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TZA1024 Datasheet(PDF) 2 Page - NXP Semiconductors |
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TZA1024 Datasheet(HTML) 2 Page - NXP Semiconductors |
2 / 20 page ![]() 1998 Oct 30 2 Philips Semiconductors Product specification Data amplifier and laser supply circuit for CD audio and video optical systems (ADALAS) TZA1024 FEATURES • Supports a wide range of voltage output mechanisms • RF amplifier designed for audio and video applications with data rates up to a maximum of n = 4 times speed • Programmable RF gain for CD-Audio/Video (CD-A/V) and CD-Read/Write (CD-R/W) discs • Adjustable equalizer for n = 1 or n = 2 times speed • Fully Automatic Laser Power Control (ALPC) including stabilization plus a separate laser supply voltage for power efficiency • Adjustable current range of ALPC output • Automatic N- or P-substrate monitor diode selection • Adjustable laser bandwidth and laser switch-on current slope using external capacitor • Protection circuit to prevent laser damage due to laser supply voltage dip • Optimized interconnection between data amplifier and Philips’ digital signal processor CD10 (SAA7324) • Wide supply voltage range • Power-down switch to reduce power consumption during standby • Low power consumption. GENERAL DESCRIPTION The TZA1024 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 preamplifier forms a versatile, programmable interface for voltage output CD mechanisms to the Philips’ digital signal processor CD10 (SAA7324). The RF bandwidth allows this device to be used in CD-A/V and CD-R/W applications with a data rate up to a maximum of n = 4 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 can be adjusted for n = 1 or n = 2 times speed with the equalizer/speed select signal. For n = 4 times speed the RF is not equalized. The TZA1024 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 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. |