Tri p ath Techn o l o g y, I n c. - T echn i cal I n fo rmation

9

TCA2002 – KLi/0.95/04.06

A m plifier Gain

The gain of an amplifier based on the TCA2002 is the product of the input stage gain and the

modulator gain. Please refer to the sections, Input Stage Design, and Modulator Feedback Design,

for a complete explanation of how to determine the external component values for the various

amplifier configurations.

MODULATOR

V

E

VINPUTSTAG

VTK2150

A

*

A

A

=

For example, using a TCA2002 with the following external components, in a Single Ended, Split

Supply Application

V

V

13.35

-

1

1.1k Ω

*

1.0k Ω

)

1.1k

(1.0k Ω

*

10.0k Ω

30.1k Ω

20k Ω

=













+

Ω

+

−

≈

In p u t Stage Desig n

The TCA2002 input stage is configured as an inverting amplifier, allowing the system designer

flexibility in setting the input stage gain and frequency response. Figure 2 shows a typical application

where the input stage is a constant gain inverting amplifier. The input stage gain should be set so

that the maximum input signal level will drive the input stage output to 4Vpp.

TCA2002

INPUT2

OAOUT2

V5

OAOUT1

+

-

CI

+

-

INV1

INPUT1

BIASCAP

AGND

RF

RI

CI

RF

AGND

INV2

V5

RI

Figure 2: Input Stage

The gain of the input stage, above the low frequency high pass filter point, is that of a simple inverting

amplifier: It should be noted that the input amplifiers are biased at approximately 2.5VDC. Thus, the

I

F

STAGE

INPUT

V

R

R

A

−

=