HDMI Impedance Calculator
HDMI 1.4 | HDMI 2.0 | HDMI 2.1
Calculate trace width and differential impedance for HDMI designs. From 1080p to 8K video, get the right 100Ω differential TMDS trace dimensions for reliable high-bandwidth video transmission.
HDMI Specifications
| HDMI Version | Bandwidth | Max Resolution | Differential Z |
|---|---|---|---|
| HDMI 1.4 | 10.2 Gbps | 4K@30Hz | 100Ω ±10% |
| HDMI 2.0 | 18 Gbps | 4K@60Hz | 100Ω ±10% |
| HDMI 2.1 | 48 Gbps | 8K@60Hz | 100Ω ±10% |
HDMI PCB Design Guidelines
100Ω Differential
HDMI TMDS signals require 100Ω differential impedance (50Ω single-ended). This is critical for all TMDS data and clock pairs.
4 Differential Pairs
HDMI uses 4 differential pairs: 3 TMDS data channels + 1 TMDS clock. Each pair must be length-matched and impedance-controlled.
Length Matching
Match all TMDS pairs to within 2mm of each other. For HDMI 2.1, tighter matching of ±0.5mm may be required for reliable operation.
Typical HDMI Trace Dimensions
4-Layer Board (1.6mm, FR4)
6-Layer Board (1.6mm, FR4)
* These are typical values. Use our calculator with your actual stackup for accurate results.
HDMI Signal Types
TMDS Signals
- • Data 0/1/2: 100Ω differential, high-speed
- • Clock: 100Ω differential
- • Length match all 4 pairs together
- • Keep away from noise sources
- • Route on inner layers if possible
Low-Speed Signals
- • DDC (I2C): Not impedance critical
- • CEC: Single-ended, low-speed
- • HPD: Hot Plug Detect, GPIO
- • +5V/GND: Power, standard traces
- • Standard routing rules apply
Calculate Your HDMI Trace Dimensions
Use our free impedance calculator to determine exact trace width and spacing for your HDMI design. Enter your stackup parameters for accurate 100Ω differential calculations.
HDMI Design FAQ
What impedance do I need for HDMI?
HDMI requires 100Ω differential impedance (±10% tolerance) for all TMDS data and clock pairs.
How long can HDMI traces be?
Keep PCB traces as short as possible, typically under 6 inches. HDMI 2.1 may require even shorter runs or low-loss materials.
Do I need controlled impedance for HDMI 1.4?
Yes. While HDMI 1.4 is more forgiving than 2.0/2.1, controlled impedance is still required for reliable operation.
Can I route HDMI on outer layers?
Yes, but inner layers (stripline) provide better shielding. If routing on outer layers, ensure adequate ground pour on adjacent layers.
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