SNAS717A April   2017  – October 2021 ADC12D1620QML-SP

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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  Converter Electrical Characteristics: Static Converter Characteristics
    6. 6.6  Converter Electrical Characteristics: Dynamic Converter Characteristics
    7. 6.7  Converter Electrical Characteristics: Analog Input/Output and Reference Characteristics
    8. 6.8  Converter Electrical Characteristic: Channel-to-Channel Characteristics
    9. 6.9  Converter Electrical Characteristics: LVDS CLK Input Characteristics
    10. 6.10 Electrical Characteristics: AutoSync Feature
    11. 6.11 Converter Electrical Characteristics: Digital Control and Output Pin Characteristics
    12. 6.12 Converter Electrical Characteristics: Power Supply Characteristics
    13. 6.13 Converter Electrical Characteristics: AC Electrical Characteristics
    14. 6.14 Electrical Characteristics: Delta Parameters
    15. 6.15 Timing Requirements: Serial Port Interface
    16. 6.16 Timing Requirements: Calibration
    17. 6.17 Quality Conformance Inspection
    18. 6.18 Timing Diagrams
    19. 6.19 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
      1. 7.1.1 Operation Summary
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input Control and Adjust
        1. 7.3.1.1 AC- and DC-Coupled Modes
        2. 7.3.1.2 Input Full-Scale Range Adjust
        3. 7.3.1.3 Input Offset Adjust
        4. 7.3.1.4 Low-Sampling Power-Saving Mode (LSPSM)
        5. 7.3.1.5 DES Timing Adjust
        6. 7.3.1.6 Sampling Clock Phase Adjust
      2. 7.3.2 Output Control and Adjust
        1. 7.3.2.1 SDR / DDR Clock
        2. 7.3.2.2 LVDS Output Differential Voltage
        3. 7.3.2.3 LVDS Output Common-Mode Voltage
        4. 7.3.2.4 Output Formatting
        5. 7.3.2.5 Test-Pattern Mode
        6. 7.3.2.6 Time Stamp
      3. 7.3.3 Calibration Feature
        1. 7.3.3.1 Calibration Control Pins and Bits
        2. 7.3.3.2 How to Execute a Calibration
        3. 7.3.3.3 On-Command Calibration
        4. 7.3.3.4 Calibration Adjust
          1. 7.3.3.4.1 Read/Write Calibration Settings
        5. 7.3.3.5 Calibration and Power-Down
        6. 7.3.3.6 Calibration and the Digital Outputs
      4. 7.3.4 Power Down
      5. 7.3.5 Low-Sampling Power-Saving Mode (LSPSM)
    4. 7.4 Device Functional Modes
      1. 7.4.1 DES/Non-DES Mode
      2. 7.4.2 Demux/Non-Demux Mode
    5. 7.5 Programming
      1. 7.5.1 Control Modes
        1. 7.5.1.1 Non-ECM
          1. 7.5.1.1.1  Dual-Edge Sampling Pin (DES)
          2. 7.5.1.1.2  Non-Demultiplexed Mode Pin (NDM)
          3. 7.5.1.1.3  Dual Data-Rate Phase Pin (DDRPh)
          4. 7.5.1.1.4  Calibration Pin (CAL)
          5. 7.5.1.1.5  Low-Sampling Power-Saving Mode Pin (LSPSM)
          6. 7.5.1.1.6  Power-Down I-Channel Pin (PDI)
          7. 7.5.1.1.7  Power-Down Q-Channel Pin (PDQ)
          8. 7.5.1.1.8  Test-Pattern Mode Pin (TPM)
          9. 7.5.1.1.9  Full-Scale Input-Range Pin (FSR)
          10. 7.5.1.1.10 AC- or DC-Coupled Mode Pin (VCMO)
          11. 7.5.1.1.11 LVDS Output Common-Mode Pin (VBG)
        2. 7.5.1.2 Extended Control Mode
          1. 7.5.1.2.1 Serial Interface
    6. 7.6 Register Maps
      1. 7.6.1 Register Definitions
  8. 8 Application Information Disclaimer
    1. 8.1 Application Information
      1. 8.1.1 Analog Inputs
        1. 8.1.1.1 Acquiring the Input
        2. 8.1.1.2 Driving the ADC in DES Mode
        3. 8.1.1.3 FSR and the Reference Voltage
        4. 8.1.1.4 Out-Of-Range Indication
        5. 8.1.1.5 AC-Coupled Input Signals
        6. 8.1.1.6 DC-Coupled Input Signals
        7. 8.1.1.7 Single-Ended Input Signals
      2. 8.1.2 Clock Inputs
        1. 8.1.2.1 CLK Coupling
        2. 8.1.2.2 CLK Frequency
        3. 8.1.2.3 CLK Level
        4. 8.1.2.4 CLK Duty Cycle
        5. 8.1.2.5 CLK Jitter
        6. 8.1.2.6 CLK Layout
      3. 8.1.3 LVDS Outputs
        1. 8.1.3.1 Common-Mode and Differential Voltage
        2. 8.1.3.2 Output Data Rate
        3. 8.1.3.3 Terminating Unused LVDS Output Pins
      4. 8.1.4 Synchronizing Multiple ADC12D1620 Devices in a System
        1. 8.1.4.1 AutoSync Feature
        2. 8.1.4.2 DCLK Reset Feature
      5. 8.1.5 Temperature Sensor
    2. 8.2 Radiation Environments
      1. 8.2.1 Total Ionizing Dose
      2. 8.2.2 Single Event Latch-Up and Functional Interrupt
      3. 8.2.3 Single Event Upset
    3. 8.3 Cold Sparing
  9. 9 Power Supply Recommendations
    1. 9.1 System Power-On Considerations
      1. 9.1.1 Control Pins
      2. 9.1.2 Power On in Non-ECM
      3. 9.1.3 Power On in ECM
      4. 9.1.4 Power-on and Data Clock (DCLK)
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Power Planes
      2. 10.1.2 Bypass Capacitors
      3. 10.1.3 Ground Planes
      4. 10.1.4 Power System Example
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
    4. 10.4 Board Mounting Recommendation
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
      2. 11.1.2 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Engineering Samples

