optimal circuit longevity. diode selection the current in the external diode (d1) changes abruptly from zero to its peak value each time the lx switch turns off. to avoid excessive losses, the diode must have a fast turn-on time and a low forward voltage. use a diode with an rms current rating of 0.5a or greater, and with a breakdown voltage >v in . schottky diodes are preferred. for high-temperature applications, schottky diodes may be inadequate due to their high leakage currents. in such cases, ultra-high-speed sili- con rectifiers are recommended, although a schottky diode with a higher reverse voltage rating can often provide acceptable performance. ii vv-v v rms load out in out in = () v esr v -i 2c v v v-v ripple(esr) peak ripple(c) peak out out out in in out 2 = = () i li vv v ripple ripple(esr) ripple(c) + ii out(max) peak = 1 2 i (v - v ) peak lim in out =+ i ns l 300
max1836/max1837 stability commonly, instability is caused by excessive noise on the feedback signal or ground due to poor layout or improper component selection. when seen, instability typically manifests itself as motorboating, which is characterized by grouped switching pulses with large gaps and excessive low-frequency output ripple during no-load or light-load conditions. pc board layout and grounding high switching frequencies and large peak currents make pc board layout an important part of the design. poor layout may introduce switching noise into the feedback path, resulting in jitter, instability, or degrad- ed performance. high-power traces, bolded in the typi- cal application circuits (figures 1 and 2), should be as short and wide as possible. additionally, the current loops formed by the power components (c in , c out , l1, and d1) should be as tight as possible to avoid radiated noise. connect the ground pins of these power components at a common node in a star-ground configuration. separate the noisy traces, such as the lx node, from the feedback network with grounded copper. furthermore, keep the extra copper on the board, and integrate it into a pseudoground plane. when using external feedback, place the resistors as close to the feedback pin as possible to minimize noise coupling. the max1837 evaluation kit shows the rec- ommended layout. applications information high-voltage step-down converter the typical application circuits? (figures 1 and 2) com- ponents were selected for 9v battery applications. however, the max1836/max1837 input voltage range allows supply voltages up to 24v. figure 6 shows a modified application circuit for high-voltage applica- tions. when using higher input voltages, verify that the input capacitor?s voltage rating exceeds v in(max) and that the inductor value exceeds the minimum induc- tance recommended in the inductor selection section. inverter configuration figure 7 shows the max1836/max1837 in a floating ground configuration. by connecting what would nor- mally be the output to the supply-voltage ground, the ic?s ground pin is forced to regulate to -5v (max183_eut50) or -3.3v (max183_eut33). avoid exceeding the maximum ratings of 24v between in and gnd, and 5.5v between out and gnd. other negative voltages may be generated by placing a resistive divider across the output capacitor and connecting the tap to fb in the same manner as the normal step-down configuration. max1836/max1837 24v internal switch, 100% duty cycle, step-down converters ______________________________________________________________________________________ 11 supplier phone fax website inductors coilcraft 847-639-6400 847-639-1469 www.coilcraft.com coiltronics 561-241-7876 561-241-9339 www.coiltronics.com sumida usa 847-956-0666 847-956-0702 www.sumida.com toko 847-297-0070 847-699-1194 www.tokoam.com capacitors avx 803-946-0690 803-626-3123 www.avxcorp.com kemet 408-986-0424 408-986-1442 www.kemet.com panasonic 847-468-5624 847-468-5815 www.panasonic.com sanyo 619-661-6835 619-661-1055 www.secc.co.jp taiyo yuden 408-573-4150 408-573-4159 www.t-yuden.com diodes central semiconductor 516-435-1110 516-435-1824 www.centralsemi.com international 310-322-3331 310-322-3332 www.irf.com nihon 847-843-7500 847-843-2798 www.niec.co.jp on semiconductor 602-303-5454 602-994-6430 www.onsemi.com zetex 516-543-7100 516-864-7630 www.zetex.com table 1. component suppliers
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 12 ______________________________________________________________________________________ max1836 max1837 in gnd lx shdn fb out input 3.6v to 18v c in 10 f d1 l1 47 h c out 100 f note: high-current paths shown with bold lines. output -3.3v or -5v figure 7. max1836/max1837 inverter configuration max1837 in gnd lx shdn fb out output 5v input 4.5v to 24v c in 10 f 25v d1 l1 47 h c out 68 f 10v c in = taiyo yuden tmk432bj106km l1 = sumida cdrh5d28-470 c out = sanyo poscap 10tpc68m d1 = nihon ep05q03l note: high-current paths shown with bold lines. figure 6. high-voltage application chip information transistor count: 731 process: bicmos part preset output voltage (v) load current (ma) max1836 ett33 3.3 125 max1836ett50 5 125 max1836eut33 3.3 125 max1836eut50 5 125 max1837 ett33 3.3 250 max1837ett50 5 250 max1837eut33 3.3 250 max1837eut50 5 250 selector guide
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters ______________________________________________________________________________________ 13 6lsot.eps package outline, sot 6l body 21-0058 1 1 g 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 .)
