The design of the Air 2's Touch ID sensor cable closely resembles that of the new generation of iPhones.

With the home button removed, we discover a single IC on the home button assembly:

NXP Semiconductors 8416A1 Touch ID Sensor

Further inspection reveals even more ICs on the front panel assembly:

Parade Technologies DP675 LCD Driver

Texas Instruments TPS65143A LCD Bias Solution For LCD Panels