1.

General description

The IP4778CZ38 is designed for HDMI receiver host interface protection. The

IP4778CZ38 includes DDC buffering, slew rate acceleration and decoupling, Hot Plug

control, backdrive protection, CEC slew rate control, optional multiplexing of DDC signals,

and high-level ESD protection diodes for all HDMI signals.

The DDC lines are buffered using a new buffering concept which decouples the internal

capacitive load from the external capacitive load. This allows higher PCB design flexibility

for the DDC lines with respect to the maximum load of 50 pF specified in the

HDMI 1.3

specification. This buffering also boosts the DDC signals, allowing the use of longer HDMI

cables having a higher capacitive load than 700 pF. The CEC slew rate limiter prevents

ringing on the CEC line and greatly reduces the number of discrete components needed

by the CEC application. HDMI receiver and system GPIO applications are simplified by an

internal Hot Plug driver module and Hot Plug control.

The DDC, Hot Plug and CEC lines are backdrive protected to guarantee HDMI interface

signals are not pulled down if the system is powered down or enters Standby mode.

All TMDS intra-pairs are protected by a special diode configuration offering a low line

capacitance of 0.7 pF only (to ground) and 0.05 pF between the TMDS pairs. These

diodes provide protection to components downstream from ESD voltages of up to

±8kV

contact in accordance with the IEC 61000-4-2, level 4 standard.

2.

Features

0.05 pF between channels ensures signal integrity

cable buffering with capacitive load (> 700 pF)

protection of

±8 kV in accordance with IEC 61000-4-2, level 4

IP4778CZ38

HDMI ESD protection, DDC buffering and hot plug control

Rev. 02 — 12 February 2009

Product data sheet