1. General description
The PTN3361B is a high-speed level shifter device which converts four lanes of low-swing
AC-coupled differential input signals to DVI v1.0 and HDMI v1.3a compliant open-drain
current-steering differential output signals, up to 1.65 Gbit/s per lane. Each of these lanes
provides a level-shifting differential buffer to translate from low-swing AC-coupled
differential signaling on the source side, to TMDS-type DC-coupled differential
current-mode signaling terminated into 50 Ω to 3.3 V on the sink side. Additionally, the
PTN3361B provides a single-ended active buffer for voltage translation of the HPD signal
from 5 V on the sink side to 3.3 V on the source side and provides a channel with active
buffering and level shifting of the DDC channel (consisting of a clock and a data line)
between 3.3 V source-side and 5 V sink-side. The DDC channel is implemented using
active I
2
C-bus buffer technology providing capacitive isolation, redriving and level shifting
as well as disablement (isolation between source and sink) of the clock and data lines.
The low-swing AC-coupled differential input signals to the PTN3361B typically come from
a display source with multi-mode I/O, which supports multiple display standards, e.g.,
DisplayPort, HDMI and DVI. While the input differential signals are configured to carry DVI
or HDMI coded data, they do not comply with the electrical requirements of the DVI v1.0 or
HDMI v1.3a specification. By using PTN3361B, chip set vendors are able to implement
such reconfigurable I/Os on multi-mode display source devices, allowing the support of
multiple display standards while keeping the number of chip set I/O pins low. See
Figure 1.
The PTN3361B main high-speed differential lanes feature low-swing self-biasing
differential inputs which are compliant to the electrical specifications of
DisplayPort
Standard v1.1
and/or
PCI Express Standard v1.1
, and open-drain current-steering
differential outputs compliant to DVI v1.0 and HDMI v1.3a electrical specifications. The
I
2
C-bus channel actively buffers as well as level-translates the DDC signals for optimal
capacitive isolation. Its I
2
C-bus control block also provides for optional software HDMI
dongle detect by issuing a predetermined code sequence upon a read command to an
I
2
C-bus specified address. The PTN3361B also supports power-saving modes in order to
minimize current consumption when no display is active or connected.
The PTN3361B is a fully featured HDMI as well as DVI level shifter. It is functionally
comparable to PTN3360B but provides additional features supporting HDMI dongle
detection and active DDC buffering. For HDMI dongles, support of HDMI dongle detection
via the DDC channel is mandatory, hence HDMI dongle applications should enable this
feature for correct operation in accordance with DisplayPort interoperability guidelines.
PTN3361B is powered from a single 3.3 V power supply consuming a small amount of
power (90 mW typ.) and is offered in a 48-terminal HVQFN48 package.
PTN3361B
HDMI/DVI level shifter with dongle detect support and active
DDC buffer
Rev. 02 — 7 October 2009 Product data sheet
