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ADV3200/ADV3201
Rev. 0 | Page 31 of 3
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ON-SCREEN DISPLAY (OSD)
The ADV3200/ADV3201 features dedicated 2:1 muxes for each
of the 32 outputs that allow external video or dc levels to be
inserted and switched in with the regular input channel. The
OSD mux switches in 20 ns, allowing for information such as
text or other picture-on-picture signals to be displayed. The
OSDSxx pins are the control switches used to switch each
corresponding OSD mux (high = OSD, low = regular input).
Pulling OSDSxx high switches the signal that appears at the
OSDxx input to the corresponding output. Setting OSDSxx
low switches the signal at INxx to the corresponding output.
This switching can be done on a pixel-by-pixel basis for each
scan line, and in this way any video signal, including graphics,
characters, or text, can be inserted to be displayed at the output.
The OSD signal must be synchronized to the incoming video
signal that it is switching between; therefore, the OSDS signal
must be correctly timed in order to correctly place the OSD
signal on the horizontal line. In addition, the OSDxx inputs do
not have the sync-tip clamp feature described in the previous
section, so the dc level must be set appropriately at the OSDxx
input.
DECOUPLING
The signal path of the ADV3200/ADV3201 is based on high
open-loop gain amplifiers with negative feedback. Dominant-
pole compensation is used on chip to stabilize these amplifiers
over the range of expected applied swing and load conditions.
To guarantee this designed stability, proper supply decoupling is
necessary. Signal-generated currents must return to their sources
through low impedance paths at all frequencies in which there
is still loop gain (up to 300 MHz at a minimum). A wideband
parallel capacitor arrangement is necessary to properly decouple
the ADV3200/ADV3201.
The VREF and VCLAMP pins should be considered reference
pins, not power supply pins, because they are both inputs to
on-chip buffers. Because the VREF pin is used as a ground
reference in the ADV3200/ADV3201, care must be taken to
produce a low noise VREF source over the entire range of
frequencies of interest.
POWER DISSIPATION
Calculation of Power Dissipation
9
8
7
6
5
4
3
15
25
35
45
55
65
75
85
AMBIENT TEMPERATURE (°C)
M
A
X
IMU
M
P
O
W
E
R
(W
)
0717
6-
003
TJ = 150°C
Figure 104. Maximum Die Power Dissipation vs. Ambient Temperature
JA
AMBIENT
MAX
JUNCTION
MAX
D
T
P
θ
=
,
(1)
For example, if the ADV3200/ADV3201 is enclosed in an environ-
ment at 45°C (TA), the total on-chip dissipation under all load
and supply conditions must not be allowed to exceed 6.5 W.
When calculating on-chip power dissipation, it is necessary to
include the rms current being delivered to the load, multiplied
by the rms voltage drop on the ADV3200/ADV3201 output
devices. For a sinusoidal output, the on-chip power dissipation
due to the load can be approximated by
PD,OUTPUT = (VPOS – VOUTPUT,RMS) × IOUTPUT,RMS
(2)
For a nonsinusoidal output, the power dissipation should be
calculated by integrating the on-chip voltage drop multiplied
by the load current over one period.
The user can subtract the quiescent current for the Class AB
output stage when calculating the loaded power dissipation. For
each output stage driving a load, subtract the quiescent power
according to
PDQ,OUTPUT = (VPOS – VNEG) × IOUTPUT,QUIESCENT
(3)
where IOUTPUT,QUIESCENT = 0.95 mA for each single-ended output pin.
For each disabled output, the quiescent power supply current in
VPOS and VNEG drops by approximately 4 mA.