 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| mp3418 400ma, 1.2mhz, synchronous, stepup converter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 1 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. the future of analog ic technology description the mp3418 is a highefficiency, synchronous, currentCmode, stepup converter with output disconnect. the mp3418 can start up from an input voltage as low as 0.8v to provide inrush current limiting, and output shortcircuit protection. the integrated, pchannel, synchronous rectifier improves efficiency and eliminates the need for an external schottky diode. the pmos disconnects the output from the input when the part shuts down. this output disconnect feature allows the output to be completely discharged, thus allowing the part to draw less than 1a in shutdown mode. the 1.2mhz switching frequency allows for smaller external components, while the internal compensation and the softstart minimize the external component count: these feature help to produce a compact solution for a wide current load range. the mp3418 is available in a small 8pin tsot23 package. features ? up to 96% efficiency ? 0.8v low voltage startup ? 0.6vto4v input range ? 1.8vto4v output range ? internal synchronous rectifier ? 1.2mhz fixedfrequency switching ? typical 38a quiescent current ? typical 0.1a shutdown current ? currentmode control with internal compensation ? true output disconnect from input ? v in >v out down mode operation ? high efficiency under lightload conditions ? very small external components ? inrush current limiting and internal soft start ? overvoltage protection ? shortcircuit protection ? tsot238 package applications ? batterypowered products ? personal medical devices ? portable media players ? wireless peripherals ? handheld computers and smartphones all mps parts are lead free and adhere to the rohs directive. for mps green status, please visit mps website under quality assu rance. mps and the future of analog ic technology are registered trad emarks of monolithic power systems, inc. typical application circuit
mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 2 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. ordering information part number* package top marking MP3418GJ tsot238 aet * for tape & reel, add suffix Cz (e.g. MP3418GJCz); package reference top view 1 2 3 4 8 7 6 5 en fb sw pgnd in out nc agnd tsot23 8 absolute maximum ratings (1) sw pin, out pin ....................... 0.5v to + 6.5v all other pins ................................. 0 .5v to +6v continuous power dissipation (t a = 25c) (2) .................................................. .............. 1.25w junction temperature .............................. 150c lead temperature .................................. . 260c storage temperature .............. C65c to +150c recommended operating conditions (3) startup voltage v st .......................... 0.8v to 4v supply voltage v in ............................ 0.6v to 4v v out .................................................. 1.8v to 4v operating junction temp. (t j ). 40c to +125c thermal resistance (4) ja jc tsot238 ............................. 100 ..... 55 ... c/w notes: 1) exceeding these ratings may damage the device. 2) the maximum allowable power dissipation is a fun ctio n of the maximum junction temperature t j (max), the junctionto ambient thermal resistance ja , and the ambient temperature t a . the maximum allowable continuous power dissipation at any ambient temperature is calculated by p d (max)=(t j (max) t a )/ ja . exceedi ng the maximum allowable power dissipation will cause excessive die temperature, and the regul ator will go into thermal shutdown. internal thermal shutdown ci rcuitry protects the device from permanent damage. 3) the device is not guaranteed to function outsid e of its operation conditions. 4) measured on jesd517 4layer board. mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 3 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. electrical characteristics v in = v en = 1.8v, v out = 3.3v, t a = 25c, unless otherwise noted. parameters symbol condition min typ max units minimum startup voltage v st 0.8 1.0 v operating input voltage v in 0.6 4 v output voltage adjust range v out 1.8 4.0 v quiescent current i qns v en =v in =1.8v, v out =3.3v, no load, measured on out pin 38 50 a shutdown current i sd v en =v out =0v, measured on in pin 0.1 1 a in undervoltage lockout v uvlo v in rising 0.4 0.5 0.6 v operation frequency f sw 1.0 1.2 1.4 mhz feedback voltage v fb 1.19 1.21 1.23 v feedback input current i fb v fb =1.25v 1 50 na nmos onresistance r nds_on 110 m nmos leakage current i n_lk v sw =6.5v 0.1 1 a pmos onresistance r pds_on 120 m pmos leakage current i p_lk v sw =6.5v, v out =0v 0.1 1 a maximum duty cycle d max 85 90 % startup current limit i st_limit 200 ma nmos current limit i sw_limit 300 400 500 ma en input high level v en _ h 0.7 v en input low level v en_l 0.1 v en input current i en connect to v in 0.6 1.2 2 ua thermal shutdown (5) 150 c over temperature hysteresis (5) 20 c notes: 5 guaranteed by design, not tested mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 4 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. typical performance characteristics performance waveforms are tested on the evaluation board in the design example section. v in = 2.4v, v out = 3.3v, l = 6.8h, c out =10uf, t a = 25c, unless otherwise noted. mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 5 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. typical performance characteristics (continued) performance waveforms are tested on the evaluation board in the design example section. v in = 2.4v, v out = 3.3v, l = 6.8h, c out =10uf, t a = 25c, unless otherwise noted. mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 6 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. typical performance characteristics (continued) performance waveforms are tested on the evaluation board in the design example section. v in = 2.4v, v out = 3.3v, l = 6.8h, c out =10uf, t a = 25c, unless otherwise noted. mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 7 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. pin functions pin # name pin function 1 in input supply. requires bypass capacitor. 