Silicon Laboratories AN1342 User manual

silabs.com | Building a more connected world. 1| Page

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

August 20, 2021

 AN1342: RS9116 CC1 Board Layout Guidelines 
Version 1.1 
 
 
 silabs.com | Building a more connected world. 2| Page 
 
 
Table of Contents 
 
1Introduction..................................................................................................................................................................3 
2Placement Guidelines.................................................................................................................................................4 
3Antenna Layout Guidelines........................................................................................................................................5 
4SDIO/SPI Layout Guidelines.......................................................................................................................................7 
5USB Layout Guidelines...............................................................................................................................................9 
6UART Layout Guidelines ..........................................................................................................................................10 
7Power Supply Layout Guidelines ............................................................................................................................11 
8GND Layout Guidelines ............................................................................................................................................13 
9Revision History........................................................................................................................................................15 
 
 
 
 

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 3| Page

1 Introduction

This Application Note provides PCB layout guidelines for the RS9116 CC1 module. These guidelines cover parts placement,

various critical traces routing like RF, Host interfaces routing like SDIO/SPI, USB, UART, power routing, and GND pour.

CC1 module placement and routing can be done within 4-layer PCB stack-up. However, designers can choose higher

number of layers, based on product needs. This document describes placement and routing considering a 4-layer stack-up

setup.

Below is the recommended layer stack-up and placement/routing considering a 4-layer stack-up. Exact PCB thickness can

be as per the layer stack-up provided by the PCB manufacturer. It is recommended to use a PCB thickness close to 1.6

mm, but designers can choose suitable thickness based on product needs.

•Layer 1: Parts Placement, Interface signals (SDIO/SPI, USB, UART)

•Layer 2: GND

•Layer 3: Power supply star routing

•Layer 4: Power supply star routing, USB & UART Interface signals and GPIOs

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 4| Page

2 Placement Guidelines

Here are the recommendations for the placement of the CC1 module and its associated parts. Parts are placed on the same

side of the CC1 module, in this Application Note. However, designers can choose to place them on either side of PCB for

achieving best placement and routing. Designers can use suitable antenna as per the product needs, like on-board PCB

trace, External PCB trace, Dipole, etc. The following steps can be sequentially followed to achieve optimal placement.

1. To get the best RF performance from CC1 circuitry and antenna, it is recommended to place the module near the

PCB edge. Antenna part guidelines must be followed for its placement and routing.

2. Decoupling capacitors are recommended to be placed on intended power pins. Decaps must be placed within 5

mm distance from the module pins.

3. VIN_3P3 Capacitor should be placed within 10mm distance from the module pin.

4. Series resistor on Clock signal of SPI or SDIO interface, must be placed close to the source of this clock signal.

It must not be placed near the module end of the signal.

Considering the above recommendations, the CC1 module and its circuitry can be placed on single side of PCB as shown

below. This takes 20 mm x 20 mm of board space approximately. Designers can choose to place the components

different from the below recommendation to suit the product needs.

Figure 1: CC1 Module and Components Placement

Antenna Keep out

Area, Etch the

'GND' plane

underneath the

Keep-out area in

all layers

VIN_3P3

Cap

RS9116-

CC1

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 5| Page

3 Antenna Layout Guidelines

The CC1 module has an integrated PCB trace antenna, and it works at both 2.4 GHz and 5 GHz. This antenna must be

positioned toward outer periphery of the PCB edge. There is also a U.FL connector on the module, through which an external

antenna can be connected. The choice between the on-board antenna and the external antenna can be made through a

software command. The guidelines below must be followed to get best RF performance from the PCB antenna and antenna

connected to U.FL connector.

1. There should be no metal planes or traces in the region under the PCB antenna and beside it for at least 3 mm.

The module should be placed such that the antenna portion is on the edge of the PCB. The figure below may be

used as a reference.

Figure 2: PCB Antenna Layout Requirement

2. The figures below show the U.FL connector integrated on the module and mating connector with external antenna.

The connector on the external antenna should be pushed down to fit into the U.FL connector connected to the

module.

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 6| Page

Figure 3: U.FL Connector Details

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 7| Page

4 SDIO/SPI Layout Guidelines

SDIO and SPI are high speed interfaces where-in clock signals can reach up to 100 MHz. High speed design guidelines

like below must be followed for the signals in these interfaces. SDIO/SPI signals include SDIO_CLK/SPI_CLK,

SDIO_CMD/SPI_CSN, SDIO_D0/SPI_MOSI, SDIO_D1/SPI_MISO, SDIO_D2/SPI_INTR, SDIO_D3.

1. The characteristic impedance of the SDIO/SPI lines should be 50 Ω.

2. Match the lengths of all SDIO/SPI lines within 100 mils tolerance.

3. Keep the SDIO_CLK/SPI_CLK trace away from nearby traces with minimum 2x distance.

4. Do not route any parallel traces above or underneath the SDIO_CLK/SPI_CLK trace.

5. Keep SDIO/SPI traces away from all clock lines and noisy power supply components such as the switcher inductors.

Avoid crossing over power supplies or ground discontinuities. SDIO/SPI traces must have a solid ground on the

layer adjacent to them.

6. Do not leave any stubs on the SDIO/SPI traces.

The image below shows the SDIO/SPI traces routing in Layer 1, as an example. The series resistor on SDIO_CLK/SPI_CLK

is placed closer to the source of this clock, rather than placing closer to the CC1 module.

Figure 4: SDIO/SPI Signals Routing in Layer 1

SDIO_D3

SDIO_D0/SPI_MOSI

SDIO_D2/SPI_INTR

SDIO_CLK/SPI_CLK

SDIO_D1/SPI_MISO

SDIO_CMD/SPI_CSN

33E Resistor

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 8| Page

Since SDIO_CMD/SPI_CSN, SDIO_D1/SPI_MISO, SDIO_D3 signals are present on the inner row pins of the module, these

must be routed in Layer 4 as shown below.

