EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 1 of 10 2007/04/10 general description the EC9410 is a 380 khz fixed frequency monolithic step down switch mode regulator with a built in internal power mosfet. it achieves 2a continuous output current over a wide input supply range with excellent load and line regulation. the device includes a voltage reference, oscillation circuit, error amplifier, internal pmos and etc. the pwm control circuit is able to adjust the duty ratio linearly from 0 to 100%. an enable function, an over current protection function and a short c ircu i t protection function are built inside. an internal compensation block is built in to minimize external component count. the EC9410 serves as ideal power supply units for portable devices. function block features z 2a constant output current z 140m ? r dson internal power pmosfet switch z up to 95% efficiency z fixed 380khz frequency z wide 3.6v to 20v input voltage range z output adjustable from 1.222v to 18v z built in frequency compensation z built in thermal shutdown function z built in current limit function z sop8 package is available z the minimum dropout up to 0.3v applications z portable dvd z lcd monitor / tv z battery charger z adsl modem z telecom / networking equipment www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 2 of 10 2007/04/10 pin assignments pin number pin name description 1,6,8 nc not connect 2 vin supply voltage input pin. EC9410 operates from a 3.6v to 20vdc voltage. bypass vin to gnd with a suitably large capacitor to eliminate noise on the input. 3 sw power switch output pin. sw is the switch node that supplies power to the output. 4 gnd ground pin. care must be taken in layout. this pin should be placed outside of the schottky diode to output capacitor ground path to prevent switching current spikes from inducing voltage noise into EC9410. 5 fb feedback pin. through an external resistor divider network, fb senses the output voltage and regulates it. the feedback threshold voltage is 1.222v. 7 en enable pin. en is a digital input that turns the regulator on or off .drive en pin high to turn on the regulator, drive it low to turn it off. ordering/ marking information package type part number marking marking information sop8 EC9410n-f EC9410-f yyww xxxxxxxx f is lead free package yy is the year of production. 06 means the product is manufactured in year of 2006. ww is the week of production. 25 means the product is manufactured in the 25 th week. xxxxxxxx is lot number. EC9410 n - f package: n = sop8 circuit type f: lead-free pin description www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 3 of 10 2007/04/10 absolute maximum ratings parameter symbol value unit input voltage v in -0.3 to 20 v feedback pin voltage v fb -0.3 to vin v enable pin voltage v en -0.3 to 12 v switch pin voltage v sw -0.3 to vin v power dissipation p d internally limited mw operating junction temperature t j 150 oc storage temperature t stg -65 to 150 oc lead temperature (soldering, 10 sec) t lead 260 oc esd (hbm) v esd 2000 v note1: stresses greater than those listed under maximum ratings may cause permanent damage to the device. this is a stress rating only and functional operati on of the device at these or any other conditions above th ose indicated in the operation is not implied. exposure to absolute maximum rating conditions for extended periods may affec t reliability. recommended operating conditions parameter symbol min. max. unit input voltage v in 3.6 20 v operating junction temperature t j -40 125 oc operating ambient temperature t a -40 85 oc www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 4 of 10 2007/04/10 electrical characteristics v cc = 12v, t a = 25 unless other wise specified. parameters symbol test condition min. typ. max. unit input voltage v in - 3.6 - 20 v shutdown supply current i stby v en =0v - 30 90 ua supply current i cc v en =2v, v fb =1.3v - 3.6 4 ma feedback voltage v fb v in = 3.6v to 23v 1.21 1.222 1.26 v feedback bias current i fb v fb =1.3v - 0.1 0.5 ua switch current limit i lim - - 3 4 a oscillator frequency f osc - 320 380 440 khz frequency of current limit or short circuit protection f osc1 v fb =0v - 42 - khz en pin threshold v en - 0.7 1.2 1.7 v i h v en =2.5v - -0.1 -1 ua en pin input leakage current i l v en =0.5v - -3 -10 ua internal pmos r dson r dson v in =12v,v fb =0v v en =12v, iout=2a - 140 - m ? max. duty cycle d max v fb =0v, i sw =0.1a - 100 - % efficiency v in =12v,vout=5v iout=2a - 92 - % thermal shutdown t otsd - - 165 - oc