SBOS531E August   2010  – June 2019 AFE031

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
  4. Revision History
  5. Description, continued
  6. Device Comparison Table
  7. Pin Configuration and Functions
    1.     Pin Functions
  8. Specifications
    1. 8.1  Absolute Maximum Ratings
    2. 8.2  ESD Ratings
    3. 8.3  Thermal Information
    4. 8.4  Electrical Characteristics: Transmitter (Tx)
    5. 8.5  Electrical Characteristics: Power Amplifier (PA)
    6. 8.6  Electrical Characteristics: Receiver (Rx)
    7. 8.7  Electrical Characteristics: Digital
    8. 8.8  Electrical Characteristics: Two-Wire Interface
    9. 8.9  Electrical Characteristics: Internal Bias Generator
    10. 8.10 Electrical Characteristics: Power Supply
    11. 8.11 Timing Requirements
    12. 8.12 Timing Diagrams
    13. 8.13 Typical Characteristics
  9. Detailed Description
    1. 9.1 Functional Block Diagram
    2. 9.2 Feature Description
      1. 9.2.1 PA Block
      2. 9.2.2 Tx Block
      3. 9.2.3 Rx Block
      4. 9.2.4 DAC Block
      5. 9.2.5 REF1 and REF2 Blocks
      6. 9.2.6 Zero Crossing Detector Block
      7. 9.2.7 ETx and ERx Blocks
    3. 9.3 Power Supplies
    4. 9.4 Pin Descriptions
      1. 9.4.1 Current Overload
      2. 9.4.2 Thermal Overload
    5. 9.5 Calibration Modes
      1. 9.5.1 Tx Calibration Mode
      2. 9.5.2 Rx Calibration Mode
    6. 9.6 Serial Interface
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Detailed Design Procedure
        1. 10.2.1.1 Line-Coupling Circuit
        2. 10.2.1.2 Circuit Protection
        3. 10.2.1.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Development Support
        1. 11.1.2.1 Powerline Communications Developer’s Kit
        2. 11.1.2.2 TINA-TI™ (Free Software Download)
        3. 11.1.2.3 TI Precision Designs
        4. 11.1.2.4 WEBENCH Filter Designer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

Rx Block

The Rx block consists of Rx PGA1, the Rx Filter, and Rx PGA2. Both Rx PGA1 and Rx PGA2 are high-performance programmable gain amplifiers. Rx PGA1 can be configured through the SPI to operate as either an attenuator or in gain. The gain steps of the Rx PGA1 are 0.25 V/V, 0.5 V/V, 1 V/V, and 2 V/V. The gain steps of the Rx PGA2 are 1 V/V, 4 V/V, 16 V/V, and 64 V/V. Configuring the Rx PGA1 as an attenuator (at gains less than 1 V/V) is useful for applications where the presence of large interference signals are present within the signal band. Attenuating the large interference allows these signals to pass through the analog Rx signal chain without causing an overload; the interference signal can then be processed and removed within the microprocessor as necessary.

The Rx Filter is a very low noise, unity-gain, fourth-order low-pass filter. The Rx Filter cutoff frequency is selectable between CENELEC A or CENELEC B, C, and D modes. The Control1 Register bit location 3 setting (CA CBCD) determines the cutoff frequency. Setting Control1 Register bit location 3 to '0' selects the CENELEC A band; setting Control1 Register bit location 3 to '1' selects the CENELEC B, C, and D bands. Because the Rx Filter is a very low noise analog filter, two external capacitors are required to properly configure the Rx Filter. Table 3 shows the proper capacitance values for CENELEC A, B, C, and D bands. Capacitor Rx C1 is connected between pin 24 and ground, and Rx C2 is connected between pin 23 and ground. For the capacitors shown, it is recommended that these components be rated to withstand the full AVDD power-supply voltage

Table 3. Recommended External Capacitors Required for Rx Filter

FREQUENCY BAND Rx C1, PIN 24 Rx C2, PIN 23 CUTOFF FREQUENCY (kHz)
CENELEC A 680 pF 680 pF 90
CENELEC B, C, D 270 pF 560 pF 145

Figure 31 illustrates the recommended connections for the Rx signal chain.

AFE031 ai_rx_signal_path_bos531.gif
For capacitor value C1, f is the desired lower cutoff frequency and RIN,PGA1 is the input resistance of Rx PGA1.
For capacitor value C2, f is the desired lower cutoff frequency and RIN,PGA2 is the input resistance of Rx PGA2.
Refer to Table 3.
Figure 31. Recommended Connections for Rx Signal Chain

As Figure 32 shows, a fourth-order passive passband filter is optional but recommended for applications where high performance is required. The external passive passband filter removes any unwanted, out-of-band signals from the signal path, and prevents them from reaching the active internal filters within the AFE031.

AFE031 ai_bpf_passive_bos531.gif
For capacitor value C, f is the desired lower cutoff frequency and RIN,PGA1 is the input resistance of Rx PGA1. Refer to Table 3.
Figure 32. Passive Bandpass Rx Filter

The following steps can be used to quickly design the passive passband filter. (Note that these steps produce an approximate result.)

  1. Choose the filter characteristic impedance, ZC:
    • For –6-db passband attenuation: R1 = R2 = ZC
    • For 0-db passband attenuation: R1 = ZC, R2 = 10 ● ZC
  2. Calculate values for C1, C2, L1, and L2 using the following equations:
  3. AFE031 q_cin02_bos531.gif

Table 4 and Table 5 shows standard values for common applications.

Table 4. Recommended Component Values for Fourth-Order Passive Bandpass Filter (0-db Passband Attenuation)

FREQUENCY BAND FREQUENCY RANGE
(kHz)
CHARACTERISTIC IMPEDANCE
(Ω)
R1
(Ω)
R2
(Ω)
C1
(nF)
C2
(nF)
L1
(μH)
L2
(μH)
CENELEC A 35 to 95 1k 1k 10k 4.7 1.5 1500 4700
CENELEC B, C, D 95 to 150 1k 1k 10k 1.7 1 1200 1500
SFSK 63 to 74 1k 1k 10k 2.7 2.2 2200 2200

Table 5. Recommended Component Values for Fourth-Order Passive Bandpass Filter (–6-db Passband Attenuation)

FREQUENCY BAND FREQUENCY RANGE
(kHz)
CHARACTERISTIC IMPEDANCE
(Ω)
R1
(Ω)
R2
(Ω)
C1
(nF)
C2
(nF)
L1
(μH)
L2
(μH)
CENELEC A 35 to 95 1k 1k 1k 4.7 1.5 1500 4700
CENELEC B, C, D 95 to 150 1k 1k 1k 1.7 1 1200 1500
SFSK 63 to 74 1k 1k 1k 2.7 2.2 2200 2200

The Rx PGA1, Rx Filter, and Rx PGA2 components have all inputs and outputs externally available to provide maximum system design flexibility. Care should be taken when laying out the PCB traces from the inputs or outputs to avoid excessive capacitive loading. Keeping the PCB capacitance from the inputs to ground, or outputs to ground, below 100 pF is recommended.

Figure 33 shows the complete Rx signal path, including the optional passive passband filter.

AFE031 ai_rx_signal_path_complete_bos531.gif
For capacitor value C1,f is the desired lower cutoff frequency and RIN,PGA1 is the input resistance of Rx PGA1.
For capacitor value C2,f is the desired lower cutoff frequency and RIN,PGA2 is the input resistance of Rx PGA2.
Refer to Table 3.
Figure 33. Complete Rx Signal Path (with Optional Bandpass Filter)