unisonic technologies co., ltd ur5512 linear integrated circuit www.unisonic.com.tw 1 of 7 copyright ? 2009 unisonic technologies co., ltd qw-r101-017,d 2a ddr bus termination regulator ? description the utc ur5512 is a linear regulator which provides up to 2 amp bi-directional driving and sinking capability for ddr sdram bus terminator application. the output termination voltage tracks the reference voltage applied at v ref pin. a resistor divider connected to v in , gnd and v ref pins is used to force a reference voltage to v ref pin. the utc ur5512 contains a high-speed operational amplifier to provide excellent response to line/load transient. an active-low shutdown (v ref ) pin provides suspend to ram (str) functionality. additional features include curr ent limiting protection, on-chip thermal shut-down protection. ? features * ddr-i and ddr-ii termination voltage applications * driving and sinking current up to 2a * low output voltage offset (within 20mv@2a) * adjustable output voltage by external resistors * suspend to ram (str) functionality * current limiting protection * thermal protection * cost-effective and easy to use sop-8 hsop-8 to-252-5 1 lead-free: ur5512l halogen-free: ur5512g ? ordering information ordering number normal lead free plating halogen free package packing ur5512-s08-r ur5512l-s08-r ur5512g-s08-r sop-8 tape reel ur5512-sh2-r ur5512l-sh2-r UR5512G-SH2-R hsop-8 tape reel ur5512-tn5-r ur5512l-tn5-r ur5512g-tn5-r to-252-5 tape reel ur5512l-s08-r (1)packing type (2)package type (3)lead plating (1) r: tape reel (2) s08: sop-8, sh2: hsop-8, tn5: to-252-5 (3) g: halogen free, l: lead free, blank: pb/sn
ur5512 linear integrated circuit unisonic technologies co., ltd 2 of 7 www.unisonic.com.tw qw-r101-017,d ? pin configurations nc: no connection ? pin description pin name pin type pin description v in i power input pin gnd o ground pin v cntl i power input pin for internal control circuit v ref i reference voltage input and active-low shutdown control pin v out o output voltage pin
ur5512 linear integrated circuit unisonic technologies co., ltd 3 of 7 www.unisonic.com.tw qw-r101-017,d ? block diagram
ur5512 linear integrated circuit unisonic technologies co., ltd 4 of 7 www.unisonic.com.tw qw-r101-017,d ? absolute maximum ratings parameter symbol rating unit v cntl control voltage v cntl -0.2 ~ 7 v v in supply voltage v in -0.2 ~ 6 v power dissipation p d internally limited w junction temperature t j +125 c storage temperature t stg -40 ~ +150 c note: absolute maximum ratings are those values beyo nd which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? recommended operating conditions parameter symbol range unit v cntl control voltage (note 1) v cntl 3.1 ~ 6 v v in supply voltage v in 1.6 ~ 5.5 v v ref input voltage v ref 0.85 ~ 1.75 v v out output voltage (note 2) v out v ref 0.02 v v out output current i out -2 ~ +2 a junction temperature t j 0 ~ +125 c notes: 1. please always keep v cntl -v out > 1.9v for good regulation. 2. the v out tracks the v ref with additional voltage offset and load regulation. ? electrical characteristics (v in = 1.8v, v cntl = 5v, v refen = 0.5v in ), ta = 25c, unless otherwise specified) parameter symbol test conditions min typ max unit input current i out = 0a 2 4 ma operation current of v cntl i cntl v ref =gnd (shutdown) 1.9 ma v ref =1.25v 200 500 na current into v ref pin i ref v ref = gnd (shutdown) 20 40 a standby current i stb v ref < 0.2v, r load = 180 ? 50 90 a output voltage output voltage offset (v out - v ref ) v o(off) i out = 0a -20 6 +20 mv load regulation v load i out = 1.5a -20 +20 mv protection current limit i limit 2.0 a thermal shutdown temperature t sd v cntl = 5v 125 180 c thermal shutdown hysteresis t sd v cntl = 5v 40 c refen shutdown v ih enable 0.6 v shutdown threshold v il shutdown 0.15 v
ur5512 linear integrated circuit unisonic technologies co., ltd 5 of 7 www.unisonic.com.tw qw-r101-017,d ? functional description general information the utc ur5512 is a linear regulator designed for ddr sdram bus terminator application. the output, v out is capable of sourcing or sinking current up to 2a peak while regulating the output voltage to within 20mv offset. the utc ur5512 has excellent response to load regulation while preventing shoot through. active-low shutdown mechanism and fault protections. the utc ur5512 is available in several packages to meet different power dissipation and surface mount applications. output voltage regulation the output voltage tracks the reference voltage applied at v ref pin. two internal npn pass transistors act as the buffered output regulate the outpu t voltage by sourcing current from v in pin or sinking current to gnd pin. an internal kelvin sensing scheme is use at the v out pin to improve load regulation at various load current. since the utc ur5512 exhibits excellent response to load transi ent, lesser amount of capacitors can be used. current limit an internal current limiting sensor is used to monito r the maximum output current to prevent damages from overload or short-circuit condition. increasing the input voltage of v in or v cntl will get higher current-limit points. shutdown and soft-start an additional function of the v ref pin is acting as a shutdown c ontrol input that can be used for suspend to ram functionality . applying and holding a voltage below 0.15v to v ref pin shuts down the output of the regulator. an external npn transistor or n-channel mosfet is used to pull down the v ref pin voltage; while applying a ?high? signal to turn on the transistor. during shutdown conditi on, the two pass transistors are turned off and the output v out will tri-state; sourcing or sinki ng no current. when releasing the v ref pin, the current through the resistor divider charges the capacitor css to initiate a soft-start cycle. thermal shutdown if the junction temperature exceeds the thermal shutdown (t j = +150c) then the part will enter a shutdown state. a thermal sensor turns off bo th pass transistors, allowing the device to cool down. after the junction temperature reduces by 40c, the regulator starts to regulate again; resulting in a pulsed output during continuous thermal overload conditions. power inputs input powers up sequence are not required for v in and v cntl . be careful; do not apply voltage to v out when there is no v cntl voltage presented. this is due to the internal parasitic diodes between v out to v in and v out to v cntl which will be forward bias. reference voltage the reference voltage is programmed by a resistor divider between v in and gnd pins. the recommended resistor is < 5k ? to maintain the accuracy of the output voltage. for im proved the performance, an external bypass capacitor can be used, located close to v ref pin to help with noise. a ceramic capacitor can be use and is selected to be greater than 0.1 f. do not place any additional loading on this reference input pin.
ur5512 linear integrated circuit unisonic technologies co., ltd 6 of 7 www.unisonic.com.tw qw-r101-017,d ? typical applications circuit 1.2v/-2 ~ +1.8a c out c ss r 1 r 2 c 1 1000 +1.8v v in gnd v ref v out nc nc v cntl nc +5v c 1 1 2 3 4 5 6 7 8 v ref = v in (v) r 2 r 1 +r 2 v out track v ref
ur5512 linear integrated circuit unisonic technologies co., ltd 7 of 7 www.unisonic.com.tw qw-r101-017,d ? typical characteristics v ref bias current, i vref ( a) dropout voltage (v) 1.2 1.0 0.6 0.4 0.2 0.0 0.0 0.5 1.0 1.5 2.5 3.0 output current (a) v in dropout voltage vs. output current 0.8 2.0 t j = 25c v ref =0.9v v cntl =5.0v 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 expec ted 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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