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5v 6a 1.2mhz synchronous boost converter ec 9288 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 1 o f 1 2 4 g18 n - rev. f 001 figu r e 1 pin c o nfigu r ation o f ec92 88 ( t o p v i e w ) general description the ec 9288 is a synchronous rectifier, fixed switching frequency (1.2mhz typical), and current - mode step - up regulator. the device allows use o f small inductors and output capacitors for usb devices. the current - mode control scheme provides fast transient respon se and good output voltage accuracy. at light loads, the EC9288 will automatically enter in pulse frequency modulation (pfm) operation to reduce the dominant switching losses. during pfm operation, the ic consumes very low quiescent current and maintains h igh efficiency over the complete load range. the EC9288 also includes current - limit and over temperature shutdown to prevent damage in the event of an output overload. the EC9288 is available in sop - 8 (exposed pad) packages. featur e s applications pin configurations
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 2 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 9288 pin description ordering information part number package marking marking information ec92 88 nn mh r sop - 8 expo sed pad 9288 llll yyww 1. llll lot no 2. yyww date code no. name function 1 v bat converter supply voltage. 2 p si power saving input. force v psi exceed 1v enter pfm. left v psi below 0.4v enter pwm mode 3 en device enable control input. force v en exceed 1v enable the device. left v en below 0.4v to shutdown. 4 gnd signal ground. connect this pin to p gnd . 5 fb converter feedback input. 6 v out converter output and ic supply voltage 7 sw converter switch pin. connect inductor here. 8 p gnd power ground . connect these pins to gnd. EC9288nn xx x r=tape & reel package type mh=sop 8(exposed pad)
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 3 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 functional block diagram fi gu r e 2 f u n c t i o n block diag r am of ec92 88
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 4 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 symbol parameter rating unit v out output and ic supply voltage (v out to gnd) - 0.3 ~ 7 v v bat converter supply voltage (v bat to gnd) - 0.3 ~ 7 v v sw sw to gnd voltage >30ns - 0.3 ~ 7 v <30ns - 0.3 ~ 9 v en and fb to gnd voltage - 0.3 ~ 7 v pgnd to gnd - 0.3 ~+0.3 v t j maximum junction temperature 150 c t stg storage temperature - 65 ~ 150 c t sdr maximum lead solderin g temperature (10 seconds) 260 absol u te maximum ra ti n gs note1: stresses beyond those listed under "absolute maxim um ratings" may cause permanent damage to the device. these are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. thermal characteristics ja is measured with the component mounted on a high effective thermal conductivity test board in free air. re co m m e nd e d o p e ra t i n g c o n d i t i o n s (note 3) symbol parameter rating unit v out output and ic supply voltage (v out to gnd) 2.7 ~5.5 v v bat converter supply voltage (v bat to gnd) 1.8 ~ v out v v sw sw to gnd voltage >30ns - 0.3 ~ v out +0.3 v <30ns - 3 ~ v ou t +3 v lbi, sync, en, lbo and fb to gnd voltage 0 ~ v out v t j junction temperature - 40 ~ 125 c t a ambient temperature - 40 ~ 85 note 3 : refer to the typical application circuit symbol parameter typical value unit ja junction - to - ambient resistance in free air (note 2) 50 jc junction - to - case resistance 20
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 5 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 electrical characteristics unless otherwise specified, these specifications apply over v bat =3.3v, v out =5v and ta= 25 symbol parameter test conditions mi n typ max unit v bat converter supply voltage range 1.8 - 5.5 v v out converter output and ic supply voltage 3.0 - 5.5 v i dd1 no switching quiescent current measured from v out , v fb =0.6v, v out =3.3v - 40 60 ua i vbat v bat quiescent current m easured from v bat , v bat =3.3v, en=h - 0.5 1 ua i vbat - sd v bat quiescent current v en =gnd, v bat =3.3v (isolate v bat & v out ) - 0.1 1 ua v uvlo v bat under voltage lockout threshold 1.6 1.7 1.8 v v ref regulated feedback voltage 490 500 510 mv i fb fb inp ut leakage current - 100 - 100 na over temperature protection (note 4) hysteresis(note 4) t j falling - 30 - o c f osc switching frequency fb=gnd 900 1200 1500 k hz r n - fet n - fet switch on resistance v out =5v - 55 - m? r p - fet p - fet switch on resis tance v out =5v - 55 - m? n - fet current limit v out =5v 6 - - a dead - time (note 4) v out =3.3v~5v - 10 - ns d max sw maximum duty cycle 85 95 - % pfm current limit - 700 - ma en en input low threshold - - 0.4 v en input high threshold 1 - - v internal pull low - 500 - k? psi psi input low threshold - - 0.4 v psi input high threshold 1 - - v i en en input leakage current v en =1.5v - 3 5 ua i psi psi input leakage current v psi =1.5v - 0.4 1 ua v zc p - fet zero current detect - +1 00 - ma v fb under voltage protection 70 75 80 %v ref uvp debounce (option) - 2 - us t otp over temperature protection (note 4) (note 4) t j rising - 150 - over temperature protection (note 4) hysteresis(note 4) t j falling - 30 - note 4: guaranteed by design, not production tested.
