AD7175-2 changing Output Data rate configuration

I'm using AD7175-2 in our Project and i tested the ADC conversion with our custom driver. i'm using it in Single conversion mode and able to read the Data from ADC. By default i'm getting data rate of 83.333KHz from ADC. I want to change the data rate to 2.5KHz by configuring the Filter configuration register.But it is not changing the data rate. Following is the configuration and the steps I follow.
ADCDevice.Reset(); //Reset device by sending 8 bytes of 0xFF
Pause(millisecs, 250);

ADCDevice.Write(ADC_ADCMODE, 0x8010); //Single Conv, Enable internal ref
Pause(millisecs, 10);

ADCDevice.Write(ADC_IFMODE, 0x0120); // Enable Reg check, DOUT_RESET
Pause(millisecs, 10);

ADCDevice.Write(ADC_ADCCH0, 0x8000); //Enable Ch 0
Pause(millisecs, 10);

ADCDevice.Write(ADC_ADCCH1, 0x0000); //Disable Ch 1
Pause(millisecs, 10);

ADCDevice.Write(ADC_ADCCH2, 0x0000); //Disable Ch 2
Pause(millisecs, 10);

ADCDevice.Write(ADC_ADCCH3, 0x0000); //Disable Ch 3
Pause(millisecs, 10);

ADCDevice.Write(ADC_SETUPCON0, 0x0000);
Pause(millisecs, 10);

ADCDevice.Write(ADC_FILTCON0, 0x0509); // 25000sps
Pause(millisecs, 10);

Start Single Conversion:
ADCDevice.Write(ADC_ADCMODE, 0x8010); //Single Conv

After every start conversion I'm getting Data ready Interrupt on DOUT pin, and the ADC read value is also correct, i mean getting the expected reading. But the data rate is 83.333KHz. For our application I want 2.5KHz data rate. When I change the data rate by writing the required rate in Filter configuration register, it is not changing. It's always the same 83.333KHz.

So I want to know how to change the ADC data output rate. Kindly let me know ASAP.