C-bus controlled economy
PAL/NTSC and NTSC
TV-processors
Preliminary specification
File under Integrated Circuits, IC02
1997 Jul 01
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
FEATURES
Available in all ICs:
• Vision IF amplifier with high sensitivity and good figures
for differential phase and gain
• PLL demodulator for the IF signal
• Alignment-free sound demodulator
• Flexible source selection with a CVBS input for the
internal signal and Y/C or CVBS input for the external
signal
• Audio switch
• The output signal of the CVBS (Y/C) switch is externally
available
• Integrated chrominance trap and band-pass filters
(auto-calibrated)
• Luminance delay line integrated
• A symmetrical peaking circuit in the luminance channel
• Black stretching of non-standard CVBS or luminance
signals
• RGB control circuit with black current stabilization and
white point adjustment
• Linear RGB inputs and fast blanking
• Horizontal synchronization with two control loops and
alignment-free horizontal oscillator
• Slow start and slow stop of the horizontal drive pulses
• Vertical count-down circuit
• Vertical driver optimized for DC-coupled vertical output
stages
2
C-bus control of various functions
• I
• Low dissipation
• Small amount of peripheral components compared with
competition ICs.
TDA837x family
GENERAL DESCRIPTION
The various versions of the TDA837x series are I
controlled single-chip TV processors which are intended to
be applied in PAL/NTSC (TDA8374 and TDA8375) and
NTSC (TDA8373 and TDA8377) television receivers.
All ICs are available in an SDIP56 package and some
versions are also available in a QFP64 package. The ICs
are pin compatible so that with one application board
NTSC and PAL/NTSC (or multistandard together with the
SECAM decoder TDA8395) receivers can be built.
Functionally this IC series is split in to 2 categories:
• Versions intended to be used in economy TV receivers
with all basic functions
• Versions with additional functions such as E-W
geometry control, horizontal and vertical zoom function
and YUV interface which are intended for TV receivers
with 110° picture tubes.
The various type numbers are given in Table 1.
The detailed differences between the various ICs are
given in Table 2.
2
C-bus
Table 1 TV receiver versions
TV RECEIVERS
ECONOMYMID/HIGH ENDECONOMYMID/HIGH END
PAL onlyTDA8374B−TDA8374BH−
PAL/NTSC (SECAM)TDA8374 and TDA8374ATDA8375 and TDA8375ATDA8374AHTDA8375AH
NTSCTDA8373TDA8377 and TDA8377A−−
525reference current input
536AGC decoupling capacitor
TDA837x family
Notes
1. In the TDA8373 and TDA8377 pin 35 (4.43 MHz crystal) is internally connected and pin 33 is just a subcarrier output
which can be used as a reference signal for comb filter ICs.
2. In the TDA8373 and TDA8374 the following pins are different (SDIP56): Pin 27: not connected; Pin 45: AVL
capacitor.
1997 Jul 0110
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
handbook, full pagewidth
VDOA
VDOB
EWD
GND2
GND2
PH1
PH2
64
63
62
61
60
59
58
1
IFIN1
2
IFIN2
EHT/PRO
DEC
AGCOUT
AUDEEM
3
4
VSAW
5
I
ref
6
AGC
7
8
DEC
9
SIF
10
AUDI
11
i.c.
12
VCO1
13
VCO2
14
PLL
15
IFVO33
16
TDA837xH
FBI/SCO
HOUT
57
56
BLPH
55
CVBSO
VP2LFBP
54
53
TDA837x family
ref
XTAL2
XTAL1
SEC
52
51
50
48
BYI
RYI
47
RYO
46
BYO
45
i.c.
44
i.c.
43
i.c.
42
i.c.
41
YOUT
40
YIN
39
RGBIN
38
BI
37
GI
36
RI
35
BCLIN
34
RO
17
SCL
18
SDA
19
BG
DEC
20
CHROMA
22
VP1V
CVBS/Y
23
24
int
P1
CVBS
21
Fig.6 Pin configuration (QFP64).
