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.

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.