Philips Semiconductors
2 x 12 W hi-fi audio power amplifier
Product specification
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)
PARAMETER
Supply voltage
Non-repetitive peak
output current
Total power dissipation
Storage temperature range
Junction temperature
Short-circuit time:
outputs short-circuited
to ground
(full signal drive)
CONDITIONS
pin 7
pin 5
SYMBOL
VP = V7-3
−VP = V5-3
pins 4 and 6
see Fig.2
see note
IOSM
Ptot
Tstg
Tj
symmetrical
power supply
tsc
asymmetrical
power supply;
VP < 32 V
(unloaded);
Ri ≥ 4 Ω
tsc
MIN.
−
−
MAX.
+21
−21
UNIT
V
V
−
4
A
−55
+150 °C
−
150
°C
−
1
hour
−
1
hour
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.
July 1994
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