The -15AZ is screened for automotive use.
16MHz
2.7 - 5.5V
ATmega328P- 15AZ
Package MA
Automotive (-40°C to 125°C)
MA Package:
32 - Lead, 7x7 mm Body Size, 1.0 mm Body Thickness 0.5 mm Lead Pitch, Thin Profile Plastic Quad Flat Package (TQFP)
So it is smaller than the AU package that I suspect is used on the SMD Uno:
32A
32-lead, 7 x 7mm body size, 1.0mm body thickness,
0.8mm lead pitch, thin profile plastic quad flat package (TQFP)