{"id":6633,"date":"2026-06-18T15:46:28","date_gmt":"2026-06-18T15:46:28","guid":{"rendered":"https:\/\/materialparts.com\/74hc138n\/"},"modified":"2026-06-18T15:46:28","modified_gmt":"2026-06-18T15:46:28","slug":"74hc138n","status":"publish","type":"post","link":"https:\/\/materialparts.com\/es\/74hc138n\/","title":{"rendered":"74HC138N"},"content":{"rendered":"

Productos<\/h2>\n

The 74HC138N from Texas Instruments is a 3-to-8 line decoder\/demultiplexer. It decodes a 3-bit binary input to one of 8 mutually exclusive active-low outputs. With active-low enable inputs and 9ns propagation delay, it is essential for address decoding, chip-select generation, and data demultiplexing. Packaged in 16-PDIP.<\/p>\n

Especificaciones<\/h2>\n\n\n\n\n\n\n\n\n\n
Logic Family<\/td>\n74HC (High-Speed CMOS)<\/td>\n<\/tr>\n
Funci\u00f3n<\/td>\n3-to-8 line decoder\/demultiplexer<\/td>\n<\/tr>\n
Inputs<\/td>\n3 address (A0-A2) + 3 enable (E1, E2, E3)<\/td>\n<\/tr>\n
Outputs<\/td>\n8 (active low, Y0-Y7)<\/td>\n<\/tr>\n
Retardo de propagaci\u00f3n<\/td>\n9ns (typ at 4.5V)<\/td>\n<\/tr>\n
Tensi\u00f3n de alimentaci\u00f3n<\/td>\n2V to 6V<\/td>\n<\/tr>\n
Paquete<\/td>\n16-PDIP<\/td>\n<\/tr>\n
Temperatura de funcionamiento<\/td>\n-40 to +85 C<\/td>\n<\/tr>\n<\/table>\n

Caracter\u00edsticas<\/h2>\n
    \n
  • 3-to-8 line decoding<\/li>\n
  • Active-low outputs for direct chip-select<\/li>\n
  • Three enable inputs (2 active-low, 1 active-high)<\/li>\n
  • Cascadable for larger decoding trees<\/li>\n
  • 9ns propagation delay<\/li>\n
  • Mutually exclusive outputs<\/li>\n<\/ul>\n

    Aplicaciones<\/h2>\n
      \n
    • Memory address decoding<\/li>\n
    • Chip-select generation for multiple peripherals<\/li>\n
    • Data demultiplexing<\/li>\n
    • I\/O port expansion<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The 74HC138N from Texas Instruments is a 3-to-8 line decoder\/demultiplexer. It decodes a 3-bit binary input to one of 8 mutually exclusive active-low outputs. With active-low enable inputs and 9ns propagation delay, it is essential for address decoding, chip-select generation, and data demultiplexing. Packaged in 16-PDIP. Key Specifications Logic Family 74HC (High-Speed CMOS) […]<\/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],"tags":[],"chip_brand":[],"class_list":["post-6633","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics"],"acf":{"brief_explanation":"3-to-8 decoder\/demultiplexer, active-low outputs, 9ns, 16-PDIP","date_code":"","package_case":"16-PDIP","in_stock":11139,"datasheet":"https:\/\/www.ti.com\/lit\/ds\/symlink\/sn74hc138.pdf","price":"$0.25 @ 1ku","product_introduction":"The 74HC138N from Texas Instruments is a 3-to-8 line decoder\/demultiplexer that takes a 3-bit binary address input and activates one of 8 active-low outputs. The three enable inputs (two active-low E1 and E2, one active-high E3) provide flexible cascading for larger decoding trees; all three must be in the enabled state for any output to be active. When enabled, the output corresponding to the binary address goes LOW while all other outputs remain HIGH. When disabled, all outputs go HIGH. This active-low output convention matches the active-low chip-select inputs of most memory and peripheral ICs, making the 74HC138 the standard address decoder in microprocessor systems. With 9ns propagation delay at 4.5V, it adds minimal delay to the address-to-chip-select path.","working_principle":"The 74HC138N uses internal AND-OR logic to decode the 3-bit address. The address inputs A0-A2 select one of 8 output lines. The enable logic requires E1=LOW, E2=LOW, and E3=HIGH for any output to be active. When enabled, the selected output Yn (where n = binary value of A2A1A0) goes LOW, while all other outputs remain HIGH. The three enable inputs serve different purposes in cascading: two 74HC138 devices can decode 4 bits (16 outputs) by connecting the MSB to one enable on each device. Similarly, four devices can decode 5 bits (32 outputs) using a fifth 74HC138 as a master decoder. The 9ns propagation delay is the time from address or enable input change to the corresponding output transition.","pin_description":"
      Pin<\/th>Name<\/th>Function<\/th><\/tr>
      1<\/td>A0<\/td>Address input bit 0 (LSB)<\/td><\/tr>
      2<\/td>A1<\/td>Address input bit 1<\/td><\/tr>
      3<\/td>A2<\/td>Address input bit 2 (MSB)<\/td><\/tr>
      4<\/td>E2<\/td>Enable input (active low)<\/td><\/tr>
      5<\/td>E1<\/td>Enable input (active low)<\/td><\/tr>
      6<\/td>E3<\/td>Enable input (active high)<\/td><\/tr>
      7<\/td>Y7<\/td>Decoded output 7 (active low)<\/td><\/tr>
      8<\/td>GND<\/td>Ground<\/td><\/tr>
      9<\/td>Y6<\/td>Decoded output 6<\/td><\/tr>
      10<\/td>Y5<\/td>Decoded output 5<\/td><\/tr>
      11<\/td>Y4<\/td>Decoded output 4<\/td><\/tr>
      12<\/td>Y3<\/td>Decoded output 3<\/td><\/tr>
      13<\/td>Y2<\/td>Decoded output 2<\/td><\/tr>
      14<\/td>Y1<\/td>Decoded output 1<\/td><\/tr>
      15<\/td>Y0<\/td>Decoded output 0<\/td><\/tr>
      16<\/td>VCC<\/td>Supply voltage (2-6V)<\/td><\/tr><\/table>","application_scenarios":"
      • Memory address decoding with active-low chip-select for 8 peripheral devices<\/li>
      • I\/O port expansion using 3 MCU address lines to select 8 output channels<\/li>
      • Cascaded 4-to-16 decoder using two 74HC138 devices<\/li>
      • Data demultiplexing from one input to 8 output destinations<\/li><\/ul>","alternative_models":"
        Model<\/th>Manufacturer<\/th>Key Difference<\/th><\/tr>
        74HC139N<\/td>TI<\/td>Dual 2-to-4 decoder in one package<\/td><\/tr>
        74HC154<\/td>TI<\/td>4-to-16 decoder, single device<\/td><\/tr>
        74HCT138N<\/td>TI<\/td>TTL-compatible inputs (2-6V)<\/td><\/tr>
        74LS138N<\/td>TI<\/td>Original TTL version, higher power<\/td><\/tr><\/table>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/posts\/6633","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=6633"}],"version-history":[{"count":0,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/posts\/6633\/revisions"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/media?parent=6633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/categories?post=6633"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/tags?post=6633"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/es\/wp-json\/wp\/v2\/chip_brand?post=6633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}