1997 Jul 0112
25
GND1
26
GND1
27
AUDO
28
FT
DEC
29
ext
CVBS
30
BLKIN
31
BO
32
MGK285
GO49
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
FUNCTIONAL DESCRIPTION
Vision IF amplifier
The IF amplifier contains 3 AC-coupled control stages with
a total gain control range which is higher than 66 dB.
The sensitivity of the circuit is comparable with that of
modern IF-ICs.
The video signal is demodulated by a PLL carrier
regenerator. This circuit contains a frequency detector and
a phase detector. During acquisition the frequency
detector will tune the VCO to the correct frequency.
The initial adjustment of the oscillator is realized via the
2
I
C-bus.
The switching, between SECAM L and L’, can also be
realized via the I2C-bus. After lock-in the phase detector
controls the VCO so that a stable phase relationship
between the VCO and the input signal is achieved.
The VCO operates at twice the IF frequency.
The reference signal for the demodulator is obtained by
using a frequency divider circuit.
The AFC output is obtained by using the VCO control
voltage of the PLL and can be read via the I2C-bus.
For fast search tuning systems the window of the AFC can
be increased by a factor of 3. The setting is realized with
the AFW bit.
Depending on the device type the AGC detector operates
on top-sync level (single standard versions) or on top-sync
and top-white level (multistandard versions).
The demodulation polarity is switched via the I2C-bus.
The AGC detector time constant capacitor is connected
externally. This is mainly because of the flexibility of the
application. The time constant of the AGC system during
positive modulation is rather long, this is to avoid visible
variations of the signal amplitude. To improve the speed of
the AGC system, a circuit has been included which detects
whether the AGC detector is activated every frame period.
When, during 3 frame periods, no action is detected the
speed of the system is increased. For signals without
peak-white information the system switches automatically
TDA837x family
to a gated black level AGC. Because a black level clamp
pulse is required for this method of operation the circuit will
only switch to black level AGC in the internal mode.
The circuits contain a second fast video identification
circuit which is independent of the synchronization
identification circuit. Consequently, search tuning is also
possible when the display section of the receiver is used
as a monitor. However, this identification circuit cannot be
made as sensitive as the slower sync identification circuit
(SL) and it is recommended to use both identification
outputs to obtain a reliable search system.
The identification output is applied to the tuning system via
2
the I
C-bus.
The input of the identification circuit is connected to pin 13,
the internal CVBS input (see Fig.1). This has the
advantage that the identification circuit can also be made
operative when a scrambled signal is received
[descrambler connected between the IF video output
(pin 6) and pin 13]. A second advantage is that the
identification circuit can be used when the IF amplifier is
not used (e.g. with built-in satellite tuners).
The video identification circuit can also be used to identify
the selected CBVS or Y/C signal. The switching between
the two modes can be realized with bit VIM.
Video switches
The circuit has two CVBS inputs (CVBS
and a Y/C input. When the Y/C input is not required pin 11
can be used as the third CVBS input. The switch
configuration is illustrated in Fig.7. The selection of the
various sources is made via the I2C-bus.
The output signal of the CVBS switch is externally
available and can be used to drive the teletext decoder, the
SECAM add-on decoder and a comb filter.
In applications with comb filters a Y/C input is only possible
when additional switches are added. In applications
without comb filters the Y/C input signal can be switched
to the CVBS output.
and CVBS
int
ext
)
1997 Jul 0113
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
handbook, full pagewidth
IDENT
VIM
VIDEO
IDENTIFICATION
S0
S0 S5
TDA837x
13
CVBS
int
CVBS
S1
S1 S6S2
17
ext
11
CVBS/Y
S3 S7S4
CHROMA CVBSO
TDA837x family
to luminance/
sync processing
to chrominance
processing
+
S8
1038
MGK301
Fig.7 Configuration CVBS switch and interfacing of video identification.
