BUY LM2917N-8 https://www.utsource.net/itm/p/6485495.html
FVC 8-Pin PDIP Rail - Rail/Tube
Description： The LM2917N-8 is a precision frequency-to-voltage converter designed to convert a frequency input into a linear voltage output. Features： Input Frequency Range: 0.1 Hz to 1 MHz Input Voltage Range: 0 to +5 V Output Voltage Range: 0 to +5 V Output Impedance: 10 kΩ Supply Voltage: +5 V Operating Temperature Range: -40°C to +85°C Package: 8-pin DIP Application： The LM2917N-8 is suitable for use in applications such as frequency-to-voltage conversion, frequency-to-current conversion, and frequency-to-resistance conversion. It is also suitable for use in frequency-to-digital conversion, frequency-to-temperature conversion, and frequency-to-pressure conversion. (For reference only)