Datasheet CVA6629S Datasheet (Calogic LLC)

Page 1
CORPORATION
Triple 180MHz
CRT Driver
CVA6629S
FEATURES
•• Rise/Fall Ti me. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5ns
•• Swing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70V
P-P
•• Symmetrical Rise and Fall Time
APPLICATION
•• CRT Driver for up to 110kHz Monito rs with Resol utio n
upto 1600 x 1280 (Non-Interlaced).
CONNECTION DIAGRAM AND SIM PLIFI ED SCHEM ATIC
DESCRIPTION
The CVA6629S contains three wideband amplifiers designed specifically to drive high resolution CRTs . It features excellent gray scale linearity and high load capacitance driving capability. This device can drive monitors with resolution of 1600 x 1280 (non-interlac ed) with pixel freque ncy of 350 MHz.
The part is housed in 12L Ceramic package with heat sink grounded.
ORDERING INFORMATION Part Package Temperature
o
CVA6629S CY12B -20
Q1
C to +100oC
Q2
5.7K
1
3
1
2
4
5
6
7
8
9
IN R
V+ R
GND R
IN G
V+ G
OUT R
OUT G
GND G
V+ B
12
11
10
IN B
OUT B
GND B
250
Q3
Q4
1j-40
CAL OGIC CORPORA TION, 237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-30 25
Page 2
CVA6629S
ABSOLUTE MAXIMUM RATINGS
Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85V
Storage Tempera tu re. . . . . . . . . . . . . . . . . . -25
o
C to +125oC
CORPORATION
Operating Temperature . . . . . . . . . . . . . . . . -20
o
C to +100oC
Lead Temperat ure . . . . . . . . . . . . . . . . . . . . . . . . . . . +300
o
C
DC ELECTRICAL CHARACTERISTICS VS = 80V, CL = 10pF, T
SYMBOL CHARACTERISTICS MIN TYP MAX UNITS
I
CC
V
IN DC
V
OUT DC
A
V
Supply Current 37 42 mA Input DC Level 1.3 1.5 1.7 V Output DC Level 36 40 44 V Voltage Ga in 10 12 14 V Gain Matching 0.2 dB
AC ELECTRICAL CHARACTERISTICS VS = 80V, CL = 10pF , V
SYMBOL CHARACTERISTICS MIN TYP MAX UNITS
t
r
t
f
BW Bandwidth 180 MHz Le Linearity 5 % OS Overshoot 4 %
Rise Time 2.8 3.5 ns Fall Time 2.7 3.5 ns
= +25oC. See Figure 1.
CASE
OUT
= 50V
P-P
, T
CASE
= +25oC. See Figure 1.
FIGURE 1. TEST CIRCUIT
V
CC
C4 C6
L1
OUTPUT
C
L
INPUT
C1
C2
R1
R2
C3
2,6,10
V
R4
1/3 CVA6629S
IN
1,5,9 V
CC
4,8,12
V
OUT
D1
R5 R6
D2
3,7,11
GND
R1 = 15 R2 = 430
R4 = 200k
R5 = 22 R6 = 22
C1 = VARIABLE 20 TO 150pF TYPICAL 68pF C2 = VARIABLE 4 to 20pF TYPICAL 17pF C3 = 75pF
C4 = 10µf/160V
µ
C6 = 0.01 C = 10pF
L
f/160V
D1 = DS464 D2 = DS464 L1 = 150nH
1Q-03
CA LOGIC CORPORA TION, 237 Whit ney Place , Fremo nt , California 9453 9, Telephone: 510-656-2900, FAX: 510-651-3025
Page 3
CORPORATION
APPLICATION INFORMATION
CVA6629S
The CVA6629S is a transimpedance amplifier with two stage feedback configurations. Any change in input current will be reflected as change in output voltage swing. A resistor in series with the input will change the CVA6629S into a voltage amplifier. The output is emitter follower with load(capacitive) driven capability.
With a true Class AB output stage, the rise and fall time is symmetric.
CVA6627S has an internal feedback resistor of 5.7K. In the absence of any input signal, the V
R
V
OUT
(DC) = (1 +
F
) VIN (DC); RB = 250Ω.
R
B
DC is set by
OUT
An input resist or RG will set the gain as
R
F
= (
V
OUT
) VIN ; RG = gain resistor.
