e u p 2627 ds2 627 ver1.1 mar. 2011 1 620khz/1.25mhz step-up dc/dc converter description the eup2627 is a high performance current mode, pwm step-up converter with pin selectable operating frequency. with an internal 3.5a, 160m mosfet, it can generate 12v at up to 500ma output current from a 5v supply. the selectable 620khz and 1.25mhz allows smaller inductors and faster transient response. an external compensation pin gives the user greater flexibility in setting loop compensation allowing the use of low esr ceramic output capacitors. soft-start is controlled with an external capacitor, which determines the input current ramp rate during start-up. when shut down, it draws 10a of current and can operate down to 2.5v input supply. these features along with 1.25mhz switching frequency makes it an ideal device for portable equipment and tft-lcd displays. the eup2627 is available in an 10-pin tdfn and msop-8 (ep) packages. the device is specified for operation over the full -40c to +85c temperature range. features 90% efficiency 3.5a, 160m power mosfet 2.5v to 5.5v input range adjustable output voltage up to 28v 620khz/1.25mhz switching frequency selection adjustable soft-start internal thermal protection small tdfn-10 and msop-8 (ep) packages rohs compliant and 100% lead (pb)-free halogen-free applications tft-lcd displays dsl modems set-top boxes pcmcia cards portable equipment handheld devices typical application circuit figure 1. v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 2 typical application circuit (continued) figur e 2. multiple-output tft lcd power supply pin configurations package type pin configurations package type pin configurations tdfn-10 msop-8 (ep) pin description pin tdfn-10 msop-8 (ep) description comp 1 1 compensation pin. output of the internal error amplifier. capacitor and resistor from c omp pin to ground. fb 2 2 voltage feedback pin. internal reference is 1.24v nominal. connect a resistor divider from v out . v out =1.24v (1+r 1 /r 2 ). shdn 3 3 shutdown control pin. pull shdn low to turn off the device. gnd 4.5 4 analog and power ground. sw 6.7 5 power switch pin. switch connected to the drain of the internal power mosfet . v in 8 6 analog power input pin. fsel 9 7 frequency select pin. when fsel is connected to gnd, switching frequency is set to 620khz. when connected to v in , switching frequency is set to 1.25mhz ss 10 8 soft-start control pin. connect a capacitor to control the converter start-up n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 3 ordering information order number package type markin g operating temperature range EUP2627JIR1 tdfn-10 xxxxx p2627 -40 c to +85c eup2627mir1 msop-8 (ep) xxxxx p2627 -40 c to +85c eup2627 lead free code 1: lead free, halogen free 0: lead packing r: tape & reel operat ing temperature range i: industry standard package type j : tdfn m: mso p block diagram figure 3. n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 4 absolute maximum ratings v in --------------------------------------------------------------------------------------- 6v sw voltages ---------------------------------------------------------------------------- 30v fb voltage ----------------------------------------------------------------------------- 6v shdn voltage ------------------------------------------------------------------------- 6v junction temperature ------------------------------------------------------------------ 150c lead temp (soldering, 10sec) --- --------------------------------------------------- 300c thermal resistance ja (msop-8_ep) --------------------------------------------------------------------- 70c/w ja (tdfn-10) ------------------------------------------------------------------------- 69c/w esd ratings human body model ---------------------------------------------------------------- 2kv operating conditions operating temperature -------------------------------------------------------- -40c to +85c supply voltage ------------------------------------------------------------------- 2.5v to 5.5v sw voltage max -------------------------------------------------------------------- 28v electrical characteristics v in =vshdn=3v. t a =-40 c to +85c. typica l values are at t a =+25c.unless otherwise noted. eup262 7 symbol parameter conditions min. typ. max. unit v out <18v 2.5 5.5 v in input voltage range 18v< v o ut <24v 4.0 5.5 v uvlo vin undercoltage lockout sw remains off below this level. v in rising,20mv hysteresis 1.92 2.15 2.35 v fb=2v (not switching) 0.5 0.8 ma fb=0v switching 1.5 2 ma i q quiescent current v shdn =0v 0.1 10 a v fb fb regulation voltage 1.20 1.24 1.27 v i b fb input bias current v fb =1.24v 100 250 na %v fb / v fb line regulation 2.5v v in 5.5v 0.08 0.15 %/v %v fb / i fb load regulation v out =8v,iload=30ma to200 ma 6.7 mv/a gm error amp transconductance i=4 a 20 45 95 mho a v error amp voltage gain 500 v/v fslct=ground 500 620 740 khz fs switching frequency fslct=v in 900 125 0 1500 khz d max maximum duty cycle 94 % i cl switch current limit 55% du ty cycle 2.6 3.5 a r dson switch