Quad-channel hybrid redrivers enhance signal integrity for HDMI applications

Diodes Incorporated has introduced two 3.3V, quad-channel, hybrid ReDrivers with integrated display data channel (DDC) listeners designed to improve signal integrity for HDMI applications and simplify system designs. The PI3HDX12311 caters to high bandwidth applications up to 12Gbps for HDMI 2.1 fixed rate link (FRL) and transition-minimised differential signalling (TMDS) up to 6Gbps. The PI3HDX6311 supports HDMI 2.0 at 6Gbps. The devices also support DisplayPort Dual-Mode (DP++) V1.1 level shifting.

The products act as an intermediary between a source (like a CPU or GPU) and a sink (like a display), compensating for signal degradation over transmission lines. The devices are appropriate for various applications, including laptop and desktop PCs, docking stations, peripheral devices, gaming consoles, DTV and commercial display panels, as well as HDMI active cables.

Both are hybrid devices that function in either limited or linear mode. For HDMI 1.4 applications, the devices operate as limited ReDrivers, where the differential output swing is pre-defined by the swing setting to ensure HDMI-compliant levels at the receptacle. In contrast, for HDMI 2.0 and 2.1 applications, they function as linear ReDrivers, where the output swing is directly proportional to the received signal, effectively acting as a trace canceller. This linear mode is inherently transparent to the link training signals, and for the PI3HDX12311, allows 8K DTV video resolution and data rates up to 48Gbps (12Gbps per channel).

The devices permit AC or DC coupling of the input and output signals, or a mixture of both, with short-circuit detection in DC coupled mode. Both devices also use pin-strapping control for operation mode, equalisation, flat-gain, output swing, and output -1dB linearity swing. The devices share features like auto selection of TX settings, IOFF support, and far-end receiver detection.

To minimise power consumption, the devices monitor the hot-plug-detect (HPD) pin in the connector to control power consumption and enter a low-power state if the HPD is low for more than 2ms. Their DDC listeners function similarly by snooping the HDMI Forum Vendor Specific Data Block (HF-VSDB) and monitoring the same Status and Control Data Channel Structure (SCDCS) offset registers.

The PI3HDX12311 and PI3HDX6311 are available in the tiny 32-pin X1-QFN2845 package, occupying a 2.85mm x 4.5mm PCB area, and operate across the -40C to +70C temperature range with 726mW (typ.) power dissipation.