Wednesday, October 21, 2009
Voltage gain is 27dB as shown, but this can be changed by using a different value resistor for the feedback path (R4, currently 22k, between pins 2 and 4). The amplifier must not be operated at any gain less than 10 (20dB) as set by R4 and R5, as it will oscillate. In some cases, an inductor may be needed in series with the output to prevent instability with capacitive loads (10 turns of 0.5mm wire wound around a 10 Ohm 1W resistor). The most common capacitive load is the speaker cable itself, and 'audiophile' leads are often worse than standard grade cables in this respect.
The 1 Ohm resistor (R6) should be a 1W or 0.5W type, and all others should be 1/4W 1% metal film (as I always recommend). All electrolytic capacitors should be rated at 50V if at all possible, and the 100nF (0.1uF) caps for the supplies should be as close as possible to the IC to prevent oscillation. C1 should be a bipolar (non-polarised) electrolytic, or may be plastic film if you prefer.
Parameter IC TDA 2050
Supply Voltage........................................... ±25 V.
Input Voltage............................................... VS.
Differential Input Voltage............................. ±15 V.
Output Peak Current (internally limited)........ 5 A.
Power Dissipation TCASE = 75°C.................. 25 W.
Storage and Junction Temperature............. -40 to 150 °C.
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