INTRODUCTION
The MC145220EVK makes it easy to exercise features of the MC145220 and build PLLs which meet individual performance requirements. The EVK is controlled through menu driven software operating on an IBM PC or compatible. Other Motorola PLL EVKs (MC145190, MC145191, MC145192, MC145200, MC145201, MC145202) in up to three–board cascades can use the same program. Frequency defaults that apply to each are automatically selected. All board functions are controlled through the printer port of an IBM PC. Up to three different EVKs may be controlled at the same time from one printer port. The functional block diagram is given in Figure 1.

FEATURES
1. The EVK is a complete working synthesizer, including VCOs.
2. Board is controlled by an IBM PC–compatible computer through the printer port.
3. Up to three boards can be operated independently through one printer port.
4. A prototype area and mounting holes are provided for VCOs, mixers, and amplifiers.
5. External reference input can be used.
6. Five element loop filter is included.
7. Frequency range of operation, step size and reference frequency can be changed in the control program.
8. Lock Detect, Out A, and Out B on any single board are accessible through the printer port.