V

OUT

RP = 10kΩ

500µA

TLV365

V

IN

V+ = +5V

Op Amps

Negative

Supply

Grounded

−V = −5V

(Additional

Negative Supply)

Figure 7-6. Swing-to-Ground

Output Voltage (V)

-3 -2.5 -2 -1.5 -1 -0.5

0

0.5

1

1.5

2

2.5

3

−20m

−15m

−10m

−5m

0

5m

10m

15m

20m

VS = ±2.75 V

Figure 7-7. Offset Voltage vs Output Swing

7.3.5 Active Filtering

The TLVx365 is well-suited for active filter applications requiring a wide bandwidth, fast slew rate, low-noise,

single-supply operational amplifier. Figure 7-8 shows a 500-kHz, second-order, low-pass filter utilizing the

multiple-feedback (MFB) topology. The components have been selected to provide a maximally-flat Butterworth

response. Beyond the cutoff frequency, roll-off is −40 dB/dec. The Butterworth response is ideal for applications

requiring predictable gain characteristics such as the anti-aliasing filter used ahead of an ADC.

C

1

1nF

C

2

150pF

R

3

549Ω

R

1

549Ω

R

2

1.24kΩ

V+

V

OUT

V

IN

V−

TLV365

Figure 7-8. Second-Order Butterworth, 500-kHz Low-Pass Filter

When considering the MFB filter , the output is inverted, relative to the input. If this inversion is not desired, then

a noninverting output can be achieved through one of these options:

• adding an inverting amplifier;

• adding an additional second-order MFB stage; or

• using a noninverting filter topology such as the Sallen-Key.

Figure 7-9 shows the Sallen-Key topology.

V

OUT

V

IN = 1VRMS

TLV365

R

3

150kΩ

R

2

19.5kΩ

C

3

220pF

R

1

1.8kΩ

C

1

3.3nF

C

2

47pF

Figure 7-9. Configured as a Three-Pole, 20-kHz, Sallen-Key Filter

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TLV365

SBOSAA8 – DECEMBER 2022

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