{"id":9979,"date":"2026-07-08T07:37:48","date_gmt":"2026-07-08T07:37:48","guid":{"rendered":"https:\/\/materialparts.com\/pcf8574t\/"},"modified":"2026-07-08T07:37:48","modified_gmt":"2026-07-08T07:37:48","slug":"pcf8574t","status":"publish","type":"post","link":"https:\/\/materialparts.com\/zh\/pcf8574t\/","title":{"rendered":"PCF8574T"},"content":{"rendered":"

\u4ea7\u54c1\u6982\u89c8<\/h2>\n

The NXP PCF8574T is an 8-bit I2C remote I\/O expander in SOIC-16 package. It provides 8 quasi-bidirectional I\/O pins controlled via the I2C bus, expanding GPIO capability for microcontrollers with limited I\/O. The interrupt output (INT) signals input change detection, reducing polling overhead.<\/p>\n

\u4e3b\u8981\u89c4\u683c<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n
Interface<\/td>\nI2C<\/td>\n<\/tr>\n
I\/O Pins<\/td>\n8 quasi-bidirectional<\/td>\n<\/tr>\n
I2C Clock Rate<\/td>\nUp to 400kHz<\/td>\n<\/tr>\n
I2C Addresses<\/td>\n8 (A0-A2 programmable)<\/td>\n<\/tr>\n
\u7535\u6e90\u7535\u538b<\/td>\n2.5V to 6.0V<\/td>\n<\/tr>\n
Interrupt Output<\/td>\nYes (active-low)<\/td>\n<\/tr>\n
\u8f93\u51fa\u7535\u6d41<\/td>\n\u00b125mA per pin<\/td>\n<\/tr>\n
Standby Current<\/td>\n10uA (typical)<\/td>\n<\/tr>\n
\u5305\u88c5<\/td>\nSOIC-16<\/td>\n<\/tr>\n
\u5de5\u4f5c\u6e29\u5ea6<\/td>\n-40\u00b0C to +85\u00b0C<\/td>\n<\/tr>\n<\/table>\n

\u7279\u70b9<\/h2>\n
    \n
  • 8 quasi-bidirectional I\/O pins<\/li>\n
  • I2C interface up to 400kHz<\/li>\n
  • 3 address pins for 8 device addresses<\/li>\n
  • Interrupt output for input change detection<\/li>\n
  • 10uA ultra-low standby current<\/li>\n
  • No direction register needed<\/li>\n
  • SOIC-16 package<\/li>\n<\/ul>\n

