?2001 fairchild semiconductor corporation www.fairchildsemi.com rev. 1.0.1 features ? 1a / 12v output low dropout voltage regulator ? to220 full-mold package (4pin) ? overcurrent protection, thermal shutdown ? overvoltage protection, short-circuit protection ? with output disable function description the ka78R12 is a low-dropout voltage regulator suitable for various electronic equipments. it provides constant volt- age power source with to-220 4 lead full mold package. dropout voltage of ka78R12 is below 0.5v in full rated current(1a). this regulator has various function such as peak current protection, thermal shut down, overvoltage pro- tection and output disable function. to-220f-4l 1. vin 2. vo 3. gnd 4. vdis 1 internal block diagram thermal shutdown bandgap reference overvoltage protection soa protection shortcircuit protection 1 4 3 2 vin vdis vo gnd high / low output on / off q1 r1 r2 - + - + 1.4 v short-circuit ka78R12 low dropout voltage regulator
ka78R12 2 absolute maximum ratings electrical characteristics (vin =15v, io = 0.5a, ta = 25 c , unless otherwise specified) note: 1.these parameters, although guaranteed, are not 100% tested in production. parameter symbol value unit remark input voltage vin 35 v - disable voltage vdis 35 v - output current io 1.0 a - power dissipation 1 pd1 1.5 w no heatsink power dissipation 2 pd2 15 w with heatsink junction temperature tj +150 c - operating temperature topr -20 ~ +80 c - parameter symbol conditions min. typ. max. unit output voltage vo - 11.7 12 12.3 v load regulation rload 5ma < io < 1a - 0.1 2.0 % line regulation rline 13v < vin < 29v - 0.5 2.5 % ripple rejection ratio rr note1 45 55 - db dropout voltage vdrop io = 1a - - 0.5 v disable voltage high vdish output active 2.0 - - v disable voltage low vdisl output disabled - - 0.8 v disable bias current high idish vdis = 2.7v - - 20 m a disable bias current low idisl vdis = 0.4v - - -0.4 ma quiescent current iq io = 0a - - 10 ma
ka78R12 3 typical perfomance characteristics figure 1.output voltage vs. input voltage figure 3.output voltage vs. disable voltage figure 5.quiescent current vs. temperature(tj) figure 2.quiescent current vs. input voltage figure 4.output voltage vs. temperature(tj) figure 6.dropout voltage vs. junction temperature 5 10 15 input voltage vin (v) 15.0 12.5 10.0 7.5 5.0 2.5 17.5 0 0 output voltage vo (v) rl= rl=12 w 20 25 8 0 output voltage vo (v) 3 disable voltage vdis (v) 0.5 1.5 1 2 2.5 15.0 12.5 10.0 7.5 5.0 2.5 17.5 0 10 8 6 4 2 0 quescent current iq ( ma ) junction temperature tj ( o c ) 75 125 0 25 50 100 -25 i 50 40 30 20 10 0 0 quescent current iq ( ma ) input voltage vin (v) rl= 5 10 15 20 25 8 i 12.04 12.02 12.00 12.06 -25 output voltage vo (v) temperature tj ( o c ) 75 125 0 25 50 100 11.96 11.94 11.92 11.98 125 0.6 0.5 0.4 0.3 0 dropout voltage vdrop (v) junction temperature tj ( o c ) 0.2 0.1 75 0 25 50 100 -25 io =1a 0.75 a 0.5 a 0.25 a
ka78R12 4 typical perfomance characteristics (continued) figure 7.power dissipation vs. temperature(ta) figure 8. overcurrent protection characteristics (typical value) -25 power dissipation p d (w) temperature tj( o c ) 75 125 0 25 50 100 15 10 5 20 0 d a output current(a) relative output voltage(%) 1.5 2.5 0 0.5 1.0 2.0 80 60 20 100 0 40 3.0 output current(a) relative output voltage(%) 1.5 2.5 0 0.5 1.0 2.0 80 60 20 100 0 40 3.0 relative output voltage(%) 1.5 2.5 0 0.5 1.0 2.0 80 60 20 100 0 40 3.0
ka78R12 5 typical application figure 1.application circuit ? ci is required if regulator is located an appreciable distance from power supply filter. ? co improves stability and transient response.(co > 47 m f) + + 1 2 3 4 vin vdis vo gnd disable signal
ka78R12 6 mechanical dimensions package dimensions in millimeters to-220f-4l
ka78R12 7 ordering information product number package operating temperature ka78R12 to-220f-4l -20 c to + 80 c
ka78R12 4/26/01 0.0m 001 stock#dsxxxxxxxx 2001 fairchild semiconductor corporation life support policy fairchild?s products are not authorized for use as critical components in life support devices or systems without the express written approval of the president of fairchild semiconductor corporation. as used herein: 1. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. a critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com disclaimer fairchild semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. fairchild does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights, nor the rights of others.
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