SBOSAA3A July 2024 – November 2024 TRF1108
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
Select an RF DAC such as the DAC39RF10 for this application because this DAC supports sampling at 10.24GSPS and the required RF signal frequency range of 4GHz. The DAC39RF10 outputs a signal level of –0.2dBm at 1GHz when operating at –1dBFS in the DES2X, 20.5mA current mode. The TRF1108 has a gain of 15.4dB and OP1dB of 12dBm at 1GHz; therefore, add approximately 9dB pad at the output of the DAC to get 6.2dBm output power. The pad loss can be reduced to 3dB if the DAC is run at –7dBFS in the 20.5mA current mode, or –1dBFS in the 10mA current mode. A 5GHz low-pass filter can optionally be added to reject the DAC images in the second Nyquist zone. From the TRF1108 specifications, the device meets the design requirement of output return loss. Table 7-2 shows the component values for attenuator and low-pass filter for the design.
SECTION | DESIGNATOR | TYPE | VALUE |
---|---|---|---|
Pad | R1 | Resistor | 22Ω |
Pad | R2 | Resistor | 94Ω |
Pad | R3 | Resistor | 22Ω |
Low-pass filter | C1 | Capacitor | 0.5pF |
Low-pass filter | C2 | Capacitor | 0.8pF |
Low-pass filter | C3 | Capacitor | 0.5pF |
Low-pass filter | L1 | Inductor | 2nH |
Low-pass filter | L2 | Inductor | 2nH |