The TLVH431IDBZR is a Texas Instruments low-voltage adjustable precision shunt regulator with 1.24V reference, 1.5% accuracy, 100uA to 70mA cathode current, and 0.25ohm output impedance. Packaged in SOT-23-3, -40C to +85C.<\/p>\n
| Vref<\/td>\n | 1.24 V<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Accuracy<\/td>\n | 1.5% (standard grade)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Cathode Current<\/td>\n | 100 uA to 70 mA<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Output Impedance<\/td>\n | 0.25 ohm typical<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Vout Range<\/td>\n | 1.24V to 18V (adjustable)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| \u0627\u0644\u062d\u0632\u0645\u0629<\/td>\n | SOT-23-3<\/td>\n<\/tr>\n<\/table>\n\u0627\u0644\u0645\u064a\u0632\u0627\u062a<\/h2>\n\u0627\u0644\u062a\u0637\u0628\u064a\u0642\u0627\u062a<\/h2>\nProduct Overview The TLVH431IDBZR is a Texas Instruments low-voltage adjustable precision shunt regulator with 1.24V reference, 1.5% accuracy, 100uA to 70mA cathode current, and 0.25ohm output impedance. Packaged in SOT-23-3, -40C to +85C. Key Specifications Vref 1.24 V Accuracy 1.5% (standard grade) Cathode Current 100 uA to 70 mA Output Impedance 0.25 ohm typical Vout […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19,13],"tags":[],"chip_brand":[138],"class_list":["post-8906","post","type-post","status-publish","format-standard","hentry","category-analog-linear-ics","category-integrated-circuits-ics","chip_brand-ti"],"acf":{"brief_explanation":"1.24V shunt ref, adj 1.24-18V, 1.5%, SOT-23-3","date_code":"","package_case":"3-Pin SOT-23 (2.92 x 1.30 x 0.9 mm)","in_stock":15000,"datasheet":"https:\/\/www.ti.com\/lit\/ds\/symlink\/tlvh432b.pdf","price":"$0.182 @ 1ku","product_introduction":"The TLVH431IDBZR is a Texas Instruments low-voltage adjustable precision shunt regulator in a 3-pin SOT-23 package. The 1.24V internal reference voltage is lower than the traditional TL431 (2.495V), making the TLVH431 ideal for 3.3V and lower-voltage power supply feedback loops. The output voltage is set to any value between 1.24V and 18V using two external resistors. The 1.5% reference accuracy (standard grade) provides stable regulation, with A-grade (1%) and B-grade (0.5%) available for tighter requirements. The wide 100uA to 70mA cathode current range allows design flexibility from micropower bias to moderate load regulation. The 0.25 ohm typical dynamic output impedance provides tight regulation against load and line variations. When used with an optocoupler, the TLVH431 forms a precise error amplifier for isolated flyback SMPS secondary-side regulation. The sharp turn-on characteristic makes it an excellent low-voltage Zener diode replacement with lower leakage and sharper knee. Packaged in SOT-23-3 rated for -40C to +85C.","working_principle":"The TLVH431 operates as a shunt regulator, similar to a Zener diode but with much sharper I-V characteristics and an adjustable breakdown voltage. The internal error amplifier compares the REF pin voltage with the internal 1.24V bandgap reference. When REF exceeds 1.24V, the amplifier drives the internal NPN pass transistor, increasing cathode current (Ik) to pull the cathode voltage down until the feedback loop equilibrium is restored. The output voltage is set by two external resistors: Vout = Vref x (1 + R1\/R2) + Iref x R1, where Iref (0.1uA typical) is negligible for R1 values below 10kohm. In flyback SMPS applications, the TLVH431 compares a fraction of the output voltage with Vref, and drives the optocoupler LED to adjust the primary-side PWM duty cycle. The low 100uA minimum cathode current enables low-bias designs, while the 70mA maximum handles the optocoupler LED current with margin.","pin_description":"
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