mosfet on resistance i sw =500ma 0.16 0.35 i l switch leakage current v sw =20v 0.2 20 a i ss charge current v ss =0v 3 5 8 a v il shdn, freq input low voltage 0.5 v v ih shdn, freq input high voltage 2 v i fslct fslct pull down current 2.4 5.5 8.2 a n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 5 typical operating characteristics 1 10 100 1000 30 35 40 45 50 55 60 65 70 75 80 85 90 95 v in =5.5v v in =3v v in =2.5v v out =8v 620khz efficiency vs. load current efficiency (%) load current (ma) -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 550 560 570 580 590 600 610 620 630 v in =5.5v 620khz switching frequency vs. temperature v in =2.5v switching frequency (kha) temperature( 0 c) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 fslct pin current vs. fslct pin voltage t=-40 0 c t=85 0 c t=25 0 c fslct pin current(ua) fslct voltage(v) -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 1.00 1.25 1.50 1.75 2.00 2.25 2.50 v in =5.5v 620khz switching i q vs. temperature v in =2.5v switching i q (ma) temperature( 0 c) -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 v in =5.5v 1.25mhz switching i q vs. temperature v in =2.5v switching i q (ma) temperature( 0 c) -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 switching current limit vs temperature v in =5v v out =12v current limit (a) temperature( 0 c) n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 6 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0.30 0.35 0.40 0.45 0.50 0.55 0.60 620khz non-switching i q vs. input voltage t= 85 0 c t= 25 0 c t= - 40 0 c non-switching i q (ma) input voltage (v) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0.35 0.40 0.45 0.50 0.55 0.60 0.65 1.25mhz non-switching i q vs. input voltage t= 85 0 c t= 25 0 c t= - 40 0 c non-switching i q (ma) input voltage (v) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 620khz switching i q vs. input voltage t= 85 0 c t= 25 0 c t= - 40 0 c switching i q (ma) input voltage (v) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 1.5 2.0 2.5 3.0 3.5 4.0 1.25mhz switching i q vs. input voltage t= 85 0 c t= 25 0 c t= - 40 0 c switching i q (ma) input voltage (v) -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 6.8 v in =5.5v ss pin current vs. temperature v in =2.5v ss pin current(ua) temperature( 0 c) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 nmos r dson vs. input voltage t = - 40 0 c t = 25 0 c t = 85 0 c nmos r dson (o) input voltage (v) n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 7 application information boost converter operations in stea dy state operating and continuous conduction mode where the inductor current is continuous, the boost converter operates in two cycles. during the first cycle, the internal power fet turns on and the schottky diode is reverse biased and cuts off the current flow to the output. the output current is supplied from the output capacitor. the voltage across the inductor is vin and the inductor current ramps up in a rate of vin/l, l is the inductance. the inductance is magnetized and energy is stored in the inductor. the change in inductor current is: for stable operation, the same amount of energy stored in the inductor must be taken out. the change in inductor current during the two cycles must be the same. i1+ i2=0 output voltage an external feedback resistor divider is required to divide the output voltage down to the nominal 1.24v reference voltage. the current drawn by the resistor network should be limited to maintain the overall converter efficiency. the maximum value of the resistor network is limited by the feedback input bias current and the potential for noise being coupled into the feedback pin. selecting r 2 in the range of 10k to 50 k . the boost converter output voltage s determined by the relationship: the nominal vfb voltage is 1.24v inductor selection the inductor selection determines the output ripple voltage, transient response, output current capability, and efficiency. its selection depends on the input voltage, output voltage, switching frequency, and maximum output current. for most applications, a 4.7h inductor is recommended for 1.25mhz application and a 10h inductor is recommended for 620khz application. the inductor maximum dc current specification must be greater than the peak inductor current required by the regulator. the peak inductor current can be calculated: output capacitor low esr capacitors should be used to minimized the output voltage ripple. multilayer ceramic capacitors (x5r and x7r) are preferred for the output capacitors because of their lower esr and small packages. tantalum capacitors with higher esr can also be used. the output ripple can be calculated as: choose an output capacitor to satisfy the output ripple and load transient requirement. a 10f to 22f ceramic capacitor is suitable for most application. for noise sensitive application, a 0.1f placed in parallel with the larger output capacitor is recommended to reduce the switching noise coupled from the sw switching node. schottky diode in selecting the