CALOGIC CVA3405T

Low Cost
Triple CRT Driver
CORPORATION
CVA3405T
FEATURES
DESCRIPTION
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The CVA3405T contains three high impedance wideband
amplifiers, designed specifically to drive a CRT. It features no
crossover distortion for excellent gray scale linearity. This device
can drive monitors with resolutions of 1280 x 1024
(non-interlaced) with pixel frequency of 180MHz.
Rise/Fall Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0ns
Swing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65VP-P
Emitter Peaking Option
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90V
Excellent Gray Scale Linearity
Consistent EMI Performance
APPLICATIONS
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CRT driver for up to 76kHz monitors with resolution up
to 1280 x 1024.
Excellent Gray Scale Linearity
The part is housed in the industry standard 11-lead TO-220
molded power package. The heat sink is grounded.
ORDERING INFORMATION
Part
Package
Temperature
CVA3405T
T11A
-20oC to +100oC
CONNECTION DIAGRAM AND SIMPLIFIED SCHEMATIC
VCC
9
11
10
VIN 1
9
8
VIN 2
EMITTER
PEAKING 3
3
2
1
VOUT
1,3,5
VCC
5
4
R4
VIN 3
7
6
R1
VBIAS
R5
VOUT 3
EMITTER
PEAKING 2
VOUT 2
R1
VBIAS
10
R6
EMITTER
PEAKING 1
VOUT 1
R3
VIN
11,9,8
R2
GND = TAB
TOP VIEW
T11A PACKAGE
1P-22
TAB = GND
EMITTER
PEAKING
2,4,7
1P-23
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
CVA3405T
CORPORATION
ABSOLUTE MAXIMUM RATINGS
Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90V
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16W
Storage Temperature . . . . . . . . . . . . . . . . . . . -50oC to +150oC
ESD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2000V
Operating Temperature . . . . . . . . . . . . . . . . . -20oC to +100oC
Lead Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . +300oC
DC ELECTRICAL CHARACTERISTICS Vs = 80V, CL = 8pF, DCINPUT BIAS = 12V, VIN = 2.6V, VOUT = 50Vp-p. TCASE = +25oC.
See Figure 1.
SYMBOL
CHARACTERISTICS
MIN
TYP
MAX
UNITS
30
mA
Icc
Supply Current, Per Channel
20
IB
Bias Current
40
VOUT DC
Output DC Level
47
50
53
V
Av
Voltage Gain
-11
-13
-15
V
Gain Matching
mA
0.5
dB
AC ELECTRICAL CHARACTERISTICS Vs = 80V, CL = 8pF, DCINPUT BIAS = 12V, VIN = 2.6V, VOUT = 40Vp-p. TCASE = +25oC.
See Figure 1.
SYMBOL
CHARACTERISTICS
MIN
TYP
MAX
UNITS
Tr
Rise Time
6
ns
Tf
Fall Time
6
ns
Le
Linearity
5
%
FIGURE 1. TEST CIRCUIT
VCC
C3
C1
D1
6
VBIAS
10
C2
CVA3405T
VIN
VIDEO 11,9,8
INPUT
2,4,7
C4
VOUT
1,3,5
C6
D2
TEKTRONIX
FET PROBE
MODEL 6201
(CAP. 1.5pF)
R1
C5
GND
TAB
R1 = 47 Ω
C1 = 0.01µF
C2 = 100µF
C3 = 0.1µF
C4 = 100µF
C5 = 27pF
C6 = 8pF
D1, D2 = FHD400
1P-24
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
CVA3405T
CORPORATION
FIGURE 2.
+80V
VBIAS
L
CVA3405T
33 Ω
R
91 Ω
SPARK
GAP
VIDEO
1P-25
FIGURE 3.
+80V
1K
VBIAS
L
CVA3405T
VIDEO
33 Ω
R
C
CVA4501
V cc
SPARK
GAP
DC BIAS
I.C.
1P-26
BIAS
APPLICATION INFORMATION
The CVA3405T is a high voltage triple CRT driver suitiable to
drive 69kHz, 1280 x 1024 CRT displays. It features a high
impedance input to match any pre-amplifier. The CVA3405T
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 0.01µf very near to
the device and a large capacitor of 10µf or more (preferable
100µf) near the device. A 0.1µf and 10µf should be connected
near the Vbias 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 CVA3405T 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 CVA3405T 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
CVA4501, 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 CVA3405T cannot be used without heat sinking. Figure 4
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 10.8W
total. The CVA3405T case temperature must be maintained
below +100oC.
If the maximum expected ambient
temperature is +50oC, then a heat sink is needed with thermal
resistance equal to or less than:
Rth =
(100 − 50oC)
= 4.6oC/W
10.8W
The CVA3405T maximum load is 600Ω to ground or V+.
The output of CVA3405T is not short circuit proof. Any resistance
to V+ or Ground should be > 600Ω.
CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
CVA3405T
CORPORATION
FIGURE 4. APPLICATION CIRCUIT
VCC 6
C3
R2
VBIAS
D1
10
C1
C4
C2
CVA3405T
VIN
L
VOUT
1,3,5
C5
VIDEO 11,9,8
INPUT
2,4,7
R3
R1
D2
R4
SPARK
GAP
DC BIAS
C6
GND
TAB
R1 = 820Ω
R2 = 22Ω
R3 = 47(1/2W) Ω
R4 = 47Ω
C1 = 0.01µF
C2 = 100µF
C3 = 0.1µF
C4 = 100µF
C5 = 2.2µF
C6 = 27pf
C7 = 40 - 120pf
D1, D2 = FHD400
L = 150 - 33nH
1P-27
TYPICAL CHARACTERISTICS
VOUT vs VIN
16
70
14
60
12
50
40
30
POWER DISSIPATION vs VCC
V OUT = 25V
POWER (W)
VOUT (V)
80
10
8
6
20
4
10
2
V OUT = VCC = 10V
0
0
0
1
2
3
4
VIN (V)
5
6
7
55
1P-18
60
65
70
75
VCC (V)
80
85
1P-19
PULSE RESPONSE
BANDWIDTH
0
VOLTS (V) 10V/DIV.
5 dB / DIV.
5
10
15
20
25
30
1MHz
10MHz
100MHz
1P-20
TIME = 20ns/DIV.
1P-29
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