Hi, @anjulatha
I didn't quite understand your difficulty.
AD9833 does not use the I2C interface (SDA/SCL).
It uses the SPI interface.
"3-wire SPI interface"
I believe that using TCA9548A will not solve your problem.
"
INTERFACING TO MICROPROCESSORS
The AD9833 has a standard serial interface that allows the part to
interface directly with several microprocessors. The device uses
an external serial clock to write the data or control information
into the device. The serial clock can have a frequency of 40 MHz
maximum. The serial clock can be continuous, or it can idle high
or low between write operations. When data or control information is written to the AD9833, FSYNC is taken low and is held
low until the 16 bits of data are written into the AD9833. The
FSYNC signal frames the 16 bits of information that are loaded
into the AD9833.
"
RV mineirin