Input | Output | Supply | |||
---|---|---|---|---|---|
ViMin | ViMax | VoMin | VoMax | Vcc | Vee |
–2.45V | +2.45V | 0.05V | 4.95V | 5V | 0V |
Gain | Cutoff Frequency (fc) | Max Frequency (fmax) | Vref |
---|---|---|---|
1V/V | 1kHz | 10kHz | 2.5V |
Design Description
The Butterworth Sallen-Key (SK) high-pass (HP) filter is a 2nd-order active filter. Vref provides a DC offset to accommodate for single-supply applications.
An SK filter is usually preferred when small Q factor is desired, noise rejection is prioritized, and when a non-inverting gain of the filter stage is required. The Butterworth topology provides a maximally flat gain in the pass band.
Design Notes
Design Steps
The first step is to find component values for the normalized cutoff frequency of 1 radian/second. In the second step the cutoff frequency is scaled to the desired cutoff frequency with scaled component values.
The transfer function for the second-order Sallen-Key high-pass filter is given by:
where,
The TLV9062 device has a GBW of 10MHz and SR of 6.5V/µs, so it meets these requirements.
Design Simulations
AC Simulation Results
Transient Simulation Results
The following image shows the filter output in response to a ± 2.5-V, 10-kHz input signal (gain is 1V / V).
The following image shows the filter output in response to a ± 2.5-V, 10-Hz input signal (gain is 0.014V / V).
Design References
Design Featured Op Amp
TLV9062 | |
---|---|
Vss | 1.8V to 5.5V |
VinCM | Rail-to-Rail |
Vout | Rail-to-Rail |
Vos | 0.3mV |
Iq | 538µA |
Ib | 0.5pA |
UGBW | 10MHz |
SR | 6.5V / µs |
#Channels | 1, 2, 4 |
www.ti.com/product/TLV9062 |
Design Alternate Op Amp
TLV316 | OPA325 | |
---|---|---|
Vss | 1.8V to 5.5V | 2.2V to 5.5V |
VinCM | Rail-to-Rail | Rail-to-Rail |
Vout | Rail-to-Rail | Rail-to-Rail |
Vos | 0.75mV | 0.150mV |
Iq | 400µA | 650µA |
Ib | 10pA | 0.2pA |
UGBW | 10MHz | 10MHz |
SR | 6V / µs | 5V / µs |
#Channels | 1, 2, 4 | 1, 2, 4 |
www.ti.com/product/OPA316 | www.ti.com/product/OPA325 |
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