    \u5e94\u7528<\/h2>\n
      \n
    • MCU GPIO expansion<\/li>\n
    • Keypad scanning<\/li>\n
    • LED array control<\/li>\n
    • LCD interface<\/li>\n
    • Industrial I\/O module<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The NXP PCF8574T is an 8-bit I2C remote I\/O expander in SOIC-16 package. It provides 8 quasi-bidirectional I\/O pins controlled via the I2C bus, expanding GPIO capability for microcontrollers with limited I\/O. The interrupt output (INT) signals input change detection, reducing polling overhead. Key Specifications Interface I2C I\/O Pins 8 quasi-bidirectional I2C Clock […]<\/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":[13,20],"tags":[1274],"chip_brand":[168],"class_list":["post-9979","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-interface-ics","tag-pcf8574t","chip_brand-nxp"],"acf":{"brief_explanation":"8-bit I2C I\/O expander, INT pin, 400kHz, SOIC-16, NXP PCF8574","date_code":"","package_case":"SOIC-16 (9.9 x 3.9 x 1.5mm)","in_stock":7647,"datasheet":"https:\/\/www.nxp.com\/docs\/en\/data-sheet\/PCF8574.pdf","price":"$0.65 @ 1ku","product_introduction":"The NXP PCF8574T is an 8-bit I2C remote I\/O expander in SOIC-16 package. It provides 8 quasi-bidirectional I\/O pins that can be individually configured as inputs or outputs without a direction register. The interrupt output (INT) signals when any input pin changes state, reducing the need for I2C polling. Three address pins allow up to 8 devices on the same I2C bus, providing up to 64 additional I\/O pins.","working_principle":"The PCF8574T uses the I2C bus (SDA, SCL) to read and write the 8 I\/O pins. The quasi-bidirectional I\/O design means each pin can serve as input or output without a direction register: writing a logic high to a pin allows it to be used as an input (external signal can pull it low), while writing a logic low drives the output low. The interrupt output (INT) goes active-low whenever any input pin changes state from its last read value, enabling efficient event-driven I\/O handling instead of continuous polling. The I2C slave address is set by the A0-A2 pins, allowing 8 unique addresses (0x20-0x27).","pin_description":"
      Pin<\/th>Name<\/th>Type<\/th>Function<\/th><\/tr>
      1<\/td>A0<\/td>Input<\/td>I2C address bit 0<\/td><\/tr>
      2<\/td>A1<\/td>Input<\/td>I2C address bit 1<\/td><\/tr>
      3<\/td>A2<\/td>Input<\/td>I2C address bit 2<\/td><\/tr>
      4<\/td>P0<\/td>I\/O<\/td>I\/O pin 0<\/td><\/tr>
      5<\/td>P1<\/td>I\/O<\/td>I\/O pin 1<\/td><\/tr>
      6<\/td>P2<\/td>I\/O<\/td>I\/O pin 2<\/td><\/tr>
      7<\/td>P3<\/td>I\/O<\/td>I\/O pin 3<\/td><\/tr>
      8<\/td>VSS<\/td>Power<\/td>Ground<\/td><\/tr>
      9<\/td>P4<\/td>I\/O<\/td>I\/O pin 4<\/td><\/tr>
      10<\/td>P5<\/td>I\/O<\/td>I\/O pin 5<\/td><\/tr>
      11<\/td>P6<\/td>I\/O<\/td>I\/O pin 6<\/td><\/tr>
      12<\/td>P7<\/td>I\/O<\/td>I\/O pin 7<\/td><\/tr>
      13<\/td>INT<\/td>Output<\/td>Interrupt output (active-low)<\/td><\/tr>
      14<\/td>SCL<\/td>Input<\/td>I2C clock<\/td><\/tr>
      15<\/td>SDA<\/td>I\/O<\/td>I2C data<\/td><\/tr>
      16<\/td>VDD<\/td>Power<\/td>Supply (2.5-6V)<\/td><\/tr><\/table>","application_scenarios":"
      • MCU GPIO expansion for button\/switch arrays<\/li>
      • 4x4 keypad scanning with interrupt<\/li>
      • LED indicator array control via I2C<\/li>
      • Character LCD parallel interface adapter<\/li>
      • Industrial digital I\/O module expansion<\/li><\/ul>","alternative_models":"
        Manufacturer<\/th>Part Number<\/th>Package<\/th>Notes<\/th><\/tr>
        TI<\/td>PCF8574DR<\/td>SOIC-16<\/td>Equivalent<\/td><\/tr>
        Microchip<\/td>MCP23008-E\/SO<\/td>SOIC-18<\/td>8-bit I2C I\/O, more features<\/td><\/tr>
        NXP<\/td>PCF8574AT<\/td>SOIC-16<\/td>Different I2C address range (0x38-0x3F)<\/td><\/tr>
        Microchip<\/td>MCP23017-E\/SO<\/td>SOIC-28<\/td>16-bit I2C I\/O expander<\/td><\/tr>
        NXP<\/td>PCA8574T<\/td>SOIC-16<\/td>Automotive qualified version<\/td><\/tr><\/table>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/9979","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/comments?post=9979"}],"version-history":[{"count":0,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/9979\/revisions"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/media?parent=9979"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/categories?post=9979"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/tags?post=9979"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/chip_brand?post=9979"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}