TZA1025

The TZA1025 is a data amplifier and laser supply circuit for voltage output mechanisms found in a wide range of audio and video CD systems. The device contains an RF amplifier and an automatic laser power control circuit.

The TZA1025 preamplifier forms an interface for voltage output CD mechanisms to the Philips' digital signal processor CD10LC (SAA7325).

The RF bandwidth allows TZA1025 to be used in CD-A/V applications with a data rate of n = 1 times speed. The RF gain can be adapted for CD-A/V discs or CD-R/W discs by means of the gain select signal.The equalizer ensures an optimal performance.

The TZA1025 can be adapted to a wide range of voltage output mechanisms by means of external resistors.The 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. The ALPC can accommodate N- or P-substrate monitor diodes.

A separate supply voltage connection for the laser allows the internal power dissipation to be reduced by connecting a low voltage supply. The laser output current range of TZA1025 can be optimized to fit the requirements of the laser diode by means of one external resistor. When a DC-to-DC converter is used, in combination with the control loop of the ALPC, the adjustable output current range provides the possibility to compensate for the extra gain a DC-to-DC converter introduces in the control loop.