TZA1015

The TZA1015 is a data amplifier and laser supply circuit for 3-beam pick-up detectors found in a wide range of CD and read-only optical systems.

The TZA1015 device contains 6 transimpedance amplifiers to amplify and filter the focus and radial photo diode voltage input signals. The preamplifier forms a versatile,programmable interface from voltage output CD mechanisms to the Philips' digital signal processor family.

The dynamic range of this preamplifier/processor combination can be optimized for the LF servo and RF data paths. The servo channel gain is set by the ADC range of the processor. The RF data channel can be programmed in the TZA1015 preamplifier.

The programmable RF bandwidth allows this device to be used in CD-A/V applications or CD-R, CD-R/W and CD-ROM applications with a data rate up to a maximum of 30´. The RF and LF gain can be adapted for CD-A/V,CD-R and CD-ROM discs or CD-R/W discs by means of a gain switch. In addition to this gain switch the RF gain is programmable to guarantee optimal playability. In order to enable minimal access time the TZA1015 generates a Fast Track Count signal which enables the decoder (ACE or MACE) to count the number of tracks during a track jump.

The TZA1015 device can accommodate astigmatic, single Foucault and double Foucault detectors and can be used with all laser and N- or P-sub monitor diodes. The Automatic Laser Power Control (ALPC) circuit will maintain control over the laser diode current. With an on-chip reference voltage generator, a constant and stabilized output power is ensured independent of ageing. A separate power supply connection allows the internal power dissipation to be reduced by connecting a low voltage supply.