SWRA004A
Figure 18. Low- and High-Band Transmit Mixer RF Input Configuration
Low- and High-Band Transmit Mixer IF Output
Figure 19 details the transmit mixer IF output configuration. The transmit mixer has a differential IF output with a 1kΩ differential 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.
The supply voltage (VCC) is applied to the IF pins with pull up inductors (L30, L31). A low-pass filter network is provided prior to the balun. This filter also acts as part of the impedance matching network. The IF response is shaped by the shunt inductor (L50) after the transformer balun. L50 is also used to block unwanted noise that could be reflected back to the mixer. The series capacitor (C50), near the TX_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 19. Low- and High-Band Transmit Mixer IF Output Configuration
TRF1500 Integrated Dual-Band RF Receiver User’s Guide | 51 |
