[{"data":1,"prerenderedAt":212},["ShallowReactive",2],{"component:tl431:en":3},{"component":4,"localizationFallbackIssues":153,"related":154,"equivalentSlugs":211},{"schemaVersion":5,"governance":6,"id":18,"mpn":19,"slug":18,"primaryCategory":20,"manufacturers":21,"lifecycleStatus":23,"shortDescription":24,"deepTechnicalOverview":25,"packages":26,"absoluteMaximums":49,"recommendedOperating":54,"parametricAttributes":59,"gotchas":112,"datasheetUrl":17,"documentationSources":127,"applicationCircuits":136,"equivalents":141,"mountedOnBoards":142,"seo":143},"1.0.0",{"publication":7,"verification":10,"provenance":15},{"status":8,"publishedDate":9},"published","2026-11-02",{"status":11,"verifiedDate":9,"verifiedBy":12,"checklist":13},"verified","Gemini (independent manufacturer documentary\u002Ftechnical\u002Fpackage review against TI SLVS543S; owner publication GO; no bench or native-human claim)",{"schema":14,"technicalFacts":14,"relationships":14,"sources":14},true,{"sourceUrls":16},[17],"https:\u002F\u002Fwww.ti.com\u002Flit\u002Fds\u002Fsymlink\u002Ftl431.pdf","tl431","TL431LP","voltage_regulator",[22],"Texas Instruments","active","Adjustable precision shunt regulator with programmable output voltage from 2.495V to 36V, 1mA to 100mA cathode current capability, and 0.2Ω typical dynamic impedance in a 3-pin TO-92 package.","The TL431 is a three-terminal adjustable precision shunt regulator manufactured by Texas Instruments (Document SLVS543S, revised May 2024). Housed in a through-hole TO-92 (LP) package with a REF-ANODE-CATHODE pinout (Pin 1 REF, Pin 2 Anode, Pin 3 Cathode), it provides a sharp turn-on characteristic and acts as an open-collector operational amplifier with a precise 2.495V bandgap voltage reference. Output voltage can be programmed from Vref (2.495V) up to 36V using two external resistors. Key operating specifications include a reference input voltage of 2.495V (2.440V to 2.550V for standard grade), low reference input current of 2µA typical (4µA max), minimum regulation current of 0.4mA typical (1.0mA max), continuous cathode current up to 100mA, and typical dynamic output impedance of 0.2Ω. The TL431 is widely utilized in precision voltage references, linear shunt regulators, overvoltage\u002Fundervoltage supervisors, and optocoupler feedback loops for isolated switch-mode power supplies.",[27],{"packageType":28,"pinCount":29,"thermalResistanceThetaJA":30,"thermalResistanceThetaJC":31,"pins":32},"TO-92",3,140,50,[33,39,45],{"pinNumber":34,"pinName":35,"electricalType":36,"isFiveVoltTolerant":14,"internalPull":37,"description":38},1,"REF","analog_in","none","Reference voltage input terminal (threshold Vref = 2.495V nominal relative to Anode; reference input current Iref ~2 µA typical)",{"pinNumber":40,"pinName":41,"electricalType":42,"isFiveVoltTolerant":43,"internalPull":37,"description":44},2,"ANODE","ground",false,"Anode terminal (connected to circuit common\u002Fground return; internal reference common)",{"pinNumber":29,"pinName":46,"electricalType":47,"isFiveVoltTolerant":14,"internalPull":37,"description":48},"CATHODE","passive","Shunt cathode terminal (current input\u002Fsink terminal; regulates voltage from Vref up to 36V with 1mA to 100mA operating current)",{"supplyVoltageMaxV":50,"outputCurrentMaxA":51,"storageTempMinC":52,"storageTempMaxC":53},37,0.15,-65,150,{"supplyVoltageMinV":55,"supplyVoltageTypV":55,"supplyVoltageMaxV":56,"ambientTempMinC":57,"ambientTempMaxC":58},2.495,36,0,70,[60,68,75,82,89,95,100,105],{"symbol":61,"name":62,"typicalValue":63,"minValue":64,"maxValue":65,"unit":66,"testCondition":67},"Vref","Reference Voltage","2.495",2.44,2.55,"V","VKA = Vref, IKA = 10 mA, TA = 25°C",{"symbol":69,"name":70,"typicalValue":71,"maxValue":72,"unit":73,"testCondition":74},"delta_Vref_temp","Reference Voltage Drift Over Temperature","14",34,"mV","VKA = Vref, IKA = 10 mA, TA = 0°C to 70°C",{"symbol":76,"name":77,"typicalValue":78,"maxValue":79,"unit":80,"testCondition":81},"delta_Vref_delta_VKA","Ratio of Change in Vref to Change in Cathode Voltage","-1.4",-2.7,"mV\u002FV","IKA = 10 mA, delta_VKA = 10 V to Vref, TA = 25°C",{"symbol":83,"name":84,"typicalValue":85,"maxValue":86,"unit":87,"testCondition":88},"Iref","Reference Input Current","2.0",4,"µA","IKA = 10 mA, R1 = 10 kΩ, R2 = open, TA = 25°C",{"symbol":90,"name":91,"typicalValue":92,"maxValue":93,"unit":87,"testCondition":94},"delta_Iref_temp","Reference Input Current Drift Over Temperature","0.4",1.2,"IKA = 10 mA, R1 = 10 kΩ, R2 = open, TA = 0°C to 70°C",{"symbol":96,"name":97,"typicalValue":92,"maxValue":34,"unit":98,"testCondition":99},"Imin","Minimum Cathode Current for Regulation","mA","VKA = Vref, TA = 25°C",{"symbol":101,"name":102,"typicalValue":103,"maxValue":34,"unit":87,"testCondition":104},"Ioff","Off-State Cathode Current","0.1","VKA = 36 V, Vref = 0 V, TA = 25°C",{"symbol":106,"name":107,"typicalValue":108,"maxValue":109,"unit":110,"testCondition":111},"ZKA","Dynamic Impedance","0.2",0.5,"Ω","VKA = Vref, IKA = 1 mA to 100 mA, f \u003C= 1 kHz, TA = 25°C",[113,118,122],{"title":114,"severity":115,"description":116,"mitigationStrategy":117},"Capacitive Load Instability (Boundary of Active Stability)","critical","The TL431 can oscillate when driving capacitive loads directly across its cathode and anode terminals without appropriate series damping. The datasheet stability boundary curves (Figure 9-14 in SLVS543S) show that load capacitances in the range of approximately 10 nF to 3 µF (depending on cathode current IKA and regulated voltage VKA) create a conditional stability loop, leading to parasitic oscillation and output ripple.","Avoid placing pure capacitive loads between 10 nF and 3 µF directly between cathode and anode. Either keep bypass capacitance small (CL \u003C 10 nF for high-frequency RF bypassing), select a sufficiently large bulk capacitor (CL > 10 µF) with adequate equivalent series resistance (ESR), or insert a small series damping resistor (typically 1 Ω to 10 Ω) in series with the bypass capacitor to keep operating points outside the instability envelope.",{"title":119,"severity":115,"description":120,"mitigationStrategy":121},"Minimum Cathode Current Requirement (1.0 mA for Full Regulation)","Unlike simple passive Zener diodes which degrade gradually at low currents, the TL431 incorporates internal active circuitry and an operational amplifier that require a minimum cathode current of 0.4 mA typical and up to 1.0 mA maximum across temperature to maintain regulation. If the net cathode current drops below this threshold, the internal amplifier loses loop gain and the cathode voltage jumps up toward the unregulated supply rail.","Size the series feed resistor RSUP so that under worst-case minimum supply voltage VSUP(min) and maximum external load current ILOAD(max), the cathode current IKA remains strictly above 1.0 mA (designing for 2 mA to 5 mA quiescent current is recommended for robust regulation margin).",{"title":123,"severity":124,"description":125,"mitigationStrategy":126},"Reference Input Current Error with High-Value Feedback Resistors","warning","The TL431 output voltage equation is VO = Vref * (1 + R1 \u002F R2) + Iref * R1. The reference terminal draws a finite bias current Iref (2 µA typical, 4 µA max at 25°C, with