PLL with VCO and lock detect — what this chip does on your board
The lock detector output is a key feature for servo loops and frequency synthesis: it gives a clean digital flag when the PLL has achieved phase lock, so a microcontroller or supervisory circuit knows the clock is stable before enabling downstream logic. The VCO is internal, so you don't need an external VCO module — just the loop filter components (typically a resistor and capacitor) to set the centre frequency and capture range.
The CD74HCT7046AE is specified for a maximum frequency of 38 MHz. That sets the upper bound on the VCO and phase detector operating range.
Through-hole DIP — prototyping and legacy board repair
The 16-pin PDIP package (0.300" body width, 7.62 mm lead spacing) is the classic breadboard-friendly DIP. It's through-hole mount, so it fits protoboard, stripboard, and socketed production boards.