SGS Thomson Microelectronics TDA9203A Datasheet

I2C BUS CONTROLLED 70MHz RGB PREAMPLIFIER

.

70MHz TYPICAL BANDWIDTH AT 4VPPOUT­PUTWITH12pFCAPACITIVELOAD

.

5.5ns TYPICAL RISE/FALL TIME AT 4V
OUTPUTWITH 12pF CAPACITIVELOAD

.

POWERFULLOUTPUTDRIVE CAPABILITY

.

BRT, CONT, DRIVE, OUTPUT DC LEVEL,
OSD CONTRAST, BACK-PORCH CLAMPING
PULSEWIDTH AREI

.

INTERNAL BACK-PORCH CLAMPING
PULSEGENERATOR

.

OSD WHITEBALANCETRACKING

.

INTERNALOSD SWITCHES

.

BLANKINGAND FAST-BLANKINGINPUTS

.

VERY LARGE DRIVE ADJUSTMENT RANGE
(48dB)

.

SEMI-TRANSPARENT BACKGROUND ON
OSD PICTURE

.

ABLCONTROL

2

C BUS CONTROLLED

TDA9203A

PP

SHRINK 24

(Plastic Package)

ORDER CODE : TDA9203A

DESCRIPTION

The TDA9203A is a digitaly controlled wideband
video preamplifier intended for use in mid range
color monitor. All controls and adjustments are
digitaly performed thanks to I
trast, brightness and DC output level of RGB sig­nals are common to the 3 channels and drive
adjustmentisseparatefor eachchannel.ThreeI
gain controlled OSD inputs can be switched with
RGBsignalsusingfastblankingcommand.Clamp­ingof RGBsignalsis performedthanksto aflexible
integrated system. The white balance adjustment
is effectiveon brightness,video and OSD signals.
The TDA9203Aworks for application using AC or
DC coupledCRT driver.

The ABL input provides a 12dB Max. attenuation
on the current contrast value according average
beamlimitation voltage.

Because of its features and due to component
saving the TDA9203Aleads to a very performant
and cost effectiveapplication.

