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  • TI Thinks Resolved

WL1831MOD: WL183X reference design ANT2 trace on ANT1 port for compact design?

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Replies: 4

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Part Number: WL1831MOD

Two questions regarding the WL183XMOD reference design:

1) I note from the documentation that a 1-dB attenuation trace must be used, presumably the reference design (image below) contains such a loss in its trace e.g. no additional requirement?

2) Is it suitable to use the ANT2 + lead trace design on the ANT1 port (to enable a compact design for single antenna WL1831 operation)?

  • Hi,

    We will look into it and get back to you ASAP. Please bear with us.

    Thanks,

    PM

  • In reply to PM:

    Hi,

    Q1: I interpret that statement as " we need to put 1dB attenuation on the RF Ports ( both RF_Ant1 and RF_Ant2 ) in order to reuse the Regulatory Certification from TI". This 1dB loss on the RF ports ( both RF_Ant1 and RF_Ant2 pins)  ensures that the Tx  Power and spurious emission are well with in  the certified limits of TI certified module.

    Q2: Yes, both traces must be 50 Ohms. Yes, they can be interchangeable. Please see the following guide lines on RF Trace routing.

    Follow these RF trace routing recommendations:

    • RF traces must have 50-Ω impedance.

    • RF traces must not have sharp corners.

    • RF traces must have via stitching on the ground plane beside the RF trace on both sides.

    • RF traces must be as short as possible. The antenna, RF traces, and module must be on the edge of the PCB product in consideration of the product enclosure material and proximity.

    Place the Antennas as far away as possible (based on available space) to each other and also orthogonal to each other ( as shown in the refence design) in order to achieve better Antenna diversity.

    Thanks,

    PM

  • In reply to PM:

    Hi,

    Thanks for the detailed reply.

    To confirm, if I use your reference antenna 2 design rotated onto antenna 1 and leave antenna 2 as NC (WL1831 or WL1835 - single antenna option only) this would meet the recommendations below, including the required 1db attenuation such that TIs regulatory certification can be re used?

    Thanks,

    Adam

  • In reply to Adam Muncey:

    Hi,

    Yes, you can use it but you need to put a 1dB Pad ( 1db attenuation) in the path. You can place the pad in between 10pF and Antenna (before L & C - matching network).

    Thanks,

    PM

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