The ON Semiconductor LC72137 is a high-performance PLL (Phase Locked Loop) frequency synthesizer designed for use in digital tuning systems. This integrated circuit (IC) is specifically engineered to meet the rigorous demands of modern communication equipment, including car radios, hi-fi tuners, and communication receivers that require precise and stable frequency control.

The LC72137 operates at a voltage ranging from 4.5V to 5.5V, making it suitable for a wide variety of applications. It is capable of handling frequencies up to 130MHz with a reference frequency of 25kHz. This allows for fine-tuning and accurate frequency synthesis, which is essential for high-quality audio and signal reception.

One of the key features of the LC72137 is its built-in programmable divider, which can divide by any number from 1,024 to 65,025. This flexibility enables the IC to be used in a broad range of frequency generation tasks. Additionally, the LC72137 includes a built-in programmable reference divider, which can be set from 1 to 8191, further enhancing its versatility.

The IC also boasts a serial data input, allowing for easy control via a microcontroller. This serial interface is compatible with most common communication protocols, simplifying the integration of the LC72137 into existing designs. Furthermore, the IC features a phase comparator and charge pump circuit, which are critical for maintaining lock in the PLL and ensuring stable frequency output.

ON Semiconductor has equipped the LC72137 with a power-down function, which helps to conserve energy when the IC is not in active use. This feature is particularly beneficial for battery-operated devices where power efficiency is paramount.

In summary, the ON Semiconductor LC72137 PLL Frequency Synthesizer is a versatile, high-performance IC suitable for a wide range of digital tuning applications. Its precision, programmability, and power efficiency make it an ideal choice for designers looking to create sophisticated and reliable communication systems.