Infineon/CYPRESS CY2545C020

The CY2545 and CY2547 have four I²C programmable PLLs available to generate output frequencies ranging from 3 to 166 MHz. The advantage of having four PLLs is that a single device generates up to four independent frequencies from a single crystal. Two sets of frequencies for each PLL can be programmed. This enables in system frequency switching using multifunction frequency select pin, FS. The CY2545 and CY2547 have a serial I²C interface that programs the configuration memory array to synthesize output frequencies by programmable output divider, spread characteristics, drive strength, and crystal load capacitance. I²C can also be used for in system control of these programmable features. The input to the CY2545 and CY2547 is either a crystal or a clock signal. The input frequency range for crystals is 8 MHz to 48 MHz. There is provision for two reference clock inputs, CLKIN and EXCLKIN with frequency range of 8 MHz to 166 MHz. For both devices, when CLKIN signal at pin 21 is used as a reference input, a valid signal at EXCLKIN (as specified in the AC and DC Electrical Specification table), must be present for the devices to operate properly. The CY2545 and CY2547 are designed to operate at internal core supply voltage of 1.8V. In the case of the high voltage part (CY2545), an internal regulator is used to generate 1.8V from the 2.5V/3.0V/3.3V VDD supply voltage at pin 22. For the low voltage part (CY2547), this internal regulator is bypassed and 1.8V at VDD pin 22 is directly used. These devices have eight clock outputs grouped in three output driver banks. The Bank 1, Bank 2, and Bank 3 correspond to (CLK1, CLK2), (CLK3, CLK4, CLK5), and (CLK6, CLK7, CLK8), respectively. Separate power supplies are used for each of these banks and they can be any of 2.5V, 3.0V, or 3.3V for CY2545 and 1.8V for CY2547 giving user multiple choice of output clock voltage levels. These devices have eight clock outputs (CLK1 - 8). There are six available clock sources for these outputs. These clock sources are: XIN/EXCLKIN, CLKIN, PLL1, PLL2, PLL3, or PLL4. Output clock source selection is done using four out of six crossbar switch. Thus, any one of these six available clock sources can be arbitrarily selected for the clock outputs. This gives user a flexibility to have up to four independent clock outputs. Two of the four PLLs (PLL3 and PLL4) have spread spectrum capability for EMI reduction in the system. The device uses a Cypress proprietary PLL and Spread Spectrum Clock (SSC) technology to synthesize and modulate the frequency of the PLL. The spread spectrum feature can be turned on or off using a multifunction control pin (CLK7/SSON). It can be programmed to either center spread range from ±0.125% to ±2.50% or down spread range from -0.25% to -5.0% with Lexmark or Linear profile. The device can store two different PLL frequency configurations, output source selection and output divider values for all eight outputs in its nonvolatile memory location. There is a multifunction programmable pin, CLK3/FS which, if programmed as frequency select input, can be used to select between these two arbitrarily programmed settings. When the frequency select pin (FS) is used to switch frequency, the outputs are glitch-free provided frequency is switched using output dividers.

• Four fully integrated phase locked loops (PLLs)
• Input frequency range: External crystal: 8 to 48 MHz; External reference: 8 to 166 MHz clock
• Wide operating output frequency range: 3 to 166 MHz
• Serial programmable over 2-wire I²C interface
• Programmable spread spectrum with center and down spread option and Lexmark and Linear modulation profiles
• VDD supply voltage options: 2.5V, 3.0V, and 3.3V for CY2545; 1.8V for CY2547
• Selectable output clock voltages independent of VDD supply: 2.5V, 3.0V, and 3.3V for CY2545; 1.8V for CY2547
• Power down, output enable, or frequency select features
• Low jitter, high accuracy outputs
• Ability to synthesize nonstandard frequencies with Fractional-N capability
• Up to eight clock outputs with programmable drive strength
• Glitch-free outputs while frequency switching
• 24-pin QFN package
• Commercial and industrial temperature ranges

• PC
• consumer
• portable
• networking