Philips TDA8501T-N1, TDA8501-N1 Datasheet

DATA SH EET
Preliminary specification File under Integrated Circuits, IC02
April 1993
INTEGRATED CIRCUITS
TDA8501
PAL/NTSC encoder
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
FEATURES
Two input stages: R, G, B and (RY), (BY), Y with multiplexing
Chrominance processing, highly integrated, includes low frequency filters for the colour difference signals, and after the modulator a bandpass filter
Fully controlled modulator produces a signal according to the PAL or NTSC standard without adjustments
A free running oscillator. Can be tuned by crystal or by an external frequency source
Output stages with separated Y + SYNC and chrominance (Y + C, SVHS), and a CVBS output. Signal amplitudes are correct for 75 driving via an external emitter follower. Internal generation of NTSC setup
Sync separator circuit and pulse shaper, to generate the required pulses for the processing, clamping, blanking, FH/2, and burst pulse
H/2 control pin. In PAL mode the internally generated H/2 is connected to this pin and the phase of this signal can be reset
Internal bandgap reference.
GENERAL DESCRIPTION
The TDA8501 is a highly integrated PAL/NTSC encoder IC which is designed for use in all applications where R, G and B or Y, U and V signals require transformation to PAL or NTSC values.The specification of the input signals are fully compatible with the specification of those of the TDA8505 SECAM-encoder.
ORDERING INFORMATION
Note
1. SOT234-1; 1996 December 2.
2. SOT137-1; 1996 December 2.
EXTENDED TYPE
NUMBER
PACKAGE
PINS PIN POSITION MATERIAL CODE
TDA8501 24 DIL plastic SOT234AH2
(1)
TDA8501T 24 SO plastic SOT137AH1
(2)
April 1993 3
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
Fig.1 Block diagram.
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
Fig.2 Pin configuration.
PINNING
U and V respectively, are the terms used to describe the colour difference signals at the output of the matrix.
SYMBOL PIN DESCRIPTION
(RY) 1 colour difference input signal, for EBU bar (75%) 1.05 V (p-p) MCONTROL 2 multiplexer switch control input; HIGH = RGB, LOW = (RY), (BY), Y
(BY) 3 colour difference input signal, for EBU bar (75%) 1.33 V (p-p) H/2 4 line pulse input/output divided-by-2 for synchronizing the internal H/2, if not used, this pin
dependent on mode selected, is either left open-circuit, or connected to VCC or to ground
(note 1) Y 5 luminance input signal 1 V nominal without sync U OFFSET 6 U modulator offset control capacitor R 7 RED input signal for EBU bar of 75% 0.7 V (p-p) V
CC
8 supply voltage; 5 V nominal G 9 GREEN input signal for EBU bar of 75% 0.7 V (p-p) V
SS
10 ground (0 V) B 11 BLUE input signal for EBU bar of 75% 0.7 V (p-p) V OFFSET 12 V modulator offset control capacitor V
REF
13 2.5 V internal reference voltage output CHROMA 14 chrominance output FLT 15 filter tuning loop capacitor CVBS 16 composite PAL or NTSC output, 2 V (p-p) nominal
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
Notes
1. Pin 4: in PAL mode, if not connected to external H2 pulse, this pin is the output for the internally generated H/2 signal. Pin 4: in NTSC mode, for internal set-up this pin is connected to ground; when internal set-up is switched off, this pin is connected to VCC.
2. The listed voltages connected to pin 17 (if VCC = + 5 V) enable the following Y (via pin 5) input signal states: 0 V = PAL mode; at pin 5, Y without sync and input blanking on 5 V = NTSC mode; at pin 5, Y without sync and input blanking on
1.8 V = PAL mode; at pin 5, Y with sync and input blanking off
3.2 V = NTSC mode; at pin 5, Y with sync and input blanking off
PAL/NTSC and Y/Y + SYNC
17 four level control pin (note 2)
NOTCH 18 Y +SYNC output via an internal resistor of 2 k; a notch filter can be connected to this pin Y +SYNC OUT 19 2 V (p-p) nominal Y +SYNC output Y +SYNC IN 20 Y +SYNC input; (from pin 22) connected to the output of the external delay line BURST ADJ 21 burst current adjustment via external resistor Y +SYNC OUT 22 Y +SYNC output 1 V (p-p) nominal, connected to the input of the external delay line OSC 23 oscillator tuning: connected to either a crystal in series with capacitor to ground, or to an
external frequency source via a resistor in series with a capacitor
CS 24 composite sync input, 0.3 V (p-p) nominal
SYMBOL PIN DESCRIPTION
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
FUNCTIONAL DESCRIPTION
The TDA8501 device comprises:
encoder circuit
oscillator and filter control
sync separator and pulse shaper.
