This part is a kind of semiconductor called AZC099-04S.

Function of this product has Low Capacitance ESD Protection Array.

Manufacturers : Amazing Micro

Image and pinout :

Some of the text within the PDF file :

AZC099-04S Low Capacitance ESD Protection Array For High Speed Data Interfaces Features ESD Protect for 4 high-speed I/O channels Provide ESD protection for each channel to IEC 61000-4-2 (ESD) ±15kV (air), ±8kV (contact) IEC 61000-4-4 (EFT) (5/50ns) Level-3, 20A for I/O, 40A for Power IEC 61000-4-5 (Lightning) 4A (8/20µs) AZC099-04S may be used to meet the ESD immunity requirements of IEC 61000-4-2, Level 4 (± 15kV air, ±8kV contact discharge). One AZC099-04S can be used to replace 4 BAV99 devices in a 5V application or a lower than 5V application. For low operating voltage applications: 5V, 4.2V, 3.3V, 2.5V Low capacitance : 1.0pF typical Fast turn-on and Low clamping voltage Array of surge rated diodes with internal equivalent TVS diode Small package saves board space Solid-state [ ... ]

AZC099-04S PDF Datasheet Download