Philips Semiconductors
Preliminary specification
SECAM decoder
FEATURES
•
Fully integrated filters
•
Alignment free
•
For use with baseband delay
GENERAL DESCRIPTION
TDA8395
The TDA8395 is a self-calibrating, fully integrated SECAM decoder. The IC should preferably be used in conjunction with
the PAL/NTSC decoder TDA8362 or TDA8366 and with the switched capacitor baseband delay circuit TDA4660. The IC
incorporates HF and LF filters, a demodulator and an identification circuit (luminance is not processed in this IC). The IC
needs no adjustments and very few external components are required. A highly stable reference frequency is required
for calibration and a two-level sandcastle pulse for blanking and burst gating.
QUICK REFERENCE DATA
SYMBOL
V
P
P
tot
V
16(p-p)
V
O(p-p)
V
O(p-p)
PARAMETER
positive supply voltage; pin 3
total power dissipation
composite video input voltage
(peak-to-peak value); pin 16
−(R−Y)
output voltage amplitude
(peak-to-peak value); pin 9
−(B−Y)
output voltage amplitude
(peak-to-peak value); pin 10
7.2
−
−
−
−
MIN.
−
−
1.0
1.05
1.33
TYP.
MAX.
8.8
220
1.5
−
−
V
mW
V
V
V
UNIT
ORDERING INFORMATION
PACKAGE
EXTENDED TYPE NUMBER
PINS
TDA8395
Note
1. SOT38-1; 1996 December 3.
16
PIN POSITION
DIL
MATERIAL
plastic
CODE
SOT38GE1
(1)
October 1991
2
Philips Semiconductors
Preliminary specification
SECAM decoder
FUNCTIONAL DESCRIPTION
The TDA8395 is a self-calibrating SECAM decoder
designed for use with a baseband delay circuit.
During frame retrace a 4.433619 MHz reference frequency
is used to calibrate the filters and the demodulator. The
reference frequency should be very stable during this
period.
The Cloche filter is a gyrator-capacitor type filter the
resonance frequency of which is controlled during the
calibration period and offset during scan; this ensures the
correct frequency during calibration.
The demodulator is a Phase-Locked Loop (PLL) type
demodulator which uses the frequency reference and the
bandgap reference to force the PLL to the required
demodulation characteristic.
The low frequency de-emphasis is matched to the PLL and
is controlled by the tuning voltage of the PLL.
A digital identification circuit scans the incoming signal for
SECAM (only line-identification is implemented). The
identification circuit needs to communicate with the
TDA8362 to guarantee that the output signal from the
decoder is only available when no PAL signal has been
identified. If a SECAM signal is decoded a request for
LIMITING VALUES
In accordance with the Absolute Maximum System (IEC 134)
SYMBOL
V
P
T
stg
T
amb
PARAMETER
positive supply voltage
storage temperature range
operating ambient temperature range
−
−25
−25
MIN.
8.8
+150
+70
MAX.
TDA8395
colour-on is transmitted to pin 1 (current is sunk). If the
signal request is granted (i.e. pin 1 is HIGH therefore no
PAL) the colour difference outputs (−(B−Y) and
−(R−Y))
from the TDA8362 are high impedance and the output
signals from the TDA8395 are switched ON.
If no SECAM signal is decoded during a two-frame period
the demodulator will be initialized before another attempt
is made also during a two-frame period. The CD outputs
will be blanked or high-impedance depending on the logic
level at pin 1.
A two-level sandcastle pulse generates the required
blanking periods and, also, clocks the digital identification
pulse on the falling edge of the burst gate pulse. To enable
the calibration period to be defined the vertical retrace is
discriminated from the horizontal retrace, this is achieved
by measuring the width of the blanking period.
UNIT
V
°C
°C
October 1991
4
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