Single-ended oscillators vs Differential outputs

Single-ended oscillators

Single-ended oscillators are easier to implement but have more sensitivity to noise and are typically a better fit only up to several hundred megahertz. Among the single-ended output types are:

TTL (transistor-to-transistor logic): 0.4 to 2.4 volts (rarely used now)

CMOS (complementary metal oxide semiconductor): 0.5 to 4.5 volts

HCMOS (high-speed CMOS):              0.5 to 4.5 volts

LVCMOS (low-voltage CMOS):            0.5 to 4.5 volts

Differential outputs

Differential outputs are more difficult to design but provide better performance in high-frequency applications, as any noise common to the differential traces cancels out. This helps maintain oscillator performance as seen by the load circuit. Differential signal types are:

PECL (positive emitter coupled logic):            3.3 to 4.0 volts

LVPECL (low-voltage PECL);                            1.7 to 2.4 volts

CML (current-mode logic):                             0.4 to 1.2 volts and 2.6 to 3.3 volts

LVDS (low-voltage differential signaling):       1.0 to 1.4 volts

HCSL (high-speed current-steering logic):      0.0 to 0.75 volts