2 out output node. source of the internal synchronous rec tifier. place the output capacitor as close as possible between out and pgnd. 3 sw output switch node. connect the inductor to sw to complete the stepup converter. 4 pgnd power ground. reference ground of the regula ted output voltage. 5 nc no connection. 6 agnd analog ground. 7 fb feedback. connect to the tap of an external resistive voltage divider from the outp ut to fb to set the output voltage. 8 en enable input. turns regulator on (v en >0.7v) or off (v en <0.1v). dont apply a voltage greater than 6.5v to this pin. mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 8 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. block diagram driver and control logic + current sense amplifier oscillator sw out agnd ea fb en bias and voltage ref 1. 21v slope comp pwm c omp startup mode control v in body control vdd in enable + + + v better soft start fb ovp clamp s thermal control + zero current cross comp out pgnd pgnd hs ls l v in on off pgnd vout pgnd cout r1 r2 cin pgnd figure 1: functional block diagram mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 9 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. operation the mp3418 is a 1.2mhz, synchronous, step up converter housed in a compact tsot23 package with true output disconnect. able to operate at lowinput voltages of less than 0.8v, the device features fixedfrequency current mode pwm control for exceptional line and load regulation. internal softstart and loop compensation simplify the design process and minimize the external components. the internal lowr ds(on) mosfets combined with power save mode operation enable the device to maintain high efficiency over a wide current load range. synchronous rectifier the mp3418 integrates an nchannel and a p channel mosfet to realize a synchronous rectifier. replacing the traditional schottky diode with a lowr ds(on) pmos improves efficiency. in a conventional synchronous rectifier, the pmos body diode is forward biased, and the current flows from v in to v out . the mp3418 allows for true output disconnect by eliminating the body diode, and prevents battery depletion when the converter shuts down. to prevent excessive inductor current, the pmos synchronous rectifier only functions when v out > (v in +200mv). startup when en is on, the mp3418 starts up with a linear charge period. during this linear charge period, the rectifier pmos turns on until the output capacitor charges to v in C200mv; the pmos current is limited during this period to around 200ma to avoid inrush current. this circuit also helps to limit the output current under short circuit conditions. after the linear charging period, the device starts switching. if v out remains below 1.7v, the part then works in freerunning mode; in this mode, the device works in open loop first at a variable frequency then at a fixed 500khz switching frequency, the duty cycle depends on the inputoutput ratio, and the switching current is limited to 400ma to avoid the startup current inrush. the internal softstart (ss) does not take charge and continues to rise following the fb voltage during the linear charging and free running period. once the output voltage reaches 1.7v, the normal closedloop operation initiates, v out starts to rise under the control of ss. it then works either in boost mode or down mode depending on v in and v out . table 1 lists the operation modes during start up. table 1: operation mode during startup sequence v out mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 10 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. monitoring circuit and error amplifier with loop compensation for peakcurrentC mode control remain active. the output ripple, which is usually around 1% peak to peak, can be reduced by increasing the output capacitance and also by adding a small feedforward capacitance (around 5.6pf). the mp3418 operates from psm to pwm mode depending on the load, which varies with the input voltage, inductor value, and the output capacitor value. undervoltage lockout undervoltage lockout prevents device startup when v in falls below 0.5v while in operation and the battery is being discharged. error amplifier the error amplifier (ea) is an internally compensated amplifier. the ea compares the internal 1.21v reference voltage against v fb to generate an error signal. the output voltage of mp3418 could be adjusted from 1.8v to 4v by connecting fb to the tap of an external voltage divider from v out to ground, as per the following equation: r1 out r2 v 1.21v (1 ) = + (1) set r1 and r2 as large as possible to achieve a low quiescent current. usually, select an r1 value larger than 300k for good stability and transient balance. current sensing lossless current sensing converts the nmos switch current signal to a voltage that can be summed with the internal slope compensator. the difference between this summed signal and the error amplifier output provides control over the peak current through the pwm. peak switch current is limited to approximately 400ma, independent of input or output voltage. the switching current signal is blanked for 60ns to enhance noise rejection. thermal protection the