SBASAI6 September   2023 ADC32RF52

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics - Power Consumption
    6. 6.6  Electrical Characteristics - DC Specifications
    7. 6.7  Electrical Characteristics - AC Specifications (Dither DISABLED)
    8. 6.8  Electrical Characteristics - AC Specifications (Dither ENABLED)
    9. 6.9  Timing Requirements
    10. 6.10 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Inputs
        1. 7.3.1.1 Input Bandwidth and Full-Scale
        2. 7.3.1.2 Input Imbalance
        3. 7.3.1.3 Overrange Indication
        4. 7.3.1.4 Analog out-of-band dither
      2. 7.3.2 Sampling Clock Input
      3. 7.3.3 SYSREF
        1. 7.3.3.1 SYSREF Capture Detection
      4. 7.3.4 ADC Foreground Calibration
        1. 7.3.4.1 Calibration Control
        2. 7.3.4.2 ADC Switch
        3. 7.3.4.3 Calibration Configuration
      5. 7.3.5 Decimation Filter
        1. 7.3.5.1 Decimation Filter Response
        2. 7.3.5.2 Decimation Filter Configuration
        3. 7.3.5.3 20-bit Output Mode
        4. 7.3.5.4 Dynamic Switching
          1. 7.3.5.4.1 2 Lane Mode
          2. 7.3.5.4.2 1 Lane Mode
        5. 7.3.5.5 Numerically Controlled Oscillator (NCO)
        6. 7.3.5.6 NCO Frequency Programming
        7. 7.3.5.7 Fast Frequency Hopping
          1. 7.3.5.7.1 Fast frequency hopping using the GPIO1/2 pins
          2. 7.3.5.7.2 Fast frequency hopping using GPIO1/2, SEN and SDATA pins
          3. 7.3.5.7.3 Fast frequency hopping using the fast SPI
      6. 7.3.6 JESD204B Interface
        1. 7.3.6.1 JESD204B Initial Lane Alignment (ILA)
          1. 7.3.6.1.1 SYNC Signal
        2. 7.3.6.2 JESD204B Frame Assembly
        3. 7.3.6.3 JESD204B Frame Assembly in Bypass Mode
        4. 7.3.6.4 JESD204B Frame Assembly with Complex Decimation - Single Band
        5. 7.3.6.5 JESD204B Frame Assembly with Complex Decimation - Dual Band
        6. 7.3.6.6 JESD204B Frame Assembly with Complex Decimation - Quad Band
      7. 7.3.7 SERDES Output MUX
      8. 7.3.8 Test Pattern
        1. 7.3.8.1 Transport Layer
        2. 7.3.8.2 Link Layer
        3. 7.3.8.3 Internal Capture Memory Buffer
    4. 7.4 Device Functional Modes
      1. 7.4.1 Digital Averaging
    5. 7.5 Programming
      1. 7.5.1 GPIO Pin Control
      2. 7.5.2 Configuration using the SPI interface
        1. 7.5.2.1 Register Write
        2. 7.5.2.2 Register Read
    6. 7.6 Register Maps
      1. 7.6.1 Detailed Register Description
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Wideband RF Sampling Receiver
        1. 8.2.1.1 Design Requirements
          1. 8.2.1.1.1 Input Signal Path
          2. 8.2.1.1.2 Clocking
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Sampling Clock
        3. 8.2.1.3 Application Curves
    3. 8.3 Initialization Set Up
      1. 8.3.1 Initial Device Configuration After Power-Up
        1. 8.3.1.1  STEP 1: RESET
        2. 8.3.1.2  STEP 2: Device Configuration
        3. 8.3.1.3  STEP 3: JESD Interface Configuration (1)
        4. 8.3.1.4  STEP 4: SYSREF Synchronization
        5. 8.3.1.5  STEP 5: JESD Interface Configuration (2)
        6. 8.3.1.6  STEP 6: Analog Trim Settings
        7. 8.3.1.7  STEP 7: Calibration Configuration
        8. 8.3.1.8  STEP 8: SYSREF Synchronization
        9. 8.3.1.9  STEP 9: Run Power up Calibration
        10. 8.3.1.10 STEP 10: JESD Interface Synchronization
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.4.1 Digital Averaging

The ADC32RF52 provides a total of eight internal single core 1.5 Gsps ADCs. Normal bypass mode uses only two ADC cores (one ADC per channel). However the additional six ADCs can be used to trade off further noise density improvement against additional power consumption. Figure 7-42 shows the internal block diagrams for the digital averaging modes. In averaging mode the output resolution is increased to 16-bit to avoid quantization noise limitation.

In 2x averaging mode (left) one external input is connected to the INx1 input where two ADC cores internally average the input signal. In 4x averaging (right) the signal has to be split externally and connected to both the INx1 and INx2 inputs where four ADC cores internally average the signal.

GUID-A6298FE4-FE81-4394-8858-2584675E70FB-low.gifFigure 7-42 Internal digital averaging (left: 2x, right: 4x)

Table 7-47 provides a trade-off comparison of the 3 different averaging mode options vs the default, non-averaged mode.

Table 7-47 Digital averaging vs full power input bandwidth (–3 dB)
# of ADCs averaged ADC inputs used for averaging Input Bandwidth (-3 dB) Selected differential input termination Noise density
Default INx1

1.6 GHz

 100 Ω -153 dBFS/Hz
2 INx1

1.5 GHz

 100 Ω -156 dBFS/Hz
4 INx1, INx2

1.5 GHz

 100 Ω -159 dBFS/Hz

Digital averaging improves decorrelated noise contributions by 3 dB per 2x AVG (ideal) while correlated noise does not improve with averaging. Some of the dominant noise sources are correlated (e.g. clock jitter (external or first clock input buffer) or power supply noise) while others (e.g. ADC thermal noise, clock distribution buffers) are decorrelated. illustrates a performance example comparison across averaging options.

SNR: When operating close to ADC fullscale, some of the SNR limitation is due to jitter and hence the SNR improvement won’t reach 3 dB (2x AVG) or 6 dB (4x AVG). As the input fullscale is reduced, the clock jitter contribution to SNR becomes less and the SNR improvement is approaching the ideal 3 dB per 2x AVG. The same phenomenon can be observed when using digital decimation. As the decimation factor increases, the close-in (correlated noise) becomes the more dominating noise unless the input signal amplitude is reduced.

SFDR: The amplitude of low order harmonics (HD2-HD5) and IMD3 typically is very similar across ADCs and thus the improvement with averaging is very small.