IT66121FN View Datasheet(PDF) - ITE Tech. INC.

Part Name

Description

Manufacturer

IT66121FN

Low Power Transmitter with HDMI1.4 3D

ITE Tech. INC. 

IT66121FN

high speeds. If not chosen carefully, these diodes coupled with less-than-optimal layout would

prevent the system from passing the SINK TMDS-Differential Impedance test in the HDMI

Compliance Test (Test ID 8-8). Besides, most general-purpose ESD diodes are relatively large in

size, forcing the high-speed differential lines to corner several times and therefore introducing

severe reflection. Carefully choosing an ESD diode that's designed for HDMI signaling could lead

to a minimum loading as well as an optimized layout. Commercially available devices such as

Semtech's RClamp0524p that take into consideration of all aspects are recommended. A layout

example is shown in Fig. 16, with referenced FR4 PCB structure included. Note that the ESD

diodes should be placed as close to the HDMI connectors as possible to yield the best ESD

performances.

Figure 16: PCB layout example for high-speed transmission lines with RClamp0524p

Notes: The PCB stack and material will affect differential impedance. The customer shall

co-work with PCB provider to obtain the real 100 ohm impedance based on actual PCB stack

and material.

Power Supply Bypassing

1. It is recommended to bypass each group of power supply pin with a 0.1µF capacitor.

2. It is also recommended that the bypass capacitor be located within about 0.5cm distance of

each power pin.

www.ite.com.tw

Nov-2011 Rev:0.99 37/39

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