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LC5121 PLL Frequency Synthesizer


This 27 MHz band, PLL frequency synthesizer LSI chip is designed specifically for CB transceivers. The LC7185-8750 incorporates PLL circuitry and a controller for CB applications on a single CMOS chip. The controller handles the PLL circuitry, frequency data ROM, channel preset/recall RAM, and LED display driver. It also supports channel preset/recall, and emergency channel call.
This PLL-circuit use a ROM programmable divide-by-N counter. The ROM-table is programmed from factory.

1SADisplay Segment A
2SBDisplay Segment B
3SCDisplay Segment C
4SDDisplay Segment D
5SEDisplay Segment E
6SFDisplay Segment F
7SGDisplay Segment G
9XOX-tal Output
10XIX-tal Input
12F inVCO Frequency Input
13VccPositive Voltage Supply
14AOLoop filter Amplifier Output
15AILoop filter Amplifier Input
16DOPhase Detector Output
17LDLoop Detected
18T/RTransmit / Receive
19EMGChannel 9
20U/DProgram UP / Program DOWN
22DIDisplay Segment Select output

Explanation of pin function terms

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