TDA9535 STMicroelectronics, TDA9535 Datasheet - Page 6

• Manufacturer Part Number: TDA9535
• Manufacturer: STMicroelectronics

Specifications of TDA9535

• Single Supply Voltage (typ): Not RequiredV
• Single Supply Voltage (min): Not RequiredV
• Single Supply Voltage (max): Not RequiredV
• Mounting: Through Hole
• Lead Free Status / RoHS Status: Supplier Unconfirmed

TDA9535
6 THEORY OF OPERATION
6.1 - General
The TDA9535 is a three-channel video amplifier
supplied by a low supply voltage: V
and a high supply voltage: V
The high values of V
put stage allow direct control of the CRT cathodes
(DC coupling mode).
In DC coupling mode, the application schematic is
very simple and only a few external components
are needed to drive the cathodes. In particular,
Figure 2. Output signal, level adjustments
6.2 - How to choose the high supply voltage value (V
The V
fully. It must be high enough to provide the neces-
sary video adjustment but set to minimum value to
avoid unecessary power dissipation.
Example:
The following example shows how the optimum
V
6/15
2
DD
– Cut-off adjustment range (B) : 25V
– Max contrast (D) : 40V
15V
17V
voltage value is determined:
DD
V
GND
DD
high supply voltage must be chosen care-
Blanking pulse
(E) Bottom Non-Linear Region
(A) Top Non-Linear Region
Video Signal
DD
supplying the amplifier out-
DD
(up to 115V).
CC
(typ.12V)
(D) Contrast Adjust. (40V Typ.)
there is no need of the DC-restore circuitry which
is used in classical AC coupling applications.
The output voltage range is wide enough
(Figure
In normal operation, the output video signal must
remain inside the linear region whatever the cut-
off / brightness / contrast adjustment is.
Case 1:
10V Brightness (C) adjusted by the preamplifier :
Case 2:
10V Brightness (C) adjusted by the G1 anode:
– Cut-off adjustment (B: typ. 25V)
– Video contrast (D: typ. up to 40V),
– Brightness (C: with the remaining voltage
DD)
range).
V
V
V
V
DD
DD
DD
DD
(B) Cut-off Adjust. (25V Typ.)
2) to provide simultaneously:
= A + B + C + D + E
= 15V + 25V + 10V + 40V + 17V = 107V
= A + B + D + E
= 15V + 25V + 40V + 17V = 97V
(C) Brightness Adjust. (10V Typ.)