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CDC2509: 3.3-V Phase-Lock Loop Clock Driver (Rev. C)
Texas Instruments

Description
The CDC2509 is a high-performance, low-skew, low-jitter, phase-lock loop (PLL) clock driver. They use a PLL to precisely align, in both frequency and phase, the feedback (FBOUT) output to the clock (CLK) input signal. They are specifically designed for use with synchronous DRAMs. The CDC2509 operates at 3.3-V VCC and provides integrated series-damping resistors that make it ideal for driving point-to-point loads. One bank of five outputs and one bank of four outputs provide nine low-skew, low-jitter copies of CLK. Output signal duty cycles are adjusted to 50 percent, independent of the duty cycle at CLK. Each bank of outputs can be enabled or disabled separately via the control (1G and 2G) inputs. When the G inputs are high, the outputs switch in phase and frequency with CLK; when the G inputs are low, the outputs are disabled to the logic-low state. Unlike many products containing PLLs, the CDC2509 does not require external RC networks. The loop filter for the PLL is included on-chip, minimizing component count, board space, and cost. Because it is based on PLL circuitry, the CDC2509 requires a stabilization time to achieve phase lock of the feedback signal to the reference signal. This stabilization time is required following power up and application of a fixed-frequency, fixed-phase signal at CLK, as well as following any changes to the PLL reference or feedback signals. The PLL can be bypassed for test purposes by strapping AVCC to ground. The CDC2509 is characterized for operation from 0°C to 70°C.
Features
Use CDCVF2509A as a Replacement for this Device Phase-Lock Loop Clock Distribution for Synchronous DRAM Applications Distributes One Clock Input to One Bank of Five and One Bank of Four Outputs Separate Output Enable for Each Output Bank External Feedback (FBIN) Pin Is Used to Synchronize the Outputs to the Clock Input On-Chip Series Damping Resistors No External RC Network Required Operates at 3.3-V VCC Packaged in Plastic 24-Pin Thin Shrink Small-Outline Package

Related Datasheets
Part Number Description Category
•  CDC2509A CDC2509A: 3.3 V Phase Lock Loop Clock Driver (Rev. C) Actives - Transistors and Diodes
•  CDC2509B CDC2509B: 3.3-V Phase-Lock-Loop Clock Driver (Rev. C) Actives - Transistors and Diodes
•  CDC2509C CDC2509C: 3.3-V Phase-Lock Loop Clock Driver (Rev. A) Actives - Transistors and Diodes
•  CDC2516 CDC2516: 3.3-V Phase-Lock Loop Clock Driver (Rev. C) Actives - Transistors and Diodes
•  CDCVF2509A 3.3-V Phase-Lock Look Clock Driver With Power Down Mode (Rev. B) Actives - Transistors and Diodes



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