up to 1.2 µA drift over temperature). If high resistor values (e.g. R1 > 100 kΩ) are selected to reduce power consumption, the Iref * R1 term introduces substantial offset error and temperature drift into the regulated output.","Design the resistor divider current Idiv = Vref \u002F R2 to be significantly larger than Iref (at least 100 times, preferably Idiv >= 200 µA to 1 mA). Selecting R2 \u003C= 10 kΩ ensures that reference input current variation contributes less than 0.1% to overall output voltage drift.",[128],{"title":129,"url":17,"type":130,"authority":131,"publisher":22,"documentNumber":132,"revision":133,"releaseDate":134,"language":135},"TL431x, TL432x Precision Programmable Reference","datasheet","primary","SLVS543","Rev. S","2024-05","EN",[137],{"title":138,"schematicSlug":139,"topology":140},"TL431 Precision Shunt Voltage Reference","tl431-precision-shunt-reference","Programmable shunt voltage regulator with series bias resistor and resistive divider.",[],[],{"canonicalUrl":144,"metaTitle":145,"metaDescription":146,"primarySearchCluster":147,"structuredDataSchema":152},"https:\u002F\u002Fcircuitbase.tech\u002Fcomponent\u002Ftl431","TL431 Precision Shunt Regulator Pinout & Specs | CircuitBase","Texas Instruments TL431 adjustable precision shunt regulator pinout (TO-92 REF-A-K), 2.495V Vref, 1mA-100mA IKA, dynamic impedance and stability gotchas.",[148,149,150,151],"tl431 pinout","tl431 datasheet","tl431 to-92","tl431 shunt regulator","Product",null,[155,173,187,203],{"id":156,"slug":156,"mpn":157,"primaryCategory":20,"manufacturers":158,"shortDescription":159,"packages":160,"packageTypes":166,"voltage":167,"recommendedOperating":172},"lm2596","LM2596",[22],"Step-down switching voltage regulator capable of driving a 3A load with 150 kHz fixed frequency, 40V input range, internal thermal shutdown, and cycle-by-cycle current limiting in TO-220 and TO-263 packages.",[161,164],{"packageType":162,"pinCount":163},"TO-220-5",5,{"packageType":165,"pinCount":163},"TO-263-5",[162,165],{"context":168,"min":169,"max":170,"typical":171},"input",4.5,40,12,{"supplyVoltageMinV":169,"supplyVoltageTypV":171,"supplyVoltageMaxV":170},{"id":174,"slug":174,"mpn":175,"primaryCategory":20,"manufacturers":176,"shortDescription":179,"packages":180,"packageTypes":185,"voltage":186},"lm7805","LM7805",[22,177,178],"STMicroelectronics","onsemi","5 V, 1.5 A fixed positive linear voltage regulator with internal current limiting and thermal shutdown, in TO-220 and D2PAK packages.",[181,183],{"packageType":182,"pinCount":29},"TO-220",{"packageType":184,"pinCount":29},"D2PAK",[182,184],{"context":168,"min":-1,"max":-1,"typical":-1,"outputTypical":163},{"id":188,"slug":188,"mpn":189,"primaryCategory":20,"manufacturers":190,"shortDescription":193,"packages":194,"packageTypes":197,"voltage":198,"recommendedOperating":202},"ams1117-3-3","AMS1117-3.3",[191,192],"Advanced Monolithic Systems","Various","1A low-dropout positive linear voltage regulator with fixed 3.3V output in SOT-223 package.",[195],{"packageType":196,"pinCount":86},"SOT-223",[196],{"context":168,"min":199,"max":200,"typical":163,"outputTypical":201},4.75,15,3.3,{"supplyVoltageMinV":199,"supplyVoltageTypV":163,"supplyVoltageMaxV":200},{"id":204,"slug":204,"mpn":205,"primaryCategory":20,"manufacturers":206,"shortDescription":207,"packages":208,"packageTypes":210,"voltage":-1},"lm317","LM317T",[177],"Adjustable 1.2V to 37V positive linear voltage regulator capable of supplying in excess of 1.5A in a TO-220 package with ADJ-OUT-IN pinout and internal thermal protection.",[209],{"packageType":182,"pinCount":29},[182],{},1793836426807]