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 6 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 typical operating characteristics
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 7 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 typical operating characteristics(cont.)
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 8 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 typical operating characteristics(cont.)
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 9 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 typical operating characteristics(cont.)
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 10 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 928 8 typical applicati on circuit function description main control loop t he EC9288 is a constant frequency, synchronous rectifier, and current - mode switching regulator. in normal operation, the internal n - channel power mosfet is turned on each cycle when the oscillator sets an internal rs latch and turned off when an internal c omparator (icmp) re sets the latch. the peak inductor current wh ich icmp resets the rs latch is controlled by the voltage on the comp node, which is the output of the error amplifie r (eamp). an external resistive divider connected between v out and ground al lows the eamp to receive an output feedback voltage v fb at fb pin. when the load current increases, it causes a slightly decrease in v fb relative to the 0.5v refe rence, which in turn causes the comp voltage to increase unt il the average inductor current ma tches the new load current. start - up a start - up oscillator circuit is integrated in the EC9288 . when the device enables, the c ircuit pumps the output voltage high. once the output voltage reaches 1.6v (typ), the main dc - dc circuitry turns on and boosts th e output voltage to the final regulation voltage. automatic pfm/pwm mode switch the EC9288 is a f ixed frequency pwm peak current modulation control step - up converter. at light loads, the EC9288 will automat ically enter in pulse frequency modulation operation to reduce t he dominant switching losses. in pfm operation, the inductor current may reach zero or reverse on each pulse. a zero current comparator turns off the p - channel synchronous mosfet, forcing dcm(discontinuous current mode) operation at light load. these contr ols get very low quiescent current, help to maintain high efficiency over the complete load range. synchronous rectification the internal synchronous rectifier eliminates the need for an external schottky diode, thus reducing cost and board space. during the cycle off - time, th e p - fet turns on and shunts the fet body diode. as a re sult, the synchronous rectifier significantly improves effici ency without the addition of an external component. conversi on efficiency can be as high as 92%.
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 11 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 9288 load disconnect driving en to ground places the ec92 88 in shutdown mode. when in shutdown, the internal power mosfet turns off, all internal circuitry shut s down and the quiescent supply current reduces t o 1 u a maximum. a special circuit is applied to disconnect the load from the input during shutdown the converter. in conventional synchronous rectifier circu its, the back - gate diode of the high side p - fet is forwar d biased in shutdown and allows current flo wing from the batte ry to the output. however, this device uses a special circuit, which takes the cathode of the back - gate diode of the hig h - side p - fet and disconnects it from the source when the reg ulator is shutdown. the benefit of this feature for the s yste m design engineer is that the battery is not depleted durin g shutdown of the converter. no additional components must be added to the design to make sure that the battery is disc onnected from the output of the converter. current - limit protection th e ec92 88 monitors the inductor current, flowing through the n - fet, and limits the current peak at current limit level to prevent loads and the ec92 88 from damages during overload conditions. over - temperature protection (otp) the over - temperature circuit li mits the junction temperature of the ec92 88. when the junction temperature exceeds 150 , a thermal sensor turn s off the both n - fet and p - fet, allowing the devices to cool . the thermal sensor allows the converters to start a soft - start process and regulate the output voltage again after the junction temperature cools by 30 . the otp is designed with a 30 hysteresis to lower the average junction temperature (t j ) during continuous thermal overload conditions, increasing the lifetime of the device.
e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 12 o f 1 2 4 g18 n - rev. f 001 5v 6a 1.2mhz synchronous boost converter ec 9288 package information sop 8l (exposed pad) p ack a ge out l ine dimensions

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