The 3pad package is new. The 3rd pad can be connected to ground. This package grounding has the big advantage of EMI reduction and the amelioration of the crystal fixation on the board – 33% more soldering connection than the common 2pad package. The electrical parameters do not change. The switch from the common 2pad to the new 3pad package can be handled without extensive tests.
A frequency tolerance of +-5ppm at 25°C and a frequency stability +-3ppm over -10°C to +55°C are possible. Standard frequency tolerances starts from +-10 ppm. The layout of the SMD crystal HC-49/US-SMD is the same as that of the competition. This compatibility makes the HC-49/US-SMD a direct drop in replacement. The SMD crystal HC-49/US-SMD can be used for all applications where a miniaturised low cost and high performance crystal clock generator is required.
The HC-49/US-SMD crystals are lead free and are RoHS compliant to the EU directive 2002/95/EG. The soldering can be effected according to JEDEC Norm J-STD-020C.