Sound circuit
The sound band-pass and trap filters have to be
connected externally. The filtered intercarrier signal is fed
to a limiter circuit and is demodulated by a PLL
demodulator. This PLL circuit automatically tunes to the
incoming carrier signal, hence no adjustment is required.
The volume is controlled via the I2C-bus. The de-emphasis
capacitor has to be connected externally.
The non-controlled audio signal can be obtained from this
pin (pin 55) (via a buffer stage).
2
The FM demodulator can be muted via the I
C-bus. This
function can be used to switch-off the sound during a
channel change so that high output peaks are prevented
(also on the de-emphasis output).
The TDA8373 and TDA8374 contain an Automatic Volume
Levelling (AVL) circuit which automatically stabilizes the
audio output signal to a certain level which can be set by
the user via the volume control. This function prevents big
audio output fluctuations due to variations of the
modulation depth of the transmitter. The AVL function can
be activated via the I2C-bus.
Synchronization circuit
The sync separator is preceded by a controlled amplifier
which adjusts the sync pulse amplitude to a fixed level.
These pulses are fed to the slicing stage which operates at
50% of the amplitude.
The separated sync pulses are fed to the first phase
detector and to the coincidence detector. The coincidence
detector is used to detect whether the line oscillator is
synchronized and can also be used for transmitter
identification. The circuit can be made less sensitive by
using the STM bit. This mode can be used during search
tuning to ensure that the tuning system will not stop at very
weak input signals. The first PLL has a very high static
steepness so that the phase of the picture is independent
of the line frequency.
The line oscillator operates at twice the line frequency.
The oscillator capacitor is internal. Because of the spread
of internal components an automatic calibration circuit has
been added to the IC. The circuit compares the oscillator
frequency with that of the crystal oscillator in the colour
decoder.
1997 Jul 0114
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
This results in a free-running frequency which deviates
less than 2% from the typical value. When the IC is
switched on the horizontal output signal is suppressed and
the oscillator is calibrated as soon as all subaddress bytes
have been sent. When the frequency of the oscillator is
correct the horizontal drive signal is switched on. To obtain
a smooth switching on and switching off behaviour of the
horizontal output stage the horizontal output frequency is
doubled during switch-on and switch-off (slow start/stop).
During that time the duty cycle of the output pulse has such
a value that maximum safety is obtained for the output
stage.
To protect the horizontal output transistor, the horizontal
drive is immediately switched off (via the slow stop
procedure) when a power-on reset is detected. The drive
signal is switched on again when the normal switch-on
procedure is followed, i.e. all subaddress bytes must be
sent and, after calibration, the horizontal drive signal will
be released again via the slow start procedure.
When the coincidence detector indicates an out-of-lock
situation the calibration procedure is repeated.
TDA837x family
For this reason this protection input can be used as ‘flash
protection’.
The drive pulses for the vertical sawtooth generator are
obtained from a vertical countdown circuit. This countdown
circuit has various windows depending on the incoming
signal (50 or 60 Hz and standard or non-standard).
The countdown circuit can be forced in various modes via
the I2C-bus. To obtain short switching times of the
countdown circuit during a channel change the divider can
be forced in the search window using the NCIN bit.
The vertical deflection can be set in the de-interlace mode
via the I2C-bus.
To avoid damage of the picture tube when the vertical
deflection fails, the guard output current of the TDA8350
and TDA8351 can be supplied to the beam current limiting
input. When a failure is detected the RGB outputs are
blanked and a bit is set (NDF) in the status byte of the
I2C-bus. When no vertical deflection output stage is
connected this guard circuit will also blank the output
signals. This can be overruled using the EVG bit.
The circuit has a second control loop to generate the drive
pulses for the horizontal driver stage. The horizontal
output is gated with the flyback pulse so that the horizontal
output transistor cannot be switched on during the flyback
time.
