OPA210 datasheet(21/44 Pages) TI2

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8.2 Typical Application

OPAx210

Output

590

2.94 k

499

39 nF

1 nF

Figure 8-2. Low-Pass Filter

8.2.1 Design Requirements

Low-pass filters are commonly used in signal processing applications to reduce noise and prevent aliasing. The

OPAx210 are designed to construct high-speed, high-precision active filters. Figure 8-2 shows a second-order,

low-pass filter commonly encountered in signal-processing applications.

Use the following parameters for this design example:

• Gain = 5 V/V (inverting gain)

• Low-pass cutoff frequency = 25 kHz

• Second-order Chebyshev filter response with 3-dB gain peaking in the pass band

8.2.2 Detailed Design Procedure

The infinite-gain, multiple-feedback circuit for a low-pass network function is shown in Figure 8-2. Use Equation

1 to calculate the voltage transfer function.

1 3

1/ R R C C

Output

(s)

Input

(s / C )(1/ R

1/ R

1/ R ) 1/ R R C C

(1)

This circuit produces a signal inversion. For this circuit, the gain at dc and the low-pass cutoff frequency are

calculated by Equation 2:

Gain

(1/ R R C C )

(2)

8.2.3 Application Curve

Figure 8-3. OPAx210 Second-Order, 25-kHz, Chebyshev, Low-Pass Filter

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OPA210, OPA2210

SBOS924H – SEPTEMBER 2018 – REVISED AUGUST 2021

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OPA210 Datasheet(PDF) 21 Page - Texas Instruments