SLOS732G June   2011  – March 2020 TRF7960A

PRODUCTION DATA.  

  1. 1Device Overview
    1. 1.1 Features
    2. 1.2 Applications
    3. 1.3 Description
    4. 1.4 Application Block Diagram
  2. 2Revision History
  3. 3Device Characteristics
    1. 3.1 Related Products
  4. 4Terminal Configuration and Functions
    1. 4.1 Pin Diagrams
    2. 4.2 Signal Descriptions
  5. 5Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Electrical Characteristics
    5. 5.5 Thermal Resistance Characteristics
    6. 5.6 Switching Characteristics
  6. 6Detailed Description
    1. 6.1  Functional Block Diagram
    2. 6.2  Power Supplies
    3. 6.3  Supply Arrangements
    4. 6.4  Supply Regulator Settings
    5. 6.5  Power Modes
    6. 6.6  Receiver – Analog Section
      1. 6.6.1 Main and Auxiliary Receiver
      2. 6.6.2 Receiver Gain and Filter Stages
    7. 6.7  Receiver – Digital Section
      1. 6.7.1 Received Signal Strength Indicator (RSSI)
        1. 6.7.1.1 Internal RSSI – Main and Auxiliary Receivers
        2. 6.7.1.2 External RSSI
    8. 6.8  Oscillator Section
    9. 6.9  Transmitter - Analog Section
    10. 6.10 Transmitter - Digital Section
    11. 6.11 Transmitter – External Power Amplifier or Subcarrier Detector
    12. 6.12 Communication Interface
      1. 6.12.1 General Introduction
      2. 6.12.2 FIFO Operation
      3. 6.12.3 Parallel Interface Mode
      4. 6.12.4 Reception of Air Interface Data
      5. 6.12.5 Data Transmission to MCU
      6. 6.12.6 Serial Interface Communication (SPI)
        1. 6.12.6.1 Serial Interface Mode Without Slave Select (SS)
        2. 6.12.6.2 Serial Interface Mode With Slave Select (SS)
      7. 6.12.7 Direct Mode
    13. 6.13 Direct Commands from MCU to Reader
      1. 6.13.1  Command Codes
      2. 6.13.2  Reset FIFO (0x0F)
      3. 6.13.3  Transmission With CRC (0x11)
      4. 6.13.4  Transmission Without CRC (0x10)
      5. 6.13.5  Delayed Transmission With CRC (0x13)
      6. 6.13.6  Delayed Transmission Without CRC (0x12)
      7. 6.13.7  Transmit Next Time Slot (0x14)
      8. 6.13.8  Block Receiver (0x16)
      9. 6.13.9  Enable Receiver (0x17)
      10. 6.13.10 Test Internal RF (RSSI at RX Input With TX On) (0x18)
      11. 6.13.11 Test External RF (RSSI at RX Input With TX Off) (0x19)
      12. 6.13.12 Register Preset
    14. 6.14 Register Description
      1. 6.14.1 Register Overview
        1. 6.14.1.1 Main Configuration Registers
          1. 6.14.1.1.1 Chip Status Control Register (0x00)
          2. 6.14.1.1.2 ISO Control Register (0x01)
        2. 6.14.1.2 Protocol Subsetting Registers
          1. 6.14.1.2.1  ISO14443B TX Options Register (0x02)
          2. 6.14.1.2.2  ISO14443A High-Bit-Rate and Parity Options Register (0x03)
          3. 6.14.1.2.3  TX Timer High Byte Control Register (0x04)
          4. 6.14.1.2.4  TX Timer Low Byte Control Register (0x05)
          5. 6.14.1.2.5  TX Pulse Length Control Register (0x06)
          6. 6.14.1.2.6  RX No Response Wait Time Register (0x07)
          7. 6.14.1.2.7  RX Wait Time Register (0x08)
          8. 6.14.1.2.8  Modulator and SYS_CLK Control Register (0x09)
          9. 6.14.1.2.9  RX Special Setting Register (0x0A)
          10. 6.14.1.2.10 Regulator and I/O Control Register (0x0B)
        3. 6.14.1.3 Status Registers
          1. 6.14.1.3.1 IRQ Status Register (0x0C)
          2. 6.14.1.3.2 Collision Position and Interrupt Mask Registers (0x0D and 0x0E)
          3. 6.14.1.3.3 RSSI Levels and Oscillator Status Register (0x0F)
        4. 6.14.1.4 Test Registers
          1. 6.14.1.4.1 Test Register (0x1A)
          2. 6.14.1.4.2 Test Register (0x1B)
        5. 6.14.1.5 FIFO Control Registers
          1. 6.14.1.5.1 FIFO Status Register (0x1C)
          2. 6.14.1.5.2 TX Length Byte1 Register (0x1D) and TX Length Byte2 Register (0x1E)
  7. 7Applications, Implementation, and Layout
    1. 7.1 TRF7960A Reader System Using SPI With SS Mode
      1. 7.1.1 General Application Considerations
      2. 7.1.2 Schematic
    2. 7.2 System Design
      1. 7.2.1 Layout Considerations
      2. 7.2.2 Impedance Matching TX_Out (Pin 5) to 50 Ω
      3. 7.2.3 Reader Antenna Design Guidelines
  8. 8Device and Documentation Support
    1. 8.1 Getting Started and Next Steps
    2. 8.2 Device Nomenclature
    3. 8.3 Tools and Software
    4. 8.4 Documentation Support
    5. 8.5 Support Resources
    6. 8.6 Trademarks
    7. 8.7 Electrostatic Discharge Caution
    8. 8.8 Export Control Notice
    9. 8.9 Glossary
  9. 9Mechanical, Packaging, and Orderable Information

Package Options

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

6.7.1.2 External RSSI

The external RSSI is mainly used for test and diagnostic to sense the amplitude of any 13.56-MHz signal at the receiver's RX_IN1 input. The external RSSI measurement is typically done in active mode when the receiver is on but transmitter output is off. The level of the RF signal received at the antenna is measured and stored in the RSSI Levels and Oscillator Status register (0x0F).

Figure 6-3 shows the relationship between the voltage at the RX_IN1 input and the 3-bit code.

TRF7960A digital_external_rssi_slos732.gifFigure 6-3 Digital External RSSI Value vs RF Input Level

The relation between the 3-bit code and the external RF field strength (A/m) sensed by the antenna must be determined by calculation or by experiments for each antenna design. The antenna Q-factor and connection to the RF input influence the result. Direct command 0x19 is used to trigger an internal RSSI measurement.

To check the internal or external RSSI value independent of any other operation:

  1. Set transmitter to desired state (on or off) using Bit 5 of the Chip Status Control register (0x00) and enable receiver using Bit 1.
  2. Check internal or external RSSI using direct commands 0x18 or 0x19, respectively. This action places the RSSI value in the RSSI register.
  3. Delay at least 50 µs.
  4. Read the RSSI register using direct command 0x0F. Values can range from 0x40 to 0x7F.
  5. Repeat steps 1 to 4 as desired; the register is reset after read.