R
G
Input and Transfer Cha racteristics
An input current swing of ±5. 2mA causes the output to c hang e by ±25V. A resistor of 390 will set the gain to -11. Input pins are internal DC feedback nodes and thus have low impedance. These pins must be fed fro m a series RC net wor k for high frequenc y empha sis.
The following section will explain how to overcome some of the problems that are typical.
1) Input drive: CVA6629S gives best results when the amplifier is driven by a fast pulse with proper voltage level. Since all pre-amplifiers have output from 0 to 8V, a level shifter is required. Using CVA4402, buffer plus level shifter, this can be easily real ized.
2) Smear: For a box pattern with white background, a shadow after the black is cal led smear. It is due to the tilt of the white level. It can easily be adjusted by adding an RC feedback network (R4, C3). The value of R4 will affect the gain, for CV A6629 S, the typical value is 200K.
3) Streaks and overshoot: For a cross-hatch pattern with white background, a whitish line will appear just after the black line, this is called s treak. Looking at the waveform it is due to undershoot of the waveform. For a Box pattern with white background, a dark black area just after white is a sign of overshoot. It is due to overshoot of the wavef or m. Adju stin g the value of C2, R1, C1 will get the optimum result. The value of C2 should be kept at minimum for less overshoot, typical is <20pF. Value of R1 should be less than 47 ohms otherwise rise and fall time will suffer. First adjust the overshoot to minimum, keeping value of C1 and R2 to minimum, then adjust the undershoot (Streak) by adjusting C3 again. Since both need to be adjusted together, this may need a few iteration to get to the opt im um r esult .
It should be n oted here that the output peaking with L1 and R3 is only to overcome the affect of stray capacitance. Keep the value of L1 to minimum, typ 150nH and R, to be 820Ω. The value of L1 depends on the associated capacitance with the board and the cable(if any). CVA6629S is specifically designed to handle extra capacitance associated with the cable(typ. 10pF) assuming the driver is not part of the neck board. The value of R3 should be less than 1K to damped the resonant ring in g.
The output of CVA6629S is not short circuit proof. Precaution is required.
Thermal Characteristics
Under normal operating conditions the CVA6629S will dissipate up to 8W. The maximum allowed case temperature is +100
o
C. To calculate maximum heatsink thermal resistance
use the following equation:
(100 50°)
Rth =
18W
= 2.8°C/W
The Thermalloy #11699 is one example of a heatsink that meets this requir emen t.
CAL OGIC CORPORA TION, 237 Whit ney Plac e, Fre m ont, California 945 39, Telephone: 510-656-2900, FAX: 510-651-3025
Page 4
CVA6629S
1Q-07
P-P
BOX PATTERN — 50V
10ns/DIV
10V/DIV
1Q-08
CROSS HATCH PATTERN
— WHITE BACKGROUND
5ns/DIV
10V/DIV
D2
R1
C2
C1
R3
L1
CRT
R4
C3
2,6,10
1,5,9
4,8,12
PRE AMP
CVA6629S
D3
3,7,11
1Q-04
R1 = 15
R2 = 390
R3 = 820
R4 = 200K R5 = 39
C1 = VARIABLE 20 TO 150pF TYPICAL 68pF C2 = VARIABLE 4 to 20pF TYPICAL 17pF
D1 = DS464 D2 = DS464 L1 = 150nH
C3 = 75pF C4 = 1
µ
F
R2
C4
R5
CVA
4402
+12V
-5V
CVA 4502
DAC
R1
FIGURE 2. APLICATION CIRCUI T
CORPORATION
ELECTRICAL CHARACTERISTICS
BOX PATTERN — 50V
10V/DIV
10ns/DIV
P-P
1Q-05
CROSS HATCH PATTERN — BLACK BACKGROUND
10V/DIV
5ns/DIV
1Q-06
CAL OGIC CORPORA TION, 237 Whit ney Plac e, Fre m ont, California 945 39, Telephone: 510-656-2900, FAX: 510-651-3025
Page 5
CORPORATION
ELECTRICAL CHARACT ERISTICS (continued)
CVA6629S
V - DEVICE INPUT (VOLTS)
V (VOLTS)
IN
OUT
2.5
1.5
0.5
V (DEVICE INPUT) vs. V
OUTIN
2
1
0
5.2
5.6
104
15.3
20.3
25.2
30.4
35.6
40.8
46.1
51.4
56.5
62.3
67.4
V (VOLTS)
OUT
V vs. V
90
OUT IN
72.47678.1
78.6
78.8
1Q-09
79
80 70 60 50 40 30 20 10
0
-5
-4
-3
-2
-1
-0
-4.5
-3.5
-2.5
-1.5
V (VOLTS)
0.511.522.533.544.555.5
-0.5
IN
1Q-10
I vs. V
15
OUTIN
10
5
0
IN (ma)
-5
-10
-15
5.2
5.6
104
15.3
20.3
25.2
30.4
35.6
40.8
46.1
51.4
56.5
V (VOLTS)
OUT
Inform at ion furni shed by Calogic is believed to be accurate and reliable. Howe ver, no responsibility is assum ed for its use: nor for any in fring eme nt of pate nts 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.
