
1995 Feb 07 7
Philips Semiconductors Preliminary specification
Video output amplifier TDA6111Q
Notes
1. If the difference between VDDL and Vip is less than 7 V, overshoot cannot be specified.
2. SVRR: The ratio of the change in supply voltage to the change in input voltage when there is no change in output
voltage.
Ovcathode output voltage overshoot VocAC = 100 V (p-p);
VocDC = 100 V square
wave; f < 1 MHz;
tr=t
f=22ns;
see Figs 4 and 5; note 1
−9−%
SVRRH high supply voltage rejection ratio f < 50 kHz; note 2 −85 −dB
SVRRL low supply voltage rejection ratio f < 50 kHz; note 2 −70 −dB
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT
Cathode output
The cathode output is protected against peak currents
(caused by positive voltage peaks during high-resistance
flash) of 5 A maximum with a charge content of 100 µC.
The cathode is also protected against peak currents
(caused by positive voltage peaks during low-resistance
flash) of 10 A maximum with a charge content of 100 nC.
Flashover protection
The TDA6111Q incorporates protection diodes against
CRT flashover discharges that clamp the cathode output
pinto theVDDH pin.The DCsupplyvoltageat theVDDH pin
has to be within the operating range of 180 to 210 V to
ensure that the Absolute Maximum Rating for VDDH of
250 V will not be exceeded during flashover. To limit the
diode current, an external 680 Ωcarbon high-voltage
resistorinserieswiththecathodeoutputanda2 kVspark
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 5 ns
and a decrease in the overshoot of approximately 4%.
VDDH to GND must be decoupled:
1. With a capacitor >20 nF with good HF behaviour
(e.g. foil). This capacitance must be placed as close
as possible to pins 6 and 4, but definitely within 5 mm.
2. Withacapacitor>10 µFon the picture tube base print
(common for three output stages).
VDDL to GND must be decoupled:
1. With a capacitor >20 nF with good HF behaviour
(e.g. ceramic). This capacitance must be placed as
close as possible to pins 2 and 4, but definitely within
10 mm.
Switch-off behaviour
The switch-off behaviour of the TDA6111Q is defined:
whenthebiascurrentbecomeszero,atVDDL (pin 2)lower
than approximately 5 V, all the output pins
(pins 7, 8 and 9) will be high.