The ECX-1247B series features small, highly stable SMD crystals within a 1.6 x 1.2 x 0.3 mm 4-pad ceramic package. These crystals are characterized by their low equivalent series resistance (ESR). The ECX-1247B offers low first year ±1 ppm aging and a tight tolerance of ±7 ppm available over the standard industrial temperature range of -40°C ~ +85°C.