Within this functional description, the term Y is used to describe the luminance signal and the terms U and V respectively, are used to describe the colour difference signals.
Encoder circuit
INPUT STAGE The input stage of the device uses two signal paths (see
Fig.1). Fast switching between the two signal paths is achieved by means of the signal path selection switch MCONTROL (pin 2).
R, B
AND G INPUT SIGNALS PATH
One signal path provides the connection for R, G and B signal inputs (via pins 7, 9 and 11) which are connected to a matrix via clamping and line blanking circuits. The signal outputs from the matrix are U, V and Y.
For an EBU colour bar of 75% the amplitude of the signal must be 0.7 V (peak-to-peak):
When selected (via MCONTROL), the U, V signals from the matrix are routed through the selection switch to the low pass filters. The Y signal from the matrix is routed through the selection switch to the adder and combined with the sync pulse from the sync separator and then connected via a buffer internally to pin 22 (Y + SYNC OUT to delay line).
(RY), (BY)
AND Y INPUT SIGNALS PATH
A second signal path provides the connection for negative colour difference signal inputs(RY),(BY) i.e. V, U (via pins 1, 3) and luminance Y (via pin 5), which are routed directly to the switch inputs via clamping and line blanking circuits.
U = 0.493 (BY) V = 0.877 (RY) Y = 0.299 R +0.587 G +0.114 B
The Y input signal (via pin 5) differs from other signal inputs, in that the timing of the internal clamp is after the sync period.
The amplitude and polarity of these colour difference and luminance input signals are processed to provide suitable switch inputs of U, V and Y signal values.
The condition for 75% colour bar is:
When selected (via MCONTROL), the U and V signals (via the switch) are routed to the low pass filters. The Y signal (via the switch) is routed via the adder and buffer to pin 22 (Y +SYNC OUT to delay line). Dependent on pin 17 conditioning, the Y signal may have external or internal sync added (see section Four level control pin).
F
OUR LEVEL CONTROL PIN
The Y input signal (via pin 5) is conditioned by use of the 4-level control pin (pin 17) to emulate either the PAL or NTSC modes, with sync and input blanking off or without sync and input blanking on.
Pin 17 may be hard wire connected to either ground (LOW for PAL mode) or VCC (HIGH for NTSC mode). External resistors can further modify the voltage level input at pin 17 to condition (pin 5) Y with sync and input blanking off or Y without sync and input blanking on. (see section PAL/NTSC and Y/Y +SYNC).
U
AND V SIGNALS
In PAL and NTSC modes the U and V (colour difference) signals at the output of the switch are configured differently as follows:
PAL mode:
after the adding of the burst pulse to U and V, these signals are connected to the input of the low pass filters. During the vertical sync period the burst pulse is suppressed.
NTSC mode:
the burst pulse is only added to U and the gain of the U and V signals is 0.95 of the gain in PAL mode. During the vertical sync period the burst pulse is suppressed.
pin 1 (RY) = 1.05 V (peak-to-peak) pin 3 (BY) = 1.33 V (peak-to-peak) pin 5 Y = 1 V (peak-to-peak) without sync
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
Fig.3 Low pass filter response for colour
difference signals (PAL mode).
(1) frequency response. (2) group delay.
Fig.4 Low pass filter response for colour
difference signals (NTSC mode).
(1) frequency response. (2) group delay.
Low pass filters The 3dB nominal frequency response level of the low
pass filters are different in PAL and NTSC modes. PAL mode: bandwidth = 1.35 MHz nominal (see Fig.3). NTSC mode: bandwidth = 1.1 MHz nominal (see Fig.4). The signal outputs of the low pass filters are connected to
the signal inputs of the U and V modulators.
