Philips OQ8868 Datasheet

INTEGRATED CIRCUITS

DATA SH EET

OQ8868

Digital Servo Integrated Circuit
Silent (DSICS)

Product specification
Supersedes data of 1996 Apr 11
File under Integrated Circuits, IC01

1997 Feb 12

Philips Semiconductors Product specification

Digital Servo Integrated Circuit Silent
(DSICS)

FEATURES

The DSICS realizes the following servo functions:

• Focus servo loop

• Radial servo loop

• Built-in access procedure

• Sledge motor servo loop

• Three line (TDA1301T-like; same on hardware level,

coefficients differ) or I2C-bus serial interface with system
controller.

Other features are:

• Single supply voltage (5 V)

• Flexible system oscillator

• Usable for single/double Foucault and astigmatic focus

• Wide range of adjustable servo characteristics possible

• Automatic focus start-up procedure and in-lock

indication

• Fast focus restart procedure

• Sophisticated track loss detection mechanism

• Extended radial error signal

• Automatic initialization and jump procedure for radial

servo

• Automatic radial error gain and offset control

• Sophisticated defect detector

• Shock detector

• Fast serial communication

• Low noise servo loops

• Automatic gain control for the complete focus and radial

loop

• Fast track counting signal input

• Steered sledge jump

• Radial actuator damping.

OQ8868

Added features are:

• High level watchdogs

• Decoder (LO9585, LO9588 or HD60) communication

support

• Application debugging support

• Pulsed sledge mode

• Auto gain control on radial and focus loop

2

C-bus serial communication

• I

• Externally available defect detector signals.

GENERAL DESCRIPTION

The Digital Servo Integrated Circuit Silent (DSICS) IC
provides all servo functions except the spindle motor
control in two-stage Compact Disc (CD) systems. It offers
a high degree of integration, combined with the low
additional cost of external components. The servo
characteristics are widely adjustable by means of a
three-wire serial interface, which offers great flexibility for
the application of different CD mechanisms.

The servo chip accepts diode currents and drives various
power stages. Proper functioning of the focus and radial
AGCs requires a digital power stage (SZA1010). It can
drive normal, CDM12-like, mechanisms.

It is the improved version of its predecessor, the DSIC2
(TDA1301).

Features that improve on its predecessor, the TDA1301T:

• Low noise in the focus loop

• Faster serial communication

• Improved jump performance.

ORDERING INFORMATION

TYPE

NUMBER

OQ8868 QFP44 plastic quad flat package; 44 leads (lead length 1.3 mm); body

1997 Feb 12 2

NAME DESCRIPTION VERSION

10 × 10 × 1.75 mm

PACKAGE

SOT307-2

Philips Semiconductors Product specification

Digital Servo Integrated Circuit Silent

OQ8868

(DSICS)

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

DDD

V

DDA

I

DDD

I

DD(q)

I

DDA

I

I

P

tot

T

amb

Notes

1. Maximum input range varies from 3.8 to 12 µA and varies with the reference current through XTLR.

2. Maximum input range varies from 1.9 to 6 µA and varies with the reference current through XTLR.

digital supply voltage 4.5 − 5.5 V
analog supply voltage 4.5 − 5.5 V
digital supply current − 17 − mA
digital quiescent supply current −−10 µA
analog supply current − 5 − mA
input current

for pins D1 to D4 note 1 −−12 µA

for pins S1 and S2 note 2 −−6µA
total power dissipation − 115 − mW
operating ambient temperature −40 −+85 °C

1997 Feb 12 3

Philips Semiconductors Product specification

Digital Servo Integrated Circuit Silent
(DSICS)

BLOCK DIAGRAM

handbook, full pagewidth

SILD

RSTI

FTC

DDA

D1

D2

D3

D4

S1

18
17
16
19

15
38

11
3

4

5

7

8

COMM

ANALOG-TO-DIGITAL

CONVERTER

ANALOG-TO-DIGITAL

CONVERTER

ANALOG-TO-DIGITAL

CONVERTER

ANALOG-TO-DIGITAL

CONVERTER

ANALOG-TO-DIGITAL

CONVERTER

SIDA/SDA

SICL/SCL

ENIIC

V

V

DDD3

30 40

CONTROL

V

DDD1

NS

NS

NS

MONITOR

OQ8868

25

DA

26

CDID

24

RAB

33

SL

32

FO

31

RA

35

RP

36

TL

37

FOK

43

LDO

27

RSTO

S2

XTLR

V

SSA

DEFI

V

refH

V

refL

XTALO

XTALI

TEST1
TEST2

9

12
10
41

2
6

22
21

1
44

ANALOG-TO-DIGITAL

CONVERTER

ANALOG-TO-DIGITAL

CONVERTER

REFERENCE

OSCILLATOR

TEST

OQ8868

ERROR

DETECTION

39

V

SSD1

34

29

V

SSD2 VSSD3 VSSD4VSSD5

14

OTD

20

INTREQ

42

DEFO

28

CLKO

1323

MGE335

Fig.1 Block diagram.