2

C serial bus. Con-

2

C

PIN CONNECTIONS

IN1

OSD1

AV

IN2

OSD2

AGND

IN3

OSD3

ABL

LGND

SDA

SCL

DD

1
2
3
4
5
6
7
8
9
10
11
12

24
23
22
21
20
19
18
17
16
15
14
13

HSYNC
PV

CC1

OUT1
PGND1
PV

CC2

OUT2
PGND2
PV

CC3

OUT3
PGND3
BLK
FBLK

9203A-01.EPS

June 1998

1/13

TDA9203A

PIN DESCRIPTION

Name Pin Type Function

IN1 1 I 1

OSD1 2 I 1

AV

3 I 12V Analog V

DD

IN2 4 I 2ndChannel Main Picture Input

OSD2 5 I 2

AGND 6 I/O Analog Ground

IN3 7 I 3

OSD3 8 I 3

ABL 9 I ABL Input

LGND 10 I/O Logic Ground

SDA 11 I/O Serial Data Line
SCL 12 I Serial Clock Line

BLOCKDIAGRAM

st

Channel Main Picture Input

st

Channel OSD Input

DD

nd

Channel OSD Input

rd

Channel Main Picture Input

rd

Channel OSD Input

Name Pin Type Function

FBLK 13 I Fast Blanking Input

BLK 14 I Blanking Input

rd

PGND3 15 I/O 3

OUT3 16 O 3
PV

17 I 3rdChannel Power V

CC3

Channel Power Ground

rd

Channel Output

CC

PGND2 18 I/O 2ndChannel Power Ground

nd

OUT2 19 O 2
PV

20 I 2ndChannel Power V

CC2

Channel Output

CC

PGND1 21 I/O 1stChannel Power Ground

st

OUT1 22 O 1
PV

23 I 1stChannel Power V

CC1

Channel Output

CC

HSYNC 24 I Horizontal Synch Input

9203A-01.TBL

AV

IN1

AGND

IN2

IN3

ABL

LGND

3

DD

1

6

4

7

9

10

TDA9203A

V

REF

BLUECHANNEL

GREEN CHANNEL

BPCP

24

LATCHES

BUS

DECODER

11 12

CLAMP

2

C

I

SCLSDAHSYNC

FBLKBLK

CONTRAST

D/A

OSD

CONT

1314

BRIGHTNESS

2

OSD1 OSD2 OSD3

5

DRIVE

8 bits

8

2

C

I

BPCP

OUTPUT

STAGE

V

REF

PV

CC1

23

OUTPUT

DC LEVEL

ADJUST

22

21

20

19
18

16

17
15

OUT1

PGND1

PV

CC2

OUT2
PGND2

OUT3

PV

CC3

PGND3

9203A-02.EPS

2/13

FUNCTIONAL DESCRIPTION
InputStage

The R, G and B signals must be fed to the three
inputsthroughcoupling capacitors(100nF).
Themaximuminput peak-to-peakvideo amplitude
is 1V.
Theinput stage includesa clampingfunction.This
clamp is using the input serial capacitor as ”mem­ory capacitor”and is gatedby an internally gener­ated”Back-Porch-Clamping-Pulse(BPCP)”.
Thesynchronizationedge of the BPCPis selected
accordingbit 0 of registerR8.
WhenB0R8 is set to 1, the BPCPis synchronized
ontheleadingedgeoftheblankingpulseBLKinputs
onPin14(seeFigure1).B7R8allowstousepositive
or negativeblankingsignal on Pin 14. Atpower on
resetTDA9203Ause onlypositive blanking.

Figure1

BLK

HSYNC

BPCP

2

Internal pulse width is controlled by I

C

WhenB0R8is clearto0, theBPCPissynchronized
onthesecondedgeof thehorizontalpulseHSYNC
inputs on Pin 24. An automatic function allows to
usepositive or negativehorizontalpulseon Pin24
(seeFigure 2).

Figure2

HSYNC

BPCP

2

Internal pulse width is controlled by I

In both case BPCP width is adjustable by I

C

2

C, B1

and B2 of registerR8 (see R8 TableP8).
Contrast Adjustment (8 bits)

The contrast adjustment is made by controlling
simultaneously the gain of three internal variable
gain amplifiers throughthe I

2

C bus interface.
The contrast adjustment allows to cover a typical
range of 48dB.

ABLControl

The TDA9203AI

2

C preamplifier provides an ABL

input (automatic beam limitation) to attenuate

TDA9203A

R,G,Bvideo signals according to beam intensity.
The operating range is 2.5V typicaly,from 5.3V to

2.8V.A typical 12dBMax. attenuationis appliedto
the signal whatever the current gain is. Refer to
Figure 3 forABL input attenuationrange.
In case of software control,the ABLinput must be
pulled to AV
consumption(see Figure 11).
ABL input voltage must not exceeed AV
resistoris 10kΩ and equivalentschematic givenin
Figure 11.

Figure 3

Attenuation (dB)

2
0

-2

-4

-6

-8

-10

-12

9203A-03.EPS

-14
123456789

BrightnessAdjustment (8 bits)
As for the contrast adjustment, the brightness is

controlledby I
The brightnessfunction consiststo add the same
DC offsetto the threeR,G, B signalsafter contrast
amplification. This DC-Offset is present only out­side the blankingpulse (see Figure 4).
The DC output level during the blanking pulse, is
forced to”INFRA-BLACK”level (V

DriveAdjustment (3x 8 bits)

9203A-04.EPS

Inordertoadjustthewhitebalance, theTDA9203A
offersthepossibilitytoadjustseparatelythe overall
gain of each complete video channel. The gain of
each channel is controlledby I
Theverylargedriveadjustmentrange(48dB)allows
differentstandardor customcolortemperature.
It can also be usedto adjustthe outputvoltagesat
the optimum amplitude to drive the C.R.T drivers,
keepingthewholecontrastcontrolforend-useronly.

