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general description the max1927/max1928 800ma step-down converters power low-voltage microprocessors in compact equip- ment requiring the highest possible efficiency. the max1927/max1928 are optimized for generating low output voltages (down to 750mv) at high efficiency using small external components. the supply voltage range is from 2.6v to 5.5v and the guaranteed minimum output current is 800ma. 1mhz pulse-width modulation (pwm) switching allows for small external components. a unique control scheme minimizes ripple at light loads, while maintaining a low 140? quiescent current. the max1927/max1928 include a low on-resistance internal mosfet switch and synchronous rectifier to maximize efficiency and minimize external component count. no external diode is needed. 100% duty-cycle operation allows for a dropout voltage of only 340mv at 800ma. other features include internal soft-start, power-ok (pok) output, and selectable forced pwm operation for lower noise at all load currents. the max1928 is available with several preset output voltages: 1.5v (max1928-15), 1.8v (max1928-18), and 2.5v (max1928-25). the max1927r has adjustable output range down to 0.75v. the max1927/max1928 are available in a tiny 10-pin ?ax package. applications wcdma handsets pdas and palmtops dsp core power battery-powered equipment features 800ma output current output voltages from 0.75v to 5v 2.6v to 5.5v input voltage range power-ok output no schottky diode required selectable forced pwm operation 1mhz fixed-frequency pwm operation 140? quiescent current soft-start 10-pin ?ax package max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters ________________________________________________________________ maxim integrated products 1 ordering information batt comp gnd ref pgnd lx pok fb v in 2.6v to 5.5v c1 c2 c c r c l1 v out 0.75v at 800ma shdn pwm max1927r c f typical operating circuit 19-2527; rev 0; 7/02 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. part preset output voltage temp range pin- package max1927 reub adj. to 0.75v -40 c to +85 c 10 ?ax max1928 eub15 1.5v -40 c to +85 c 10 ?ax max1928eub18 1.8v -40 c to +85 c 10 ?ax max1928eub25 2.5v -40 c to +85 c 10 ?ax 1 2 3 4 5 10 9 8 7 6 pok batt lx pgnd fb ref gnd pwm max1927r max1928 max top view comp shdn pin configuration
max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v batt = 3.6v, shdn = batt, c ref = 0.1?, t a = 0? to +85? , unless otherwise noted. typical values are at t a = +25?.) 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. batt, pwm, pok, comp, shdn to gnd ...............-0.3v to +6v pgnd to gnd .......................................................-0.3v to +0.3v lx, ref, fb to gnd ................................-0.3v to (v batt + 0.3v) continuous power dissipation (t a = +70?) 10-pin ?ax (derate 5.6mw/? above +70?) ...........444mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter conditions min typ max units batt input voltage 2.6 5.5 v undervoltage lockout threshold v batt rising or falling (35mv hysteresis) 2.15 2.35 2.55 v no load, pulse skipping, pwm = gnd 140 240 a quiescent current 1mhz switching 2 ma quiescent current in dropout 190 340 a shutdown supply current shdn = gnd 0.1 10 a reference and error amp max1927r 0.738 0.75 0.762 max1928-15 1.477 1.5 1.523 max1928-18 1.773 1.8 1.827 fb voltage accuracy max1928-25 2.462 2.5 2.538 v max1928 5 10 15 a fb input current max1927r 10 150 na max1927r 250 max1928-15 210 max1928-18 175 transconductance (g m ) max1928-25 125 s reference voltage accuracy 1.231 1.25 1.269 v reference supply rejection 2.6v < v batt < 5.5v 0.5 2 mv pwm controller v batt = 3.6v 0.25 0.4 p-channel on-resistance v batt = 2.6v 0.3 0.5 ? v batt = 3.6v 0.17 0.3 n-channel on-resistance v batt = 2.6v 0.2 0.35 ? current-sense transresistance (r cs ) 0.48 v/a p-channel current-limit threshold 1.1 1.3 1.6 a p-channel pulse-skipping current threshold 0.11 0.13 0.15 a n-channel negative current-limit threshold -0.55 a
