RC4157M Ver la hoja de datos (PDF) - Fairchild Semiconductor

Número de pieza

componentes Descripción

Fabricante

RC4157M

High Performance Quad Operational Amplifiers

Fairchild Semiconductor 

PRODUCT SPECIFICATION

RC4156/RC4157

R5

100K

V1 R3*

VN

R8*

R4

10K

2

4156/57 1

3A

C1

1000 pF

R1**

6

4156/57 7

5B

C2

1000 pF

R2** 9

4156/57 8

10 C

R6

R7*

100K

VHP

Highpass

Ouput

V BP

Bandpass

Output

VLP

Lowpass

Output

* Input connections are chosen for inverting or non-inverting response. Values of

R3,R7,R8 determine gain and Q.

** Values of R1 and R2 determine natural frequency.

65-0751

Figure 15. 2-Pole State-Variable Active Filter

characteristics. The values shown for C1, C2, R4, R5 and R6

are arbitrary. Pre-selecting their values will simplify the filter

tuning procedures, but other values can be used if necessary.

The generalized transfer function for the state-variable active

filter is:

T(s) = a---2---s---2---+-----a---1---s----+-----a---0

s2 + b1s + b0

Filter response is conventionally described in terms of a nat-

ural frequency ω0 in radians/sec, and Q, the quality of the

complex pole pair. The filter parameters ω0 and Q relate to

the coefficients in T(s) as:

ω0 =

b0

and

Q

=

ω-----0-

b0

The input configuration determines the polarity (inverting or

non-inverting), and the output selection determines the type

of filter response (lowpass, bandpass, or highpass).

Notch and all-pass configurations can be implemented by

adding another summing amplifier.

Bandpass filters are of particular importance in audio and

telecommunication equipment. A design approach to band-

pass filters will be shown as an example of the state-variable

configuration.

Design Example Bandpass Filter

For the bandpass active filter (Figure 16) the input signal is

applied through R3 to the inverting input of the summing

amplifier and the output is taken from the first integrator

(VBP). The summing amplifier will maintain equal voltage at

the inverting and non-inverting inputs (see Equation 1).

----R----3---R-----5----

----R----3---R-----4----

----R----4---R-----5----

--------R----3----+-----R-----5--------

R4 + ----R----3---R-----5----

VHP

(

s

)

+

--------R----3----+-----R-----4--------

R5 + ----R----3---R-----4----

VLP

(

s

)

+

--------R----4----+-----R-----5--------

R3 + ----R----4---R-----5----

VIN(

s

)

+

-------R-----7--------

R6 + R7

VB

P(

s

)

R3 + R5

R3 + R4

R4 + R5

Equation 1.

8

REV. 1.0.1 6/13/01

Share Link: