The PCA9536 can support I2C bus frequencies up to 400 kHz.
Yes, the PCA9536 can be used as a level shifter for I2C signals. It has built-in level shifting capabilities that allow it to translate I2C signals from one voltage domain to another.
To configure the PCA9536 for use with multiple I2C masters, you need to use the PCA9536's internal arbitration logic. This involves setting the ARB_EN bit in the Configuration Register to enable arbitration, and then configuring the PCA9536's slave address to match the address of the I2C master that is currently controlling the bus.
The maximum number of PCA9536 devices that can be connected to the same I2C bus is limited by the I2C bus's addressing capabilities. Since each PCA9536 device has a unique address, you can connect up to 128 devices to the same I2C bus (assuming a 7-bit address space). However, the actual number of devices that can be connected may be limited by the bus's capacitance and other electrical characteristics.
No, the PCA9536 is not designed to control high-current devices such as LEDs. It is intended for use with low-current devices such as sensors, switches, and other digital inputs. If you need to control high-current devices, you should use a separate driver or switch IC that is designed for that purpose.