company blog about [Supplied by Renesas] 8T49N240-991NLGI FemtoClock® NG Ultra High performance jitter attenuator

Mingjiada Electronics 【Supply Renesas】8T49N240-991NLGI FemtoClock® NG Ultra High Performance Jitter attenuator!

Product Description:

The 8T49N240-991NLGI is a fractional feedback single-channel jitter attenuator with a frequency conversion function. It is equipped with three integer and one decimal output divider, allowing up to four different output frequencies to be produced, ranging from 8kHz to 867MHz. These frequencies are completely independent of the input reference frequency and the crystal reference frequency. The output can be selected from LVPECL, LVDS, HCSL or LVCMOS output levels.

The 8T49N240 accepts up to two differential or single-ended input clocks and one fundamental mode crystal oscillator input. The internal PLL can lock either the input reference clock or just the crystal oscillator to act as a frequency synthesizer. The PLL can use the second input as a redundant backup of the primary input reference, but in this case the frequencies of the two input clock references must be integer dependent.

The device supports uninterrupted reference switching between input clocks. The device monitors signal loss (LOS) for both input clocks and generates an alarm when an input clock failure is detected. Supports automatic and manual uninterrupted reference switching options. The LOS behavior can be set to support gapped or gapped clocks.

The 8T49N240 supports hold. An initial accuracy of 50ppB is maintained from the time all available input reference voltage sources are detected to be lost. It maintains the historical average operating point of the PLL, which may be returned with a limited phase slope in hold mode.

Product features:

• Four differential outputs
• Excellent jitter performance:
• Working mode: synthesizer, jitter attenuator
• It works with basic mode crystals from 10MHz to 54MHz
• Initial holding accuracy is +50ppb
• A maximum of two LVPECL, LVDS, LVHSTL, or LVCMOS input clocks are accepted
• The accepted frequency range is 8kHz to 875MHz
• Automatic and manual clock selection, uninterrupted switching
• Clock input monitoring, including support for gap timing
• Three outputs generate an LVPECL/LVDS/HCSL clock, and one output generates an LVPECL/LVDS/HCSL/LVCMOS clock
• Output frequency range from 8kHz to 867MHz (differential)
• Output frequency range from 8kHz to 250MHz (LVCMOS)
• Three integer frequency dividers with fixed frequency dividers
• A decimal output divider
• Leak break pin
• Phase slope limit and full uninterrupted switching option to control output clock phase transients
• Programmable loop bandwidth Settings range from 0.2Hz to 6.4kHz
• Optional quick lock feature
• Four universal I/O pins with optional status and control support:
• Two outputs enable control inputs to control four clocks
• Manual clock selection control input
• Lock, hold and signal loss alarm output
• Registers can be programmed via I2C or external I2C EEPROM
• All models support 2.5V or 3.3V power mode, and some models support 1.8V
• Ambient operating temperature: -40°C to 85°C
• Package: 6mm x 6mm x 0.9mm 40-VFQFN, lead-free (RoHS 6 compliant)

Applications:

• OTN, including ITU-T G.709 (2009) FEC
• CPRI interface
• Optical fiber
• 40G/100G Ethernet
• Gb Ethernet, Terabit IP switch/router