SNAA377 December   2025 LMK05318 , LMK05318B , LMK5B12204 , LMK5B12212 , LMK5B33216 , LMK5B33414 , LMK5C22212A , LMK5C23208A , LMK5C33216 , LMK5C33216A , LMK5C33414A

 

  1.   1
  2.   Trademarks
  3.   Abstract
  4. 1Introduction
  5. 2General Termination Guidelines
    1. 2.1 Identify the Driver and Receiver Requirements
    2. 2.2 Determine the Coupling Type
      1. 2.2.1 DC-Coupled Signal
      2. 2.2.2 AC-Coupled Signal
  6. 3Differential
    1. 3.1 Setting the Common-Mode Voltage (Thevenin Termination)
    2. 3.2 LVPECL
      1. 3.2.1 DC-Coupled LVPECL
      2. 3.2.2 AC-Coupled LVPECL
    3. 3.3 LVDS
      1. 3.3.1 DC-Coupled LVDS
      2. 3.3.2 AC-Coupled LVDS
    4. 3.4 HSDS
      1. 3.4.1 DC-Coupled HSDS
      2. 3.4.2 AC-Coupled HSDS
    5. 3.5 HCSL
      1. 3.5.1 DC-Coupled HCSL
      2. 3.5.2 AC-Coupled HCSL
    6. 3.6 LP-HCSL
      1. 3.6.1 DC-Coupled LP-HCSL
      2. 3.6.2 AC-Coupled LP-HCSL
  7. 4Single-Ended
    1. 4.1 LVCMOS
      1. 4.1.1 DC-Coupled LVCMOS (Series Termination)
      2. 4.1.2 AC-Coupled LVCMOS (Series Termination)
    2. 4.2 Differential P or N
      1. 4.2.1 DC-Coupled Differential P or N
  8. 5Summary
  9. 6References

3.5.2 AC-Coupled HCSL

Apply AC-coupling capacitors to the HCSL output when interfacing with non-HCSL receivers or to reconfigure the VCM.

External Termination

AC-Coupled HCSL to LVPECL

For HCSL to LVPECL translation, place the resistors to ground before the AC-coupling capacitors to provide the DC return path for the HCSL driver. Use a resistor network after the capacitors to set the common-mode voltage to VCC – 1.3V for the LVPECL receiver.

AC-coupled HCSL to LVPECL Figure 3-24 AC-coupled HCSL to LVPECL

AC-Coupled HCSL to LVDS With External Termination and Internal Biasing

For translation with an LVDS receiver that accepts the VCM of an HCSL output and/or has internal biasing, terminate the HCSL driver with resistors to ground and the LVDS receiver with a differential resistor.

AC-Coupled HCSL to LVDS with External Termination and Internal Biasing Figure 3-25 AC-Coupled HCSL to LVDS with External Termination and Internal Biasing

AC-Couple HCSL to LVDS With External Termination and Biasing

For translation with an LVDS receiver that is not internally biased, terminate the HCSL driver with resistors to ground and reconfigure the common-mode voltage to 1.2V using a resistor network.

AC-Coupled HCSL to LVDS with External Termination and Biasing Figure 3-26 AC-Coupled HCSL to LVDS with External Termination and Biasing

AC-Coupled HCSL to LVDS With Internal Termination and Biasing

For translation with an LVDS receiver that is biased and terminated, only terminate the HCSL driver with resistors to ground.

AC-Coupled HCSL to LVDS with Internal Termination and Biasing Figure 3-27 AC-Coupled HCSL to LVDS with Internal Termination and Biasing