schottky diode, the reverse break down voltage, forward current and forward voltage drop must be considered for optimum converter performance. the diode must be rated to handle 3.5a, the current limit of the eup2627. the breakdown voltage must exceed the maximum output voltage. low forward voltage drop, low leakage current, and fast reverse recovery will help the converter to achieve the maximum efficiency. l out v in v t2 l i - = sw f d-1 t2 = 0 l out v in v sw f d1 l in v sw f d = - - + d1 1 in v out v - = ? ? ? ? ? ? ? ? += 2 r 1 r 1 fb v out v freq out vl ) in v out (v in v 1/2 in v out v out i l(peak) i - + = esr out i o c sw f d out i o v + = n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 8 input capacitor the value of the input capacitor depends the input and output voltages, the maximum output current, the inductor value and the noise allowed to put back on the input line. for most applications, a minimum 10f is required. for applications that run close to the maximum output current limit, input capacitor in the range of 22f to 47f is recommended. the eup2627 is powered from the vin. high frequency 0.1f by-pass cap is recommended to be close to the vin pin to reduce supply line noise and ensure stable operation. loop compensation the eup2627 incorporates an transconductance amplifier in its feedback path to allow the user some adjustment on the transient response and better regulation. the eup2627 uses current mode control architecture which has a fast current sense loop and a slow voltage feedback loop. the fast current feedback loop does not require any compensation. the slow voltage loop must be compensated for stable operation. the compensation network is a series rc network from comp pin to ground. the resistor sets the high frequency integrator gain for fast transient response and the capacitor sets the integrator zero to ensure loop stability. for most applications,the compensation resistor in the range of 2k to 30k and the compensation capacitor in the range of 1nf to 10nf. soft-start the soft-start is provided by an internal 5a current source charges the external css, the peak mosfet current is limited by the voltage on the capacitor. this in turn controls the rising rate of the output voltage. the regulator goes through the start-up sequence as well after the shdn pin is pulled to hi. frequency selection the eup2627 switching frequency can be user selected to operate at either at constant 620khz or 1.25mhz. connecting fsel pin to ground sets the pwm switching frequency to 620khz. when connect fsel high or vdd, switching frequency is set to 1.25mhz. shut-down control the eup2627 shuts down to reduce the supply current to 0.1 a when shdn is low. in this mode, the internal refere nce, error amplifier, comparators, and biasing circuitry turn off while the n-channel mosfet is turned off. the boost converters output is connected to in via the external inductor and catch diode. maximum output current the output current capability of the eup2627 is a function of current limit, input voltage, operating frequency, and inductor value. the output current capability is governed by the following equation: where: il=moset current limit avg-l i = average inductor current l i d = inductor ripple current vdiod e = schottky diode forward voltage, typically, 0.6v fs = switching frequency, 620khz or 1.25mhz d = mosfet turn-on ratio: layout considerations good pc board layout and routing are required in high-frequency switching power supplies to achieve good regulation, high efficiency, and stability. it is strongly recommended that the evaluation kit pc board layouts be followed as closely as possible. place power components as close together as possible, keeping their traces short, direct, and wide. avoid interconnecting the ground pins of the power components using vias through an internal ground plane. instead, keep the power components close together and route them in a star ground configuration using component-side coper, then connect the star ground to internal ground using multiple vias. ( ) l i2/1 avg - l i l i d+ = s f diode vo vl in v in vdiode v o v in v l i + - ? ? ? ? ? ? - + = ? ? ? ? ? ? ? ? ? ? ? ? d 1 out i avg-l i - = diode vout v in v 1d + -= n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 9 packaging information tdfn-1 0 millimeters inche s symbols min. max. min. max. a 0.70 0.80 0.028 0.031 a1 0.00 0.05 0.000 0.002 d 2.90 3.10 0.114 0.122 e1 1.70 0.067 e 2.90 3.10 0.114 0.122 l 0.30 0.50 0.012 0.020 b 0.18 0.30 0.007 0.012 e 0.50 0.020 d1 2.40 0.094 n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
eup2627 ds2627 ver1.1 mar. 2011 10 msop-8 (ep) millimeters inches symbols min. max. min. max. a - 1.10 - 0.043 a1 0.00 0.15 0.000 0.006 d 3.00 0.118 e 4.70 5.10 0.185 0.201 e1 3.00 0.118 d1 1.28 2.30 0.050 0.091 e2 1.21 1.72 0.048 0.068 l 0.40 0.80 0.016 0.031 b 0.22 0.38 0.008 0.015 e 0.65 0.026 detaila a n ~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? w w w . g o f o t e c h . c o m
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