Philips tda1301 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TDA1301T

Digital servo processor (DSIC2)

Product speciﬁcation File under Integrated Circuits, IC01

Philips Semiconductors

January 1996

Philips Semiconductors Product speciﬁcation

Digital servo processor (DSIC2) TDA1301T

FEATURES

The DSIC2 realizes the following servo functions:

• Diode signal preprocessing

• Focus servo loop

• Radial servo loop

• Sledge motor servo loop

• Three-line serial interface via the microcontroller

The other features include:

• Full digital signal processing

• Low power consumption, down to 30 mW

• Low voltage supply 3 to 5.5 V

• Integrated analog-to-digital converters and digital servo

loop filters

• Double speed possible

• Easy application

– Single supply voltage – Small number of external components; only

6 decoupling capacitors – Flexible system oscillator circuitry – Usable for single/double Foucault and astigmatic

focus – Full automatic radial error signal initialization offset

control and level initialization for track position

indicator – No external adjustments required; no component

ageing – Wide range of adjustable servo characteristics – Simple 3-line serial command interface

– 28-pin SO package – Great flexibility towards different CD mechanisms – Full and transparent application information

• High robustness/shock insensitivity – Sophisticated track-loss (TL) detection mechanism – Fast focus restart procedure – Extended radial error signal – Adjustable radial shock detector – Defect drop-out detector

• Fully automatic jump procedure for radial servo

• Automatic focus start-up procedure and built-in FOK

(Focus OK)

• Fast radial jump or access procedure

• Self-operational servo-control without continuous

communication via the microcontroller

• Direct communication to photodiode optics; no external preprocessing.

GENERAL DESCRIPTION

The TDA1301T is a fully digital servo processor which has been designed to provide all servo functions, except the spindle motor control, in two-stage three-spot compact disc systems. The device offers a high degree of integration, combined with the low additional cost of external components. The servo characteristics have a wide range of adjustment via a three-line serial interface. This offers an enormous flexibility with respect to applications for different CD mechanisms. The circuit is optimized for low-power low-voltage applications.

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

DDD

DDA

DDD

DDA

DDD(q)

i(cd)

i(sd)

tot

amb

digital supply voltage 3.0 − 5.5 V analog supply voltage 3.0 − 5.5 V digital supply current − 5 − mA analog supply current − 5 − mA digital quiescent supply current −−10 µA central diode input currents (D1 to D4) note 1 −−15.8 µA satellite diode input currents (R1 and R2) note 1 −−7.9 µA total power dissipation − 50 − mW operating ambient temperature −40 − +85 °C

Note

= 4.2336 MHz; VRL = 0 V; VRH = 2.5 V (externally applied).

1. f

sys

January 1996 2

Philips Semiconductors Product speciﬁcation

Digital servo processor (DSIC2) TDA1301T

ORDERING INFORMATION

EXTENDED TYPE

NUMBER

TDA1301T 28 SO28L plastic SOT136A

BLOCK DIAGRAM

PINS PIN POSITION MATERIAL CODE

PACKAGE

January 1996 3

Fig.1 Block diagram.

Philips Semiconductors Product speciﬁcation

Digital servo processor (DSIC2) TDA1301T

PINNING

SYMBOL PIN DESCRIPTION

RST 1 reset input (active LOW) LDON 2 laser drive on output V

SSA

D1 5 unipolar current input

D2 6 unipolar current input

D3 7 unipolar current input

D4 9 unipolar current input

R1 10 unipolar current input

R2 11 unipolar current input

DDA

XTAL

ref

TEST1 14 test input 1 TEST2 15 test input 2 OTD 16 off-track detector output CLKO 17 clock output XTALO 18 oscillator output XTALI 19 oscillator input V

DDD1

SSD

RA 22 radial actuator output FO 23 focus actuator output SL 24 sledge output SILD 25 serial interface load input SICL 26 serial interface clock input SIDA 27 serial interface data input/output V

DDD2

3 analog ground 4 reference input for reference voltage

generator

(central diode signal input)

8 reference input for ADC

(central diode signal input)

(satellite diode signal input)

(satellite diode signal input) 12 analog supply voltage 13 oscillator reference input

20 digital power supply 1 21 digital ground

28 digital power supply 2

Fig.2 Pin configuration.

January 1996 4

Philips Semiconductors Product speciﬁcation

Digital servo processor (DSIC2) TDA1301T

FUNCTIONAL DESCRIPTION Three spots front-end

The photo detector in a two-stage three-spots compact disc system normally contains six discrete elements. Four of these elements (in the event of single Foucault: three elements) carry the central aperture (CA) signal while the other two elements (satellite signals) carry the radial tracking information. Besides the HF signal, which is finally applied to both of the audio channels, the central aperture also contains information for the focus servo loop. To enable the HF signal to be processed, the frequency contents of the central aperture signal must be divided into an HF data part and an LF servo part. The HF signal is processed outside the DSIC2 by the TDA1302 or a discrete amplifier-equalizer. The necessary crossover point, to extract the LF servo part, is compensated for in the amplifier.

Diode signal processing

The analog signals from the photo detectors are converted into a digital representation using analog-to-digital converters. The ADCs are designed to convert unipolar currents into a digital code. The dynamic range of the input currents is adjustable within a given range and is dependent on the ADC input reference voltages V

and VRH. The maximum current for the central diodes signals is given in equation (1).

i max()

VRHVRL–()1.5 106–×××= µA[]

sys

(1)

The maximum current for the satellite signals is given in equation (2).

i max()

VRHVRL–()0.75 106–×××= µA[]

sys

(2)

is generated internally. There are four different levels (1.0, 1.5, 2.0 and 2.5 V) which can be selected under software control. In the application VRL is connected to V

. It is also possible to drive VRH with an external

SSA

voltage source but in this situation the internal voltage source has to be switched off (software controlled).

Signal conditioning

The digital codes retrieved from the ADCs are applied to logic circuitry to obtain the various control signals. The signals from the central aperture detectors are processed so that the normalized focus error signal (FE) given in equation (3) is realized:

D1 D2–

---------------------D1 D2+

D3 D4–

–=

---------------------D3 D4+

(3)

Where the detector set-up is assumed to be as illustrated in Fig.3.

January 1996 5

Fig.3 Diode configuration.

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