Category: Software
Product Number: LTC1668
Hello
I am using LTC1668 for a DDS. The Fclock is set to 50MHz. As digital data in, I am sending a sine wave created by a processor running inside an FPGA. The circuit uses a differential I to V converter as specified in the data sheet figure 16. I am using a fast AD826 op amp for the converter.
Things work well until the signal frequency (sine wave) is below around 2MHz. After that, the frequency response drop exponentially to almost zero at Op amp out. I also checked voltage diff created with a simple resistor based I to V converter (no op amp in this setup) and results are same.
With 50MHZ sampling clock, this should be able to handle much higher signal frequency. Not sure what I am doing wrong.
Some help is much appreciated.
Thanks
D
