Qorvo DW3000 Application Note

Increasing range using an external lna

Advertisement

Quick Links

1 Introduction

This application note provides an overview of an Ultra-Wideband (UWB) wireless transceiver communication
system and link budget. The document reviews UWB transceiver performance, focusing on the receiver
cascaded system noise figure and overall system sensitivity improvements, both with and without an external
discrete Low Noise Amplifier (LNA) and Band-Pass Filter (BPF).
1
Introduction ................................................................................................................................................. 1
1.1
Overview.............................................................................................................................................. 2
1.2
Hardware and Software Modifications ................................................................................................ 2
2
Hardware Description ................................................................................................................................. 3
2.1
Overview.............................................................................................................................................. 3
2.2
Designing an LNA Scheme ................................................................................................................. 4
2.2.1
Calculating the Noise Figure .......................................................................................................... 5
2.2.2
Example of Noise Figure Calculation ............................................................................................. 5
2.2.3
Dynamic Range Calculation ........................................................................................................... 6
2.2.4
Example Calculation of Highest Supportable Signal Power .......................................................... 7
2.3
Control Signals .................................................................................................................................... 7
2.4
Power Supplies ................................................................................................................................... 7
2.5
Detailed Schematic ............................................................................................................................. 8
2.6
RF Paths and PCB Layout .................................................................................................................. 8
2.7
List of Suitable Components ............................................................................................................... 8
3
Software Implementation ............................................................................................................................ 9
3.1
Introduction .......................................................................................................................................... 9
3.2
Register Programming ........................................................................................................................ 9
3.3
Source Code Changes ...................................................................................................................... 10
4
Other Considerations ................................................................................................................................ 11
4.1
Effect on Antenna Delay and Antenna Calibration ............................................................................ 11
4.2
Effect on Transmitter Maximum Power ............................................................................................. 11
4.3
Potential Receiver Saturation ............................................................................................................ 11
4.4
RF Blocking Performance ................................................................................................................. 11
References ....................................................................................................................................................... 12
Abbreviations .................................................................................................................................................... 12
Important Notices .............................................................................................................................................. 12
Document History ............................................................................................................................................. 12
Subject to change without notice | All rights reserved.
APS304 Rev 1.0;
Increasing Range Using an
®

Table of Contents

© 2024 Qorvo, Inc.
External LNA
DW3000/QM33100
Application Note
Page 1 of 12
www.qorvo.com

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the DW3000 and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Summary of Contents for Qorvo DW3000

  • Page 1: Table Of Contents

    RF Blocking Performance ......................... 11 References ............................... 12 Abbreviations ..............................12 Important Notices .............................. 12 Document History ............................. 12 © 2024 Qorvo, Inc. Subject to change without notice | All rights reserved. www.qorvo.com APS304 Rev 1.0; Page 1 of 12...
  • Page 2: Overview

    RX nodes) and the acceptable system performance limits for particular applications (acceptable packet error rate, for example). The transmit output power of the QM33100 and DW3000 are limited by design to a maximum value of -31 dBm/MHz. This is more than adequate to meet the regulatory maximum limit of -41.3 dBm/MHz. That limit applies in most countries where UWB is permitted and provides some margin to allow for PCB, temperature, antenna and enclosure losses.
  • Page 3: Hardware Description

    Figure 2: Basic scheme for incorporating an LNA The noise figure of the LNA must be lower than the noise figure of the DW3000/QM33100. The LNA can provide 10 to 30 dB of gain depending on the channel frequency and the amplifier used.
  • Page 4: Designing An Lna Scheme

    �� The QM33100 and DW3000 have a noise figure of 7 to 8 dB depending on the channel and the frame parameters. The sensitivity of the DW3000 receiver is between -93.2 dBm and -100 dBm and for the QM33100, between -92.8 dBm and -102.6 dBm.
  • Page 5: Calculating The Noise Figure

    2.2.2 Example of Noise Figure Calculation Taking the scheme shown in Figure 3, above, we have a BPF and an LNA followed by the DW3000/QM33100 transceiver. The table below gives some typical gain and NF values for these stages and converts them into linear gain and noise factor.
  • Page 6: Dynamic Range Calculation

    This is a 5 dB reduction in overall noise figure compared to the case with no LNA since the QM33100 and DW3000 have a noise figure of 8 dB. Referring to Equation 3, the 5 dB ���� reduction will result in 5 dB improvement in the receiver sensitivity.
  • Page 7: Example Calculation Of Highest Supportable Signal Power

    2.3 Control Signals The DW3000/QM33100 transceiver provides GPIO signals to control switching of the path between the transceiver RF pins and the antenna, to include or exclude the LNA, depending on whether the transceiver is in RX or TX mode.
  • Page 8: Detailed Schematic

    AC coupling is used throughout to remove DC components in the signal. Figure 6: Hardware schematic using QM14068 and DW3000/QM33100 2.6 RF Paths and PCB Layout The frequency of the RF signals (6.25 – 8.25 GHz) and the bandwidths (500 MHz) are high, so attention must be paid to the RF signal trace layout.
  • Page 9: Software Implementation

    DW3000/QM33100 3 Software Implementation 3.1 Introduction There is little software interaction required to control an external LNA. Because the DW3000/QM33100 hardware supports this mode of operation, the software simply needs to enable the relevant portions of the hardware. Enabling the hardware consists of correctly configuring the relevant GPIO pin to act as the control for the external RF switches.
  • Page 10: Source Code Changes

    To disable LNA/PA functionality, set bits 0 and 1 to 0. Return Parameters: none Please also refer to the QM33100 Software API Guide for details on the setlnapamode() function. © 2024 Qorvo, Inc. Subject to change without notice | All rights reserved. www.qorvo.com APS304 Rev 1.0;...
  • Page 11: Other Considerations

    When a transmitter is near a receiver with an LNA, the incident signal power at the RF pins can be so strong as to saturate the DW3000/QM33100 receiver and drive it into compression. This can result in incorrect operation and an increase in packet error rate. Special care should be taken to ensure that such a situation does not arise if an LNA is being used.
  • Page 12: References

    INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Without limiting the generality of the foregoing, Qorvo products are not warranted or authorized for use as critical components in medical, life-saving, or life-sustaining applications, or other applications where a failure would reasonably be expected to cause severe personal injury or death.

This manual is also suitable for:

Qm33100

Table of Contents