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CC400DK
User Manual
22 pgs1.08 Mb0

Texas Instruments CC400DK User Manual

User Manual
Rev. 1.5
CC400DK Development Kit
Table of contents
TABLE OF CONTENTS............................................................................................................ 2
INTRODUCTION ....................................................................................................................... 3
EVALUATION BOARD............................................................................................................. 3
DESCRIPTION ........................................................................................................................... 4
LAYOUT SKETCHES AND CIRCUIT DRAWINGS............................................................................... 9
BILL OF MATERIALS................................................................................................................. 15
USING THE DEVELOPMENT KIT.......................................................................................... 19
APPENDIX A........................................................................................................................... 20
A.1 FINE TUNING PROCEDURE OF LNA/PA MATCHING NETWORK.......................................... 20
Introduction
The CC400 single chip transceiver includes many features and great flexibility which makes the chip suitable for a very large number of applications and system requirements. The CC400 Development Kit is designed to make it very easy for the user to evaluate transceiver performance and in short time develop his own applications.
The Development Kit includes two evaluation boards with a complete CC400 transceiver, voltage regulator and PC interface circuitry. Using the evaluation board connected to a PC running the SmartRF
®
Studio software, various system parameters can be changed and
tested by key-strokes.
Technical features:
RF power up to 25mW (14dBm) programmable in 1dB steps
-112 dBm sensitivity for 10
-3
bit error rate (1.2kbps, 20kHz frequency separation)
Logic level data input/output (Manchester coded)
Selectable RF filtering (SAW or LC)
Selectable IF filtering
All set-up controlled by PC
Selectable 3V or 4-10Vunregulated voltage supply inputs
This user manual describes how to get started with the Development Kit. You will also find detailed description of the evaluation board and advice how to develop your own applications. For details on how to use the SmartRF
®
Studio software please refer to the SmartRF® Studio
user manual.
Your SmartRF
®
CC400DK Development Kit should contain the following items:
Evaluation circuit boards (PCB) 2 ex
CC400 single chip transceiver 5 ex
PC parallel port extension cable 2 ex 25-pin D-sub, male-female, 3m
Adapter 4 ex SMA male-BNC female Antenna 2 ex 50Ω, λ/4 monopole, SMA male
Quick Start Instructions
SmartRF
®
CD-ROM
The evaluation board includes a significant number of components for great flexibility. However, only a minor part of these components are required in an actual application. Check the datasheet for a typical application circuitry.
Evaluation board
The kit includes an evaluation circuit board (PCB) with the following items:
• CC400
• Necessary external surface mounted devices, SMD, for the chip.
• Voltage regulator 4V-10V to 3V regulated voltage.
• Possibilities to apply a 3V voltage source directly (chosen by switches or connectors
at the board).
• Voltage-level interface circuits between the CC400 (3V) and the parallel port of the
computer (5V).
• Connector for a PC parallel port cable.
• Connector for antenna and modulation data in/out.
• Edge connector for future use.
This board is designed with great flexibility so that you can evaluate the circuit performance for several circuit configurations, and in development of your own applications. A layout sketch of the evaluation board is shown in chapter 0.
Description
The evaluation circuit board constitutes of three main parts. These are the RF-section, the voltage supply and the PC-interface. The PC-interface contains voltage level shift circuit, which buffers the control lines.
Voltage supply
You can chose between applying a 4-10V non-regulated supply voltage or a 3V regulated supply voltage by setting a switch on the board (SPDT). If a non-regulated supply voltage is applied, an on board regulator generates a regulated 3V supply. A diode prevents damage if wrong polarity is used for the non-regulated input. The connector has five contacts, which is shown below. In addition to the three supply voltage contacts, there are two contacts, which can be used to measure the DC current to the CC400 chip. A short jumper is placed between these two contacts for the circuit to work. If you want to measure the DC current, replace the jumper with an amperemeter (as shown in the figure below). The current range is from 0 to 70 mA.
Figure: The power connector with an amperemeter attached.
RF-section
The RF section consists of a CC400 chip with external components. The different components are explained below.
The loop filter
The PLL loop filter contains the components C121-C123 and R121-R123. The software program calculates the component values. Using the calculated component values for the loop filter will give an optimum loop bandwidth for the selected system parameters.
