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EN 48
9.
SD-5.31SL
OPU connector
1
TR-
2
TR+
3
FO-
4
FO+
5
PDDVD
6
VCC
7
VR
8
GND
9
LDDVD
10
LDCD
11
VR
12
GND
13
PDCD
14
GND
15
RFOUT
16
C
17
B
OPU
DVDLD
18
A
Connector
CDLD
19
D
20
F
21
E
22
VCC
23
VS
24
GND
Loader Interface
The SP3721A is a single chip analogue front-end IC that
contains the servo functions, RF attenuator, AGC and
programmable equalizer/filter for the CD/DVD drive system
and a dual auto laser power control (APC) circuit to support the
twin laser system.
The servo block includes mirror detection, defect detection,
dual auto laser power control, tracking zero crossing, focus
error, centre error and tracking error detection circuits.
RF Interface
The SP3721A provides the RF interface for both DVD and CD
signals. DVD signals can be AC coupled into the device
through the differential input pins DVDRFP and DVDRFN,
while the CD signal interface is single-ended through the
CDRF pin. Both inputs are coupled to the PUHRF line from the
OPU.
Servo Interface
The SP3721A also provides the voltage-input interface for
photo detector signals used in the servo block, to detect centre
errors, focusing errors, and tracking errors. These signals
include the output from the quad cell photo detectors (A, B, C,
Circuit Descriptions, List of Abbreviations, and IC Data Sheets
Tray connector
1
2
3
4
5
TR+
TR-
FO+
FO-
MVREF2
TL3472
MC34072
VC21
VC25
PIN
VC21
PI
MEVO
CEI
Laser control
FEI
TEI
TEXI
SDFCT
DVDLDO
CDLDO
SBAD
SEFGC
MIRR
SLDC
DVDMDI
SCS
SP-3721A
CDMDI
SDATA
SCLK
A
B
RFO
C
D
E
F
RFOUT
Figure 9-3 Block diagram front-end.
OUTSW
INSW
LD-
Slot
Motor
LD+
connector
OUTSW
connector
GND
INSW
H1+
H1-
H2+
LD+
SL+
H2-
LD-
SL-
H3+
H3-
Servo driver
Spindle motor driver
BA5954FP
SFOCUS
STRACK
TRAYSW
RFRP
SSLEG
DRVSB
ALi
M5705
UPA[1:3]
UPD[0:15]
Power-on
LDS
reset
UDS
HDTACKn
HDMARQ
HDMACK
ATAPIINTn
IDECS0n
IDECS1n
ATAPIRSTn
ATAPI connector
From Back-end Host
D) and CD photo detectors (E, F, PD1, PD2), which are directly
connected from the pick-up.
The servo block includes focusing error detection, tracking
error detection, centre error detection, defect detection,
tracking zero crossing output, mirror detection and dual auto
laser power control circuits.
The servo interface accommodates both single laser and twin-
laser pickups.
Auto Laser Power Control (APC)
The SP3721A provides dual APC circuits for a DVD laser and
a CD laser. The DVD APC circuit has a selectable high or low
power mode of operation. The CD APC circuit is fixed at low
power or high gain mode.
Only one APC circuit can be operating at any given time. When
either or both of the APC circuits are "off", the output will be
fixed to the supply voltage.
Transistors 7000 and 7001 will function as laser drivers and are
controlled via the DVDLDO and CDLDO laser power control
lines.
HOMESW
Motor connector
SL-
1
2
SL+
3
GND
4
HOMESW
5
H+
6
H-
7
H3-
8
H3+
A1
9
H2-
A2
10
H2+
A3
11
H1-
VH
12
H1+
13
A1
14
A2
15
A3
BA6849FP
SMOTOR
SSPDON
SFGIN
SB
MA[0:15]
A16
MD[0:7]
MFSCS
MPSEN
MWR
RA[0:11]
RD[0:15]
RRAS
RCAS
RWE
ROE
Clock
circuit
CL 36532043_009.eps
Flash/ROM
M29F002BT-70K1-T
EDO DRAM
256K x 16
SOJ40
KAS161622D
020603
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