{"id":7999,"date":"2026-06-28T06:38:11","date_gmt":"2026-06-28T06:38:11","guid":{"rendered":"https:\/\/materialparts.com\/lm7809ct\/"},"modified":"2026-06-28T11:44:16","modified_gmt":"2026-06-28T11:44:16","slug":"lm7809ct","status":"publish","type":"post","link":"https:\/\/materialparts.com\/es\/lm7809ct\/","title":{"rendered":"LM7809CT"},"content":{"rendered":"

Productos<\/h2>\n

The LM7809CT from onsemi\/Fairchild is a 3-terminal 1A positive voltage regulator that provides a fixed 9V output from an unregulated input \u2014 the 9V sibling in the LM78XX series in a TO-220 package.<\/p>\n

Especificaciones<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Output Voltage<\/td>\n9V (fixed, \u00b14% tolerance)<\/td>\n<\/tr>\n
Corriente de salida<\/td>\n1A (with heatsink)<\/td>\n<\/tr>\n
Input Voltage Range<\/td>\n11.5V to 24V (recommended)<\/td>\n<\/tr>\n
Maximum Input Voltage<\/td>\n35V<\/td>\n<\/tr>\n
Dropout Voltage<\/td>\n2V @ IO = 1A<\/td>\n<\/tr>\n
Corriente de reposo<\/td>\n5-8 mA<\/td>\n<\/tr>\n
Ripple Rejection<\/td>\n55-68 dB @ 120Hz<\/td>\n<\/tr>\n
Short Circuit Current<\/td>\n230 mA<\/td>\n<\/tr>\n
Peak Current<\/td>\n2.2A<\/td>\n<\/tr>\n
Thermal Resistance<\/td>\nR\u03b8JC = 5\u00b0C\/W, R\u03b8JA = 65\u00b0C\/W<\/td>\n<\/tr>\n
Temperatura de funcionamiento<\/td>\n-40\u00b0C to +125\u00b0C<\/td>\n<\/tr>\n
Paquete<\/td>\nTO-220-3 (10.4 x 4.6mm, tab)<\/td>\n<\/tr>\n<\/table>\n

Caracter\u00edsticas<\/h2>\n
    \n
  • Fixed 9V output, no external components needed<\/li>\n
  • Internal thermal overload protection<\/li>\n
  • Internal short-circuit current limiting<\/li>\n
  • Output transistor safe-area compensation<\/li>\n
  • Dropout voltage only 2V at full load<\/li>\n<\/ul>\n

    Aplicaciones<\/h2>\n
      \n
    • 9V power supply for battery-powered equipment<\/li>\n
    • Guitar pedal power<\/li>\n
    • Audio preamplifier supply<\/li>\n
    • 9V logic supply from 12V battery<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The LM7809CT from onsemi\/Fairchild is a 3-terminal 1A positive voltage regulator that provides a fixed 9V output from an unregulated input \u2014 the 9V sibling in the LM78XX series in a TO-220 package. Key Specifications Output Voltage 9V (fixed, \u00b14% tolerance) Output Current 1A (with heatsink) Input Voltage Range 11.5V to 24V (recommended) […]<\/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":[13,24],"tags":[],"chip_brand":[138],"class_list":["post-7999","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-microcontrollers-processors","chip_brand-ti"],"acf":{"brief_explanation":"9V 1A fixed positive voltage regulator, TO-220, thermal\/short protection","date_code":"","package_case":"TO-220-3 (10.4 x 4.6 x 15.75mm, 2.54mm pitch, through-hole, metal tab for heatsink)","in_stock":8000,"datasheet":"https:\/\/www.mouser.com\/datasheet\/2\/308\/LM7815-1120980.pdf","price":"$0.70 @ 1ku","product_introduction":"The LM7809CT from onsemi (formerly Fairchild) is a 3-terminal fixed positive voltage regulator providing a regulated 9V output at up to 1A. It is part of the industry-standard LM78XX family, sharing the same TO-220 package, pinout, and internal protection circuitry as the LM7805 and LM7812. The 9V output is particularly useful for powering 9V battery-operated equipment from a 12V supply (common in automotive and battery-backed systems), guitar effects pedals, and audio preamplifiers. Like all 78XX regulators, it requires only two external capacitors (0.33\u00b5F input, 0.1\u00b5F output) for stable operation. The 2V dropout voltage means the input must be at least 11V to maintain regulation at full load. The internal thermal shutdown protects against overheating (activates at ~150\u00b0C junction), and the short-circuit current limiter restricts output current to ~230mA during a fault. The TO-220 package with its metal tab can be heatsink-mounted for continuous 1A operation; without a heatsink, the package dissipates about 2W in free air. The CT suffix denotes the TO-220 package from onsemi.","working_principle":"The LM7809CT uses an internal bandgap reference, error amplifier, and series pass transistor to maintain a constant 9V output. The error amplifier compares a fraction of the output voltage (via an internal resistor divider) with the bandgap reference (~1.25V). If the output voltage drops below 9V, the error amplifier increases drive to the pass transistor, raising the output. If the output rises above 9V, the drive is reduced. The thermal protection circuit monitors the junction temperature: when it exceeds approximately 150\u00b0C, the pass transistor is turned off, preventing damage. The current limiter senses the voltage across an internal sense resistor in series with the pass transistor: when the voltage exceeds ~0.6V (corresponding to ~230mA in short-circuit condition), the drive is reduced to limit current. The safe-area protection reduces current limit as the input-output differential increases, keeping the pass transistor within its safe operating area. Input capacitor (0.33\u00b5F) prevents oscillation when the input source has high impedance; output capacitor (0.1\u00b5F) improves transient response.","pin_description":"\n
      Pin<\/th>Name<\/th>Type<\/th>Description<\/th><\/tr>\n
      1<\/td>INPUT<\/td>Power Input<\/td>Unregulated input voltage. Must be at least 3.4V (Vout + Vdropout \u2248 3.4V) for proper regulation. Maximum 35V. Bypass with 0.33\u00b5F ceramic capacitor to GND if supply is more than 6 inches from the regulator.<\/td><\/tr>\n
      2<\/td>GND<\/td>Ground<\/td>Common ground reference. The TO-220 tab is electrically connected to this pin and serves as the primary heat dissipation path. Use thermal compound and heatsink for currents above 500mA.<\/td><\/tr>\n
      3<\/td>OUTPUT<\/td>Power Output<\/td>Regulated 0.9V DC output at up to 1A continuous current with \u00b14% tolerance. Bypass with 0.1\u00b5F ceramic capacitor to GND to improve transient response and output impedance. Do not apply external voltage higher than 0.9V to prevent reverse bias damage.<\/td><\/tr>\n<\/table>\n