Adjustments can be made to the horizontal shift, vertical
shift, vertical slope, vertical amplitude and the S-correction
via the I2C-bus. In the TDA8375A, TDA8377A, TDA8375
and TDA8377 the E-W drive can also be adjusted via the
I2C-bus. The TDA8375 and TDA8377 have a flexible zoom
adjustment possibility for the vertical and horizontal
deflection. When the horizontal scan is reduced to display
4 : 3 pictures on a 16 : 9 picture tube an accurate video
blanking can be switched on to obtain well defined edges
on the screen. The geometry processor has a differential
output for the vertical drive signal and a single-ended
output for the E-W drive (TDA8375A, TDA8377A,
TDA8375 and TDA8377). Overvoltage conditions (X-ray
protection) can be detected via the EHT tracking pin.
When an overvoltage condition is detected the horizontal
output drive signal will be switched off via the slow stop
procedure. However, it is also possible that the drive is not
switched off and that just a protection indication is given in
the I2C-bus output byte. The choice is made via the input
bit PRD. The ICs have a second protection input on the
phase-2 filter capacitor pin. When this input is activated the
drive signal is switched off immediately (without slow stop)
and switched on again via the slow start procedure.
Chrominance and luminance processing
The circuit contains a chrominance band-pass and trap
circuit. The filters are realized by using gyrator circuits.
They are automatically calibrated by comparing the tuning
frequency with the crystal frequency of the decoder.
The luminance delay line and the delay for the peaking
circuit are also realized by using gyrator circuits.
The centre frequency of the chrominance band-pass filter
is 10% higher than the subcarrier frequency. This
compensates for the high frequency attenuation of the IF
saw filter. During SECAM reception the centre frequency
of the chrominance trap is reduced to obtain a better
suppression of the SECAM carrier frequencies. All ICs
have a black stretcher circuit which corrects the black level
for incoming video signals which have a deviation between
the black level and the blanking level (back porch).
The TDA8375A, TDA8377A, TDA8375 and TDA8377
have a defeatable coring function in the peaking circuit.
Some of the ICs have a YUV interface so that picture
improvement ICs such as the TDA9170 (contrast
improvement), TDA9177 (sharpness improvement) and
TDA4556 and TDA4566 (CTI) can be applied. When the
TDA4556 or TDA4566 is applied it is possible to increase
the gain of the luminance channel by using the GAI bit in
subaddress 03 so that the resulting RGB output signals
will not be affected.
1997 Jul 0115
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
and NTSC TV-processors
Colour decoder
Depending on the IC type the colour decoder can decode
NTSC signals (TDA8373 and TDA8377) or PAL/NTSC
signals (TDA8374 and TDA8375). The circuit contains an
alignment-free crystal oscillator, a killer circuit and two
colour difference demodulators. The 90° phase shift for the
reference signal is made internally.
The TDA8373 and TDA8377 contain an Automatic Colour
Limiting (ACL) circuit which prevents over saturation
occurring when signals with a high chroma-to-burst ratio
are received. This ACL function is also available in the
TDA8374 and TDA8375, however, it is only active during
the reception of NTSC signals.
The TDA8373 and TDA8377 have a switchable colour
difference matrix (via the I
reproduction can be adapted to the market requirements.
In the TDA8374 and TDA8375 the colour difference matrix
switches automatically between PAL and NTSC, however,
it is also possible to fix the matrix in the PAL standard.
The TDA8374 and TDA8375 can operate in conjunction
with the SECAM decoder TDA8395 so that an automatic
multistandard decoder can be realized. The subcarrier
reference output for the SECAM decoder can also be used
as a reference signal for a comb filter. Consequently, the
reference signal is continuously available when PAL or
NTSC signals are detected and only present during the
vertical retrace period when a SECAM signal is detected.