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 14 ______________________________________________________________________________________ package information (continued) (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 .) 6, 8, &10l, dfn thin.eps h 1 2 21-0137 package outline, 6,8,10 & 14l, tdfn, exposed pad, 3x3x0.80 mm
max1836/max1837 24v internal switch, 100% duty cycle, step-down converters 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. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 15 ? 2006 maxim integrated products is a registered trademark of maxim integrated products, inc. package information (continued) (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 .) common dimensions symbol min. max. a 0.70 0.80 d 2.90 3.10 e 2.90 3.10 a1 0.00 0.05 l 0.20 0.40 pkg. code n d2 e2 e jedec spec b [(n/2)-1] x e package variations 0.25 min. k a2 0.20 ref. 2.300.10 1.500.10 6 t633-1 0.95 bsc mo229 / weea 1.90 ref 0.400.05 1.95 ref 0.300.05 0.65 bsc 2.300.10 8 t833-1 2.00 ref 0.250.05 0.50 bsc 2.300.10 10 t1033-1 2.40 ref 0.200.05 - - - - 0.40 bsc 1.700.10 2.300.10 14 t1433-1 1.500.10 1.500.10 mo229 / weec mo229 / weed-3 0.40 bsc - - - - 0.200.05 2.40 ref t1433-2 14 2.300.10 1.700.10 t633-2 6 1.500.10 2.300.10 0.95 bsc mo229 / weea 0.400.05 1.90 ref t833-2 8 1.500.10 2.300.10 0.65 bsc m o229 / weec 0.300.05 1.95 ref t833-3 8 1.500.10 2.300.10 0.65 bsc m o229 / weec 0.300.05 1.95 ref -drawing not to scale- h 2 2 21-0137 package outline, 6,8,10 & 14l, tdfn, exposed pad, 3x3x0.80 mm 2.300.10 mo229 / weed-3 2.00 ref 0.250.05 0.50 bsc 1.500.10 10 t1033-2 revision history pages changed at rev 3: 1, 7, 8, 12
e nglish ? ???? ? ??? ? ??? what's ne w p roducts solutions de sign ap p note s sup p ort buy comp any me mbe rs m axim > p roduc ts > p ower and battery m anagement max1836, max1837 24v internal switch, 100% duty c ycle, step-down c onverters quickview technical documents ordering info more information all ordering information notes: other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales . 1. didn't find what you need? ask our applications engineers. expert assistance in finding parts, usually within one business day. 2. part number suffixes: t or t&r = tape and reel; + = rohs/lead-free; # = rohs/lead-exempt. more: see full data sheet or part naming c onventions . 3. * some packages have variations, listed on the drawing. "pkgc ode/variation" tells which variation the product uses. 4. devices: 1-21 of 21 m ax1836 fre e sam ple buy pack age : type pins footprint drawing code/var * te m p rohs/le ad-fre e ? m ate rials analys is max1836eut50#g16 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6fh-6 * -40c to +85c rohs/lead-free: rohs qualified materials analysis max1836eut33#tg16 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6fh-6 * -40c to +85c rohs/lead-free: rohs qualified materials analysis max1836eut50#tg16 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6fh-6 * -40c to +85c rohs/lead-free: rohs qualified materials analysis max1836eut50 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1836eut33 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1836eut33-t sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1836eut50-t sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1836ett33+ thin qfn (dual);6 pin;10 mm dwg: 21-0137i (pdf) use pkgcode/variation: t633+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1836ett33+t thin qfn (dual);6 pin;10 mm dwg: 21-0137i (pdf) use pkgcode/variation: t633+2 * -40c to +85c rohs/lead-free: lead free materials analysis m ax1837 fre e sam ple buy pack age : type pins footprint drawing code/var * te m p rohs/le ad-fre e ? m ate rials analys is max1837eut33#g16 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6fh-6 * -40c to +85c rohs/lead-free: rohs qualified materials analysis max1837eut33#tg16 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6fh-6 * -40c to +85c rohs/lead-free: rohs qualified materials analysis max1837eut50#g16 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6fh-6 * -40c to +85c rohs/lead-free: rohs qualified materials analysis
max1837eut50 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1837eut50#tg16 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6fh-6 * -40c to +85c rohs/lead-free: rohs qualified materials analysis max1837eut33 sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1837eut50-t sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1837eut33-t sot-23;6 pin;9 mm dwg: 21-0058i (pdf) use pkgcode/variation: u6f-6 * -40c to +85c rohs/lead-free: no materials analysis max1837ett50+ thin qfn (dual);6 pin;10 mm dwg: 21-0137i (pdf) use pkgcode/variation: t633+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1837ett33+ thin qfn (dual);6 pin;10 mm dwg: 21-0137i (pdf) use pkgcode/variation: t633+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1837ett33+t thin qfn (dual);6 pin;10 mm dwg: 21-0137i (pdf) use pkgcode/variation: t633+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1837ett50+t thin qfn (dual);6 pin;10 mm dwg: 21-0137i (pdf) use pkgcode/variation: t633+2 * -40c to +85c rohs/lead-free: lead free materials analysis didn't find what you need? next day product selection assistance from applications engineers parametric search applications help quickview technical documents ordering info more information des c ription key features a pplic ations /u s es key spec ific ations diagram data sheet a pplic ation n otes des ign guides e ngineering journals reliability reports software/m odels e valuation kits p ric e and a vailability samples buy o nline p ac kage i nformation lead-free i nformation related p roduc ts n otes and c omments e valuation kits doc ument ref.: 1 9 -1 9 1 9 ; rev 3 ; 2 0 0 6 -0 8 -1 0 t his page las t modified: 2 0 0 7 -0 6 -1 4 c ontac t us: send us an email c opyright 2 0 0 7 by m axim i ntegrated p roduc ts , dallas semic onduc tor ? legal n otic es ? p rivac y p olic y

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