VFC32KUE4 is a Volt to Frequency and Frequency to Volt by Texas Instruments, in 14-SOIC (0.154, 3.90mm Width) package, rated for 0°C to +70°C. This part is discontinued. FPGACenter specializes in sourcing obsolete components.
XR4151CP-F is a Voltage to Frequency by MaxLinear in 8-DIP (0.300", 7.62mm) package. This part is discontinued. FPGACenter specializes in sourcing obsolete components.