The drive adjustment is located after the CON­TRAST,BRIGHTNESSand OSDswitchblocks,so
that the white balance will remains correct when
BRT is adjusted, and will also be correct on OSD
portionof the signal.

through a resistor to limit power

DD

2

C.

).

DC

2

C (8bits each).

DD

. Input

VIN(V)

9203A-0X .EPS

3/13

TDA9203A

FUNCTIONAL DESCRIPTION(continued)
OSD Inputs

TheTDA9203Aincludes allthe circuitrynecessary
tomixOSDsignals intotheRGBmain-picture.Four
pins arededicated to this function as follow.
Three TTL RGB On Screen Displayinputs (Pin 2,
5 and 8). These three inputs are connectedto the
three outputs of the corresponding ON-SCREEN­DISPLAYprocessor(ex : STV942x).
One Fast Blanking Input (FBLK, Pin 13) which is
also connected to the FBLK output of the same
ON-SCREEN-DISPLAYprocessor.

When a high level is present on FBLK, the IC will
acts as follow:

- The three main picture RGB input signals are
internally switched to the internal input clamp
referencevoltage.

- The three output signals are set to voltages cor­respondingto the state(0 or 1)on thethree OSD
inputs (see Figure4).

Example:

If FBLK = 1 and OSD1, OSD2, OSD3) = 1, 0, 1
respectively.
Then OUT1, OUT2, OUT3 will be equal to V
V

BRT,VOSD

where: V
BRTis the brightnessDC level I

,

BRT=VBLACK

+ BRT, V

OSD=VBRT

2

C adjustable.
OSD is the On-Screen Display signal value I
adjustablefrom 0V to 5.5V

bystep of 0.36V.

PP

Semi-transparent function is controlled thanks to
Bit6 of R8register(seeTable1).
When semi-transparent mode is activated, video
signalis dividedby 2 (CONT).

Table 1

FBLK OSD1 OSD2 OSD3 B6R8

0 x x x 0 Video
1 x x x 0 OSD (1)
0 x x x 1 Video
1 0 x x 1 OSD
1x1x1 OSD
1xx01 OSD
1 1 0 1 1 Semi-trans-

Notes : 1. All OSD colors are displayed.

2. One OSD color is displayed as semi-transparent video
without effect on brightness and DC level adjustment.

Signal (OUTn)

parent (2)

+ OSD

Output

OSD

2

C

Output Stage

Thethreeoutputstagesincorporatethreefunctions
which are :

- The blanking stage : When high level is applied
to the BLK input (Pin 14), the three outputs are
switchedto a voltagewhich is 400mV lower than
the BLACK level. The black level is the output
voltagewithminimumbrightness wheninput sig­nal video amplitude is equalto ”0”.

- The output stage itself : It is a large bandwidth
output amplifier whichallow to deliverup to 5V
on the threeoutputs(for 0.7V videosignal onthe
inputs).

- The output CLAMP : The IC also incorporates
three internal output clamp (sample and hold
system) which allow to DC shift the three output
signals. The DC output voltage is adjustable
through I

2

C with4 bits. Practicaly, the DC output
level allowto adjustthe BLK level (V
underV

)from0.9Vto 2.9Vwith12 x165mV.

BLACK

Theoverallwaveforms ofthe outputsignalaccord­ing to the different adjustment are shown in Fig-

,

ures 4 and 5.

Serial Interface

2

The 2-wiresserial interface is an I

C interface.
The slave address of the TDA9203A is DC (in
hexadecimal).

A6 A5 A4 A3 A2 A1 A0 W

11011100

Data Transfer

The host MCU can write data into the TDA9203A
registers.Read mode is not available.
To write data into the TDA9203A,after a start,the
MCU must send (see Figure6) :

2

- The I

C addressslavebytewitha lowlevel forthe

R/W bit.

- The byte of the internal register address where

the MCU wants to write data(s).

- The data.
All bytes are sent MSB bit first and the write data

transteris closedby a stop.

=400mV

DC

PP

4/13