unisonic technologies co., ltd LC1126 preliminary linear integrated circuit www.unisonic.com.tw 1 of 6 copyright ? 2013 unisonic technologies co., ltd qw-r102-050.a ultra low output voltage linear n-fet controller ? description the utc LC1126 is an ultra low output voltage linear n-fet controller designed to provide well supply voltage for front-side-bus termination on mot herboards and nb applications. the utc LC1126 integrates many functions. a power-on-reset (por) circuit monitors supply voltages to prevent wrong operations. a pok indicates the out put status with time delay which is set internally. it can control other converter for power sequence. it can available for sc-59-6 package. the utc LC1126 can be enabled by other power system. a 0.5v reference voltage with 2% accuracy providing tight regulation of the output voltage, enable control, open drain power good signal, under-voltage protection and soft start. ? features * mlcc and poscap stable * 0.5v2% reference voltage * internal soft-start * enable control * fast transient response * under-voltage short circuit protection * power ok output with a delay time * adjustable output voltage down to 0.5v * drive n-channel mosfets sot-26 4 5 3 2 1 6 ? ordering information ordering number package packing lead free halogen free LC1126l-ag6-r LC1126g-ag6-r sot-26 tape reel LC1126l-ag6-r (1)packing type (2)package type (3)halogen free (1) r: tape reel (2) ag6: sot-26 (3) l: lead free, g: halogen free
LC1126 preliminary linear integrated circuit unisonic technologies co., ltd 2 of 6 www.unisonic.com.tw qw-r102-050.a ? marking information ? pin configuration ? pin description pin no. pin name description 1 v cc input voltage 2 gnd ground 3 pok power ok output pin 4 en h: normal operation, l: shutdown 5 fb feedback pin 6 drv gate drive to n-fet
LC1126 preliminary linear integrated circuit unisonic technologies co., ltd 3 of 6 www.unisonic.com.tw qw-r102-050.a ? block diagram gnd en v cc fb drv pok pok delay + - 92% v ref 0.25v uv + - + - vref=0.5v error amp power-on reset enable thermal shutdown soft-start and control logic
LC1126 preliminary linear integrated circuit unisonic technologies co., ltd 4 of 6 www.unisonic.com.tw qw-r102-050.a ? absolute maximum rating (t a =25c, unless otherwise specified) parameter symbol ratings unit supply voltage vcc -0.3~7 v drv to gnd -0.3~v cc +0.3 v power dissipation p d 0.4 w junction temperature t j -40~+125 c operating temperature t opr -40~+85 c storage temperature t stg -65~+150 c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? electrical characteristics (v in =1.5v, v shdn =v in , t a =25c, c in =c out =1f, unless otherwise noted.) parameter symbol test conditions min typ max unit supply voltage range v cc 4.5 5.5 v input voltage uvlo threshold v uvlo v cc rising 3.75 v input voltage uvlo hysteresis v hyst v cc falling 0.25 v supply current i cc en=v cc 0.4 0.8 ma shutdown current i sd en=0v -1 1 a feedback voltage v fb 0.49 0.5 0.51 v feedback pin input current i fb vfb=0.5v -100 100 na soft start time tss 1 ms en pin logic high threshold voltage v enh enable 1.3 v v enl disable 0.5 v en pin input current i en i out =0ma, v in =5v -1 +1 a output voltage uvlo threshold v th ( uv ) v fb falling 0.2 0.25 0.3 v ton duty t on v fb <0.25v 30 % drv output current i drv ( src ) sourcing, v fb =0.48v 20 ma i drv ( sink ) sinking, v fb =0.52v 20 ma drv pin output voltage v drv v fb =0.48v, v cc =5v, no load 4.9 5.0 v pok threshold voltage for power ok v pok v fb rising 90% 93% 96% vfb pok threshold voltage for power not ok v pnok v fb falling 82% 85% 88% vfb pok low voltage pok sinks 1ma 50 100 mv pok delay time t delay 0.8 2 10 ms thermal shutdown temperature t sd 150 c thermal shutdown hysteresis 50 c
LC1126 preliminary linear integrated circuit unisonic technologies co., ltd 5 of 6 www.unisonic.com.tw qw-r102-050.a ? function descriptions power-on-reset a power-on-reset (por) circuit monitors the vcc pin voltage (vcc) for power-on-reset function to prevent wrong operation. the built-in por circui t keeps the output shutting off until in ternal circuit is operating properly.. internal soft-start an internal soft-start provides an intern al soft-start circuitry to control rise rate of the output vo ltage and limit the current surge during start-up. the typical soft-start interval is about 1ms. output voltage regulation an error amplifier working with a temperature compens ated 0.5v reference and an out put nmos regulates output to the preset voltage. the error ampl ifier designed with high bandwidth and dc gain provides very fast transient response and less load regulation. under-voltage protection (uvp) utc LC1126 monitors the voltage on fb pin after soft-start pr ocess is finished. therefore the uvp is disabling during soft-start. when the voltage on fb pin falls below the under-voltage threshold, the uvp circuit shuts off the output immediately. after a while (~70% duty), utc LC1126 starts a new soft-start to regulate output. thermal shutdown a thermal shutdown circuit limits the junction temperature of utc LC1126 . when the junction temperature exceeds +150c, a thermal sensor turns off the output nm os, allowing the device to cool down. the regulator regulates the output again thro ugh initiation of new soft-start cycle after the junction temperature cools by 50c, resulting in a pulsed output during cont inuous thermal overload conditions. ? typical application circuit v cc =5v c3 0.1f u1 v cc 1 2 gnd 3 pok utc LC1126 drv fb en 6 5 4 10k 56pf q1 mosfet n r1 43k r2 39k c2 10f 4.7f c1 v out =1.05v v in =1.5v v out =0.5v* (1+ r1 r2 ) c4
LC1126 preliminary linear integrated circuit unisonic technologies co., ltd 6 of 6 www.unisonic.com.tw qw-r102-050.a utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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