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LVDS: Advantages and Disadvantages of Low Voltage Differential Signaling

lvds signal interface low voltage data transfer differential signaling

This page explores the pros and cons of the LVDS (Low Voltage Differential Signaling) interface. It outlines the benefits and drawbacks of using LVDS in various applications.

What is LVDS?

LVDS stands for Low Voltage Differential Signaling. The primary standard for LVDS is defined in TIA/EIA-644. IEEE 1596.3 serves as an alternative standard.

It uses a current output of approximately 4 mA and is designed to drive a 100 Ohm load, aligning with its output impedance of around 100 Ohms.

LVDS signal interface

LVDS finds applications in backplane transceivers, clock distribution, and high-speed data transfer between boards or links on the same PCB. It can operate at data speeds up to 3.125 Gbps. LVDS signals may or may not require AC coupling after the 100 Ohm load.

Benefits or Advantages of LVDS

Here are the advantages of using LVDS:

  • Lower Power Consumption: It consumes less power compared to LVPECL and other signal types.
  • Smaller Voltage Swing: It operates with a smaller voltage swing of about 350 mV.
  • Noise Rejection: Offers good ground noise rejection and common-mode noise rejection.
  • Signal Integrity: Supports longer line lengths and higher signaling rates due to maintaining good signal integrity.
  • Low EMI Emissions: Has lower EMI emissions compared to TTL/CMOS interfaces.
  • Easy Implementation: Relatively easy to implement in CMOS ICs.
  • No External Biasing: LVDS output doesn’t require external biasing.
  • Versatile Signal Support: Supports data, clock, and control signals.

Drawbacks or Disadvantages of LVDS

Here are the disadvantages of using LVDS:

  • No Multipoint Support: Unlike M-LVDS, RS485, and CAN interfaces, it doesn’t support multipoint applications.
  • Reduced Jitter Performance: It has reduced jitter performance compared to PECL signal interfaces.
  • Limited Data Rates: While it supports data rates up to 3.125 Gbps, other interfaces like HCSL, LVPECL, or CML are needed for higher data rates.
  • Higher Cost: Generally more expensive.
  • Twisted Cable Requirement: Typically requires twisted-pair cable.