Which standard the TDA8374 and TDA8375 can decode
depends on the external crystals. The crystal to be
connected to pin 34 must have a frequency of 3.5 MHz
(NTSC-M, PAL-M or PAL-N). Pin 35 can handle crystals
with a frequency of 4.4 and 3.5 MHz. Because the crystal
frequency is used to tune the line oscillator, the value of
the crystal frequency must be communicated to the IC via
the I2C-bus. It is also possible to use the IC in the so called
‘3-norma’ mode for South America. In that event one
crystal must be connected to pin 35 and the other two to
pin 34. Switching between the 2 latter crystals must be
performed externally. Consequently, the search loop of the
decoder must be controlled by the microcontroller.
To prevent calibration problems of the horizontal oscillator
the external switching between the two crystals should be
performed when the oscillator is forced to pin 35.
2
C-bus) so that the colour
TDA837x family
For a reliable calibration of the horizontal oscillator it is
very important that the crystal indication bits (XA and XB)
are not corrupted. For this reason the crystal bits can be
read in the output bytes so that the software can check the
2
C-bus transmission.
I
RGB output circuit and black current stabilization
The colour difference signals are matrixed with the
luminance signal to obtain the RGB signals. Linear
amplifiers have been chosen for the RGB inputs so that the
circuit is suited for signals that are input from the SCART
connector. The insertion blanking can be switched on or off
using the IE1 bit. To ascertain whether the insertion pin
has a (continuous) HIGH level or not can be read via the
IN1 bit. The contrast and brightness control operate on
internal and external signals.
The output signal has an amplitude of approximately 2 V
(black-to-white) at nominal input signals and nominal
settings of the controls. To increase the flexibility of the IC
it is possible to add OSD and/or teletext signals directly at
the RGB outputs. This insertion mode is controlled via the
insertion input. The action to switch the RGB outputs to
black has some delay which must be compensated for
externally.
The black current stabilization is realized by using a
feedback from the video output amplifiers to the RGB
control circuit. The black current of the 3 guns of the
picture tube is internally measured and stabilized.
The black level control is active during 4 lines at the end of
the vertical blanking. The vertical blanking is adapted to
the incoming CVBS signal (50 or 60 Hz). When the flyback
time of the vertical output stage is longer than the 60 Hz
blanking time, or when additional lines need to be blanked
(e.g. for close captioning lines) the blanking can be
increased to the same value as that of the 50 Hz blanking.
This can be set using the LBM bit. The leakage current is
measured during the first line and, during the following
3 lines, the 3 guns are adjusted to the required level.
The maximum acceptable leakage current is ±100 µA.
The nominal value of the black current is 10 µA. The ratio
of the currents for the various guns automatically tracks
with the white point adjustment so that the background
colour is the same as the adjusted white point.
1997 Jul 0116
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
TDA837x family
and NTSC TV-processors
The input impedance of the black current measuring pin is
14 kΩ. To prevent the voltage on this pin exceeding the
supply voltage during scan an internal protection diode
has been included.
When the TV receiver is switched on the black current
stabilization circuit is not active, the RGB outputs are
blanked and the beam current limiting input pin is
short-circuited. Only during the measuring lines will the
outputs supply a voltage of 4.2 V to the video output stage
2
C-bus specification
I
Table 3 Slave address (8A)
A6A5A4A3A2A1A0R/W
1000101I/O
The slave address is identical for all types. The
subaddresses of the various types are slightly different.
The list of subaddresses for each type is given in
Tables 4, 6, 8 and 10.
TART-UP PROCEDURE
S
to ascertain whether the picture tube is warming up. As
soon as the current supplied to the measuring input
exceeds a value of 190 µA the stabilization circuit will be
activated. After a waiting time of approximately 0.8 s the
blanking and beam current limiting input pins are released.
The remaining switch-on behaviour of the picture is
determined by the external time constant of the beam
current limiting network.
on when the oscillator is calibrated. Each time before the
data in the IC is refreshed, the status bytes must be read.
If POR = 1, then the procedure given above must be
carried out to restart the IC. When this procedure is not
followed the horizontal frequency in the TDA8374 and
TDA8375 may be incorrect after power-up or a power dip.
