e u p 2511 ds2 511 ver1.3 jun. 2012 1 h qi boost converter with 2.1a switch in tiny sot-23 package description the EUP2511 is a high performance current mode, pwm step-up converter. with an internal 2.1a, 150m mosfet, it can generate 5v at up to 900ma output current from a 3.6v supply. the fixed 600khz operating frequency allows small inductors and fast transient response. the internal compensation structure will reduce board size and the application cost. integrated internal soft-start also reduces inrush current during start-up. the EUP2511 regulates the output voltage up to 6v from either a 2-cell nimh/nicd or a single-cell li-ion battery. the EUP2511 is offered in sot23-5 package. typical application circuit features 90% efficiency 2.1a, 150m power mosfet adjustable output voltage input voltage range 2.7v-5v 600khz operating frequency 0.5 a shutdown current available in sot23-5 package rohs compliant and 100% lead(pb)-free halogen-free applications mobile phones gps pnd portable media handheld games figure1. v?mw`r?y?b? w w w . g o f o t e c h . c o m
EUP2511 ds2511 ver1.3 jun. 2012 2 typical application circuit (continued) figu r e2. pin configurations package type pin configurations sot23-5 pin description pin sot23-5 desc ription en 1 shutdown pin logic input. high = enabled, low = shutdown. gnd 2 ground. in 3 input voltage. input range: 2.7v to 5v. sw 4 switch pin. drain of the internal power switch. fb 5 feedback pin. 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
EUP2511 ds2511 ver1.3 jun. 2012 3 ordering information order number package type mark ing operating temperature range EUP2511vir1 sot23-5 xxxxx au00 -40 c to 85c EUP2511 l ead free code 1: lead free, halogen free packing r: tape & reel operating temperature range i: industry standard package type v:sot23 block diagram fig u re3. 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
EUP2511 ds2511 ver1.3 jun. 2012 4 absolute maximum ratings supply voltage, in ----------------------------------------------------------------------------------------- -0.3v to 6v sw ------------------------------------------------------------------------------------------------------------ -0.3v to 6v the other pins ---------------------------------------------------------------------------------------------- -0.3v to 6v power dissipation, pd@ t a =25c sot2 3-5 -------------------------------------------------------------------------------------------------------- 0.488w package thermal resistance ja (sot23-5) -------------------------------------------------------------------------------------------------- 205c/w maximum junction temperature ---------------------------------------------------------------------------- 125c lead temperature (soldering, 10sec.) ---------------------------------------------------------------------- 260c storage temperature range -------------------------------------------------------------------------- -65c to 150c recommended operating conditions min. max. unit supply voltage, v in 2.7 5 v operating free-air temperature, t a -40 85 c electrical characteristics (v in =3.3v, v out =5v, i out =200ma, c out =10f, c in =2.2f, l1=4.7h, r1=41.2k , r2 =13.3k , t a =-40c to 85c. unle ss otherwise noted. typical values are at t a = 25c) eup251 1 symbol parameter conditions min. typ. max. unit supply voltage 3.3 5.5 v uvlo under voltage lock out rising or falling 2.2 2.37 2.6 v i cc supply current cont inuous switching, v in =3.3v 0.6 1 ma i sd shutdown current v in =3.3v, v en <0.4v 0.1 1 a oscillator f osc switching frequency 450 600 750 khz d max maximum duty cycle 60 7 0 80 % reference voltage v fb feedback voltage 1.2 1.255 1.3 v mosfet v in =3.6v 0.1 8 0.3 r dson on resistance of mosfet v in =5v 0.1 5 0.25 i lim current limit 1.7 2.1 2.4 a control and protection v en1 shutdown voltage 0.4 0.7 v v en2 enable voltage 0.7 1.4 v i en en pin input leakage current 0. 1 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
