1 Features

• 2:8 Differential Buffer
• Selectable Clock Inputs Through Control terminal
• Universal Inputs Accept LVPECL, LVDS, and LVCMOS/LVTTL
• Eight LVPECL Outputs
• Maximum Clock Frequency: 2 GHz
• Maximum Core Current Consumption: 73 mA
• Very Low Additive Jitter: <100 fs,rms in 10 kHz to 20 MHz Offset Range:
  • 57 fs, rms (typical) at 122.88 MHz
  • 48 fs, rms (typical) at 156.25 MHz
  • 30 fs, rms (typical) at 312.5 MHz
• 2.375-V to 3.6-V Device Power Supply
• Maximum Propagation Delay: 450 ps
• Maximum Output Skew: 20 ps
• LVPECL Reference Voltage, V_{AC_REF}, Available for Capacitive-Coupled Inputs
• Industrial Temperature Range: –40°C to 85°C
• Supports 105°C PCB Temperature
  (Measured with a Thermal Pad)
• ESD Protection Exceeds 2 kV (HBM)
• Available in 5-mm × 5-mm QFN-28 (RHD) Package

2 Applications

• Wireless Communications
• Telecommunications/Networking
• Medical Imaging
• Test and Measurement Equipment

3 Description

The CDCLVP1208 is a highly versatile, low additive jitter buffer that can generate eight copies of LVPECL clock outputs from one of two selectable LVPECL, LVDS, or LVCMOS inputs for a variety of communication applications. It has a maximum clock frequency up to 2 GHz. The CDCLVP1208 features an on-chip multiplexer (MUX) for selecting one of two inputs that can be easily configured solely through a control terminal. The overall additive jitter performance is less than 0.1 ps, RMS from 10 kHz to 20 MHz, and overall output skew is as low as 20 ps, making the device a perfect choice for use in demanding applications.

The CDCLVP1208 clock buffer distributes one of two selectable clock inputs (IN0, IN1) to eight pairs of differential LVPECL clock outputs (OUT0, OUT7) with minimum skew for clock distribution. The CDCLVP1208 can accept two clock sources into an input multiplexer. The inputs can be LVPECL, LVDS, or LVCMOS/LVTTL.

The CDCLVP1208 is specifically designed for driving 50-Ω transmission lines. When driving the inputs in single-ended mode, the LVPECL bias voltage (V_{AC_REF}) should be applied to the unused negative input terminal. However, for high-speed performance up to 2 GHz, differential mode is strongly recommended.

The CDCLVP1208 is packaged in a small 28-pin,
5-mm x 5-mm QFN package and is characterized for operation from –40°C to 85°C.

1. For all available packages, see the orderable addendum at the end of the datasheet.

Functional Block Diagram

Differential Output
Peak-to-Peak Voltage vs Frequency