Maintaining an identical I²C addressing scheme is especially important in automotive systems that employ multiple TCA9539-Q1 GPIO expanders on a shared bus, such as body electronics and zonal controller architectures. The TCA9539AQPWRQ1 can be introduced into these systems without requiring changes to I²C address maps or software configuration.

For applications requiring a larger number of unique I²C addresses, device also offers related device variant with orderable part number TCA9539BQPWRQ1 with expanded address capability allowing another four unique I²C addresses as shown in Table 2-2. This allows up to eight unique devices on the same I²C bus if using both TCA9539AQPWRQ1 and TCA9539BQPWRQ1 as shown in Figure 2-1

Although the TCA9539AQPWRQ1 is designed as a drop-in replacement, TI recommends validating system-level requirements such as supply voltage, GPIO loading, power-up behavior, and thermal margin when migrating any device.