July 1994 4
Philips Semiconductors Product specification
2 x 12 W hi-fi audio power amplifier
TDA1521
TDA1521Q
FUNCTIONAL DESCRIPTION
This hi-fi stereo power amplifier is designed for mains fed applications. The circuit is designed for both symmetrical and
asymmetrical power supply systems. An output power of 2 × 12 watts (THD = 0,5%) can be delivered into an 8 Ω load
with a symmetrical power supply of ± 16 V.
The gain is fixed internally at 30 dB. Internal gain fixing gives low gain spread and very good balance between the
amplifiers (0,2 dB).
A special feature of this device is a mute circuit which suppresses unwanted input signals during switching on and off.
Referring to Fig.13, the 100 µF capacitor creates a time delay when the voltage at pin 3 is lower than an internally fixed
reference voltage. During the delay the amplifiers remain in their DC operating mode but are isolated from the
non-inverting inputs on pins 1 and 9.
Two thermal protection circuits are provided, one monitors the average junction temperature and the other the
instantaneous temperature of the power transistors. Both protection circuits activate at 150 °C allowing safe operation to
a maximum junction temperature of 150°C without added distortion.
RATINGS
Limiting values in accordance with the Absolute Maximum System (IEC 134)
Note
For asymmetrical power supplies (at short circuiting of the load) the maximum supply voltage is limited to VP = 28 V.
If the total internal resistance of the supply (Ri) > 4 Ω, the maximum unloaded supply voltage is increased to 32 V.
PARAMETER CONDITIONS SYMBOL MIN. MAX. UNIT
Supply voltage pin 7 V
P
= V
7-3
− +21 V
pin 5 −V
P
= V
5-3
−−21 V
Non-repetitive peak
output current pins 4 and 6 I
OSM
− 4A
Total power dissipation see Fig.2 P
tot
Storage temperature range T
stg
−55 +150 °C
Junction temperature T
j
− 150 °C
Short-circuit time: see note
outputs short-circuited
to ground symmetrical
(full signal drive) power supply t
sc
− 1 hour
asymmetrical
power supply;
V
P
< 32 V
(unloaded);
R
i
≥ 4 Ω t
sc
− 1 hour