Texas Instruments TRF1500 manual Design Considerations, External Components

SWRA004A

Design Considerations

The successful integration of a TRF1500 receiver device into a design is dependent upon the performance of the external components and the quality of the board design and layout.

External Components

Component tolerance and Q specifications (where applicable) should be observed during the selection of any external components. The TRF1500 data sheet, TI literature number SLWS041A, includes a Bill of Materials (BOM) detailing components with proven performance, that are used on the evaluation board. The location and orientation of components should also be taken into consideration for maximum performance and manufacturability. For example, the low-band image rejection is dependent on an external Surface Acoustic Wave (SAW) component. This filter is used to reject signal outside the band of the receiver and has been chosen to maximize the TRF1500 performance, while maintaining minimum size and cost.

Board Design and Impedance Matching

The quality of the board layout is also critical to the TRF1500 performance. Correct transmission line impedances must be maintained throughout the design to insure maximum performance. Correct transmission line impedances can be maintained by using proper line widths and board stack-up in relation to the dielectric constant of the board material.

Utilizing the correct external component to match the device impedance to board transmission line impedance is also very important.

For measurement simplicity, the evaluation board utilizes RF Balun transformers for impedance matching selected differential inputs and outputs to single-ended inputs and outputs. Please note that the Baluns are used only for evaluating the device on the evaluation board and do not have to be included in the end user’s application.

To minimize unwanted signal interference and coupling, digital lines should be routed around and away from the receiver. On a multi-layer board, running a separate plane for the digital lines is highly recommended. Power supply lines should be filtered and regulated as close as possible at the device terminal.

TRF1500 Integrated Dual-Band RF Receiver User’s Guide 13