OP176

REV. 0

–8–

APPLICATIONS

Short Circuit Protection

The OP176 has been designed with output short circuit

protection. The typical output drive current is

±50 mA. This

high output current and wide output swing combine to yield an

excellent audio amplifier, even when driving large signals, at low

power and in a small package.

Total Harmonic Distortion

Total Harmonic Distortion + Noise (THD + N) of the OP176

is well below 0.001% with any load down to 600

Ω. However,

this is dependent upon the peak output swing. In Figure 23 it is

seen that the THD + Noise with 3 V rms output is below

0.001%. In the following Figure 24, THD + Noise is below

0.001% for the 10 k

Ω and 2 kΩ loads but increases to above

0.01% for the 600

Ω load condition. This is a result of the

output swing capability of the OP176. Notice the results in

Figure 25, showing THD vs. V

FIGURE 23. THD + Noise vs. Frequency

0.1

0.010

0.001

0.0001

20

100

1k

10k

20k

2k

Ω

10k

Ω

Figure 24. THD + Noise vs. R

LOAD

Figure 25. THD + Noise vs. Output Amplitude (V rms)

The output of the OP176 is designed to maintain low harmonic

distortion while driving 600

Ω loads. However, driving 600 Ω

loads with very high output swings results in higher distortion if

clipping occurs.

To attain low harmonic distortion with large output swings,

supply voltages may be increased. Figure 26 shows the perfor-

mance of the OP176 driving 600

Ω loads with supply voltages

varying from

±18 volts to ±20 volts. Notice that with ±18 volt

supplies the distortion is fairly high, while with

±20 volt supplies

it is a very low 0.0007%.

0.1

0.010

0.001

0.0001

20

100

1k

10k

20k

Figure 26. THD + Noise vs. Supply Voltage

0.1

0.010

0.001

.0001

20

100

1k

10k

20k

0.1

0.010

0.001

.0001

20

100

1k

10k

20k