{"id":7900,"date":"2026-06-28T03:26:45","date_gmt":"2026-06-28T03:26:45","guid":{"rendered":"https:\/\/ic-vendor.com\/pcf8574at\/"},"modified":"2026-06-28T11:46:27","modified_gmt":"2026-06-28T11:46:27","slug":"pcf8574at","status":"publish","type":"post","link":"https:\/\/ic-vendor.com\/es\/pcf8574at\/","title":{"rendered":"PCF8574AT"},"content":{"rendered":"

Productos<\/h2>\n

The PCF8574AT is a remote 8-bit I\/O expander for the I2C bus from NXP Semiconductors with quasi-bidirectional ports, interrupt output, and 100kHz I2C interface in an SOIC-16 package.<\/p>\n

Especificaciones<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Number of I\/O<\/td>\n8 (quasi-bidirectional)<\/td>\n<\/tr>\n
Interface<\/td>\nI2C (standard-mode, 100kHz max)<\/td>\n<\/tr>\n
Tensi\u00f3n de alimentaci\u00f3n<\/td>\n2.5V to 6V<\/td>\n<\/tr>\n
Standby Current<\/td>\n2.5\u00b5A typical (static)<\/td>\n<\/tr>\n
I2C Addresses<\/td>\n8 programmable (3 address pins A0, A1, A2)<\/td>\n<\/tr>\n
Slave Address (PCF8574A)<\/td>\n0x38 – 0x3F<\/td>\n<\/tr>\n
Slave Address (PCF8574)<\/td>\n0x20 – 0x27<\/td>\n<\/tr>\n
Max Sink Current per I\/O<\/td>\n25mA<\/td>\n<\/tr>\n
Total Package Sink Current<\/td>\n80mA<\/td>\n<\/tr>\n
Source Current per I\/O<\/td>\n0.1mA (weak internal pull-up)<\/td>\n<\/tr>\n
Interrupt Output<\/td>\nActive-low, open-drain (INT)<\/td>\n<\/tr>\n
Port Default (Power-On)<\/td>\nInputs (HIGH with 100\u00b5A weak pull-up)<\/td>\n<\/tr>\n
Temperatura de funcionamiento<\/td>\n-40\u00b0C to +85\u00b0C<\/td>\n<\/tr>\n
Paquete<\/td>\nSOIC-16 (10.3 x 10.3mm)<\/td>\n<\/tr>\n<\/table>\n

Caracter\u00edsticas<\/h2>\n
    \n
  • 8 quasi-bidirectional I\/O pins (no direction register needed)<\/li>\n
  • I2C bus interface up to 100kHz<\/li>\n
  • Active-low open-drain interrupt output (INT)<\/li>\n
  • 3 hardware address pins for 8 device addresses<\/li>\n
  • 2.5\u00b5A static standby current<\/li>\n
  • Latched outputs directly drive LEDs<\/li>\n
  • 25mA sink current per I\/O pin<\/li>\n
  • PCF8574A has different I2C base address from PCF8574<\/li>\n
  • Up to 16 devices (8 PCF8574 + 8 PCF8574A) on one I2C bus = 128 I\/Os<\/li>\n<\/ul>\n

