TZA1038HW,118 NXP Semiconductors, TZA1038HW,118 Datasheet - Page 40

• Manufacturer Part Number: TZA1038HW,118
• Description: IC DVD SIGNAL PROC 48-HTQFP
• Manufacturer: NXP Semiconductors

Specifications of TZA1038HW,118

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 48-TQFP Exposed Pad, 48-eTQFP, 48-HTQFP, 48-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 935273843118; TZA1038HW-T; TZA1038HW-T

Philips Semiconductors
11.3
Bit PWRON can be used to bring the TZA1038HW into
STANDBY mode reducing the supply current to
approximately 0.5 mA.
11.4
11.4.1
It is useful to compensate for electrical offset, especially
with pick-ups that give a low output signal. It is possible to
compensate for each individual servo channel. Due to
internal circuitry, the TZA1038HW servo channels can
handle only signals positive with respect to the reference
input OPUREF. Therefore the potentially negative offset
from the pick-up must first be cancelled. The LF
can be programmed to do this, and will apply this to all six
channels at the same time. The LF
to 0, 5, 10 or 15 mV.
As a second step, the offset between each channel can be
compensated by connecting the DACs to each individual
DAC (C
DACs can be programmed between 0 and 20 mV with
approximately 1.25 mV resolution. Where the LF
increases the outputs signal level, the individual DACs
decrease the output signal. In this way the output signal
can be set very close to zero. The range of DACs, LF
C
bit SERVOOS.
The output current of servo channel A is calculated by:
In case the laser is switched off, the term (V
represents the electrical offset from the pick-up.
The procedure to cancel the offset is:
1. Activate the pick-up and switch off the laser.
2. Set LF
3. Measure the output currents off all relevant servo
4. If all outputs represent a signal >5 mV equivalent input
5. Measure each output and increase C
This procedure needs only to be done once, or after a
longer time when temperature may have changed the
pick-up offset.
2003 Sep 03
I
OA
OFFS
High speed advanced analog DVD signal
processor and laser supply
outputs.
voltage, decrease V
outputs represent a signal <5 mV equivalent input
voltage, go to step 5.
output current is close enough to zero.
=
and R
Energy saving
Initial DC and gain setting strategy
------------------------------------------------------------------------------------------------------------------------ -
OFFSA
V
E
A
LECTRICAL OFFSET FROM PICK
OFFS
–
OFFS
V
to C
OPUREF
to its maximum value.
can be tripled with control
OFFSD
, R
LFOFFS
+
V
OFFSE
14 k
FLOFFS
then repeat step 3; if all
and R
–
OFFS
V
COFFSA
-
OFFSF
UP
DAC can be set
OFFS
A
). These
until the
OFFS
V
OFFS
A
OPUREF
LFC
OFFS
DAC
DAC
)
,
40
The test pin OCENTRAL can be useful to follow this
procedure. This pin can be programmed to output a copy
of the signal OA to OD (see register 12).
11.4.2
The servo gain has to be chosen dependant on the
reflectivity of the disc. So this needs to be done each time
when a new disc is inserted in the mechanism. A trial and
error procedure should find the optimal setting. Gain can
be set in 3 dB steps.
11.4.3
Once the gains in the servo path have been set, the
average DC level at the inputs can be calculated from the
value of the servo output signals:
Where I
pins OA to OD.
This value is a good estimate to use initially to set the
RF DC compensation, V
of the RF
of G
In cases where a DC coupling between TZA1038HW and
the decoder is made, a fine tuning of the RF DC
compensation can be done during play. The zero-crossing
level of the data-eye pattern can be used to judge the
correct DC compensation level.
11.4.4
The choice of RF gain is determined by the modulation of
the disc, therefore the modulation needs to be checked
each time a new disc is inserted in the mechanism. A trial
and error procedure should be sufficient to find the
optimum setting. For optimum use of the dynamic range:
V
I
Use G
be set in the range 0 to 6 dB to leave an additional gain
of 6 dB free to use during disc defects
Use G
when G
increased
G
settings than in 6 and 18 dB setting
A similar procedure can be followed for RFSUM.
=
2
1
.
shows better noise performance in 12 and 24 dB
------------------------------------------------------------------------ -
A
LFC
Ox
3
1
G
DC
G
OFFS
1
and G
for fine tuning and AGC, so initially this should
AIN SETTING SERVO
is the average value of the output currents at
AIN SETTING
–
has reached its maximum then G
LEVEL IN
I
V
DACs are scaled with the programmed gain
Ox
LFOFFS
2
to set the gain, increase G
14 k
RF
+
RF
RFOFFS
V
PATH
COFFSx
PATH
. The range and resolution
TZA1038HW
Product specification
1
2
first,
should be