www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 5 of 10 2007/04/10 typical performance characteristics switching frequency vs. temperature v fb vs. temperature icc vs. temperature efficiency vs. load (vin=10v) www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 6 of 10 2007/04/10 typical application circuit typical application circuit @ 5v/2a typical application circuit @ 3.3v/2a EC9410 EC9410 www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 7 of 10 2007/04/10 typical application circuit (continued) typical application circuit (with ceramic output capacitor) @ 5v/2a typical application ci rcuit (with ceramic output capacitor) @ 3.3v/2a EC9410 EC9410 www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 8 of 10 2007/04/10 schottky rectifier selection guide EC9410 lists some rectifier manufacturers. 2a load current vin (max) part number vendor b220 diodes, inc. sk23 pan jit international 20v sr22 pan jit international output vo l t a g e vs r1, r2 resistor selection guide (vout = (1+r1/r2)*1.222v) EC9410 vout vs. r1, r2 select table vout r1 r2 1.8v 3.9k 8.2k 2.5v 3.2k 3k 3.3v 6.2k 3.6k 5v 6.2k 2k 9v 13k 2k 12v 16k 1.8k www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 9 of 10 2007/04/10 function description vin this is the positive input supply for the ic switching regulator. a suitable input bypass capacitor must be present at this pin to minimize voltage transients and to s upply the switching current s needed by the regulator gnd circuit ground. sw internal switch. the voltage at this pin switches bet ween (vin ? vgs) and approximately ? 0.5v, with a duty cycle of approximately vout / vin. to minimize coupli ng to sensitive circuitry, the pc board copper area connected to this pin should be kept a minimum. fb senses the regulated output voltage to complete the feedback loop. en allows the switching regulator circuit to be shutdown using logic level signals thus dropping the total input supply current to approximately 30ua. pulling this pin below a threshold voltage of approximately 0.7 v turns the regulator down, and pulling this pin above 1.3v (up to a maximum of 12v) shuts the regulator on. for automatic starup condition, can be implemented by the addition of a resistive voltage divider from vin to gnd. thermal considerations the sop8 package needs a heat sink under most conditio ns. the size of the heat sink depends on the input voltage, the output voltage, the load current and the ambient temperature. the EC9410 junction temperature rises above ambient temperature for a 2a load and differ ent input and output voltages. the data for these curves was taken with the EC9410 (sop8 package) operating as a buck-switching regulator in an ambient temperature of 25 oc (still air). these temperature rise numbers are all approximate and there are many factors that can affect these temperatures. higher ambient temperatures require more heat sinking. for the best thermal performance, wide copper traces and generous amounts of printed circuit board copper should be used in the board layout.(once exception to this is the output (switch) pin, which should not have large areas of copper.) large areas of copper provide the be st transfer of heat (lower thermal resistance) to the surrounding air, and moving air lowers the thermal resistance even further. package thermal resistance and junction temperature ri se numbers are all approximate, and there are many factors that will affect these numbers. some of these factors include board size, s hape, thickness, position, location, andeven board temperature. other factors are, trace width, total printed circuit copper area, copper thickness, single or double-sided, multi-layer board and the amount of solder on the board. the effectiveness of the pc board to dissipate heat also depends on the size, quantity and spacing of other components on the board, as well as whether the surrounding air is still or moving. furthermore, some of these components such as the catch diode will add heat to the pc board and the heat can vary as the input voltage changes. for the inductor, depending on the physical size, type of core material and the dc resistance, it could either act as a heat sink taking heat away from the board, or it could add heat to the board. www.datasheet.co.kr datasheet pdf - http://www..net/
EC9410 2a 380khz 20v pwm buck dc/dc converter e-cmos corp. ( www.ecmos.com.tw ) page 10 of 10 2007/04/10 outline drawing for sop-8 www.datasheet.co.kr datasheet pdf - http://www..net/
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