SWRS045F January   2006  – November 2018 CC1021

PRODUCTION DATA.  

  1. 1Device Overview
    1. 1.1 Features
    2. 1.2 Applications
    3. 1.3 Description
    4. 1.4 Functional Block Diagram
  2. 2Revision History
  3. 3Terminal Configuration and Functions
    1. 3.1 Pin Diagram
    2. 3.2 Pin Configuration
  4. 4Specifications
    1. 4.1  Absolute Maximum Ratings
    2. 4.2  ESD Ratings
    3. 4.3  Recommended Operating Conditions
    4. 4.4  RF Transmit
    5. 4.5  RF Receive
    6. 4.6  RSSI / Carrier Sense
    7. 4.7  Intermediate Frequency (IF)
    8. 4.8  Crystal Oscillator
    9. 4.9  Frequency Synthesizer
    10. 4.10 Digital Inputs / Outputs
    11. 4.11 Current Consumption
    12. 4.12 Thermal Resistance Characteristics for VQFNP Package
  5. 5Detailed Description
    1. 5.1  Overview
    2. 5.2  Functional Block Diagram
    3. 5.3  Configuration Overview
      1. 5.3.1 Configuration Software
    4. 5.4  Microcontroller Interface
      1. 5.4.1 Configuration Interface
      2. 5.4.2 Signal Interface
      3. 5.4.3 PLL Lock Signal
    5. 5.5  4-wire Serial Configuration Interface
    6. 5.6  Signal Interface
      1. 5.6.1 Synchronous NRZ Mode
      2. 5.6.2 Transparent Asynchronous UART Mode
      3. 5.6.3 Synchronous Manchester Encoded Mode
        1. 5.6.3.1 Manchester Encoding and Decoding
    7. 5.7  Data Rate Programming
    8. 5.8  Frequency Programming
      1. 5.8.1 Dithering
    9. 5.9  Receiver
      1. 5.9.1  IF Frequency
      2. 5.9.2  Receiver Channel Filter Bandwidth
      3. 5.9.3  Demodulator, Bit Synchronizer and Data Decision
      4. 5.9.4  Receiver Sensitivity versus Data Rate and Frequency Separation
      5. 5.9.5  RSSI
      6. 5.9.6  Image Rejection Calibration
      7. 5.9.7  Blocking and Selectivity
      8. 5.9.8  Linear IF Chain and AGC Settings
      9. 5.9.9  AGC Settling
      10. 5.9.10 Preamble Length and Sync Word
      11. 5.9.11 Carrier Sense
      12. 5.9.12 Automatic Power-Up Sequencing
      13. 5.9.13 Automatic Frequency Control
      14. 5.9.14 Digital FM
    10. 5.10 Transmitter
      1. 5.10.1 FSK Modulation Formats
      2. 5.10.2 Output Power Programming
      3. 5.10.3 TX Data Latency
      4. 5.10.4 Reducing Spurious Emission and Modulation Bandwidth
    11. 5.11 Input and Output Matching and Filtering
    12. 5.12 Frequency Synthesizer
      1. 5.12.1 VCO, Charge Pump, and PLL Loop Filter
      2. 5.12.2 VCO and PLL Self-Calibration
      3. 5.12.3 PLL Turn-on Time versus Loop Filter Bandwidth
      4. 5.12.4 PLL Lock Time versus Loop Filter Bandwidth
    13. 5.13 VCO and LNA Current Control
    14. 5.14 Power Management
    15. 5.15 On-Off Keying (OOK)
    16. 5.16 Crystal Oscillator
    17. 5.17 Built-in Test Pattern Generator
    18. 5.18 Interrupt on Pin DCLK
      1. 5.18.1 Interrupt Upon PLL Lock
      2. 5.18.2 Interrupt Upon Received Signal Carrier Sense
    19. 5.19 PA_EN and LNA_EN Digital Output Pins
      1. 5.19.1 Interfacing an External LNA or PA
      2. 5.19.2 General-Purpose Output Control Pins
      3. 5.19.3 PA_EN and LNA_EN Pin Drive
    20. 5.20 System Considerations and Guidelines
      1. 5.20.1 SRD Regulations
      2. 5.20.2 Narrowband Systems
      3. 5.20.3 Low Cost Systems
      4. 5.20.4 Battery Operated Systems
      5. 5.20.5 High Reliability Systems
      6. 5.20.6 Frequency Hopping Spread Spectrum Systems (FHSS)
    21. 5.21 Antenna Considerations
    22. 5.22 Configuration Registers
      1. 5.22.1 Memory
  6. 6Applications, Implementation, and Layout
    1. 6.1 Application Information
      1. 6.1.1 Typical Application
    2. 6.2 Design Requirements
      1. 6.2.1 Input / Output Matching
      2. 6.2.2 Bias Resistor
      3. 6.2.3 PLL Loop Filter
      4. 6.2.4 Crystal
      5. 6.2.5 Additional Filtering
      6. 6.2.6 Power Supply Decoupling and Filtering
    3. 6.3 PCB Layout Guidelines
  7. 7Device and Documentation Support
    1. 7.1 Device Support
      1. 7.1.1 Device Nomenclature
    2. 7.2 Documentation Support
      1. 7.2.1 Community Resources
    3. 7.3 Trademarks
    4. 7.4 Electrostatic Discharge Caution
    5. 7.5 Export Control Notice
    6. 7.6 Glossary
  8. 8Mechanical Packaging and Orderable Information
    1. 8.1 Packaging Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

