UTC431

UTC431 PROGRAMMABLE PRECISION REFERENCE DESCRIPTION LI NEAR I NTEGRATED CI RCUI T The UTC431 is three-terminal adjustable regulator with a guaranteed thermal stability over applicable temperature ranges. The output Voltage may be set to any value between Vref(approximately 2.5V) and 26 V with two external resistors.These devices have provides a very sharp turn-on characteristic, making these devices excellent replacement for zener diodes in many applications. 1 FEATURE *Programmable output Voltage to 36V *Low dynamic output impedance 0.2Ω *Sink current capability of 1.0 to 100mA *Equivalent full-range temperature coefficient of 50ppm/°C typical *Temperature compensated for operation over full rated operating temperature range *Low output noise voltage *Fast turn on response TO-92 1:Ref; 2:Anode; 3:Cathode BLOCK DIAGRAM CATHODE REFERENCE REFERENCE (R) ANODE(A) CATHODE (K) 2.5V Vref ANODE YOUW ANG ELECTRONI CO. CS LTD 1 UTC431 CHARACTERISTICS Cathode Voltage Cathode Current Range(Continuous) Reference Input Current Range Power Dissipation D,Z Suffix Package N Suffix Package Operating temperature Storage temperature Temperature LI NEAR I NTEGRATED CI RCUI T SYMBOL VKA IKA Iref PD ABSOLUTE MAXIMUM RATINGS (Operating temperature range applies unless otherwise specified)) VALUE 37 -100~+150 0.05~+10 770 1000 0~70 -65~+150 °C UNITS V mA mA mW mW °C °C Topr Tstg RECOMMENDED OPERATING CONDITIONS Characteristic Cathode Voltage Cathode Current Symbol VKA IKA Min VREF 1.0 Typ Max 36 100 Unit V mA ELECTRICAL CHARACTERISTICS(Ta=25°C,unless otherwise specified) Characteristic Reference Input Voltage Symbol Vref Test conditions VKA=VREF,IKA=10mA VKA=VREF,IKA=10mA TMIN≤TA≤TMAX ∆VKA=10V~VREF IKA=10mA MIN TYP MAX UNIT V mV mV/V 2.440 2.495 2.550 4.5 -1.0 17 -2.7 Deviation of reference Input Voltage ∆Vref/∆T Over temperature(note 1) Ratio of Change in Reference Input ∆Vref/∆VKA Voltage to the Change in Cathode Voltage Reference Input Current Deviation of Reference Input Current Over Ful l Temperature Range Minimum cathode current for regulation Off-state cathode Current Dynamic Impedance Note TMIN=0°C,TMAX=+70°C Iref ∆Iref/∆T IKA(min) IKA(OFF) ZKA ∆VKA=36V~10V IKA=10mA,R1=10k¡,R2=∞ IKA=10mA,R1=10kΩ,R2=∞ TA= full Temperature VKA=VREF VKA=36V,VREF=0 VKA=VREF,IKA=1 to 100mA f≤1.0kHz -0.5 1.5 0.4 0.45 0.05 0.15 -2.0 4 1.2 1.0 1.0 0.5 µA µA mA µA Ω YOUW ANG ELECTRONI CO. CS LTD 2 UTC431 TEST CIRCUITS INPUT IKA R1 VKA INPUT LI NEAR I NTEGRATED CI RCUI T VKA IKA INPUT VKA IKA(OFF) UTC431 VREF R2 IREF UTC431 VREF UTC431 VKA=VREF*(1+R1/R2)+IREF*R1 Fig 7 Test Circuit For VKA=VREF Fig 8 Test Circuit for VKAƒVREF Fig 9 Test Circuit For IKA(OFF) TYPICAL APPLICATION Vi Vi Vo Vi R1 COMMON IN Vo UTC7805 OUT R1 Vo R1 VREF R2 VREF R2 VREF R2 UTC431 Vo=(1+R1/R2)*VREF UTC431 Vo=(1+R1/R2)*VREF UTC431 Vo=(1+R1/R2)*VREF Fig 10 Shutdown Regulator Fig 11 Output Control of a Three -Terminal Fixed Regulator Fig 12 Higher-current Shunt Regulator Vi Io Vi Vo Rs Io RCL Vo Rs UTC431 IO=VREF/RS UTC431 RS=VREF/RCL Fig 13 Constant-current Sink Fig 14 Current Limiting or Current Source YOUW ANG ELECTRONI CO. CS LTD 3 UTC431 Fig 1 Cathode Current Vs Cathode Voltage 125 100 LI NEAR I NTEGRATED CI RCUI T Fig 2 Cathode Current Vs Cahode Voltage TYPICAL PERFORMANCE CHARACTERISTICS 800 Cathode Current (mA) Ta=25k VKA=VREF 600 Ta=25k VKA=VREF 75 50 25 0 -25 -50 -75 -100 -2 Cathode Current (µA) 400 IKA(min) 200 0 -200 -1 0 1 2 3 -2 -1 0 1 2 3 Cathode Voltage (V) Cathode Voltage (V) 0 -5 Fig 3 Change in Reference Input Voltage Vs Cathode voltage 7 Fig 4 Pulse Response Ta=25k Input and Output Voltage (V) 40 Change In Reference INput Voltage (mV) -10 -15 -20 -25 -30 -35 -40 0 5 10 15 20 25 IKA=100mA Ta=25k 6 5 4 3 2 1 0 30 35 0 1 2 3 4 5 6 7 Cathode Voltage (V) Time (µs) Fig 5 Dynamic Impedance Vs Frequency 10 2 Fig 6 Small Signal Voltage Amplification Vs Frequency 70 Ta=25k IKA=1mA~100mA IKA=0mA to 100mA Impedance ( ) 10 1 Ta=25k 60 50 40 30 20 10 0 Ta=25k IKA=10mA 10 0 10 -1 Voltage Amplification (dB) 3 4 5 6 7 10 10 10 10 10 -10 3 10 10 4 10 5 10 6 10 7 Frequency (Hz) Frequency (Hz) YOUW ANG ELECTRONI CO. CS LTD 4