SWRA004A
High-Band IF Output
Figure 15 details the high-band mixer IF output configuration. The high-band mixer has a differential IF output with a 1kΩ differential output impedance. For evaluation purposes, a 16:1 transformer balun, with an insertion loss of 1.8 dB, is used to transform the 1kΩ differential output to a single-ended output which is then matched to 50Ω. In the actual application, the IF output is usually connected to a narrow band channel select filter with a differential input and the transformer balun is not required.
The supply voltage (VCC) is applied to the IF terminals with pull- up inductors (L21, L22). A low-pass filter network is provided prior to the balun. The filter also acts as part of the impedance matching network. The IF response is shaped by the shunt-L (L52) after the transformer balun. L52 is also used to block unwanted noise that could be reflected back to the mixer. The series capacitor (C51) near the HB_IF_OUT port is used as a dc block for evaluation purposes and does not have to be implemented in the end-users system.
Figure 15. High-Band IF Output Configuration
38 | TRF1500 Integrated Dual-Band RF Receiver User’s Guide |
