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www.fairchildsemi.com KA78R12 Low Dropout Voltage Regulator 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 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. TO-220F-4L 1 1. Vin 2. Vo 3. GND 4. Vdis Internal Block Diagram Q1 Vin 1 2 Vo THERMAL SHUTDOWN OVERVOLTAGE PROTECTION BANDGAP REFERENCE + 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 Input Voltage Disable Voltage Output Current Power Dissipation 1 Power Dissipation 2 Junction Temperature Operating Temperature Symbol Vin Vdis Io Pd1 Pd2 Tj Topr Value 35 35 1.0 1.5 15 +150 -20 ~ +80 Unit V V A W W °C °C Remark No Heatsink With Heatsink - Electrical Characteristics (Vin =15V, Io = 0.5A, Ta = 25°C , unless otherwise specified) Parameter Output Voltage Load Regulation Line Regulation Ripple Rejection Ratio Dropout Voltage Disable Voltage High Disable Voltage Low Disable Bias Current High Disable Bias Current Low Quiescent Current Symbol Vo Rload Rline RR Vdrop VdisH VdisL IdisH IdisL Iq 5mA < Io < 1A 13V < Vin < 29V note1 Io = 1A Output Active Output Disabled Vdis = 2.7V Vdis = 0.4V Io = 0A Conditions Min. 11.7 45 2.0 Typ. 12 0.1 0.5 55 Max. 12.3 2.0 2.5 0.5 0.8 20 -0.4 10 Unit V % % dB V V V µA mA mA Note: 1.These parameters, although guaranteed, are not 100% tested in production. 2 KA78R12 Typical Perfomance Characteristics 17.5 50 Output voltage Vo(V) 15.0 12.5 RL= 8 Quescent current Iq(mA) i 40 10.0 7.5 RL=12 30 20 RL= 5.0 2.5 0 0 5 10 15 20 25 10 0 0 5 10 8 15 20 25 Input voltage Vin (V) Input voltage Vin (V) Figure 1.Output Voltage vs. Input Voltage Figure 2.Quiescent Current vs. Input Voltage 17.5 12.06 12.04 12.02 12.00 11.98 Output voltage Vo(V) 15.0 12.5 10.0 7.5 5.0 2.5 0 0 0.5 1 1.5 2 2.5 3 Output voltage Vo(V) 11.96 11.94 11.92 -25 0 25 50 75 100 125 Disable voltage Vdis (V) TEMPERATURE Tj(oC) Figure 3.Output Voltage vs. Disable Voltage Figure 4.Output Voltage vs. Temperature(Tj) Quescent current Iq(mA) i Dropout voltage Vdrop(V) 10 8 0.6 0.5 0.4 Io=1A 0.3 0.75A 0.2 0.5A 0.1 0.25A 0 -25 6 4 2 0 -25 0 25 50 75 100 125 0 25 50 75 100 125 Junction temperature Tj( oC) Junction temperature Tj(o C) Figure 5.Quiescent Current vs. Temperature(Tj) Figure 6.Dropout Voltage vs. Junction Temperature 3 KA78R12 Typical Perfomance Characteristics (continue