max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters _______________________________________________________________________________________ 3 electrical characteristics (continued) (v batt = 3.6v, shdn = batt, c ref = 0.1f, t a = 0 c to +85 c , unless otherwise noted. typical values are at t a = +25 c.) parameter conditions min typ max units n-channel synchronous rectifier turn-off threshold 20 ma lx leakage current v batt = 5.5v, lx = gnd or batt -20 0.1 +20 a maximum duty cycle 100 % pwm = gnd 0 minimum duty cycle pwm = batt 15 % internal oscillator frequency 0.85 1 1.15 mhz thermal shutdown threshold 15 c hysteresis 160 d eg r ees pok comparator batt operating voltage range i pok = 0.1 ma 1 5.5 v output low voltage v fb = 0.5v, i pok = 1ma 0.01 0.1 v output high leakage current v pok = 5.5v 1 a max1927r 0.650 0.675 0.700 max1928-15 1.305 1.350 1.395 max1928-18 1.566 1.620 1.674 pok threshold max1928-25 2.175 2.250 2.325 v output valid to pok release delay pok transitions to high impedance 20ms after v fb > v pok 15 20 25 ms logic inputs ( shdn , pwm) logic input high 2.6v < v batt < 5.5 v 1.6 v logic input low 2.6v < v batt < 5.5 v 0.6 v logic input current v batt = 5.5v 0.1 1 a electrical characteristics (v batt = 3.6v, shdn = batt, c ref = 0.1f, t a = -40 c to +85 c , unless otherwise noted.) parameter conditions min max units batt input voltage 2.6 5.5 v undervoltage lockout threshold v batt rising or falling (35mv hysteresis) 2.15 2.55 v quiescent current no load, pulse skipping, pwm = gnd 240 a quiescent current in dropout 340 a shutdown supply current shdn = gnd 10 a reference and error amp max1927r 0.732 0.768 max1928-15 1.47 1.53 max1928-18 1.764 1.836 fb voltage accuracy max1928-25 2.45 2.55 v fb input current max1928 5 15 a
max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters 4 _______________________________________________________________________________________ electrical characteristics (continued) (v batt = 3.6v, shdn = batt, c ref = 0.1f, t a = -40 c to +85 c , unless otherwise noted. typical values are at t a = +25 c.) parameter conditions min max units fb input current max1927r 150 na reference voltage accuracy 1.22 1.269 v reference-supply rejection 2.6v < v batt < 5.5v 2 mv pwm controller v batt = 3.6v 0.4 p-channel on-resistance v batt = 2.6v 0.5 ? v batt = 3.6v 0.30 n-channel on-resistance v batt = 2.6v 0.35 ? p-channel current-limit threshold 1.1 0.10 1.6 a p-channel pulse-skipping current threshold 0.10 0.16 a lx leakage current v batt = 5.5v, lx = gnd or batt -20 +20 a maximum duty cycle 100 % minimum duty cycle pwm = gnd 0 % internal oscillator frequency 0.8 1.2 mhz pok comparator batt operating voltage range i pok = 0.1 ma 1 5.5 v output low voltage v fb = 0.5v, i pok = 1ma 0.1 v output high leakage current v pok = 5.5v 1 a max1927r 0.650 0.700 max1928-15 1.305 1.395 max1928-18 1.566 1.674 pok threshold max1928-25 2.175 2.325 v output valid to pok release delay pok transitions to high impedance 20ms after v fb > v pok 15 25 ms logic inputs ( shdn , pwm) logic input high 2.6v < v batt < 5.5 v 1.6 v logic input low 2.6v < v batt < 5.5 v 0.6 v logic input current v batt = 5.5v 1 a
max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters _______________________________________________________________________________________ 5 max1927 toc01 load current (ma) efficiency (%) 100 10 50 60 70 80 90 100 40 1 1000 max1927r efficiency vs. load current v in = 5v v in = 3.6v v out = 3.3v max1928-25 efficiency vs. load current max1927 toc02 load current (ma) efficiency (%) 100 10 50 60 70 80 90 100 40 1 1000 v in = 5v v in = 3.6v max1928-18 efficiency vs. load current max1927 toc03 load current (ma) efficiency (%) 100 10 40 50 60 70 80 90 100 30 1 1000 v in = 5v v in = 2.7v v in = 3.6v v out = 1.8v max1928-15 efficiency vs. load current max1927 toc04 load current (ma) efficiency (%) 100 10 40 50 60 70 80 90 100 30 1 1000 v out = 1.5v v in = 2.7v v in = 3.6v v in = 5v max1927r efficiency vs. load current max1927 toc05 load current (ma) efficiency (%) 100 10 40 50 60 70 80 90 100 30 1 1000 v out = 1v v in = 2.7v v in = 3.6v v in = 5v max1928-25 dropout voltage vs. load current max1927 toc06 load current (a) dropout voltage (mv) 0.9 0.8 0.6 0.7 0.2 0.3 0.4 0.5 0.1 50 100 150 200 250 300 350 400 450 500 0 0 1.0 v in = 2.5v max1928-18 output voltage vs. load current max1927 toc07 load current (ma) output voltage (v) 900 800 600 700 200 300 400 500 100 1.72 1.74 1.76 1.78 1.80 1.82 1.84 1.86 1.88 1.90 1.70 0 1000 v in = 3.6v max1927 toc08 input voltage (v) input current ( a) 5.0 4.5 0.5 1.0 1.5 2.5 3.0 3.5 2.0 4.0 50 100 150 200 250 300 350 400 0 0 5.5 no-load input current vs. input voltage oscillator frequency vs. input voltage max1927 toc09 input voltage (v) oscillator frequency (mhz) 5.1 4.6 4.1 3.6 3.1 0.96 0.98 1.00 1.02 1.04 1.06 0.94 2.6 5.6 t a = +85 c t a = +25 c t a = -40 c typical operating characteristics (circuits of figure 3 and 4, t a = +25 c, unless otherwise noted.)