device has an internal temperature monitor if the die temperature exceeds 150c, the switches turn off. once the output drops below 1.7v, it will turn on.. output disconnect and inrush limiting the mp3418 is designed to allow true output disconnect by eliminating the internal pmos rectifiers body diode conduction. this feature allows v out to go to 0v during shutdown and draw 0a from the input source. it also allows for inrush current limiting at startup, which minimizes surge currents at the input supply. note that to optimize output disconnect, exclude the external schottky diode between sw and v out . to minimize voltage overshoot on the sw pin due to stray inductance, keep the output filter capacitor as close as possible to the v out pin and use very low esr/esl ceramic capacitors tied to a clean ground plane. shortcircuit protection unlike most stepup converters, the mp3418 allows for short circuits on the output. in the event of a short circuit, the device first turns of f the nmos when the sensed current reaches the current limit. the device then enters a linear charge period with the current limited as with the startup period. in addition, the thermal regulation circuit further controls the input current if the die temperature rises above 150c. down mode (v in >v out ) operation the mp3418 will continue to regulate the output voltage even when the input voltage exceeds the output voltage. this is achieved by terminating the switching at the synchronous pmos and applying v in statically on its gate. this ensures that the slope of the inductor current will reverse while current flows to the output. since the pmos no longer acts as a lowimpedance switch in this mode, power dissipation increases within the ic to cause a sharp drop in efficiency. limit the maximum output current to maintain an acceptable junction temperature. mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 11 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. application information component selection input capacitor selection low esr input capacitors reduce input switching noise and reduce the peak current drawn from the battery. it follows that ceramic capacitors are also a good choice for input decoupling and should be located as close as possible to the device. add a ceramic capacitor larger than 4.7f in parallel with a 100nf ceramic capacitor close to the ic. output capacitor selection the output capacitor requires a minimum capacitance value of 10f at the programmed output voltage to ensure stability over the full operating range. a higher capacitance value may be required to lower the output ripple and also the transient response. low esr capacitors, such as x5r or x7rtype ceramic capacitors, are recommended. assuming that the esr is zero, estimate the minimum output capacitance to support the ripple in the pwm mode as. o out(max) in(min) o s out(max) i (v v ) c f v v ? (2) where, v out(max) = maximum output voltage v in(min) = minimum input voltage i o =output current f s = switching frequency v= acceptable output ripple additional output capacitance may also be required for applications where v in v out to reduce ripple in psm mode and to ensure stability in pwm mode, especially at higher output load currents. inductor selection the mp3418 can use small surfacemount inductors due to its 1.2mhz switching frequency. inductor values between 4.7h and 10h are suitable for most applications. larger values of inductance will allow slightly greater output current capability (and lower the psm threshold) by reducing the inductor ripple current. increasing the inductance above 10h will increase component size while providing little improvement in output current capability. the minimum inductance value is given by: in(min) out(max) in(min) out(max) l s v (v v ) l 2 v i f ? (3) where i l is the acceptable inductor current ripple the inductor current ripple is typically set at 30% to 40% of the maximum inductor current. highfrequency ferritecore inductor materials reduce frequencydependent power losses and improve efficiency compared to cheaper powderediron cores. the inductor should have low dcr (inductor series resistance without saturated windings) to reduce the resistive power loss; further reducing the dcr will significantly improve efficiency when dcr< mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect mp3418 rev 1.0 www.monolithicpower.com 13 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. typical application circuits sw l out in p gnd fb en r1 r2 c 2a vout 1.8v 1.2v c 1a 18 3 2 7 4 a gnd 6 nc 5 v in mp3418 6.8 h c 1b 4.7 f 10 f 0.1 f 0.1 f c 2b 365k 750k 100k r3 figure 3: boost circuit. v in =1.2v, v out =1.8v. mp3418 C 400ma, 1.2mhz, synchronous, stepup conver ter with output disconnect notice: the information in this document is subject to cha nge without notice. users should warrant and guaran tee that third party intellectual property rights are not infringe d upon when integrating mps products into any appli cation. mps will not assume any legal responsibility for any said applic ations. mp3418 rev. 1.0 www.monolithicpower.com 14 2/7/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibi ted. ? 2013 mps. all rights reserved. package information tsot238 front view note: 1) all dimensions are in millimeters. 2) package length does not include mold flash, protrusion or gate burr. 3) package width does not include interlead flash or protrusion. 4) lead coplanarity ( bottom of leads after forming) shall be 0.10 millimeters max. 5) jedec reference is mo193, variation ba. 6) drawing is not to scale. top view recommended land pattern seating plane side view detail ''a'' see detail ''a '' |
Price & Availability of MP3418GJ
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |