Analog Devices Logo in Center Middle.

Label:

5
3
4

8
F

Newer map: https://siliconpr0n.org/map/ad/ad534/mcmaster_mz_mit20x/

Old map: http://siliconpr0n.org/map/ad/ad534/mcmaster_unitron/

Datasheet: http://www.analog.com/static/imported-files/data_sheets/AD534S_die.pdf‎