The TL431ACLP from Texas Instruments is a precision programmable shunt voltage reference with 0.5% initial accuracy (A grade). Adjustable from 2.495V to 36V via external resistor divider, it is the industry standard for feedback regulation in isolated power supplies. Packaged in TO-92-3.<\/p>\n
| Reference Voltage<\/td>\n | 2.495V +\/-0.5% (A grade, 25C)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Adjustable Range<\/td>\n | 2.495V to 36V<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Cathode Current Range<\/td>\n | 1mA to 100mA<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Dynamic Impedance<\/td>\n | 0.2 Ohm (typ)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Temperature Stability<\/td>\n | 6mV (typ over -40 to +85C)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Paquete<\/td>\n | TO-92-3<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||
| Temperatura de funcionamiento<\/td>\n | -40 to +85 C<\/td>\n<\/tr>\n<\/table>\nCaracter\u00edsticas<\/h2>\nAplicaciones<\/h2>\nProduct Overview The TL431ACLP from Texas Instruments is a precision programmable shunt voltage reference with 0.5% initial accuracy (A grade). Adjustable from 2.495V to 36V via external resistor divider, it is the industry standard for feedback regulation in isolated power supplies. Packaged in TO-92-3. Key Specifications Reference Voltage 2.495V +\/-0.5% (A grade, 25C) Adjustable Range […]<\/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":[13,29],"tags":[],"chip_brand":[138],"class_list":["post-6602","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-power-management-ics-pmic","chip_brand-ti"],"acf":{"brief_explanation":"Precision shunt reference, 2.495V +\/-0.5%, adjustable to 36V, TO-92","date_code":"","package_case":"TO-92-3","in_stock":9969,"datasheet":"https:\/\/www.ti.com\/lit\/ds\/symlink\/tl431.pdf","price":"$0.30 @ 1ku","product_introduction":"The TL431ACLP from Texas Instruments is a three-terminal adjustable shunt voltage reference that combines a precision bandgap reference, error amplifier, and open-collector NPN transistor in a single TO-92 package. The internal reference voltage of 2.495V +\/-0.5% (A grade) is accessible on the REF pin, and the cathode voltage can be programmed from VREF to 36V using an external resistor divider. The device operates as a shunt regulator: when the REF pin voltage exceeds 2.495V, the cathode conducts more current, pulling the voltage down. This behavior makes it ideal for feedback regulation in isolated switching power supplies, where it drives an optocoupler LED to control the primary-side PWM. The 0.2 Ohm dynamic impedance ensures tight regulation. The TL431ACLP is the A-accuracy grade in TO-92 for -40 to +85C operation.","working_principle":"The TL431ACLP uses a bandgap reference circuit that generates a stable 2.495V from the sum of a PTAT (proportional to absolute temperature) voltage and the base-emitter voltage of a transistor (which has a negative temperature coefficient). When properly designed, these opposing temperature coefficients cancel, producing a temperature-stable reference. The error amplifier compares the REF pin voltage to the internal 2.495V reference. When REF exceeds 2.495V, the error amplifier drives the output NPN transistor harder, increasing cathode current and pulling the cathode voltage lower. The external resistor divider from cathode to REF to ground sets the desired output voltage: VOUT = VREF x (1 + R1\/R2). The minimum cathode current of 1mA must be maintained for proper regulation.","pin_description":"
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