IP4778CZ38 Datasheet, PDF (1/26 Pages) NXP Semiconductors – HDMI ESD protection, DDC buffering and hot plug control

IP4778CZ38
HDMI ESD protection, DDC buffering and hot plug control
Rev. 02 — 12 February 2009
Product data sheet
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 ±8 kV
contact in accordance with the IEC 61000-4-2, level 4 standard.
2. Features
I HDMI 1.3 compliant
I Pb-free and RoHS compliant
I Robust ESD protection without degradation after several ESD strikes
I Low leakage even after several hundred ESD discharges
I Very high diode switching speed (ns) and low line capacitance of 0.7 pF to ground and
0.05 pF between channels ensures signal integrity
I DDC capacitive decoupling between system side and HDMI connector side and drive
cable buffering with capacitive load (> 700 pF)
I Hot Plug control for direct connection to system GPIO
I CEC ringing prevention by slew rate limiter
I DDC and Hot Plug enable signal for multiplexing and backdrive protection
I All TMDS lines with integrated rail-to-rail clamping diodes with downstream ESD
protection of ±8 kV in accordance with IEC 61000-4-2, level 4
I Matched 0.5 mm trace spacing