SBAS988 November   2023 ADC34RF55

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics - Power Consumption
    6. 5.6  Electrical Characteristics - DC Specifications
    7. 5.7  Electrical Characteristics - AC Specifications (Dither DISABLED)
    8. 5.8  Electrical Characteristics - AC Specifications (Dither ENABLED)
    9. 5.9  Timing Requirements
    10. 5.10 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Analog Inputs
        1. 6.3.1.1 Input Bandwidth and Full-Scale
        2. 6.3.1.2 Input Imbalance
        3. 6.3.1.3 Over Range Indication
        4. 6.3.1.4 Analog out-of-band dither
      2. 6.3.2 Sampling Clock Input
      3. 6.3.3 ADC Foreground Calibration
        1. 6.3.3.1 Calibration Control
        2. 6.3.3.2 ADC Switch
        3. 6.3.3.3 Calibration Configuration
      4. 6.3.4 SYSREF
        1. 6.3.4.1 SYSREF Capture Detection
      5. 6.3.5 Decimation Filter
        1. 6.3.5.1 Decimation Filter Response
        2. 6.3.5.2 Decimation Filter Configuration
        3. 6.3.5.3 20-bit Output Mode
        4. 6.3.5.4 Numerically Controlled Oscillator (NCO)
        5. 6.3.5.5 NCO Frequency Programming Using the SPI Interface
        6. 6.3.5.6 Fast Frequency Hopping
          1. 6.3.5.6.1 Fast frequency hopping using the GPIO1/2 pins
          2. 6.3.5.6.2 Fast frequency hopping using GPIO1/2, SEN and SDATA pins
          3. 6.3.5.6.3 Fast frequency hopping using the fast SPI
      6. 6.3.6 JESD204B Interface
        1. 6.3.6.1 JESD204B Initial Lane Alignment (ILA)
          1. 6.3.6.1.1 SYNC Signal
        2. 6.3.6.2 JESD204B Frame Assembly
          1. 6.3.6.2.1 JESD204B Frame Assembly in Bypass Mode
          2. 6.3.6.2.2 JESD204B Frame Assembly with Real Decimation - Single Band
          3. 6.3.6.2.3 JESD204B Frame Assembly with Complex Decimation - Single Band
          4. 6.3.6.2.4 JESD204B Frame Assembly with Decimation - Dual Band
        3. 6.3.6.3 SERDES Output MUX
      7. 6.3.7 Test Pattern
        1. 6.3.7.1 Transport Layer
        2. 6.3.7.2 Link Layer
        3. 6.3.7.3 Internal Capture Memory Buffer
    4. 6.4 Device Functional Modes
      1. 6.4.1 Bypass Mode
      2. 6.4.2 Digital Averaging
    5. 6.5 Programming
      1. 6.5.1 GPIO Pin Control
      2. 6.5.2 Configuration using the SPI interface
        1. 6.5.2.1 Register Write
        2. 6.5.2.2 Register Read
    6. 6.6 Register Maps
      1. 6.6.1 Detailed Register Description
  8. 7 Application Information Disclaimer
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Wideband RF Sampling Receiver
      2. 7.2.2 Design Requirements
        1. 7.2.2.1 Input Signal Path
        2. 7.2.2.2 Clocking
      3. 7.2.3 Detailed Design Procedure
        1. 7.2.3.1 Sampling Clock
      4. 7.2.4 Application Curves
    3. 7.3 Initialization Set Up
      1. 7.3.1 Initial Device Configuration After Power-Up
        1. 7.3.1.1  STEP 1: RESET
        2. 7.3.1.2  STEP 2: Device Configuration
        3. 7.3.1.3  STEP 3: JESD Interface Configuration (1)
        4. 7.3.1.4  STEP 4: SYSREF Synchronization
        5. 7.3.1.5  STEP 5: JESD Interface Configuration (2)
        6. 7.3.1.6  STEP 6: Analog Trim Settings
        7. 7.3.1.7  STEP 7: Calibration Configuration
        8. 7.3.1.8  STEP 8: SYSREF Synchronization
        9. 7.3.1.9  STEP 9: Run Power up Calibration
        10. 7.3.1.10 Step 10: JESD Interface Synchronization
        11. 7.3.1.11 Step 11: NCO Configuration
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Third-Party Products Disclaimer
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

6.3.4 SYSREF

The SYSREF input signal is used to reset internal digital blocks and align them to the internal multi-frame clock to achieve deterministic latency subclass 1. The SYSREF input signal can be AC or DC coupled (selected via SPI register option) as shown in Figure 6-20. The ADC34RF55 has internal 100-Ω termination for DC coupling and internal biasing when using AC coupling.

A register mask can be used to only give SYSREF to the NCO (see NCO section) in the decimation filter block. Leave all other blocks such as JESD interface unaffected.

When giving a periodic SYSREF signal, the frequency must be a sub-harmonic of the internal local multi-frame clock (LMFC). The LMFC frequency is determined by the selected decimation: frames per multi-frame setting (K), samples per frame (S), and the device sampling frequency (FS).

Table 6-11 LMFC and SYSREF settings for different operating modes
Operating ModeLMFS ModeLMFC Clock FrequencySYSREF Frequency
DDC Bypass Mode84810FS / (20 x K)FS / (N x 20 x K)
8422FS / (4 x K)FS / (N x 4 x K)
DecimationVariousFS / (D x S x K)FS / (N x D x S x K)

Where N is an integer value (1, 2, 3...).

After enabling SYSREF input, the internal SYSREF input ignores any incoming SYSREF pulse after the first 16 pulses.

GUID-4B4D8AFD-70D7-4CE9-9B16-C35892C94267-low.gifFigure 6-20 SYSREF Input Circuitry

The internal synchronization using the external SYSREF signal can be enabled with the following register writes.

Table 6-12 Register Write Example for Enabling SYSREF Synchronization
ADDRDATADESCRIPTION
0x050x02Select DIGITAL page
0x2360x02Enable internal SYSREF input and clear SYSREF pulse counter
0x2360x03Starts internal SYSREF counter

AC coupling with internal biasing of the SYSREF input can be enabled with the following SPI register writes.

Table 6-13 Register Write Example for Enabling SYSREF AC Coupling
ADDRDATADESCRIPTION
0x050x40Select ANALOG page
0xB40x01Enable external AC coupling with internal biasing on SYSREF