4

4655C–CORD–03/06

U4083B

3.3

Pin 4: Amplifier Input V

There are two identical operational amplifiers. Amplifier 1 has an open-loop gain

≥ 80 dB at

100Hz (Figure 8-2 on page 7), whereas the closed-loop gain is set by external resistors, R

R

approximately 1.5 MHz. A closed-loop gain of 46 dB is recommended for a frequency range of

300Hz to 3400Hz (voice band). Amplifier 2 is internally set to a gain of –1.0 dB (0 dB). The out-

puts of both amplifiers are capable of sourcing and sinking a peak current of 200 mA. Output

voltage swing is between 0.4V and V

Figure 8-19 on page 13).

The output DC offset voltage between Pins 5 and 8 (V

back resistor, R

Bias current of Amplifier 1 which is constant with respect to V

through R

amount.

The output offset voltage specified in the electrical characteristics is measured with the feedback

resistor (R

account the bias current as well as internal offset voltages of the amplifiers.

3.4

Pin 6: Supply and Power Dissipation

Power dissipation is shown in Figure 8-8 on page 9 to Figure 8-10 on page 10 for different loads.

Distortion characteristics are given in Figure 8-11 on page 10 to Figure 8-13 on page 11.

where

T

T

R

Power dissipated within the IC in a given application is found from the following equation:

P

I

I

The IC's operating range is defined by a peak operating load current of ±200 mA (Figure 8-8 on

page 9 to Figure 8-13 on page 11). It is further specified with respect to different loads (see Fig-

ure 8-14 on page 12). The left (ascending) portion of each of the three curves is defined by the

power level at which 10% distortion occurs. The center flat portion of each curve is defined by

the maximum output current capability of the integrated circuit. The right (descending) portion of

each curve is defined by the maximum internal power dissipation of the IC at 25°C. At higher

ambient temperatures, the maximum load power must be reduced according to the above men-

tioned equation.

P

totmax

T

jmax

T

amb

–

R

thJA

---------------------------------

=