max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters 6 _______________________________________________________________________________________ typical operating characteristics (continued) (circuits of figure 3 and 4, t a = +25 c, unless otherwise noted.) max1927 toc10 input voltage (v) maximum load current (a) 5.1 4.6 4.1 3.6 3.1 0.2 0.4 0.6 0.8 1.0 1.2 1.4 v out = 1.8v v out = 2.5v v out = 1v 0 2.6 5.6 maximum load current vs. input voltage startup waveform max1927 toc11 1ms/div 5v/div 1v/div 200ma/div shdn v out i in pok waveform max1927 toc12 20ms/div 5v/div 2v/div 2v/div shdn v out pok heavy-load switching waveforms max1927 toc13 400ns/div 10mv/div 200ma/div 5v/div v out (ac-coupled) i l lx light-load switching waveforms max1927 toc14 2ms/div 10mv/div 200ma/div 5v/div v out (ac-coupled) i l lx load transient max1927 toc15 100 s/div 100mv/div 250ma 900ma 500ma/div v out (ac-coupled) i load line transient max1927 toc16 1ms/div 10mv/div 2v/div 4.2v 3v v out (ac-coupled) v in
max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters _______________________________________________________________________________________ 7 pin description pin name function 1 pwm forced-pwm input. drive to gnd to use pwm at medium to heavy loads and pulse-skipping at light loads. drive to batt to force pwm operation at all loads. 2 gnd ground 3 ref internal 1.25v reference. bypass to gnd with a 0.1f capacitor. 4fb output feedback sense input. to set the output voltage to the preset voltage (max1928), connect fb directly to the output. to adjust the output voltage (max1927r), connect fb to the center of an external resistor- divider between the output and gnd. fb regulation voltage is 0.75v. 5 comp compensation input. see the compensation, stability, and output capacitor section for compensation component selection. 6 shdn shutdown control input. drive low to shut down the converter. drive high for normal operation. 7 pgnd power ground 8 lx inductor connection to the drains of the internal power mosfets. 9 batt supply voltage input. connect to a 2.6v to 5.5v source. bypass to gnd with a low-esr 10f capacitor. 10 pok power-ok open-drain output. once the soft-start routine has completed, pok goes high impedance 20ms after fb exceeds 90% of its expected final value. n n p p slope compensation power-ok control 1mhz osc bias comp batt pwm control 1.25v reference pfm current comparator pwm comparator pwm ilim comparator to comp n-channel current comparator pgnd pok fb ref max1927r only gnd max1928 only lx shdn max1927 max1928 figure 1. simplified functional diagram
max1927/max1928 detailed description the max1927/max1928 pwm step-down dc-dc con- verters accept inputs as low as 2.6v, while delivering 800ma to output voltages as low as 0.75v. these devices operate in one of two modes to optimize noise and quiescent current. under heavy loads, max1927/ max1928 operate in pulse-width modulation (pwm) mode and switch at a fixed 1mhz frequency. under light loads, they operate in pfm mode to reduce power consumption. in addition, both devices provide selec- table forced pwm operation for minimum noise at all load currents. pfm operation and pwm control scheme the pfm mode improves efficiency and reduces quies- cent current to 140a at light loads. the max1927/ max1928 initiate pulse-skipping pfm operation when the peak inductor current drops below 130ma. during pfm operation, the max1927/max1928 switch only as necessary to service the load, reducing the switching frequency and associated losses in the internal switch, synchronous rectifier, and inductor. during pfm mode, a switching cycle initiates when the error amplifier senses that the output voltage has dropped below the regulation point. if the output volt- age is low, the p-channel mosfet switch turns on and conducts current to the output filter capacitor and load. the pmos switch turns off when the pwm comparator is satisfied. the max1927/max1928 then wait until the error amplifier senses a low output voltage to start again. some jitter is normal during the transition from pfm to pwm with loads around 100ma. this has no adverse impact on regulation. at loads greater than 130ma, the max1927/max1928 use a fixed-frequency, current-mode, pwm controller capable of achieving 100% duty cycle. current-mode feedback provides cycle-by-cycle current limiting, superior load and line response, as well as overcurrent protection for the internal mosfet and synchronous rectifier. a comparator at the p-channel mosfet switch detects overcurrent conditions exceeding 1.1a. during pwm operation, the max1927/max1928 regu- late output voltage by switching at a constant frequency and then modulating the power transferred to the load using the pwm comparator (figure 1). the error-amp output, the main switch current-sense signal, and the slope compensation ramp are all summed at the pwm comparator. the comparator modulates the output power by adjusting the peak inductor current during the first half of each cycle based on the output-error volt- age. the max1927/max1928 have relatively low ac- loop gain coupled with a high-gain integrator to enable the use of a small, low-valued, output filter capacitor. the resulting load regulation is 0.3% (typ) from 0 to 800ma. forced pwm operation to force pwm-only operation, connect pwm to batt. forced pwm operation is desirable in sensitive rf and data-acquisition applications to ensure that switching noise does not interfere with sensitive if and data sam- pling frequencies. a minimum load is not required dur- ing forced pwm operation because the synchronous rectifier passes reverse inductor current as needed to allow constant frequency operation with no load. forced pwm operation has higher quiescent current than pfm (2ma typ compared to 140a) due to contin- uous switching. 100% duty-cycle operation the maximum on-time can exceed one internal oscilla- tor cycle, which permits operation at 100% duty cycle. as the input voltage drops, the duty cycle increases until the internal p-channel mosfet stays on continu- ously. dropout voltage at 100% duty cycle is the output current multiplied by the sum of the internal pmos on- resistance (typically 0.25 ? ) and the inductor resis- tance. near dropout, switching cycles can be skipped, reducing switching frequency. however, voltage ripple remains small because the current ripple is still low. synchronous rectification an n-channel synchronous rectifier eliminates the need for an external schottky diode and improves efficiency. the synchronous rectifier turns on during the second half of each cycle (off-time). during this time, the volt- age across the inductor is reversed, and the inductor current falls. in normal mode, the synchronous rectifier is turned off when either the output falls out of regula- tion (and another on-time begins) or when the inductor current approaches zero. in forced pwm mode, the synchronous rectifier remains active until the beginning of a new cycle. shutdown mode driving shdn to gnd places the max1927/max1928 in shutdown mode. in shutdown, the reference, control circuitry, internal switching mosfet, and synchronous rectifier turn off and the output becomes high imped- ance. drive shdn high for normal operation. input cur- rent falls to 0.1a (typ) during shutdown mode. pok output pok is an open-drain output that goes high impedance 20ms after the soft-start ramp has concluded and v fb is within 90% of the threshold. pok is low impedance when in shutdown. low-output-voltage, 800ma, pwm step-down dc-dc converters 8 _______________________________________________________________________________________
applications information output voltage selection the max1927/max1928 have preset output voltages. in addition, the max1927r has an adjustable output. to set the output voltage at the preset voltage, connect fb to the output. see table 1 for a list of the preset volt- ages and their corresponding part numbers. the output voltage for the max1927r is adjustable from 0.75v to the input voltage by connecting fb to a resistor-divider between the output and gnd (figure 2). to determine the values of the resistor-divider, first select a value for feedback resistor r2 between 5k ? to 50k ? . r1 is then given by: where v fb is 0.75v. input capacitor selection capacitor equivalent series resistance (esr) is a major contributor to input ripple in high-frequency dc-dc converters. ordinary aluminum-electrolytic capacitors have high esr and should be avoided. low-esr alu- minum electrolytic capacitors are acceptable