Audio Power Amp. 60W with TDA7294

Audio Power Amplifier 60W with TDA7294

TDA7294_60w_1.gif (9657 bytes)

�� TDA7294 �� , �� . �� , �� 8� �� 4�. �� 50W rms �� 8� �� 0.1%. �� 1,4� C/W �� . �� . �� . �� 145-150�C, �� , �� Mute �� Standby �� JP1-2, �� . � �� [R3-C6 �� R4-C5] �� . �� .

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�� +/-40V. �� +/-30V �� , �� . � �� 80VA �� 150VA. �� 30 �� 60mA � �� 10000�F �� .

The TDA7294 amplifier module is a monolithic integrated circuit. It is intended for use as an audio class AB amplifier in hi-fi applications. It has a wide voltage range and output current capability, enabling it to supply the highest power into both 4 ohm and 8n ohm loads. With the addition of a handful of parts and a suitable power supply, this module will deliver 50W RMS into 8-ohm with 0.1% THD. you the user must supply a heavy duty heatsink rated at 1.4�C/W. Pin 10 is the MUTE input and pin 9 provides a STANDBY mode. Muting should always take place before standby mode is selected. Connecting these pins permanently to the supply rail (insert links) ensures that the amplifier comes on immediately on power up. Increasing the time constants R3-C6 and R4-C5 may eliminate any switch-on clicks. The IC has internal thermal protection that causes the mute to cut in at 145�C and switches the amplifier into standby at 150�C. Do not operate the module without a heatsink. The heatsink tab on the TDA7294 IC is internally connected to the negative supply rail. If the module is mounted inside an earthed metal enclosure then the IC must be insulated from the heatsink. If not, the negative supply rail will be shorted to ground.

POWER SUPPLY

The maximum supply voltage of the IC is +/-40V. However the maximum dissipation of the IC would be exceeded when using a 4-ohm load at that voltage. Therefore the supply voltage used should be kept down to a safe +/-30V. The mains transformer used to power the module should be rated at a minimum of 80VA. If you want to run two modules in a stereo amplifier you can use a common power supply. In this case the transformer should be rated at 150VA.

Source: Quasar Elec.

Specifications
Input sensitivity	1.3V (50W into 8W)
Input impedance	10K
Frequency response	15Hz - 100kHz
Slew rate	10V/uS
Output power	50W into 8W (0.1% THD)
Output power	82W into 4W (0.1% THD)
S/N ratio	105dBa (1W / 8W)
THD (40W into 8W)	0.002% (1kHz)
THD (40W into 8W)	< 0.04% (20Hz - 20kHz)
Power Supply	+/-30Vdc

Parts List for Power Amplifier
R1=180ohm	C5-6=10uF 63V Electrolytic	J2=3pin connector
R2-3-5=10Kohm	C7=22uF 63V Electrolytic	J3=2pin connector
R4=22Kohm	C8=33uF 25V Electrolytic
R6=680ohm	C9-10=1000uF 63V Electrolytic	All Resistors is 1/4W 1%
C1=1.5uF 63V MKT Polyester	IC1=TDA7294 on Heatsink	All Electrolytic Capacitors is Axial
C2=2.7nF 63V MKT Polyester	J1=2pin connector with 2.54mm step
C3-4=100nF 100V MKT Polyester	JP1-2=2pin Jumper with 2.54mm step

Power Supply

Power_supply2.gif (8388 bytes)

Parts List for Power supply
TR1=230Vac//2X22Vac	80VA for single Amplifier	C1=22nF 630V Polyester MKT	C8-9=10.000uF 63V For dual Amplifier*
TR1=230Vac//2X22Vac	150VA for dual Amplifier	C2....5=22nF 100V Polyester MKT	C10-11=1uF 63V Polyester MKT
BR1=Diode Bridge >15A		C6-7=10.000uF 63V For single Amplifier	F1=Fuse 0.5A slow

Sam Electronic Circuits 02/04

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