www.fairchildsemi.com KA78R12 Low Dropout Voltage Regulator Features Description • • • • • The KA78R12 is a low-dropout voltage regulator suitable for various electronic equipments. It provides constant voltage 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 protection and output disable function. 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 TO-220F-4L 1 1. Vin 2. Vo 3. GND 4. Vdis Internal Block Diagram Vin Q1 1 Vo OVERVOLTAGE PROTECTION THERMAL SHUTDOWN BANDGAP REFERENCE 2 + R1 SOA PROTECTION HIGH / LOW Vdis 4 + OUTPUT ON / OFF R2 1.4V SHORT-CIRCUIT SHORTCIRCUIT PROTECTION 3 GND Rev. 1.0.1 ©2001 Fairchild Semiconductor Corporation KA78R12 Absolute Maximum Ratings 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 Tj +150 °C - Topr -20 ~ +80 °C - Junction Temperature Operating Temperature Electrical Characteristics (Vin =15V, Io = 0.5A, Ta = 25°C , unless otherwise specified) Parameter Output Voltage Symbol Conditions Min. Typ. Max. Unit 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 % 45 55 - dB - - 0.5 V 2.0 - - V Ripple Rejection Ratio RR note1 Dropout Voltage Vdrop Io = 1A Disable Voltage High VdisH Output Active Disable Voltage Low VdisL Output Disabled - - 0.8 V Disable Bias Current High IdisH Vdis = 2.7V - - 20 µA Disable Bias Current Low IdisL Vdis = 0.4V - - -0.4 mA Io = 0A - - 10 mA Quiescent Current Iq Note: 1.These parameters, although guaranteed, are not 100% tested in production. 2 KA78R12 Typical Perfomance Characteristics Quescent i current Iq(mA) 50 12.5 RL= 10.0 7.5 RL=12Ω 5.0 40 30 20 RL= 8 15.0 8 Output voltage Vo(V) 17.5 10 2.5 0 0 5 0 10 15 20 25 0 5 Input voltage Vin (V) 15 20 25 Figure 2.Quiescent Current vs. Input Voltage 17.5 12.06 15.0 12.04 Output voltage Vo(V) Output voltage Vo(V) Figure 1.Output Voltage vs. Input Voltage 12.5 12.02 10.0 12.00 7.5 5.0 11.98 11.96 2.5 11.94 0 0 0.5 1 1.5 2 2.5 11.92 -25 3 0 Disable voltage Vdis (V) 25 50 75 100 125 TEMPERATURE Tj(oC) Figure 3.Output Voltage vs. Disable Voltage Figure 4.Output Voltage vs. Temperature(Tj) Dropout voltage Vdrop(V) 10 Quescent i current Iq(mA) 10 Input voltage Vin (V) 8 6 4 2 0.6 0.5 0.4 Io=1A 0.3 0.75A 0.2 0.5A 0.1 0.25A 0 -25 0 25 50 75 100 125 Junction temperature Tj( oC) Figure 5.Quiescent Current vs. Temperature(Tj) 0 -25 0 25 50 75 100 125 Junction temperature Tj(o C) Figure 6.Dropout Voltage vs. Junction Temperature 3 KA78R12 Typical Perfomance Characteristics (continued) 100 Relative output voltage(%) Power dissipation PDD(W) 20 15 10 5 0 -25 60 40 20 0 0 25 50 TEMPERATURE 75 100 125 a TJ( oC) Figure 7.Power Dissipation vs. Temperature(Ta) 4 80 0 0.5 1.0 1.5 2.0 2.5 3.0 Output Current(A) Figure 8. Overcurrent Protection Characteristics (Typical Value) KA78R12 Typical Application Vo Vin 1 2 + + 3 GND 4 Vdis Disable Signal 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 µF) 5 KA78R12 Mechanical Dimensions Package Dimensions in millimeters TO-220F-4L 6 KA78R12 Ordering Information Product Number Package Operating Temperature KA78R12 TO-220F-4L -20 °C to + 80°C 7 KA78R12 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. 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 4/26/01 0.0m 001 Stock#DSxxxxxxxx 2001 Fairchild Semiconductor Corporation