Overview
The CDCE949PWRG4, produced by Texas Instruments, is a programmable 4-PLL VCXO clock synthesizer. This device is part of the CDCEx949 family, which includes high-performance, low-cost clock generators. The CDCE949 is capable of generating up to nine output clocks from a single input frequency, utilizing up to four independent configurable PLLs. It supports in-system programmability and features nonvolatile EEPROM to store customer settings. The device is designed to operate in a wide temperature range of –40°C to 85°C and is packaged in a TSSOP (Thin Shrink Small Outline Package).
Key Specifications
| Parameter | Description |
|---|---|
| PLLs | 4 independent configurable PLLs |
| Output Clocks | Up to 9 output clocks |
| Output Frequency | Free selectable up to 230MHz |
| Input Clock | External crystal (8MHz to 32MHz) or LVCMOS clock signal |
| Output Supply Voltage | 2.5V or 3.3V (CDCE949), 1.8V (CDCEL949) |
| Temperature Range | –40°C to 85°C |
| Package | TSSOP (24 pins) |
| Jitter | Low period jitter: 60ps (typical) |
| VCXO Pull-Range | ±150ppm |
| EEPROM | Nonvolatile EEPROM for storing customer settings |
Key Features
- In-system programmability and nonvolatile EEPROM to store customer settings.
- Flexible input clocking concept with external crystal or LVCMOS clock signal.
- On-chip VCXO for synchronization with an external control signal.
- Low-noise PLL core with integrated PLL loop filter components.
- Low period jitter of 60ps (typical).
- Separate output supply pins for 2.5V, 3.3V, or 1.8V operation.
- Three user-definable control inputs (S0, S1, S2) for various control functions.
- Programmable SSC (Spread-Spectrum Clocking) for EMI reduction.
- Support for generating highly accurate clocks for various applications such as video, audio, USB, IEEE1394, RFID, Bluetooth, WLAN, Ethernet, and GPS.
Applications
- Video and audio systems requiring precise clock frequencies.
- USB, IEEE1394, and other interface applications.
- Networking technologies such as WLAN, Bluetooth, Ethernet, and GPS.
- TI-DaVinci™, OMAP™, and DSPs requiring common clock frequencies.
- RFID and other wireless communication systems.
Q & A
- What is the CDCE949PWRG4?
The CDCE949PWRG4 is a programmable 4-PLL VCXO clock synthesizer produced by Texas Instruments.
- How many output clocks can the CDCE949 generate?
The CDCE949 can generate up to nine output clocks from a single input frequency.
- What is the range of the output frequency?
The output frequency can be programmed up to 230MHz.
- What types of input clocks does the CDCE949 support?
The device supports external crystal (8MHz to 32MHz) or LVCMOS clock signals.
- What is the temperature range of the CDCE949?
The device operates within a temperature range of –40°C to 85°C.
- What is the purpose of the on-chip VCXO?
The on-chip VCXO allows synchronization of the output frequency to an external control signal, such as a PWM signal.
- How does the CDCE949 reduce EMI?
The device supports programmable SSC (Spread-Spectrum Clocking) which can be Center-Spread or Down-Spread clocking to reduce EMI.
- What is the role of the EEPROM in the CDCE949?
The nonvolatile EEPROM stores customer settings and allows for in-system programming.
- What are the user-definable control inputs used for?
The three user-definable control inputs (S0, S1, S2) can be used for frequency selection, SSC parameter adjustment, PLL bypass, power down, and output-disable function control.
- What development tools are available for the CDCE949?
Development tools include the CDCE949 Performance Evaluation Module, EEPROM Programming Board, and TI's ClockPro software.
