Triple CRT Driver
CVA1405T
FEATURES
·
·
Rise/Fall Time (at the Cathode) . . . . . . . . . . . . . . . . 9.0ns
·
·
Swing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65V
P-P
·
·
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100V
·
·
Pin to Pin Compatible to CVA2404T
APPLICATIONS
·
·
CRT driver for up to 64kHz monitors with resolution up
to 1024 x 768
DESCRIPTION
The CVA1405T contains three wideband amplifiers, designed
specifically to drive a CRT. The device can drive monitors with
resolutions up to 1024 x 768 (non-interlaced).
The product is housed in the industry standard 11 lead
TO-220 molded power package.
ORDERING INFORMATION
Part
Package
Temperature
CVA1405T
T11A
-20
o
C to +100
o
C
CORPORATION
CONNECTION DIAGRAM
OUT
OUT
11
10
9
8
7
6
5
4
3
2
1
IN
TOP VIEW
T11A PACKAGE
V 2
V 1
V
V 2
BIAS
V
CC
1L-38
OUT
V 3
IN
V 3
IN
V 1
GND
GND
GND
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
1T-18B
6
V
CC
1,3,5
V
O
11,9,8
V
IN
7,4,2,TAB
10
V
BIAS
Preliminary Product Information
ABSOLUTE MAXIMUM RATINGS
Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100V
Storage Temperature . . . . . . . . . . . . . . . . . . . -25
o
C to +125
o
C
Operating Temperature . . . . . . . . . . . . . . . . . -20
o
C to +100
o
C
Lead Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . +300
o
C
CVA1405T
FIGURE 1. TEST CIRCUIT
GND,TAB
1T-38
V
IN
V
BIAS
C1 = 0.01
m
F
C2 = 100
m
F
C3 = 0.1
m
F
D1, D2 = FHD400
C4 = 100
m
F
C6 = 8pF
C6
C4
C3
C2
C1
D2
D1
VIDEO
INPUT
V
CC
11,9,8
10
1,3,5
V
OUT
TEKTRONIX
FET PROBE
MODEL 6201
(CAP. 1.5pF)
CVA1405T
7,4,2
6
DC ELECTRICAL CHARACTERISTICS V
s
= 80V, DC
INPUT BIAS
= 12V, V
IN
= 2.5V, T
CASE
= +25
o
C.
See Figure 1.
SYMBOL
CHARACTERISTICS
MIN
TYP
MAX
UNITS
I
cc
Supply Current @ 1MHz
15
18
mA
V
OUT DC
Output DC Level
50
54
58
V
A
v
Voltage Gain
13
15
17
V
Gain Matching
0.2
dB
AC ELECTRICAL CHARACTERISTICS (at the cathode) V
s
= 80V, C
L
= 8pF, DC
INPUT BIAS
= 12V, V
IN
= 2.4V, V
OUT
= 50V
p-p
.
T
CASE
= +25
o
C. See Figure 1.
SYMBOL
CHARACTERISTICS
MIN
TYP
MAX
UNITS
T
r
Rise Time
9
11
ns
T
f
Fall Time
9
11
ns
L
e
Linearity
5
%
OS
Overshoot/Undershoot
3
%
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
CORPORATION
CVA1405T
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
APPLICATION INFORMATION
The CVA1405T is a high voltage triple CRT driver suitiable to
drive 69kHz, 1024 x 768 CRT displays. It features a high
impedance input to match any pre-amplifier. The CVA1405T
has a true class AB output stage that results in excellent gray
scale linearity and consistent EMI performance.
As with any high speed amplifier used in CRT display
applications, specific precaution should be taken to get the
required performance. Power supply should be by pass as
close to the device pin as possible. Use 0.01
µ
f very near to
the device and a large capacitor of 10
µ
f or more (preferable
100
µ
f) near the device. A 0.1
µ
f and 10
µ
f should be connected
near the V
bias
pin (#10). Arc protection is very essential. Fast
diodes together with the spark gap will achieve sufficient
protection. However, in certain applications depends on the
tubes a high value of resistor is required to reduce the current
into the CVA1405T during arcing. This will result in less than
desireable performance some of which can be restored by
using a peaking inductor at the output pin,
Figure 2. Another
way to achieve this is by using a RC network at the output of
the device and use a peaking inductor at the tube,
Figure 3.
The rise and fall time of the CVA1405T may suffer due to
stray capacitances associated with the PC Board and other
components. It can be improved by carefully designing the
PC Board where the output stage and input stage ground path
are seperated. Calogic will assist customers in the layout of
the PC Board that will result in quick EMI passage and better
performance. The output peaking should be used only to
restore the performance loss due to stray capacitances. Over
peaking will cause excessive ringing that will have better
results but poor EMI. The DC restore circuit is also important
when considering the high frequency performance. Using
CVA4502, DC Bias IC, better results can be obtained and
high frequency performance can be maximixed.
THERMAL CONSIDERATIONS
Power supply current increases as the input signal increases
and consequently power dissipation also increases.
The CVA1405T cannot be used without heat sinking. The
calculations below shows the power dissipated in each
channel over the operating voltage range of the device.
Under white screen conditions, i.e.: 25V output, dissipation
increases to 8.1W total. The CVA1405T case temperature
must be maintained below +100
o
C. If the maximum expected
ambient temperature is +50
o
C, then a heat sink is needed
with thermal resistance equal to or less than:
R
th
=
(
100
-
50
o
C
)
8.1W
=
6.2
o
C/W
The output of CVA2405T is not short circuit proof.
FIGURE 2.
1T-39
V
BIAS
VIDEO
CVA1405T
+80V
L
R
91
9
SPARK
GAP
33
9
FIGURE 3.
1T-46
V
BIAS
VIDEO
CVA1405T
+80V
1K
SPARK
GAP
33
9
C
CVA4502
BIAS
DC BIAS
I.C.
Vcc
L
R
CORPORATION
CVA1405T
Information furnished by Calogic is believed to be accurate and reliable. However, no responsibility is assumed for its use: nor for any infringement of patents or other
rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of Calogic.
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
FIGURE 4. APPLICATION CIRCUIT
1T-41
GND,TAB
V
BIAS
C1 = 0.01
m
F
C2 = 100
m
F
C3 = 0.1
m
F
C4 = 100
m
F
C5 = 2.2
m
F
D1, D2 = FHD400
L = 330 - 390nH
R3 = 47
W
R4 = 47(1/2W)
W
R7 = 33
W
R8 = 39
W
R10 = 680
W
R3
R4
C4
C3
C2
C1
D2
D1
V
CC
10
1,3,5
V
OUT
C5
SPARK
GAP
CVA1405T
R5
L
V
IN
VIDEO
INPUT
11,9,8
DC BIAS
7,4,2
6
CORPORATION
TYPICAL CHARACTERISTICS
1T-42
20ns/DIV
1V/DI
V
RISE TIME
-2V
8V
-55.6ns
144.4ns
1T-43
20ns/DIV
1V/DI
V
FALL TIME
-2V
8V
-55.6ns
144.4ns
1T-44
20ns/DIV
1V/D
IV
CROSS HATCH
BLACK BACKGROUND
-2V
8V
-55.6ns
144.4ns
1T-45
20ns/DIV
1V/D
IV
CROSS HATCH
WHITE BACKGROUND
-2V
8V
-21.6ns
178.4ns
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