The component values used in the CC400EB is selected for 9.6 kbit/s data rate, but can also be used for evaluation of lower data rates.
The transmitted frequency is FSK modulated, which means that the bits ‘0’ and ‘1’ has different frequencies, see Frequency separation in chapter 4.1.1.5 in SmartRF
®
Studio user
manual.
Note: If you need a shorter switching time between the two frequencies, the PLL settling time has to be shorter. To find the new component values that you need for the loop filter, the software program can be used as a calculator. Using a higher data rate value will give you a larger loop bandwidth, but also an increase in the side-band noise on the carrier. A warning may appear when increasing the data rate. To get around this warning, try to set the X-tal accuracy to zero. Do not update the device when doing this, but use Enter to calculate the values and return to your earlier settings afterwards.
External IF filter
The evaluation board is equipped with an external 455kHz ceramic filter. Input and output impedance to the CC400 is 1.5kΩ, and the bandwidth is approximately 30kHz.
4-10V
0V
3V
I
out
A
The LOCK signal
A LOCK signal is connected to the parallel port interface to be monitored by the software. The signal tells you if the synthesiser frequency is in lock. It is also available at a test pin, TP2, and is active high.
NOTE: If Power Down mode is selected when the LOCK signal is high, the current consumption will be approximately 23 uA. This is due to the current flowing from the LOCK pin into the external buffer transistor (Q2). This transistor could be replaced with a MOSFET to avoid this trickle current. Without this extra load the CC400 Power Down current is less than 1 uA.
The modulation input/output
The modulation input/output (DIO) is connected to a separate connector. The connector type is SMA female. The data to be sent has to be Manchester encoded (also known as bi-phase­level coding). The Manchester code ensures that the signal has no DC component, which is necessary for the FSK demodulator. The Manchester code is based on transitions; a “0” is encoded as a low-to-high transition, a “1” is encoded as a high-to-low transition. See figure below. Maximum data-rate is 9.6 kbit/s and is chosen in the software. To test your module use a 3V
pp
logic level with 1-10 kHz square wave.
Time
TX data
1 0 1 1 0 0 0 1 1 0 1
LNA/PA matching
The input/output matching network is optimised for 433.92MHz operation. The component values are calculated in the software program, and consist of C51, C61, L51 and L61. Using the specified component values for the input/output match will give an optimum match at the specified operating frequency. Minor tuning of the component values may be necessary to compensate for layout parasitics at other frequencies or other layouts. See appendix A.
The Voltage Controlled Oscillator (VCO)
The VCO tank on the evaluation board is optimised for the 433MHz band, covering approximately 410 – 450MHz. The tank contains the components C91, C92, C93, L91 and the variable capacitance D2.
To operate in other frequency bands, C93 and L91 can be altered. To increase the operation frequency C93 or L91 (or both) should be decreased (use 8.2nH for L91, and 1.5pF or 1.8pF for C93). To decrease the operation frequency C93 or L91 (or both) should be increased (use 12nH for L91, and 2.7pF or 3.3pF for C93).
To find the tuning range for the new VCO tank, set the RF frequency to 300 MHz and 500 MHz in the software, update the device and measure the output frequency. In this way the VCO tank will be tuned to its minimum and maximum operation frequency respectively.
For further details, please contact Chipcon.
The crystal oscillator
Crystal frequency is set to 12.000 MHz, X1. The crystal oscillator circuit has a trimmer capacitor, CT152, which reduces the initial tolerance of the crystal to zero by careful adjustment using a precision frequency counter. The crystal used at this board has ±10 ppm initial tolerance and ±10 ppm drift over the –10 to +70 °C temperature range. The crystal oscillator has an AC coupled (C153) test pin for external clock injection, TP1. Be sure to remove the crystal when an external clock is used. The external clock should have amplitude of 1-3V
pp
. If using other crystals they should be designed for 12pF load capacitance.
The preselector filter options
There are three preselector filter options: LC-filter, SAW filter, or no filter used. Each of the three filter alternatives is equipped with a female SMA antenna connector. To choose between the three filters there is a zero ohm resistor that can be moved (R61-R63).
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