TCA9535: 110Hz PWM output

The TCA9535 has no internal clock. You would have to switch the output pin manually from the I²C master. At 400 kHz, one write transaction would need about 70 µs, so this would, in theory, be possible.

It would be much easier to do this with a microcontroller's PWM output pin.

SK,

Like Clemens stated, no internal clock present that would allow configurability for PWM duty cycle. What Clemens is suggested is to constantly write to the IO expander device by turning ON/OFF output ports to make a psuedo PWM waveform on the p-port side. 110Hz seems possible with this method of repeated i2c writes to the expander. 

Either MCU PWM output pin is way easier, and will not take up as much bandwidth on the I2C bus using this method. 

Consider TCA6507 for configurable PWM outputs. This would also save much bandwidth on the i2c bus. 

Regards,

Tyler