7.4.1 DES/Non-DES Mode

The ADC12D1620 device can operate in dual-edge sampling (DES) or non-DES mode. In non-DES mode, inputs are sampled at the sampling clock frequency. Depending on whether channels are powered down, one or two inputs may be sampled. The DES mode enables a single analog input to be sampled by both I and Q channels. One channel samples the input on the rising edge of the sampling clock and the other samples the input signal on the falling edge of the sampling clock. A single input is thus sampled twice per clock cycle, resulting in an overall sample rate of twice the sampling clock frequency. Because DES mode uses both I and Q channels to process the input signal, both channels must be powered up for the DES mode to function properly.

See Dual-Edge Sampling Pin (DES) for information on how to select the DES mode. In non-ECM only the I input may be used for the DES mode input. In ECM, either the I or Q input may be selected by first using the DES bit (Addr: 0h; Bit: 7) to select the DES mode. Setting the DEQ bit (Addr: 0h; Bit: 6) selects the Q input, while leaving the default value of DEQ=0 selects the I input.

Two other DES modes are available. These provide improved input bandwidth compared to DESI and DESQ modes, but require driving the I and Q inputs with identical in-phase signals.

The DESIQ mode is selected by setting the DIQ bit (Addr: 0h; Bit: 5). In this mode the I and Q input signals are connected to the I and Q converter channels and also connected to each other internally to enable better I to Q signal matching compared with the DESCLKIQ mode discussed next.

DESCLKIQ mode is similar to the DESIQ mode, except that the I and Q channels remain electrically separate internal to the ADC12D1620. For this reason, the I to Q signal matching is slightly worse, and spurious performance is degraded compared to DESIQ mode. DESCLKIQ input bandwidth is slightly better than the DESIQ bandwidth. The DCK bit (Addr: Eh; Bit: 6) is used to select the 180° sampling-clock mode.

Table 7-7 summarizes the relative bandwidth and SFDR performance of the DES sampling modes:

Table 7-7 DES Mode Comparison
DES MODEINPUTS DRIVENINPUT BANDWIDTHSFDR PERFORMANCE
DESI, DESQI or QLowestHighest
DESIQI and QMidMid
DESCLKIQI and QHighestLowest

In the DES mode, the output data must be carefully interleaved in order to reconstruct the sampled signal. If the device is programmed into the 1:4 demux DES mode, the data is effectively demultiplexed by 1:4. If the sampling clock is 1600 MHz, the effective sampling rate is doubled to 3.2 GSPS, and each of the 4 output buses has an output rate of 800 MSPS. All data is available in parallel. To properly reconstruct the sampled waveform, the four words of parallel data that are output with each DCLK must be correctly interleaved. The sampling order is as follows, from the earliest to the latest: DQd, DId, DQ, DI (see Figure 6-3). If the device is programmed into the nondemux DES mode, two words of parallel data are output with each edge of the DCLK in the following sampling order, from the earliest to the latest: DQ, DI (see Figure 6-4).