BUF08832_14 Datasheet, PDF (20/31 Pages) Texas Instruments – Programmable Gamma-Voltage Generator and High Slew Rate VCOM with Integrated Two-Bank Memory

BUF08832
SBOS476C – AUGUST 2009 – REVISED JULY 2011
OUTPUT PROTECTION
The BUF08832 output stages can safely source and
sink the current levels indicated in Figure 1 and
Figure 2. However, there are other modes where
precautions must be taken to prevent to the output
stages from being damaged by excessive current
flow. The outputs (OUT1 through OUT8, and V_COM)
include ESD protection diodes, as shown in
Figure 22. Normally, these diodes do not conduct and
are passive during typical device operation. Unusual
operating conditions can occur where the diodes may
conduct, potentially subjecting them to high, even
damaging current levels. These conditions are most
likely to occur when a voltage applied to an output
exceeds (V_S) + 0.5V, or drops below GND – 0.5V.
One common scenario where this condition can occur
is when the output pin is connected to a sufficiently
large capacitor, and the BUF08832 power-supply
source (V_S) is suddenly removed. Removing the
power-supply source allows the capacitor to
discharge through the current-steering diodes. The
energy released during the high current flow period
causes the power dissipation limits of the diode to be
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exceeded. Protection against the high current flow
may be provided by placing current-limiting resistors
in series with the output, as shown in Figure 13.
Select a resistor value that restricts the current level
to the maximum rating for the particular pin.
V_S
BUF08832
ESD Current
Steering Diodes
OUTX
or
V_COM
Figure 22. Output Pins ESD Protection
Current-Steering Diodes
20
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