What Is LVDS?

LVDS, short for low-voltage differential signalling, is an electrical method for sending fast digital data down a pair of wires or PCB traces. Instead of switching one wire between 0 V and a supply voltage, the transmitter drives a small constant current of about 3.5 mA around a loop formed by the two wires and a 100 ohm resistor at the receiver. Reversing the direction of the current flips the voltage across that resistor between about +350 mV and −350 mV, and the receiver reads the sign of the difference as a 1 or a 0.

National Semiconductor introduced LVDS in the mid-1990s, and the electrical layer is standardised as ANSI/TIA/EIA-644. That standard defines voltages and currents only, not a data format, so LVDS appears inside many protocols: display links, camera interfaces, FPGA I/O and backplanes.

Two properties made it popular. Noise picked up by the cable appears equally on both wires, so the receiver cancels it out, and the equal and opposite currents radiate very little interference. The small voltage swing also lets it switch fast while drawing little power.

In computing, “LVDS” almost always means the display interface between a motherboard and an LCD panel. Strictly, the protocol is FPD-Link (later OpenLDI), which runs over LVDS signalling, but the industry uses the electrical name for the whole link. The board’s transmitter serialises the red, green and blue pixel data, plus sync signals, onto a few pairs at seven bits per clock cycle, and the panel’s timing controller converts them back.

Industrial and embedded panels kept LVDS long after laptops moved on, because it is simple, well understood and available on panels from 5″ to 24″ with long production lives. Most of our 3.5″ single board computers and many industrial Mini-ITX motherboards have an LVDS header for exactly this reason: they are built into panel PCs, kiosks and machine HMIs with an internal display.

Two choices define every LVDS panel connection. Colour depth sets how many data pairs a channel needs, and resolution sets whether one channel is fast enough or two are needed, with odd and even pixels sent on separate channels.

The figures are typical, because the limit is the pixel clock each transmitter and panel supports, usually up to around 85–112 MHz per channel. A 1920 × 1080 panel at 60 Hz needs about 148.5 MHz in total, so it is almost always dual channel.

24-bit panels add one more detail: the bit mapping. The VESA and JEIDA formats put the colour bits on the pairs in a different order, and a mismatch shows as washed-out or wrong colours rather than no picture. The board’s BIOS or display settings, the panel datasheet and the cable all have to agree.

An LVDS cable is a short internal harness of twisted pairs, usually with a fine-pitch connector at each end. The board end is often a Hirose DF13, DF19 or DF20 header, and the panel end is often a JAE FI-X or I-PEX connector, but pin-outs differ between board and panel makers, so an LVDS cable is normally built for one board and one panel. Check these points before ordering one.

Embedded DisplayPort (eDP), defined by VESA, is the internal panel interface that has replaced LVDS in laptops and most new designs. eDP sends packets over one to four high-speed lanes with an auxiliary channel for panel control, so it reaches higher resolutions with fewer wires and supports power-saving features such as panel self-refresh.

Intel and AMD processors from roughly the mid-2010s onwards no longer drive LVDS natively. Boards that still offer it add an eDP- or DisplayPort-to-LVDS bridge chip, which is why many current boards list both. LVDS remains a sound choice for existing panel designs and long-life industrial displays. eDP suits new designs, higher resolutions and thinner cabling. Our guide to open frame displays vs embedded LCD display kits covers how the panel interface fits into the wider display choice, and our Pico-ITX single board computers include models with LVDS and others with eDP.

When a project uses an internal display, we pair the board, panel and LVDS or eDP harness as standard, set the panel voltage, timings and backlight control, and test the complete display before it ships.