TCA7408 8-bit I/O Expander

By Texas Instruments 410

TCA7408 8-bit I/O Expander

Texas Instruments' 8-bit I/O expander for the two-line bidirectional bus (I2C) is designed to provide general-purpose remote I/O expansion via the I2C interface [serial clock (SCL) and serial data (SDA)]. The major benefit of this device is its wide VCC range. It can operate from 1.65 V to 3.6 V on the GPIO-port side and 1.65 V to 5.5 V on the SDA/SCL side. This allows the TCA7408 to interface with next-generation microprocessors and microcontrollers on the SDA/SCL side, where supply levels are dropping down to conserve power.

The bidirectional voltage-level translation in the TCA7408 is provided through VCCI. VCCI should be connected to the VCC of the external SCL/SDA lines. This indicates the VCC level of the I2C bus to the TCA7408.

Features

  • Operating power-supply voltage range of 1.65 V to 3.6 V
  • Allows bidirectional voltage-level translation and GPIO expansion between:
  • 1.8 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V GPIO port
  • 2.5 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V GPIO port
  • 3.3 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V GPIO port
  • 5 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V GPIO port
  • Standby current consumption of <2 µA at 1.8 V
  • Active current consumption of:
    • <2 µA at 1.8 V 100 kHz clock
    • <5 µA at 1.8 V 400 kHz clock
  • 100 kHz, 400 kHz fast mode
  • Internal power-on-reset and watchdog timer

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