11

TP2311/TP2312 / TP2314

10MHz Bandwidth, Low Noise Precision Op-amps

www.3peakic.com.cn

Rev. A04

Figure 3. TP2311 EMIRR IN+ vs Frequency

ACTIVE FILTER

The TP2311 is well-suited for active filter applications that require a wide bandwidth, fast slew rate, low-noise,

single-supply operational amplifier. Figure 4 shows a 20-kHz, second-order, low-pass filter using the multiplefeedback

(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 that require predictable gain

characteristics, such as the anti-aliasing filter used in front of an ADC.

One point to observe when considering the MFB filter is that the output is inverted, relative to the input. If this inversion

is not required, or not desired, a noninverting output can be achieved through one of these options:

1. adding an inverting amplifier;

2. adding an additional second-order MFB stage;

½

TP2311

3000pF

22k

Ω

22k

Ω

2.7k

Ω

10k

Ω

100pF

2000pF

20

p

f

kHz



Figure 4. TP2311 Configured as a Three-Pole, 20-kHz, Sallen-Key Filter

PCB Surface Leakage

0

10

20

30

40

50

60

70

80

90

100

40

400

4000

Frequency (MHz)