      Pin assignment follows standard TO-220-3 layout: Pin 1 (left) = Input, Pin 2 (center) = Ground\/Tab, Pin 3 (right) = Output, when viewed from the front with pins pointing down. The metal tab on the back is electrically connected to Pin 2 (GND) and must be insulated from the heatsink when the heatsink is not at ground potential. Output capacitance of 0.1\u00b5F is required for stability; input capacitance of 0.33\u00b5F is recommended when the input supply is remote.<\/p>","application_scenarios":"

        \n
      • Basic 9V Supply:<\/strong> 12V battery \u2192 INPUT; GND to ground; 0.33\u00b5F input cap, 0.1\u00b5F output cap; OUTPUT = 9V regulated for guitar pedals<\/li>\n
      • 12V to 9V Converter:<\/strong> 12V automotive \u2192 INPUT; OUTPUT = 9V for 9V-rated equipment; dropout 2V allows regulation from 12V (9V + 2V = 11V minimum)<\/li>\n
      • Split Supply (\u00b19V):<\/strong> LM7809CT for +9V; LM7909CT for -9V; center-tapped transformer; dual supply for op-amp circuits<\/li>\n
      • Adjustable Output:<\/strong> Add resistor between GND and ground: VOUT = 9V + (IQ \u00d7 R); or use LM317T for full adjustability<\/li>\n<\/ul>","alternative_models":"\n
        Model<\/th>Manufacturer<\/th>Key Difference<\/th>Package<\/th>Specs<\/th><\/tr>\n
        LM7809ACT<\/td>onsemi<\/td>Tighter output tolerance: \u00b12% vs \u00b14% for precision power supply applications<\/td>TO-220-3<\/td>0.9V\/1A<\/td><\/tr>\n
        L7809CV<\/td>STMicroelectronics<\/td>Direct equivalent with 1.5A output current, internal thermal shutdown and current limiting<\/td>TO-220-3<\/td>0.9V\/1.5A<\/td><\/tr>\n
        MC7809CTG<\/td>onsemi<\/td>Current production replacement with identical electrical specifications and RoHS compliance<\/td>TO-220-3<\/td>0.9V\/1A<\/td><\/tr>\n
        KA7809<\/td>onsemi\/Fairchild<\/td>Budget-friendly version with \u00b14% tolerance and standard 1A output current rating<\/td>TO-220-3<\/td>0.9V\/1A<\/td><\/tr>\n
        MC7809ABD2TG<\/td>onsemi<\/td>Surface-mount DPAK version with \u00b12% A-grade tolerance for compact PCB layouts<\/td>DPAK-3<\/td>0.9V\/1A<\/td><\/tr>\n
        LM2940CT-0.9<\/td>TI<\/td>Low-dropout version with 0.5V max dropout at 1A for battery-powered and automotive systems<\/td>TO-220-3<\/td>0.9V\/1A LDO<\/td><\/tr>\n<\/table>\n

        LM7809CT is a 0.9V fixed positive voltage regulator in TO-220-3 with 1A output and \u00b14% tolerance. The ACT suffix offers \u00b12% precision. For surface-mount designs, use MC7809ABD2TG (DPAK). For battery-powered systems, the LM2940CT-0.9 LDO version reduces dropout to 0.5V. All 7809 variants are pin-compatible (IN-GND-OUT) and require only input\/output capacitors.<\/p>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/posts\/7999","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/comments?post=7999"}],"version-history":[{"count":1,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/posts\/7999\/revisions"}],"predecessor-version":[{"id":8212,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/posts\/7999\/revisions\/8212"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/media?parent=7999"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/categories?post=7999"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/tags?post=7999"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/chip_brand?post=7999"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}