SAA7108AE PHILIPS [NXP Semiconductors], SAA7108AE Datasheet - Page 108

• Manufacturer Part Number: SAA7108AE
• Description: HD-CODEC
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
17.1
Figure 55 shows a possible reconstruction filter for the
digital-to-analog converters. Due to its cut-off frequency of
17.2
The analog output voltages are dependent on the total
load (typical value 37.5 ), the digital gain parameters and
the I
settings).
The digital output signals in front of the DACs under
nominal (nominal here stands for the settings given in
Tables 75 to 82 for example a standard PAL or NTSC
signal) conditions occupy different conversion ranges, as
indicated in Table 49 for a
Table 49 Digital output signals conversion range
17.3
Use separate ground planes for analog and digital ground.
Connect these planes only at one point directly under the
device, by using a 0
Use separate supply lines for the analog and digital supply.
Place the supply decoupling capacitors close to the supply
pins.
Use L
the decoupling capacitors to minimize radiation energy
(EMC).
Place the analog coupling (clamp) capacitors close to the
analog input pins. Place the analog termination resistors
close to the coupling capacitors.
Be careful of hidden layout capacitors around the crystal
application.
2004 Jun 29
Digital settings
Digital output
Analog settings
Analog output
6 MHz, it is not suitable for HDTV applications.
HD-CODEC
SET/OUT
2
C-bus settings of the DAC reference currents (analog
bead
Reconstruction filter
Analog output voltages
Suggestions for a board layout
(ferrite coil) in each digital supply line close to
CVBS, SYNC TIP-TO-WHITE VBS, SYNC TIP-TO-WHITE
resistor directly at the supply stage.
see Tables 75 to 82
e.g. B DAC = 1FH
100
1.23 V (p-p)
100
1014
colour bar signal.
see Tables 75 to 82
e.g. G DAC = 1BH
108
1.00 V (p-p)
By setting the reference currents of the DACs as shown in
Table 49, standard compliant amplitudes can be achieved
for all signal combinations; it is assumed that in
subaddress 16H, parameter DACF = 0000b, that means
the fine adjustment for all DACs in common is set to 0 %.
If S-video output is desired, the adjustment for the C
(chrominance subcarrier) output should be identical to the
one for VBS (luminance plus sync) output.
Use serial resistors in clock, sync and data lines, to avoid
clock or data reflection effects and to soften data energy.
The SAA7108AE; SAA7109AE crystal temperature
depends on the PCB it is soldered on. For normal airflow
conditions at a maximum ambient temperature of 70 C it
will be sufficient to provide:
881
PCB dimensions at least 2000 mm
PCB at least 4 layers
At least 50 vias (connecting PCB layers) close to the
chip
Metal coverage at least 60 % on at least 2 PCB layers
near the chip.
SAA7108AE; SAA7109AE
e.g. R DAC = G DAC = B DAC = 0BH
RGB, BLACK-TO-WHITE
see Table 70
0.70 V (p-p)
876
Product specification
2