Figure 5: SDIO/SPI Signals Routing in Layer 4

SDIO_D3

SDIO_D1/

SPI_MISO

SDIO_CMD/

SPI_CSN

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 9| Page

5 USB Layout Guidelines

USB signals can reach speeds of 480 Mbps. Guidelines for the differential signals USB_DP and USB_DM must be followed.

1. It is highly recommended that the two USB differential signals (USB_DP and USB_DN) be routed in parallel with a

spacing (i.e., a) that achieves 90 Ω of differential impedances and 45 Ω for each trace.

2. To minimize crosstalk between the two USB differential signals (USB_DP and USB_DN) and other signal traces

routed close to them, it is recommended that a minimum spacing of 3xa be maintained for low-speed non-periodic

signals and a minimum spacing of 7xa be maintained for high-speed periodic signals.

3. It is recommended that the total trace length of the signals between RS9116 part and USB connector (or USB host

part) be less than 450 mm.

4. If the USB high-speed signals are routed on the Top layer, best results will be achieved if Layer 2 is a continuous

GND plane. Furthermore, there must be only one ground plane under high-speed signals and avoid the high-speed

signals crossing from GND plane to another GND plane.

5. Do not route the USB differential lines close to edge of the board.

The image below shows USB differential traces routing in Layer 1, as an example.

Figure 6: USB Signals Routing in Layer 1

USB_DP

USB_DM

AN1342: RS9116 CC1 Board Layout Guidelines

Version 1.1

silabs.com | Building a more connected world. 10 | Page

6 UART Layout Guidelines

The guidelines below must be followed for UART signals. The signals are UART1_TX, UART1_RX, UART1_RTS,

UART1_CTS.

1. Keep the UART signals away from noisy sources or other sensitive signals.

2. UART signals can be routed with multiple vias. However, ensure return path is closer to the signals.

The image below shows UART traces routing in Layer 1, as an example.

Figure 7: UART Signals Routing in Layer 1

All the UART pins are located inside. So, traces for these signals can be routed in Layer4 as shown below.

Figure 8: UART Signals Routing in Layer 4

UART1_TX

UART1_RTS

UART1_RX

UART1_CTS

UART1_RX

UART1_RTS

UART1_TX

UART1_CTS

This manual suits for next models

Table of contents

Other Silicon Laboratories Microcontroller manuals

Silicon Laboratories

Silicon Laboratories C8051F02 Series User manual

Silicon Laboratories

Silicon Laboratories UG172 User manual

Silicon Laboratories

Silicon Laboratories EFR32FG23 User manual

Silicon Laboratories

Silicon Laboratories Wireless M-Bus-EK User manual

Silicon Laboratories

Silicon Laboratories C8051F310 User manual

Silicon Laboratories

Silicon Laboratories EM35 Series User manual

Silicon Laboratories

Silicon Laboratories C8051F540DK User manual

Silicon Laboratories

Silicon Laboratories SLSTK3701A User manual

Silicon Laboratories

Silicon Laboratories CP2501DK User manual

Silicon Laboratories

Silicon Laboratories C8051F930 User manual

Silicon Laboratories

Silicon Laboratories EFM32 Installation and operating instructions

Silicon Laboratories

Silicon Laboratories Si4010 Series User manual

Silicon Laboratories

Silicon Laboratories EFM8SB1-SLSTK2010A User manual

Silicon Laboratories

Silicon Laboratories EFM8UB1-SLSTK2000A User manual

Silicon Laboratories

Silicon Laboratories C8051F912 User manual

Silicon Laboratories

Silicon Laboratories C8051F310DK-T User manual

Silicon Laboratories

Silicon Laboratories UG338 User manual

Silicon Laboratories

Silicon Laboratories C8051F30 series User manual

Silicon Laboratories

Silicon Laboratories C8051F02 Series User manual

Silicon Laboratories

Silicon Laboratories EFM8SB2 User manual

Silicon Laboratories

Silicon Laboratories C8051T622 User manual

Silicon Laboratories

Silicon Laboratories C8051F58 Series User manual

Silicon Laboratories

Silicon Laboratories WF200 User manual

Silicon Laboratories

Silicon Laboratories C8051F41 Series User manual

Popular Microcontroller manuals by other brands

AMS

AMS AS7261 Demo Kit user guide

Novatek

Novatek NT6861 manual

Espressif Systems

Espressif Systems ESP8266 SDK AT Instruction Set

Nuvoton

Nuvoton ISD61S00 ChipCorder Design guide

STMicrolectronics

STMicrolectronics ST7 Assembler Linker user manual

Texas Instruments

Texas Instruments Chipcon CC2420DK user manual

Lantronix

Lantronix Intrinsyc Open-Q 865XR SOM user guide

NEC

NEC 78GK0S/K 1+ Series Application note

Mikroe

Mikroe SEMITECH N-PLC Click Application note

Intel

Intel Agilex user guide

Cypress

Cypress CY4607 HX2VL quick start guide

DIGITAL-LOGIC

DIGITAL-LOGIC MICROSPACE manual

Texas Instruments

Texas Instruments TMS320F2837 D Series Workshop Guide and Lab Manual

CYPRES

CYPRES CY14NVSRAMKIT-001 user guide

Texas Instruments

Texas Instruments INA-DUAL-2AMP-EVM user guide

Espressif Systems

Espressif Systems ESP8266EX Programming guide

Abov

Abov AC33M8128L user manual

Laird

Laird BL654PA user guide