Clock Gen 4 Click is a compact add-on board that contains both a clock generator and a multiplier/jitter reduced clock frequency synthesizer. This board features the CS2200-CP, an analog PLL architecture comprised of a Delta-Sigma fractional-N frequency synthesizer from Cirrus Logic. This clocking device utilizes a programmable phase lock loop and allows frequency synthesis and clock generation from a stable reference clock. It generates a low-jitter PLL clock from an external crystal, supports both I²C and SPI for full software control, and also has configurable auxiliary clock output. This Click board™ is suitable for MCU clock source, or in applications like digital effects processors, digital mixing consoles, and many more.

Clock Gen 4 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

Clock Gen 4 Click is based on the CS2200-CP, an analog PLL architecture comprised of a Delta-Sigma fractional-N frequency synthesizer from Cirrus Logic. The Delta-Sigma fractional-N frequency synthesizer has a very high resolution for Input/Output clock ratios, low phase noise, a wide range of output frequencies, and the ability to quickly tune to a new frequency. This synthesizer multiplies the timing reference clock by the value of N to generate a stable and low-jitter PLL clock available on the connector labeled as PLL Clock. This Click board™ also has another connector marked as AUX Clock that outputs a buffered version of one of the input/output clocks, or a status signal, depending on register configuration.

The analog PLL based frequency synthesizer uses a low-jitter timing reference clock as time and phase reference for the internal voltage controlled oscillator (VCO). The phase comparator compares the fractional-N divided clock with the original timing reference and generates a control signal that is filtered by the internal loop filter to generate the VCO’s control voltage that sets its output frequency. The Delta-Sigma modulator modulates the loop integer divide ratio to get the desired fractional ratio between the reference clock and the VCO output. This allows fast lock times for a wide range of output frequencies without the need for external filter components.

Clock Gen 4 Click provides the possibility of using both I2C and SPI interfaces with a maximum frequency of 100 kHz for I2C and 6 MHz for SPI communication. The selection can be performed by positioning SMD jumpers labeled as COMM SEL to an appropriate position. Note that all the jumpers must be placed to the same side, or else the Click board™ may become unresponsive. While the I2C interface is selected, the CS2200-CP allows the choice of the least significant bit (LSB) of its I2C peripheral address. This can be done by using the SMD jumper labeled as ADDR SEL.

This Click board™ is designed to be operated only with a 3.3V logic voltage level. A proper logic voltage level conversion should be performed before the Click board™ is used with MCUs with different logic levels. However, the Click board™ comes equipped with a library that contains easy to use functions and an example code that can be used as a reference for further development.

• Interface: I²C, SPI
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V
• Supply Voltage: Min. 3.1V, Typ. 3.3V, Max. 3.5V
• PLL Clock Output Frequency: Min. 6MHz, Max. 75MHz
• Output Frequency Synthesis Resolution: Min. 0ppm, Max. ±0.5ppm
• Operating Temperature Range: Min. -10°C, Max. +70°C

• Schematic
• CS2200-CP Datasheet
• mikroSDK
• GitHub