CX25836/7 is a video decoder family of ICs from Conexant.
CX2583x chips are supported by the Linux kernel using the cx25840 driver.
The only difference between the chips is that the CX25837 comes in two different packages and has a version that is pin compatible with the CX25840/1/2/3 chips.
Analog video inputs
Analog audio inputs
The CX2583x ICs lack Audio decoding capabilities.
Note: the CX2583x chips do have an AUX_PLL which can be output from the chip as an audio clock.