1997 Feb 12 4

Philips Semiconductors Product specification

Digital Servo Integrated Circuit Silent
(DSICS)

PINNING

SYMBOL PIN DESCRIPTION

TEST1 1 test input 1 (LOW for normal operation); internal pull-down
V

refH

D1 3 unipolar current input (central diode signal input)
D2 4 unipolar current input (central diode signal input)
D3 5 unipolar current input (central diode signal input)
V

refL

D4 7 unipolar current input (central diode signal input)
S1 8 unipolar current input (central diode signal input)
S2 9 unipolar current input (central diode signal input)
V

SSA

V

DDA

XTLR 12 reference current input
V

SSD5

OTD 14 off track detector (output)
RSTI 15 reset input (active HIGH)
SILD 16 serial host interface load
SICL/SCL 17 serial host interface clock /I
SIDA/SDA 18 serial host interface data /I
ENIIC 19 enable I2C-bus serial format (active LOW)
INTREQ 20 interrupt request output (active LOW)
XTALI 21 oscillator input
XTALO 22 oscillator output
V

SSD4

RAB 24 serial decoder interface load (output)
DA 25 serial decoder interface data (input/output)
CDIC 26 serial decoder interface clock (output)
RSTO 27 reset output (active LOW)
CLKO 28 clock buffer output
V

SSD3

V

DDD3

RA 31 radial actuator output
FO 32 focus actuator output
SL 33 sledge output
V

SSD2

RP 35 radial polarity signal
TL 36 track loss signal
FOK 37 focus OK output
FTC 38 fast track counting input (internal pull-down)
V

SSD1

V

DDD1

2 high reference for A/D converter (input)

6 low reference for A/D converter (input)

10 analog ground
11 analog supply voltage

13 digital ground 5

2

C-bus clock (SCL)

2

C-bus data (SDA)

23 digital ground 4

29 digital ground 3
30 digital supply voltage 3

34 digital ground 2

39 digital ground
40 digital supply voltage 1

OQ8868

1997 Feb 12 5

Philips Semiconductors Product specification

Digital Servo Integrated Circuit Silent
(DSICS)

SYMBOL PIN DESCRIPTION

DEFI 41 defect detector input (connected to DEFO)
DEFO 42 defect detector output
LDO 43 laser drive on output (open drain, active LOW)
TEST2 44 test input 2 (low for normal operation)

handbook, full pagewidth

RP
35

SSD2

V
34

TEST1

V

refH

D1
D2
D3

V

refL

D4
S1
S2

V

SSA

V

DDA

DDD1

DEFO

LDO
43

DEFI

42

41

TEST2

44

1
2
3
4
5
6
7
8
9

10

11

SSD1

V

V

40

39

OQ8868

FTC
38

FOK
37

TL
36

OQ8868

33

SL
FO

32
31

RA

30

V

DDD3

V

29

SSD3

28

CLKO
RSTO

27

CDIC

26

DA

25
24

RAB
V

23

SSD4

12

13

14

15

16

OTD

SILD

SSD5

V

RSTI

XTLR

Fig.2 Pin configuration.

FUNCTIONAL DESCRIPTION
Servo input circuits

This IC has been designed for Compact Disc drives for
audio and data applications and uses diode currents as
input signals.

The analog signals from the diode pre-processor are
converted into a digital representation using
analog-to-digital (A/D) converters.

1997 Feb 12 6

21

17

18

SICL/SCL

SIDA/SDA

19

ENIIC

20

XTALI

INTREQ

22

MGE334

XTALO

Signal conditioning

The digital codes retrieved from the A/D converters are
connected to a logic circuit, to obtain the various control
signals. The signals from the central aperture detectors
are processed in such a way that the following normalized
focus error signal is generated:

FE

n

D1 D2–

---------------------­D1 D2+

D3 D4–

–=

---------------------­D3 D4+

where the detector set-up is assumed as shown in Fig.3.