SDAA267 January   2026 TCA9539-Q1 , TCA9539A-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction to TCA9539A-Q1 I2C GPIO expander
  5. 2Key Specification Comparison: TCA9539A-Q1 vs TCA9539-Q1
    1. 2.1 I²C Addressing Scheme and Compatibility
    2. 2.2 Multidevice and Zonal Architectures
  6. 3Why Use Interrupts with I²C GPIO Expanders?
  7. 4Application Examples Using TCA9539A-Q1
    1. 4.1 Zonal Controller
    2. 4.2 Infotainment and ADAS Peripheral Control
    3. 4.3 Automotive Body Control Module (BCM)
    4. 4.4 Audio and Peripheral Monitoring
  8. 5Summary
  9. 6References

1 Introduction to TCA9539A-Q1 I2C GPIO expander

GPIO expanders are commonly used in automotive systems to increase input and output (I/O) availability while minimizing microcontroller pin count and routing complexity. The TCA9539-Q1 device is widely adopted in body electronics and control modules. The orderable part number TCA9539AQPWRQ1 extends this portfolio as a drop-in upgrade for automotive applications such as:

  • Body control modules
  • Door, mirror, and seat control modules
  • Automotive lighting and LED control
  • Switch and sensor input monitoring
  • Zonal controllers

The TCA9539A-Q1 provides 16-bits of GPIO expansion for I2C bus designed for 1.65V to 5.5V. Key specifications and features include:

  • AEC-Q100 qualification
  • 400kHz I2C Fast mode
  • Interrupt (INT pin) asserted when an input port changes state
  • Polarity Inversion
  • Hardware RESET pin
  • Two I2C address schemes: TCA9539AQPWRQ1 and TCA9539BQPWRQ1 each enabling four addresses or a total of eight unique addresses on the I2C bus.