We have some really neat PLL experimenter packages, each contains the PLL chip, reference crystal, PIC microcontroller (preprogrammed to operate the PLL chip) and small on-board components. These are not "complete" in that you have to provide your own oscillator circuit. We have made it easy to experiment with different oscillators, rf amplifiers and such in the on-board prototyping area. We also provide numerous schematics with component values to assist in designing your own oscillator using either discrete transistors and components, ICs or VCOs from Mini-Circuits. These are kits you have to assemble, but the design is straightforward allowing you to concentrate on your project rather than fighting the PLL part of the design. To build a low-power fm transmitter for instance, add an oscillator, rf amp stage and audio source. For an RF Signal Generator, add the oscillator, a single stage RF amp and a cable rather than an antenna. Tuning is easy, the onboard keypad area is used like dialing a phone number. Fine tuning is available in 10KHz steps or smaller, depending on the kit you choose.
PLL-EXP1 $34.95This one uses the MC145170 PLL chip and will operate from 400 KHz up to a maximum of around 185 MHz, depending on your oscillator. Step size is 10KHz, tuning is just like dialing a phone number. You enter a 5 digit number on the keypad (* and # keys are for fine tuning up and down) which becomes your frequency. For instance, 1-2-3-0-5 would tune to 123.05 MHz or 123,050 KHz. 0-9-3-3-0 would take you to 93.3 MHz and so on. Leading zeroes must be entered. The onboard microcontroller wakes up, scans the keypad, sets up the PLL chip and goes back to sleep whenever a key is pressed. A status LED lets you know whether you need to enter another digit or if the microcontroller is asleep.
Holes are provided near the prototyping area to connect a modulation signal as well as the two connections between the VCO and the MC145170. Also provided are holes for easy jumpering of both a regulated +5VDC (switched) and the unregulated battery or supply voltage. The prototype area has "bussed" rows of holes, using small traces that are easily cut and removed from between pads where a connection needs to be broken. We have found this approach much easier to use than the traditional "pad per hole" scheme that requires adding jumpers. Overall board size is approximately 2" x 5" and includes both the keypad area and the prototyping area.
PLL-EXP1-1K $34.95this is just like the PLL-EXP-1 above except tuning is in 1K increments and maximum frequency is 65.536MHz - due to the size of the N Register in the MC145170.
PLL-VFO $119.95This one is a serious amateur radio project waiting to happen. It consists of a two-board set and has all the features you want or need for use at or below 185 MHz. The top board contains an LCD to display tuned frequency and mode (tranmsit or recieve), a keypad and an eeprom memory to store not only the last-tuned frequency but also a user selected offset (for superhet receivers)above or below the tuned frequency. The LED lock indicator tells you at a glance if the circuit is locked or not. The bottom board contains the MC145170 PLL chip, an area for a Colpitts oscillator or an optional VCO using HC4046 or CD4046, and a generous prototyping area. Fine tuning is in 1K steps to 65MHz, over 65MHz to 185MHz tuning is in 5K steps. Includes an MV104 varactor diode and a selection of toroids and shielded inductor. This one is at home in a superhet receiver design or an AM or FM transmitter.
These files are all in the Adobe Acrobat (.pdf) format. While you do not need these to use our PLL-EXP1 or PLL-EXP2 platforms, the App Notes files will be useful if you want to experiment with designing your own loop filters. Download the data sheets to learn more about MC145170 or the obsolete devices MC145191 and MC145193. These are all copies originally downloaded from Motorola's website, placed here for your convenience.
AN-535 PLL Design Fundamentals