5.8 Frequency Programming

Programming the frequency word in the configuration registers sets the operation frequency. There are two frequency words registers, termed FREQ_A and FREQ_B, which can be programmed to two different frequencies. One of the frequency words can be used for RX (local oscillator frequency) and the other for TX (transmitting carrier frequency) in order to be able to switch very fast between RX mode and TX mode. They can also be used for RX (or TX) at two different channels. The F_REG bit in the MAIN register selects frequency word A or B.

The frequency word is located in FREQ_2A:FREQ_1A:FREQ_0A and FREQ_2B:FREQ_1B:FREQ_0B for the FREQ_A and FREQ_B word respectively. The LSB of the FREQ_0 registers are used to enable dithering (see Section 5.8.1).

The PLL output frequency is given by Equation 2 in the frequency band 402 to 470 MHz, and by Equation 3 in the frequency band 804 to 930 MHz.

Equation 2. CC1021 eq002_PLL_A_swrs045.gif
Equation 3. CC1021 eq003_PLL_B_swrs045.gif

The BANDSELECT bit in the ANALOG register controls the frequency band used. BANDSELECT = 0 gives 402 to 470 MHz, and BANDSELECT = 1 gives 804 to 930 MHz.

The reference frequency is the crystal oscillator clock frequency divided by REF_DIV (3 bits in the CLOCK_A or CLOCK_B register), a number between 1 and 7, as shown in Equation 4.

Equation 4. CC1021 eq004_fref_swrs045.gif

FSK frequency deviation is programmed in the DEVIATION register. The deviation programming is divided into a mantissa (TXDEV_M[3:0]) and an exponent (TXDEV_X[2:0]).

Generally REF_DIV should be as low as possible, but the requirements shown in Equation 5 must be met in the frequency band 402 to 470 MHz.

Equation 5. CC1021 eq005_REF_DIV_A_swrs045.gif

The requirements shown in Equation 6 must be met in the frequency band 804 to 930 MHz.

Equation 6. CC1021 eq006_REF_DIV_B_swrs045.gif

The PLL output frequency equations give the carrier frequency, fc , in transmit mode (centre frequency). The two FSK modulation frequencies are given by Equation 7 and Equation 8.

Equation 7. f0 = fc – fdev
Equation 8. f1 = fc + fdev

Where: fdev is set by the DEVIATION register.

fdev is set by the DEVIATION register shown in Equation 9 in the frequency band 402 to 470 MHz.

Equation 9. fdev = fref × TXDEV_M × 2(TXDEV_X –16)

fdev is set by the DEVIATION register shown in Equation 10 in the frequency band 804 to 930 MHz.

Equation 10. fdev = fref × TXDEV_M × 2(TXDEV_X –15)

OOK (On-Off Keying) is used if TXDEV_M[3:0] = 0000.

The TX_SHAPING bit in the DEVIATION register controls Gaussian shaping of the modulation signal.

In receive mode, the frequency must be programmed to be the LO frequency. Low side LO injection is used, hence Equation 11.

Equation 11. fLO = fc – fIF

Where: fIF is the IF frequency (ideally 307.2 kHz).