cxa1982q Sony Electronics, cxa1982q Datasheet - Page 21
cxa1982q
Manufacturer Part Number
cxa1982q
Description
Rf Signal Processing Servo Amplifier For Cd Players
Manufacturer
Sony Electronics
Datasheet
1.CXA1982Q.pdf
(30 pages)
Commands
The input data to operate this IC is configured as 8-bit data; however, below, this input data is represented by
2-digit hexadecimal numerals in the form $XX, where X is a hexadecimal numeral between 0 and F.
Commands for the CXA1982Q can be broadly divided into four groups ranging in value from $0X to $2X.
1. $0X (“FZC” at SENS pin (Pin 24))
These commands are related to focus servo control.
The bit configuration is as shown below.
Four focus-servo related switches exist: FS1, FS2, FS4, and DEFECT corresponding to D0 to D3, respectively.
$00
$02
$03
By alternating the commands between $02 and $03, the focus search voltage can be constructed. (Fig. 2)
$04
Fig. 2. Constructing the search voltage by alternating between $02 and $03. (Voltage at Pin 6)
D7
0
When FS1 = 0, Pin 8 is charged to (22µA – 11µA)
If, in addition, FS2 = 0, this voltage is no longer transferred, and the output at Pin 6 becomes 0V.
From the state described above, the only FS2 becomes 1. When this occurs, a negative signal is output
to Pin 6. This voltage level is obtained by equation 1 below.
(22µA – 11µA)
From the state described above, FS1 becomes 1, and a current source of +22µA is split off.
Then, a CR charge/discharge circuit is formed, and the voltage at Pin 8 decreases with the time as
shown in Fig. 1 below.
When the fact that the RF signal is missing is detected and the scratches on the disc are detected with
DEFECT = 0, DFCT (FS3) is turned ON.
This time constant is obtained with the 50k resistance and an external capacitor.
D6
0
0V
$
50k
D5
0
00 02
Fig. 1. Voltage at Pin 8 when FS1 gose from 0
resistance between Pins 6 and 7
D4
0
0V
03
FS4
D3
50k
02
– 21 –
DEFECT
D2
50k = 0.55V.
03
FS2
D1
. . . .
02
FS1
D0
Equation 1
1
00
CXA1982Q