U
AND VMODULATORS
Two four-quadrant multipliers are used for quadrature amplitude modulation of the U and V signals. The level of harmonics produced by the modulated signals are minimal, because of real multiplication with sinewave carriers.
The unbalance of the modulators is minimized by means of a control loop and two external capacitors, pin 6 for the U modulator and pin 12 for the V modulator. The timing of the control loop is triggered by the H/2 pulse, so that during one sync period the U control is active and during the next sync period the V control is active. In this way, when U and V are both zero, the suppressed carrier is guaranteed to be at a low level.
The internal oscillator circuit generates two sinewave carriers (0 degree and 90 degree). The '0 degree' (0) carrier is connected to the U modulator and the '90 degree' (1) carrier is connected to the V modulator.
PAL mode:
switched sequentially by the H/2 pulse, the V signal is modulated alternately with the direct and inverse carrier.
the internal H/2 pulse can be forced into a specific phase by means of an external pulse connected to pin 4 (H/2). Forcing is active at HIGH level. If not used pin 4 can be left open-circuit or connected to ground. If pin 4 is left open, the internally generated H/2 pulse (output) is connected to this pin.
NTSC mode:
alternation of the V modulation is not allowed. If pin 4 is not used for set-up control (see Y +SYNC, CVBS and Chrominance outputs), it can be left open-circuit or connected to ground.
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
CHROMINANCE BLANKING The signal outputs from the modulators are connected to
the signal input of the chrominance blanking circuit. To avoid signal distortion that may be caused by the control loop, the signal outputs of the modulators are blanked during the sync period. This prevents signal distortion during the adding of the sync pulse at the CVBS output circuit.
BANDPASS FILTER A wide symmetrical bandpass filter is used so that a
maximum performance of the chrominance for Y +C (SVHS) is guaranteed. This wide curve is possible because of the minimal signal level of the harmonics within the modulators see Figs (PAL mode: 5 and 6); (NTSC mode: 7 and 8) which illustrate the nominal response for PAL and NTSC modes.
Fig.5 Band pass filter nominal frequency
response (PAL mode).
Fig.6 Band pass filter nominal frequency/group
delay response (PAL mode).
(1) frequency response. (2) group delay.
Philips Semiconductors Preliminary specification
PAL/NTSC encoder TDA8501
Fig.7 Band pass filter nominal frequency
response (NTSC mode).
Fig.8 Band pass filter nominal frequency/group
delay response (NTSC mode).
(1) frequency response. (2) group delay.
Y +SYNC, CVBS AND CHROMINANCE OUTPUTS The Y signal from the matrix, or the Y signal from pin 5,
(selected via the switch) is added with the composite sync signal of the sync separator (dependent on pin 17 conditioning). The output of the adder, nominal 1 V (peak-to-peak), is connected to pin 22 (see Fig.1). Pin 22 is connected to an external delay line.
The delay line is necessary for correct timing of the Y + SYNC signal with the chrominance signal. The output resistor of the delay line is connected to V
REF
(pin 13). The output of the external delay line is connected to (input) pin 20.
The Y +SYNC (delayed) input signal at pin 20 is amplified via a buffer to a level of 2 V (peak-to-peak) nominal and connected to pin 19 (Y + SYNC output).
The Y + SYNC (delayed) input signal at pin 20 is also connected via an internal resistor of 2 k to the input of the CVBS adder stage. After the internal resistor of 2 k, and before the input of the CVBS adder, an external notch filter can be connected via pin 18.
The chrominance output of the bandpass filter is added with Y +SYNC signal via the CVBS adder. The CVBS (combined video and blanking signal) output of the adder is connected to pin 16 with a nominal amplitude of 2 V (peak-to-peak).
The chrominance output of the bandpass filter is amplified via a buffer and connected to pin 14. The chrominance amplitude corresponds with the value of Y + SYNC signal output at pin 19. Together both outputs give the Y +C (SVHS) signals.
B
LACK AND BLANKING LEVELS IN PAL AND NTSC MODES
PAL mode: Fig.9 illustrates the nominal Y + SYNC signal at pin 22, the difference between black and blanking level is 0 mV.
NTSC mode: Fig.10 illustrates the nominal Y + SYNC signal at pin 22, the difference between black and blanking level is 53 mV.
Because of the difference between the black and blanking level in the NTSC mode, there are two options for NTSC.
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