A low power sine wave generator can be derived by driving a square wave into the bandpass filter. A complete schematic is shown in Figure 4a. The LTC6992-1 easily configures as a 50% duty cycle 10kHz square wave, and can drive the relatively benign loading seen in the bandpass filter.
Figures 4b and 4c show the LTC6992-1 output and bandpass filter output. THD of the sine wave is –30.5 dBc. Note, even harmonics that appear in the distortion products of the filtered output already appear in the source square wave.
The LTC®6258/LTC6259/LTC6260 are single/dual/quad operational amplifiers with low noise, low power, low supply voltage, and rail-to-rail inputs and outputs. They are unity gain stable with or without capacitive loads. They feature 1.3MHz gain-bandwidth product, 0.24V/μs slew rate while consuming only 20μA of supply current per amplifier operating on supply voltages ranging from 1.8V to 5.25V. The combination of low supply current, low supply voltage, high gain bandwidth product and low noise makes the LTC6258 family unique among rail-to-rail input/output op amps with similar supply current. These operational amplifiers are ideal for power efficient applications.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.