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Philips Semiconductors
Video output amplifier
Flashover protection
The TDA6106Q incorporates a protection diode against
CRT flashover discharges that clamp the cathode output
voltage to a maximum of V
current, an external 1.5 k carbon high-voltage resistor in
series with the cathode output and a 2 kV spark gap are
needed (for this resistor-value, the CRT has to be
connected to the main PCB). This addition produces an
increase in the rise and fall times of approximately 7.5 ns
and a decrease in the overshoot of approximately 1.3%.
1997 Mar 03
x
V i
0
x
150
140
V oc
100
60
50
Fig.4 Output voltage (pin 8 falling edge) as a function of AC input signal.
+ V
. To limit the diode
DD
diode
s t
overshoot (in %)
t f
t
pd
V
to GND must be decoupled:
DD
1. With a capacitor larger than 20 nF with good HF
behaviour (e.g. foil). This capacitor must be placed as
close as possible to pins 6 and 4, but definitely within
5 mm.
2. With a capacitor larger than10 F on the picture tube
base print (shared by three output stages).
Switch-off behaviour
The output pins of the TDA6106Q are still under the control
of the input pin for a supply voltage down to approximately
30 V.
7
Product specification
TDA6106Q
t
51
49
t
MGA975
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