and rela- tively inexpensive. low-esr tantalum capacitors or polymer capacitors are better and provide a compact solution for space-constrained surface-mount designs. ceramic capacitors have the lowest esr overall. the input filter capacitor reduces peak currents and noise at the input voltage source. connect a low-esr bulk capacitor ( 10f typ) to the input. select this bulk capacitor to meet the input ripple requirements and voltage rating rather than capacitance value. use the following equation to calculate the maximum rms input current: compensation, stability, and output capacitor the max1927/max1928 are externally compensated with a resistor and a capacitor (see figure 3, r c and c c ) in series from comp to gnd. an additional capaci- tor (c f ) may be required from comp to gnd if high- esr output capacitors are used. the capacitor inte- grates the current from the transimpedance amplifier, averaging output capacitor ripple. this sets the device speed for transient response and allows the use of small ceramic output capacitors because the phase- shifted capacitor ripple does not disturb the current regulation loop. the resistor sets the proportional gain of the output error voltage by a factor g m ? r c . increasing this resistor also increases the sensitivity of the control loop to output ripple. the resistor and capacitor set a compensation zero that defines the system s transient response. the load creates a dynamic pole, shifting in frequency with changes in load. as the load decreases, the pole fre- quency decreases. system stability requires that the compensation zero must be placed to ensure adequate phase margin (at least 30 at unity gain). the following is a design procedure for the compensation network: 1) select an appropriate converter bandwidth (f c ) to stabilize the system while maximizing transient response. this bandwidth should not exceed 1/10 of the switching frequency. 2) calculate the compensation capacitor, c c , based on this bandwidth: for the max1927: c v ir g r rr f c out out max cs m c = ? ? ? ? ? ? ? ? ? ? ? ? + ? ? ? ? ? ? ? ? ? ? ? ? () 12 12 1 2 i i v vvv rms out in out in out = ? () rr v v out fb 12 1 = ? ? ? ? ? ? ? max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters _______________________________________________________________________________________ 9 lx fb r1 r2 50k ? max1927r figure 2. setting the adjustable output voltage part preset output voltage max1927r 0.75v, adjustable max1928-15 1.5 v max1928-18 1.8 v max1928-25 2.5 v table 1. fb regulation voltages
max1927/max1928 for the max1928: resistors r1 and r2 are external to the max1927 (see the setting the output voltage section). i out(max) is the maximum output current, r cs = 0.48v/a, and g m = 250s for the max1927. see the electrical characteristics table for max1928 g m values. select the closest standard c c value that gives an acceptable bandwidth. 3) calculate the equivalent load impedance, r l , by: 4) calculate the compensation resistance (r c ) to can- cel out the dominant pole created by the output load and the output capacitance: solving for r c gives: 5) calculate the high-frequency compensation pole to cancel the zero created by the output capacitor s esr: 1 2 1 2 = rc rc esr out c f r rc c c l out c = 1 2 1 2 = rc r c l out c c r v i l out out max = () c v ir g f c out out max cs m c = ? ? ? ? ? ? ? ? ? ? ? ? () ? ? ? ? ? ? () 11 2 low-output-voltage, 800ma, pwm step-down dc-dc converters 10 ______________________________________________________________________________________ batt comp gnd ref pgnd lx pok fb v in 2.6v to 5.5v c1 10 f c2 10 f c c 1200pf r c 18k ? l1 cdrh4d18 4.7 h v out 1.8v at 800ma shdn pwm max1928-18 c f 22pf c3 0.1 f figure 3. applications circuit for the max1928 batt comp ref pgnd lx pok fb v in 2.6v to 5.5v c1 10 f c2 10 f c c 680pf r c 15k ? l1 cdrh4d18 4.7 h v out 1v at 800ma shdn max1927r c f 22pf c3 0.1 f r1 16.5k ? 1% r2 49.9k ? 1% gnd pwm figure 4. applications circuit for the max1927