    Aplicaciones<\/h2>\n
      \n
    • LED signs and displays<\/li>\n
    • Keypad and button matrix scanning<\/li>\n
    • GPIO expansion for microcontrollers<\/li>\n
    • Industrial control and PLC<\/li>\n
    • Mobile device peripheral control<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The PCF8574AT is a remote 8-bit I\/O expander for the I2C bus from NXP Semiconductors with quasi-bidirectional ports, interrupt output, and 100kHz I2C interface in an SOIC-16 package. Key Specifications Number of I\/O 8 (quasi-bidirectional) Interface I2C (standard-mode, 100kHz max) Supply Voltage 2.5V to 6V Standby Current 2.5\u00b5A typical (static) I2C Addresses 8 […]<\/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":[],"chip_brand":[168],"class_list":["post-7900","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-interface-ics","chip_brand-nxp"],"acf":{"brief_explanation":"8-bit I2C I\/O expander, quasi-bidirectional, INT pin, SOIC-16","date_code":"","package_case":"SOIC-16 (10.3 x 10.3 x 2.35mm, 1.27mm pitch)","in_stock":3200,"datasheet":"https:\/\/www.nxp.com\/docs\/en\/data-sheet\/PCF8574_PCF8574A.pdf","price":"$0.65 @ 1ku","product_introduction":"The PCF8574AT from NXP Semiconductors is a remote 8-bit I\/O expander that communicates via the I2C bus, adding 8 general-purpose I\/O pins to any I2C-capable microcontroller. The eight quasi-bidirectional ports can each serve as an input or output without requiring a data-direction register\u2014writing a 1 to a port configures it as an input (weak 100\u00b5A pull-up active), while writing a 0 drives the pin LOW with a strong sink transistor. The active-low open-drain interrupt output (INT) signals the host when any input pin changes state, eliminating the need for continuous I2C polling. The PCF8574A variant has a different I2C base address (0x38-0x3F) from the PCF8574 (0x20-0x27), allowing up to 16 devices (128 I\/Os) on a single bus. The 2.5\u00b5A static current makes it ideal for battery-powered designs. The T suffix denotes the SOIC-16 package.","working_principle":"The PCF8574AT uses quasi-bidirectional I\/O ports that simplify interface design by eliminating the need for a direction register. Each port pin has three components: a weak 100\u00b5A current source pulling to VDD, a strong pulldown transistor that activates when the output latch is 0, and a momentary strong pull-up that activates briefly when the output latch transitions from 0 to 1 (to accelerate rising edges). When used as an output, writing 0 turns on the strong pulldown (sinking up to 25mA), and writing 1 allows the weak pull-up to hold the pin HIGH. When used as an input, the port must first be written to 1 (default after power-on reset). An external device then pulls the pin LOW or lets it remain HIGH. Reading the port returns the actual pin state regardless of the output latch value. The interrupt output (INT) is an open-drain active-low signal that activates whenever any input pin state differs from the last-read value. This allows the host MCU to connect INT to an interrupt pin and only perform I2C reads when the I\/O state has actually changed. Communication uses standard I2C: the master sends START + 7-bit slave address + R\/W bit. For a write, the next byte is latched to the output port. For a read, the slave returns the current port pin states.","pin_description":"\n
      Pin<\/th>Name<\/th>Type<\/th>Description<\/th><\/tr>\n
      1<\/td>A0<\/td>Input<\/td>I2C address bit 0<\/td><\/tr>\n
      2<\/td>A1<\/td>Input<\/td>I2C address bit 1<\/td><\/tr>\n
      3<\/td>A2<\/td>Input<\/td>I2C address bit 2<\/td><\/tr>\n
      4<\/td>P0<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 0<\/td><\/tr>\n
      5<\/td>P1<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 1<\/td><\/tr>\n
      6<\/td>P2<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 2<\/td><\/tr>\n
      7<\/td>P3<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 3<\/td><\/tr>\n
      8<\/td>VSS<\/td>Power<\/td>Ground<\/td><\/tr>\n
      9<\/td>P4<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 4<\/td><\/tr>\n
      10<\/td>P5<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 5<\/td><\/tr>\n
      11<\/td>P6<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 6<\/td><\/tr>\n
      12<\/td>P7<\/td>I\/O<\/td>Quasi-bidirectional I\/O port bit 7<\/td><\/tr>\n
      13<\/td>INT<\/td>Output<\/td>Interrupt output (active-low, open-drain)<\/td><\/tr>\n
      14<\/td>SCL<\/td>Input<\/td>I2C serial clock<\/td><\/tr>\n
      15<\/td>SDA<\/td>I\/O<\/td>I2C serial data (open-drain)<\/td><\/tr>\n
      16<\/td>VDD<\/td>Power<\/td>Supply (2.5V to 6V)<\/td><\/tr>\n<\/table>","application_scenarios":"
        \n
      • LED Matrix:<\/strong> 8 pins sink 25mA each to drive 8 LEDs directly; add more PCF8574 for larger displays<\/li>\n
      • Keypad Scan:<\/strong> 4 outputs + 4 inputs scan a 4x4 matrix; INT pin interrupts MCU on any key press<\/li>\n
      • GPIO Expansion:<\/strong> Add 8 I\/O to an MCU with only 2 pins (SDA, SCL); 16 devices per bus = 128 I\/O from 2 MCU pins<\/li>\n
      • Relay Driver:<\/strong> 25mA sink per pin directly drives 5V relay coils through ULN2803 darlington array<\/li>\n
      • Low-Power Design:<\/strong> 2.5\u00b5A static current; INT eliminates polling, reducing MCU wake time in battery systems<\/li>\n<\/ul>","alternative_models":"\n
        Model<\/th>Manufacturer<\/th>Key Difference<\/th>Package<\/th>Specs<\/th><\/tr>\n
        PCF8574T<\/td>NXP<\/td>Same but different I2C base address (0x20), SOIC-16<\/td>-<\/td>-<\/td><\/tr>\n
        PCF8574AP<\/td>TI<\/td>TI's equivalent, DIP-16 through-hole<\/td>-<\/td>-<\/td><\/tr>\n
        PCA9557PW<\/td>NXP<\/td>Drop-in replacement, TSSOP-20, with config registers<\/td>-<\/td>-<\/td><\/tr>\n
        MCP23008-E\/SO<\/td>Microchip<\/td>8-bit I2C expander, config registers, SOIC-18<\/td>-<\/td>-<\/td><\/tr>\n
        MAX7317ATG+T<\/td>ADI\/Maxim<\/td>10-bit I2C expander, PWM, TSSOP-24<\/td>-<\/td>-<\/td><\/tr>\n<\/table>\n

        PCF8574AT is an 8-bit I2C I\/O expander from NXP in SOIC-16 with address 0x38-0x3F. The PCF8574T provides address 0x20-0x27. The PCF8574AP uses DIP-16 with address 0x38-0x3F. The MCP23008-E\/SO from Microchip provides 8-bit I2C I\/O with configurable interrupt in SOIC-18. The MAX7311 from ADI\/Maxim offers 16-bit I2C I\/O. The PCA8574 from NXP provides a newer I\/O expander with improved ESD. The TCA9554 from TI offers 8-bit I2C I\/O with interrupt in VQFN-16.<\/p>"},"_links":{"self":[{"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/posts\/7900","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/comments?post=7900"}],"version-history":[{"count":0,"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/posts\/7900\/revisions"}],"wp:attachment":[{"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/media?parent=7900"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/categories?post=7900"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/tags?post=7900"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/ic-vendor.com\/es\/wp-json\/wp\/v2\/chip_brand?post=7900"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}