The CDCE937 and CDCEL937 devices are modular PLL-based, low-cost, high-performance, programmable clock synthesizers, multipliers, and dividers. The devices generate up to seven output clocks from a single input frequency. Each output can be programmed in-system for any clock frequency up to 230 MHz, using one of the three integrated configurable PLLs. The CDCx937 has separate output supply pins, VDDOUT, which is 1.8 V for CDCEL937 and 2.5 V to 3.3 V for CDCE937.

The input accepts an external crystal or LVCMOS clock signal. If an external crystal is used, an on-chip load capacitor is adequate for most applications. The value of the load capacitor is programmable from 0 to 20 pF.

Additionally, a selectable on-chip VCXO allows synchronization of the output frequency to an external control signal, that is, the PWM signal.

The deep M/N divider ratio allows the generation of 0 ppm audio/video, networking (WLAN, BlueTooth, Ethernet, GPS) or Interface (USB, IEEE1394, Memory Stick) clocks from a reference input frequency such as 27 MHz.

All PLLs supports SSC (Spread-Spectrum Clocking). SSC can be Center-Spread or Down-Spread clocking which is a common technique to reduce electro-magnetic interference (EMI).

Based on the PLL frequency and the divider settings, the internal loop filter components are automatically adjusted to achieve high stability and optimized jitter transfer characteristic of each PLL.

The device supports non-volatile EEPROM programming for ease-customized application. The device is preset to a factory default configuration (see Default Device Setting). The device can be reprogrammed to a different application configuration before PCB assembly, or reprogrammed by in-system programming. All device settings are programmable through SDA/SCL bus, a 2-wire serial interface.

Three programmable control inputs, S0, S1 and S2, can be used to control various aspects of operation including frequency selection changing the SSC parameters to lower EMI, PLL bypass, power down, and choosing between low level or 3-state for output-disable function.

The CDCx937 operates in a 1.8-V environment. The CDCx937 is characterized for operation from –40°C to 85°C.