SLLA598 October   2022 TDP1204 , TMDS1204

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2HDMI2.1 Key Features
    1. 2.1 Bandwidth
    2. 2.2 Dynamic HDR
    3. 2.3 Auto Low-Latency Mode
    4. 2.4 Variable Refresh Rate
    5. 2.5 Quick Frame Transport
    6. 2.6 Quick Media Switching
    7. 2.7 Enhanced Audio Return Channel
  5. 3TDP1204 and TMDS1204
    1. 3.1 TMDS1204 Fan-Out Buffer
    2. 3.2 TMDS 1204 SIGDET_OUT
    3. 3.3 TMDS1204 DC Gain Adjustment
    4. 3.4 TDP1204 DDC Buffer
  6. 4Summary
  7. 5References

3 TDP1204 and TMDS1204

With the introduction of the HDMI2.1 specification, the maximum data rate per lane has been increased to 12 Gbps. The signal condition or the quality of the lane becomes paramount in order to deliver a smooth and rich video and audio experience for the consumer. With any multi-gigabit signal, the signal integrity starts to degrade from transmission line insertion loss, crosstalk, inter-symbol interference, noise, and reflections as the data rate increases.

To compensate these signal integrity degradations, Texas Instruments introduces two redrivers for HDMI2.1, TDP1204 and TMDS1204. Both TDP1204 and TMDS1204 are HDMI 2.1 redrivers supporting data rates up to 12 Gbps per lan. They are backwards compatible for HDMI 1.4b and HDMI 2.0b. The high-speed differential inputs and outputs can either be AC-coupled or DC-coupled, which qualifies the TDP1204 and TMDS1204 to be used as a DP++ (AC-coupled) to HDMI level shifter or HDMI (DC-coupled) to HDMI redriver. The TDP1204 can support both 3 and 4 lane HDMI 2.1 FRL at 3, 6, 8, 10, and 12-Gbps.

Both TDP1204 and TMDS1204 are hybrid redrivers, which means they can operate either as linear or limited redriver. Both source and sink applications can be supported with this hybrid redriver approach.

When configured as a limited redriver, the TDP1204 and TMDS1204 differential output voltage levels are independent of the graphics process unit (GPU) output levels, ensuring HDMI specification compliant levels at the HDMI receptacle. The limited redriver mode is recommended for HDMI source applications.

When configured as a linear redriver, the TDP1204 and TMDS1204 differential output levels are a linear function of the GPU output levels, enabling the redriver to be transparent to the link training and operate as a channel shortener. Linear redriver mode is recommended for HDMI sink applications.

Table 3-1 highlights the major features difference between the TDP1204 and TMDS1204. It is up to the system design requirement when choosing between TDP1204 and TMDS1204.

Table 3-1 TDP1204 and TMDS1204 Feature Comparison
Features TDP1204 TMDS1204
Fan-out buffer to separate HDMI1.4/2.0 clock and HDMI2.1 data lane 3 No Yes
SIGDET_OUT signal detect output No Yes
DDC level shifter (5 V to 1.2 V/1.8 V/3.3 V) Yes No
DC gain adjustment from the pin strap mode No Yes