SCAS928D May   2012  – April 2019 CDCUN1208LP

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Pin Configuration Overview
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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  Digital Input Electrical Characteristics – OE (SCL), INSEL, ITTP, OTTP, Divide (SDA/MOSI), ERC(ADDR/CS), Mode
    6. 6.6  Universal Input (IN1, IN2) Characteristics
    7. 6.7  Clock Output Buffer Characteristics (Output Mode = LVDS)
    8. 6.8  Clock Output Buffer Characteristics (Output Mode = HCSL)
    9. 6.9  Clock Output Buffer Electrical Characteristics (Output Mode = LVCMOS)
    10. 6.10 Clock Output Buffer Electrical Characteristics (Output Mode = LVCMOS) (Continued)
    11. 6.11 Clock Output Buffer Electrical Characteristics (Output Mode = LVCMOS) (Continued)
    12. 6.12 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Test Configurations
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Device Control Using Configuration Pins
        1. 8.3.1.1 Configuration of Output Type (OTTP)
        2. 8.3.1.2 Configuration of Edge Rate Control (ERC)
        3. 8.3.1.3 Control of Output Enable (OE)
      2. 8.3.2 Input Ports (IN1, IN2)
        1. 8.3.2.1 Configuration of the Input Type (ITTP)
        2. 8.3.2.2 Configuration of the IN2 Divider (INDIV)
      3. 8.3.3 Smart Input Multiplexer (INMUX)
        1. 8.3.3.1 Pin Configuration of the Smart Input Multiplexer (INMUX)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Device Control Using the Host Interface
        1. 8.4.1.1 OE and INSEL in Host Configuration Mode
    5. 8.5 Programming
      1. 8.5.1 Host Interface Hardware Information
        1. 8.5.1.1 SPI Communication
          1. 8.5.1.1.1 CDCUN1208LP SPI Addressing
          2. 8.5.1.1.2 Writing to the CDCUN1208LP
          3. 8.5.1.1.3 Reading From the CDCUN1208LP
          4. 8.5.1.1.4 Block Write/Read Operation
        2. 8.5.1.2 I2C Communication
          1. 8.5.1.2.1 Message Transmission
            1. 8.5.1.2.1.1 Data and Address Bits
            2. 8.5.1.2.1.2 Special Symbols – Start (S) and Stop (P)
            3. 8.5.1.2.1.3 Special Symbols – Acknowledge (ACK)
            4. 8.5.1.2.1.4 Generic Message Frame
            5. 8.5.1.2.1.5 CDCUN1208LP Message Format
            6. 8.5.1.2.1.6 CDCUN1208LP Device Addressing (I2C Address)
            7. 8.5.1.2.1.7 CDCUN1208LP Device Addressing (Register Address)
          2. 8.5.1.2.2 I2C Master and Slave Handshaking
          3. 8.5.1.2.3 Block Read/Write
          4. 8.5.1.2.4 I2C Timing
    6. 8.6 Register Maps
      1. 8.6.1 Device Registers
        1. 8.6.1.1 Device Registers: Register 00-07
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 PCI Express Applications
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
    3. 9.3 Systems Examples
  10. 10Power Supply Recommendations
    1. 10.1 CDCUN1208LP Power Consumption
    2. 10.2 Device Power Supply Connections and Sequencing
    3. 10.3 Device Inputs (IN1, IN2)
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.3 Systems Examples

Figure 44 shows a typical application in which the receiver is off-board. The PCIe Specification (CEM2.0) requires that all source termination is on the motherboard (not on the daughter card). For this reason, the termination resistors are placed as shown. Additionally, source resistors are employed to eliminate ringing. In this case, ZL can vary between 40 Ω and 60 Ω and RS can range from 22 Ω to 33 Ω.

CDCUN1208LP off_board_rx_cas928.gifFigure 44. Typical Configuration – Off-Board Receiver

Figure 45 shows a typical application in which the receiver is on-board. In this case, series resistors are not required to eliminate ringing as proper termination is achieved. In this case, two termination resistors, ZL = 49.9 Ω, are placed close to the receiver.

CDCUN1208LP on_board_conn_cas928.gifFigure 45. Typical Configuration – On-Board Connection