solving for c f gives: or 22pf, whichever is greater. standard application circuits figures 3 and 4 are standard applications circuits for the max1927/max1928. figure 3 illustrates the preset output voltages (max1928), while figure 4 shows the adjustable configuration (max1927). table 2 lists part numbers and suppliers for the components used in these circuits. pc board layout and routing high switching frequencies and large peak currents make pc board layout a very important part of design. good design minimizes emi, noise on the feedback paths, and voltage gradients in the ground plane, all of which can result in instability or regulation errors. connect the inductor, input filter capacitor, and output filter capacitor as close together as possible and keep their traces short, direct, and wide. connect their ground pins at a single common node in a star ground configuration. the external voltage feedback network should be very close to the fb pin, within 0.2in (5mm). keep noisy traces, such as those from the lx pin, away from the voltage feedback network. position the bypass capacitors as close as possible to their respective pins to minimize noise coupling. for optimum performance, place input and output capacitors as close to the device as possible. connect gnd and pgnd to the highest quality system ground. the max1928 evalua- tion kit illustrates an example pc board layout and rout- ing scheme. chip information transistors: 3282 process: bicmos c rc r f esr out c = max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc converters ______________________________________________________________________________________ 11 part part number manufacturer phone website inductor cdrh3d16-4r7 sumida usa 847-956-0666 japan 81-3-3607-5111 www.sumida.com input/output capacitors jmk212bj106mg taiyo yuden 408-573-4150 www.t-yuden.com comp capacitor grm1881x1h561j murata 770-436-1300 www.murata.com ref capacitor emk107bj104ka taiyo yuden 408-573-4150 www.t-yuden.com table 2. suggested parts/suppliers
max1927/max1928 low-output-voltage, 800ma, pwm step-down dc-dc 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. 12 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ? 2002 maxim integrated products printed usa is a registered trademark of maxim integrated products. 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 .) 10lumax.eps package outline, 10l umax/usop 1 1 21-0061 i rev. document control no. approval proprietary information title: top view front view 1 0.498 ref 0.0196 ref s 6 side view bottom view 0 0 6 0.037 ref 0.0078 max 0.006 0.043 0.118 0.120 0.199 0.0275 0.118 0.0106 0.120 0.0197 bsc inches 1 10 l1 0.0035 0.007 e c b 0.187 0.0157 0.114 h l e2 dim 0.116 0.114 0.116 0.002 d2 e1 a1 d1 min - a 0.940 ref 0.500 bsc 0.090 0.177 4.75 2.89 0.40 0.200 0.270 5.05 0.70 3.00 millimeters 0.05 2.89 2.95 2.95 - min 3.00 3.05 0.15 3.05 max 1.10 10 0.60.1 0.60.1 ? 0.500.1 h 4x s e d2 d1 b a2 a e2 e1 l l1 c gage plane a2 0.030 0.037 0.75 0.95 a1
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 max1927, max1928 low-output-voltage, 800ma, pwm step-down dc -dc 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: 1-18 of 18 m ax1927 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 max1927reub umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1927reub+t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1927reub+ umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1927seub-t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1927seub umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1927reub-t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis m ax1928 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 max1928eub25+ umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1928eub18+ umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1928eub15+t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1928eub15+ umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1928eub18+t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1928eub25-t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis
max1928eub25 umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1928eub18-t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1928eub18 umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1928eub15-t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1928eub15 umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10-2 * -40c to +85c rohs/lead-free: no materials analysis max1928eub25+t umax;10 pin;15 mm dwg: 21-0061j (pdf) use pkgcode/variation: u10+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 -2 5 2 7 ; rev 0 ; 2 0 0 2 -0 8 -2 9 t his page las t modified: 2 0 0 7 -0 7 -1 6 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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