Overview
The LC72121 and the LC72121M and the LC72121V are high input sensitivity (20 mVrms at 130 MHz) PLL frequency synthesizers for 3 V systems. These ICs are serial data (CCB) compatible with the LC72131, and feature the improved input sensitivity and lower spurious radiation (provided by a redesigned ground system) required in high-performance AM/FM tuners.

Functions
● High-speed programmable divider
    — FMIN: 10 to 160 MHz ... Pulse swallower technique (With built-in divide-by-2 prescaler)
    — AMIN: 2 to 40 MHz ... Pulse swallower technique 0.5 to 10 MHz ... Direct division technique
● IF counter
    — IFIN: 0.4 to 15 MHz ... For AM and FM IF counting
● Reference frequency
    — One of 12 reference frequencies can be selected (using a 4.5 or 7.2 MHz crystal element) 1, 3, 5, 9, 10, 3.125, 6.25, 12.5, 15, 25, 50, and 100 kHz
● Phase comparator
    — Supports dead zone control.
    — Built-in unlocked state detection circuit
    — Built-in deadlock clear circuit
● An MOS transistor for an active low-pass filter is built in.
● I/O ports
    — Output-only ports: 4 pins
    — I/O ports: 2 pins
    — Supports the output of a clock time base signal.
● Operating ranges
    — Supply voltage: 2.7 to 3.6 V
    — Operating temperature: – 40 to 85°C
● Package
    — DIP22S, MFP24S, SSOP24
● Comparison with the LC72131/M
    — Serial data compatible (CCB)
    — Identical pin functions
    — Two VSS pins were added.
    — The DIP version is pin compatible (VSS pins were inserted as the DIP22S NC pins.)
    — The MFP product provides a modified pin assignment (The MFP20 package was replaced by an MFP24 package, and extra VSS pins were added.)
    — The SSOP24 is a newly developed package that has the same pin assignment as the MFP24S product.