TZA1024 datasheet(2/20 Pages) PHILIPS

2 / 20 page

1998 Oct 30

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.

TZA1024 Datasheet(PDF) 2 Page - NXP Semiconductors

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