EUP2511 ds2511 ver1.3 jun. 2012 5 switching duty cycle vs. temperature 72 72. 2 7 2.4 72.6 72.8 73 73.2 73.4 -40 -10 20 50 80 110 140 temperature ( ) duty cycle (%) vin=3.3v vin=4.5v typical operating characteristics test condition figure 1. figure4. figu r e6. figure8. figure5. figure7. figure9. efficiency vs. load current vout=5v 80 85 90 9 5 1 00 0 200 400 600 800 1000 load current (ma) efficiency (%) vin=2.7v vin=3.3v vin=4.5v max load current vs. vin vout=5v 0 200 4 0 0 600 800 1000 1200 1400 1600 2.5 3 3.5 4 4.5 5 vin (v) max load current (ma) feedback voltage vs. temperature 1.23 1.2 3 5 1.24 1.245 1.25 1.255 -40 10 60 110 160 temperature ( ) feedback voltage (v) r ds(on) vs. temperature 0 50 10 0 1 50 200 250 300 -40 -20 0 20 40 60 80 100 120 temperature ( ) r ds(on) (m ) vin=3.3v vin=4.5v r ds(on) vs. vin 0 50 10 0 1 50 200 250 2.5 3 3.5 4 4.5 5 vin (v) r ds(on) (m ) 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
EUP2511 ds2511 ver1.3 jun. 2012 6 typical operating characteristics (continued) test condition figure 1. figure10. test condition figure 2. figure 1 2. figure11. figure 1 3. current limit vs. vin 1.9 2 2.1 2.2 2. 3 2 .5 3 3.5 4 4.5 5 vin (v) current limit (a) typical switching waveform il vsw vin vout efficie ncy vs loa d curre nt 81% 84% 87% 90% 93% 96% 0 200 400 600 800 1000 load current (ma) efficiency (%) vin=3v vin=3.3v max loa d current vs vin 500 700 900 1100 1300 1500 1700 1900 2100 2.5 3.5 4.5 vin (v) max load current (ma) vout=5v 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
EUP2511 ds2511 ver1.3 jun. 2012 7 application information the EUP2511 uses a 600khz fixed-frequency, curren t-mode regulation architecture to regulate the output voltage. the EUP2511 measures the output voltage through an external resistive voltage divider and compares that to the internal 1.25v reference to generate the error voltage. the current-mode regulator compares the error voltage to the inductor current to regulate the output voltage. the use of current-mode regulation improves transient response and control loop stability. output voltage an external feedback resistor divider is required to divide the output voltage down to the nominal 1.25v 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 r2 in the range of 10k to 50 k . the boost converter output voltage s determined by the relationship: ? ? ? ? ? ? ? ? += 2 r 1 r 1 fb v out v the nominal vfb voltage is 1.255v inducto r 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 600khz.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 e s r 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 l oad t ransient requirement. a 4.7f to 10f ceramic capacitor is suitable for most application. 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 2a, the current limit of the EUP2511. 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. selecting input capacitor for boost converter an input capacitor is required to serve as an energy reservoir for the current which must flow into the coil each time the switch turns on. this capacitor must have extremely low esr, so ceramic is the best choice. a nominal value of 4.7f is recommended, but larger values can be used. since this capacitor reduces the amount of voltage ripple seen at the input pin, it also reduces the amount of emi passed back along that line to other circuitry. maximum output current the output current capability of the EUP2511 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, 600khz. d = mosfet turn-on ratio: 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 + = ( ) 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
EUP2511 ds2511 ver1.3 jun. 2012 8 layout considerations high frequency switching regulators require very careful layout for stable operation and low noise. all components must be placed as close to the ic as possible. sw is of high noise, a small area is recommended on pcb layout to reduce emi and high frequency noise injection. all feedback components must be kept close to the fb pin to prevent noise injection on the fb pin trace. the ground return of c1 and c2 should be tied close to the gnd pin. 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
EUP2511 ds2511 ver1.3 jun. 2012 9 package information sot23- 5 millimeters inche s symbols min. max. min. max. a - 1.30 - 0.052 a1 0.00 0.15 0.000 0.006 d 2.90 0.114 e1 1.60 0.063 e 2.60 3.00 0.102 0.118 l 0.30 0.60 0.012 0.024 b 0.30 0.50 0.012 0.020 e 0.95 0.037 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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