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Application of the TDA6120 wideband video output amplifier AN96073 APPLICATION NOTE
Application of the
TDA6120 wideband
video output amplifier
AN96073
Philips
Semiconductors Philips Semiconductors
___________________________________________________________________
TDA6120Q


Application Note
Wideband video output amplifier

AN96073
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Abstract
This report gives a description of the TDA6120Q wideband video output amplifier together with
application aspects
© Philips Electronics N.V. 1997
All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the
copyright owner. The information presented in this document does not form part of any quotation or contract, is
believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher
for any consequence of its use. Publication thereof does not convey nor imply any license under patent- or other
industrial or intellectual property rights. Philips Semiconductors
___________________________________________________________________
TDA6120Q


Application Note
Wideband video output amplifier

AN96073
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Application of the
TDA6120Q wideband
Video output amplifier
AN96073
Author(s):
E.H. Schutte
Design & Application Video Group, Consumer IC's Nijmegen,
The Netherlands
Keywords
Video amplifier
Rise & Falltime
Flash-protection
Dissipation
Date: 15th July, 1997 Philips Semiconductors
___________________________________________________________________
TDA6120Q


Application Note
Wideband video output amplifier

AN96073
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Summary
This note gives the device description of the TDA6120Q RGB wideband video output
amplifier and provides the user with basic hints to obtain an optimal performance in
the application.
The TDA6120Q includes one video output amplifier (30MHz/125Vpp) in a plastic DIL-
bent -SIL power package DBS13P, using high-voltage DMOS technology, and is
intended to drive the cathodes of a CRT in a high demanding market of High
Resolution TVs and monitors. The device is provided with a black current
measurement output for automatic black current stabilisation (ABS).
The following application aspects will be described:
External components calculation.
Circuit application & Application hints.
Flash-over protection.
Furthermore two wideband concepts are described within this report.
One video concept for typical TV applications, using the combination
TDA4780 (monolithic RGB processor ) and the TDA6120Q.
This combination has a total bandwidth of 22MHz and is suitable for High Resolution
TV,MUSE and VGA (SVGA with limites bandwidth performance ).
It features gamma and blue stretch and has automatic black current stabilisation(ABS).
The other concept is designed for monitor applications, using the combination of
TDA4882 monitor pre-amplifier and the TDA6120Q .
This combination has a total bandwidth of 30-60 MHz ( depending on the cathode
output swing requirement and is suitable for VGA, SVGA and XGA applications.
By means of this application note one is able to decide which components can be
changed and what the consequences will be. This is important because the
component choice is often a compromise and depends on the requirements defined
by the customer. Philips Semiconductors
___________________________________________________________________
TDA6120Q


Application Note
Wideband video output amplifier

AN96073
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TABLE OF CONTENTS:
1.0 INTRODUCTION
7
2.0 QUICK REFERENCE DATA
8
3.0 CIRCUIT DESCRIPTION.
10
- 3.1 Block diagram description.
10
- 3.2 Functional pin description.
12
- 3.3 Internal pin configuration.
13
- 3.4 Protection circuits...
13
4.0 DESIGN CONSIDERATIONS.
14
- 4.1 Basic aspects amplifier part.
14
- 4.2 Voltage gain
15
- 4.3 DC to DC transfer...
15
- 4.4 Pole zero cancellation...
15
- 4.5 Stability.
16
- 4.6 Black current measurement output...............................................
16
- 4.7 Flash-over protection....................................................................
16
5.0 EXTERNAL COMPONENTS CALCULATION................................
17
- 5.1 Feedback resistor......................................................................
17
- 5.2 Input resistor..........................................................................
17
- 5.3 Speed-up capacitor...................................................................
18
- 5.4 Reference voltage ....................................................................
18
- 5.5 Vdd & Vcc decoupling...............................................................
18
- 5.6 Decoupling recarding flash........................................................
19
- 5.7 Flash diodes.................................................................................
19
- 5.8 Additional components.................................................................
20
6.0 DISSIPATION & HEATSINK CALCULATION.....................................
21
- 6.1 Static and dynamic dissipation...........................................
21
- 6.2 Heatsink calculation...............................................................
22
- 6.3 Absolute worst case conditions.............................................
22
- 6.4 A more practical approach regarding dissipation...............
23
7.0 CIRCUIT APPLICATION & APPLICATION HINTS............................
24
Application diagram of the TDA6120Q.....................................
38
Partlist..........................................................................................
39
Evaluation board layout & component view.................................
40
- 7.1 Design-in sequence of the TDA6120Q...........................
24
- 7.2 Printed circuit board...........................................................
24
- 7.3 Cross-talk...............................................................................
26
- 7.4 Switch off behaviour..................................................................
27
- 7.6 Flash- over protection............................................................
30

- 7.7 Black- current stabilisation........................................................
33 Philips Semiconductors
___________________________________________________________________
TDA6120Q


Application Note
Wideband video output amplifier

AN96073
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8.0 PERFORMANCE EVALUATION.........................................................
34
- 8.1 Bandwidth........................................................................................
34
- 8.2 Multi-burst performance...................................................................
34
- 8.3 Cross-talk.........................................................................................
35
- 8.4 Rise and Fall time.............................................................................
35
- 8.5 Flash test..........................................................................................
35
9.0 ACKNOWLEDGMENT...................................................................................
37
10.0 REFERENCES...........................................................................................
37
11.0 APPENDIX
- Imperfections of the TDA6120Q......................................................
49
-"Passive" interface add-on board.....................................................
50

- TDA4882 add-on board...................................................................
54

- TDA4780 add-on board......................................................................
62 Philips Semiconductors
___________________________________________________________________
TDA6120Q


Application Note
Wideband video output amplifier

AN96073
-7-
1.0 INTRODUCTION

The aim of this application note is to describe the basic operation of the TDA6120Q
Wideband RGB video output amplifier and provide the user with basic hints to realise an
optimal performance in the application.
The TDA6120Q includes one video output amplifiers in a plastic DIL-bent -SIL power
package DBS13P, using high-voltage DMOS technology, and is intended to drive of a CRT in
a high demanding market of High Resolution TVs and monitors.
The device is provided with a black current measurement output for automatic black current
stabilisation (ABS).
The TDA6120Q does not include flash protection diodes, therefore it is necessary to apply an
external flash diode for each channel.
Two video output concepts are described in this report.
One video concept concept for typical TV applications, using the combination
TDA4780 [(monolithic RGB processor ) add-on board ] and the TDA6120Q
[ main board]. This combinat