1. Practical application of High Speed Design: WIFI transceiver
James Lightner
EECS713 - Fall 2017

2. What is a WIFI Transceiver?
RF design varies
The benefit of using a module
Serial Communications
Inclusion of the antenna varies between module.
The benefit of using a module is that you don’t have to re-invent the whole wifi stack. They take care of all the encyption/ decoding/ and encryption

3. What Needs High Speed Design?
Serial Communications
I2C/I2S
SPI
SDIO
UART
USB
Other digital lines
Memory
JTAG
Design rules not specific to WIFI Transceiver
I started project wanting to answer the question:
If I want to include a module into my design, what do I need to know about high speed/ do I even need high speed?

4. Serial Communications
Part Number
SPI
I2C
UART
SDIO
USB
Serial Communications
TEXAS INSTRUMENTS
CC3100
Cypress
CYW43143
ATMEL
ATWINC3400
Even modules with the same interfaces can be very different
TEXAS INSTRUMENTS
WL1837MOD

5. SDIO This is the same communication standard as “SD Cards”
Iron man the movie is 5.08 GB in 1080p
At default speed that is 6.8 minutes
At UHS-III that is 13.8 seconds

6. “SDIO signals traces (CLK, CMD, D0, D1, D2, and D3) must be routed in parallel to each other and as short as possible (less than 12 cm). In addition, every trace length must be the same as the others. There should be enough space between traces – greater than 1.5 times the trace width or ground – to ensure signal quality, especially for the SDIO_CLK trace. Remember to keep these traces away from the other digital or analog signal traces. TI recommends adding ground shielding around these buses.”
TI uses High speed and default speed for SDIO, specifying 3ns rise time
3ns rise time means a line length of about 4.16 inches in stripline configuration
12cm is about 4.72 inches

7. USB Transfer speeds for the un-viewable USB 1.0 – 1.5mb/s
USB is 90 ohms differentail, so needs 45 ohm termination resistors
USB 2.0 spec for Cypress CYW41343
USB 2.0 Spec is tr of 500ps
.7 of an inch for stripline configuration

8. I2C Standard, Fast Mode and Fast Mode Plus
Fastest transition time is 50ns
70 inches
100kb/s
I2C was developed by NXP
Iron Man in hours

9. SPI Not Specified / Technology Specific
For the ATMEL ATWINC15x0-MR210xB , rise time is 7ns
SPI does not have a set speed and is dependent on the technology using it
Rise time is 7ns meaning that you need to be under 10 inches

10. System Design Schematic and layout of the Cypress CYW43143
Thermal analysis
Decoupling and bypass selection and placement
Board stack design
I chose Cypress because of its two fastest interfaces
The rest of the report covers the rest of the Serial interfaces
Design of a module to another package
Detailed timing analyis
Decoupling and bypass selection and placement
Board stack design
Transmission line design and routing

11. Questions?