LVDS vs M-LVDS: Key Differences Explained

This page compares LVDS and M-LVDS, outlining the similarities and differences between these two interface types.

Introduction:

LVDS (Low Voltage Differential Signaling) and M-LVDS are differential signaling methods used for high-speed communication over two wires. LVDS is typically used for point-to-point links, whereas M-LVDS is designed for multipoint links. In both, data is decoded based on the voltage difference between two complementary electrical signals.

Both interfaces improve noise immunity and minimize electromagnetic emissions.

LVDS: Point-to-Point Communication

LVDS is primarily defined in the TIA/EIA-644 standard, with an alternative standard in IEEE 1596.3. It’s often considered a low-power alternative to ECL and PECL interfaces.

It finds applications in:

• Clock distribution
• High-speed backplanes
• Data communication between boards
• Data communication between links on a single PCB

Image Courtesy: Analog Devices, Inc.

Advantages of LVDS:

• Data communication at speeds up to 1 Gbps or higher.
• Increased immunity to noise.
• Reduced EM emissions.
• Low power operation.
• A common mode range that allows for differences of up to +/- 1 V in GND offset.

M-LVDS: Multipoint Communication

M-LVDS extends LVDS to handle multipoint applications. Its specifications are defined in the TIA/EIA-899 standard. Compared to RS485 and CAN interfaces, M-LVDS supports high-speed communication links at lower power and over greater distances than standard LVDS.

Image Courtesy: Analog Devices, Inc.

M-LVDS supports up to 32 nodes on a single bus and offers the following additional features:

• Extended common mode range
• Increased driver output strength
• Controlled transition times
• Option of failsafe receivers for bus idle conditions

Similar to LVDS, it is also used for applications like clock distribution, termination, data encoding and synchronization, and isolation.

M-LVDS uses a higher differential output voltage and supports an extended common mode range.

LVDS vs. M-LVDS: Key Differences

The following table highlights the key differences between LVDS and M-LVDS: