TDA1302T Datasheet, PDF (1/18 Pages) NXP Semiconductors – Data amplifier and laser supply circuit for CD player and read only optical systems

TDA1302_1 2 Wed Sep 14 13:30:56 1994
Philips Semiconductors
Data amplifier and laser supply circuit for
CD player and read only optical systems
Preliminary specification
TDA1302T
FEATURES
• Six input buffer amplifiers with low-pass filtering and with
virtually no offset
• HF data amplifier with a high or low gain mode
• Two built-in equalizers for single or double-speed mode
ensuring high performance in both modes
• Fully automatic laser control including stabilization and
an ON/OFF switch, plus a separate supply (V_DDL) for
power reduction
• Adjustable laser bandwidth and laser switch-on current
slope
• Protection circuit to prevent laser damage due to supply
voltage dip
• Optimized interconnectiion between pick-up detector
and digital servo processor (TDA1301T)
• Wide supply voltage range
• Wide temperature range
• Low power consumption.
GENERAL DESCRIPTION
The TDA1302T is a data amplifier and laser supply circuit
for three-beam pick-up detectors applied in a wide range
of mechanisms for Compact Disc and read only optical
systems. The device contains 6 amplifiers which amplify
and filter the focus and radial diode signals and provides
an equalized RF signal suitable for single or double speed
mode; the mode can be switched by means of the speed
control pin. The device can accommodate astigmatic,
single foucault and double foucault detectors and can be
applied to all N-sub laser/monitor diode units even though
the circuit has been optimized for the Philips CDM12
mechanisms and the digital servo controller TDA1301T.
After a single initial adjustment the circuit will maintain
control over the laser diode current thus resulting in a
constant light output power which is independent of
ageing. The IC is mounted in a small-outline package to
enable it to be mounted close to the laser pick-up unit on
the sledge.
QUICK REFERENCE DATA
SYMBOL
PARAMETER
V_DD
supply voltage (pin 18)
Diode current amplifiers
G_dn
I_os(d)
B
amplification
diode output offset current
3 dB bandwidth
RFE amplifier (built-in equalizer)
t_d(eq)
t_d(f)
equalization delay
flatness delay
Laser supply
I_o(l)
output current
CONDITIONS
MIN. TYP. MAX. UNIT
3.4
−
5.5
V
I_i(d) = 1.67 µA
−
1.55
−
dB
−
−
100
nA
50
−
−
kHz
f_i = 0.3 MHz
double-speed
−
320
−
ns
−
5
−
ns
V_DDL = 3 V
−
−
−100 mA
ORDERING INFORMATION
TYPE NUMBER
TDA1302T
NAME
SO24
PACKAGE
DESCRIPTION
plastic small outline package; 24 leads; body width 7.5 mm
VERSION
SOT137-1
September 1994
2