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NXP Semiconductors has launched an HDMI companion chip for mobile devices including smartphones, smartbooks and netbooks.

The HDMI companion chip provides bidirectional level shifting between the 1.8/3.3V (range between 1.62V and 3.63V) at the host side and the 5V of the HDMI connector side for the display data channel (DDC), consumer electronics control (CEC) and the hot plug detect (HPD).

All these lines, along with the HDMI 5V supply line, also offer a high level of ESD protection according to IEC61000-4-2, level four.

The chip is offered in a 12-pin QFN package (2.1 x 2.5 x 0.5mm) with a 0.4mm pitch, which allows optimised direct routing for HDMI type C or type D connectors.

System designs using the IP4791CZ12 as an HDMI companion chip can easily pass the HDMI compliance test, NXP said.

Users of the HDMI companion chip benefit from direct and easy PCB routing, a high integration rate and the option for Auto-Eco functionality, as well as robustness against ESD strikes and EMI distortion.

Mobile devices are in a transition from an analogue video interface such as CVBS (colour video baseband signal) towards a digital interface such as HDMI supporting high-definition (HD) resolution.

To transmit video signals from mobile devices such as mobile phones, netbooks, tablet computers, notebooks, media players and digital cameras, the HDMI interface is frequently used in the latest designs.

The HDMI interface provides the video and audio signals via the transition minimised differential signalling (TMDS) lines.

These high-speed lines are typically protected by special multi-channel, low-capacitance ESD protection diodes, which can be placed on the high-speed lines in a ‘straight-through-routing’ layout.

In addition to the TMDS lines, the HDMI interface consists of the following control lines: DDC, which handles data transfer for content protection and television resolution; CEC, which makes it possible to control several applications over one remote control; and HPD, which initiates the connection between the HDMI sink (for example, a receiver in a digital television or projector) and the mobile device.

System chips for mobile applications typically run at lower voltage levels than the standardised 5V at the HDMI interface.

The IP4791CZ12 provides bidirectional level shifting and buffering to bridge these different voltage levels.

The pins are protected with ESD protection diodes according to IEC61000-4-2 level four (+/- 8kV contact).

The IP4791CZ12 can be placed directly behind the HDMI connector on the PCB.

Therefore, the energy of an ESD strike is directed towards the ground plane before reaching the HDMI transmitter.

The integrated buffers have also a positive effect in case of ESD strikes.

They do not pass on the remaining clamping voltage from the ESD strike to the system-on-a-chip (SoC), thereby providing it with the best possible protection.

The SoCs are manufactured in small node size CMOS processes for economy and speed, which makes robust ESD protection necessary.

In addition, the buffers also block the EMI distortions on the DDC, CEC and the HPD lines.

For the HPD, DDC and CEC applications, pull-up resistors and a CEC pull-up current source with a low leakage current are included as well.

With this high-integration concept, the system chip with the HDMI transmitter is connected directly over the IP4791CZ12 towards the HDMI port without the need for additional external components.

This ‘clean interface’ concept simplifies the PCB layout and reduces design time and effort for customers.

Due to the option for an Auto-Eco mode, there is no need for a dedicated GPIO pin on the system controller to supervise power management in the IP4791CZ12, as long as the design has no standby functionality, such as wake-up via CEC.

Connecting the Active-pin to the Hotplug-pin on the connector automatically enables or disables the IP4791CZ12.

A design-in package is available, which includes example PCB layouts.

The IP4791CZ12 is available in a thin QFN package: HXSON12 (2.1 x 2.5 x 0.5mm), which is Pb-free and RoHS compliant.

NXP Semiconductors

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