62.3
76
67.4
72.4
78.1
79
78.6
78.8
1Q-11
CA LOGIC CORPORA TION, 237 Whit ney Place , Fremo nt , California 9453 9, Telephone: 510-656-2900, FAX: 510-651-3025
Page 6
CORPORATION
PACKAGE DIM ENSIO NS
CVA6627S
Page 7
CVA6627S
CORPORATION
Page 8
CORPORATION
APPLICATION INFORMATION
The CVA6627S is an transimpedance amplifier with two stage feedback configurations. Any change in input current will be reflected as change in output voltage swing. A resistor in series with the input will change the CV A6627 S in to a volta g e amplifier. The output is emitter follwer with load(capacitive) driven capability. (see schematic).
Both intput and output stage has separate by pass capacitor. Emitter capacitor is included to improve the dynamic performance for large voltage swing. With true Class AB output stage, the rise and fa ll time is sym m et ric.
CVA6627S has an internal feedback resistor of 5.7K. In the absencs of any input signal, the vout DC is set by
R
(DC) = (1 +
V
out
F
) Vin (DC); RB = 250Ω
R
b
An input resist or RG will set the gain as
R
F
= (
V
out
) Vin ; Rg = gain resistor
R
g
CVA6627S
value of L to minimum, typ 150 150nH and R to be 820. The value of L depends on the associated capacitance with the board and the cable(if any). CVA6627S is specifically designed to handle extra capacitance associated with the cable(typ. 10pF) assuming the driver is not part of the neck board. The value of R should be less than 1K to damped the resonant ring in g.
The output of CVA6627S is not short circuit proof. Precaution is requried.
Input and Transfer ch ara ct eri st ic s
An input current swing of ±4, 4ma causes the output to change by ±25V. A resistor of 430 will set the gain to -13. Input pins are internal dc feedback nodes and thus have low impedance. These pins must be fed fro m a series RC net wor k for high frequenc y empha sis.
Following section will explain how to overcome some of the problems that are typical.
1) Input drive: CVA6627 gives best results when the amplifer is driven by a fast pulse with proper voltage level. Since all pre-amplieriers have output from 0 to 8V, a level shifter is requried, also most pre-amplifiers cannot drive large capacitive load to drive a buffer is requried. A simple t ransist or like 25C4693 and a zener with -5V supply can do the job with little affect on the r esp onse .
2) Smear: On the monitor for a box pattern with white background a shado after the black is called smear. It is due to tilt of the white level. It can easily be adjusted by adding R C feedback network (R1, C1). The value of R1 will affect the gain, for CVA6627S the typical value is 200K. The value of C1 will be adjusted t o get opt im um ringin g.
3) Streks and overshoot: For a cross-hatch pattern with white backgorund, a whitish line will appear just after the black line, this is called streak. Looking at the wave form it is due to undershoot of the waveform. For a Box pattern with white background a dark black area just after white is a sign of overshoot. It is due to overshoot of the waveform. Adusting the value of C2, R2, C3 will get the optimum result. The value of C2 should be kept at minimum for less overshoot, typical is <20pF. V alue of R2 shold be less than 47 ohms other wise rise and fall time will suffer. First adjust the overhoot to minimum, keeping value of C2 and R2 minimum, then adjust the undershoot(Streak) by adusuting C3 again. Since both need to be adjusted together, this may need few iteration to get to the optimum result .
It should be noted here that the output peaking with L and R3 is only to overcome the affect of stray capacitance. Keep the
Page 9
CVA6629S
CORPORATION
CORPORATION
Inform at ion furni shed by Calogic is believed to be accurate and reliable. Howe ver, no responsibility is assum ed for its use: nor for any in fring eme nt of pate nts 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.
CAL OGIC CORPORA TION, 237 W hitn ey Place, Fremont, Californ ia 94539, Telephone: 510-656-2900, FAX: 510-651-3025
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