Read the status bytes until POR = 0 and send all
subaddress bytes. The horizontal output signal is switched
1997 Jul 0117
Philips SemiconductorsPreliminary specification
I2C-bus controlled economy PAL/NTSC
TDA837x family
and NTSC TV-processors
TDA8373
Valid subaddresses: 00 to 16 (subaddresses 04 to 07 are not used), subaddress FE is reserved for test purposes.
Auto-increment mode available for subaddresses.
Table 4 Inputs
FUNCTION
Control 000INAINBINC0FOAFOB00
Control 10100DLSTBPOC011
Hue02AVLAKBA5A4A3A2A1A0
Horizontal Shift (HS)03VIMGAIA5A4A3A2A1A0
Vertical Slope (VS)08NCINSTMA5A4A3A2A1A0
Vertical Amplitude (VA)09VIDLBMA5A4A3A2A1A0
S-Correction (SC)0A0EVGA5A4A3A2A1A0
Vertical shift (VSH)0BSBLPRDA5A4A3A2A1A0
White point R0C00A5A4A3A2A1A0
White point G0D00A5A4A3A2A1A0
White point B0EMAT0A5A4A3A2A1A0
Peaking0F0000A3A2A1A0
Brightness10RBL0A5A4A3A2A1A0
Saturation11IE10A5A4A3A2A1A0
Contrast12AFWIFSA5A4A3A2A1A0
AGC takeover130VSWA5A4A3A2A1A0
Volume control14SMFAVA5A4A3A2A1A0
Adjustment IF-PLL15L’FAA6A5A4A3A2A1A0
Spare1600000000
Valid subaddresses: 00 to 16 (subaddresses 04 to 07 are not used), subaddress FE is reserved for test purposes.
Auto-increment mode available for subaddresses.
Table 6 Inputs (notes 1 and 2)
FUNCTION
Control 000INAINBINC0FOAFOBXAXB
Control 101FORFFORSDLSTBPOCCM2CM1CM0
Hue02AVLAKBA5A4A3A2A1A0
Horizontal Shift (HS)03VIMGAIA5A4A3A2A1A0
Vertical Slope (VS)08NCINSTMA5A4A3A2A1A0
Vertical Amplitude (VA)09VIDLBMA5A4A3A2A1A0
S-Correction (SC)0A0EVGA5A4A3A2A1A0
Vertical shift (VSH)0BSBLPRDA5A4A3A2A1A0
White point R0C00A5A4A3A2A1A0
White point G0D00A5A4A3A2A1A0
White point B0EMAT0A5A4A3A2A1A0
Peaking0F0000A3A2A1A0
Brightness10RBL0A5A4A3A2A1A0
Saturation11IE10A5A4A3A2A1A0
Contrast12AFWIFSA5A4A3A2A1A0
AGC takeover13MODVSWA5A4A3A2A1A0
Volume control14SMFAVA5A4A3A2A1A0
Adjustment IF-PLL15L’FAA6A5A4A3A2A1A0
Spare1600000000
SUB
ADDRESS
D7D6D5D4D3D2D1D0
DATA BYTE
Notes
1. The AVL and MOD bit are not available in the TDA8374A.
2. In the TDA8374B the AVL and MOD bit is also missing and the CM0 to CM2 and CD0 to CD2 bits have less
possibilities because this IC can only decode PAL or PAL/SECAM signals (when the TDA8395 is applied).
000internal CVBS plus audiointernal CVBS
001external CVBS plus audioexternal CVBS
010Y/C plus external audioY/C (Y plus C)
011CVBS3 plus external audioCVBS3
100Y/C plus internal audiointernal CVBS
110Y/C plus external audioexternal CVBS
Table 13 Phase 1 (ϕ-1) time constant
FOAFOBMODE
00normal
01slow and gated
10slow/fast and gated
11fast