RENESAS 8T49N240-030NLGI8

The 8T49N240 is a single-channel jitter attenuator with frequency translation using fractional feedback. It features three integer dividers and one fractional divider, enabling generation of up to four distinct output frequencies ranging from 8kHz to 867MHz. These frequencies are fully independent of the input reference frequency and crystal reference frequency. Output levels are selectable among LVPECL, LVDS, HCSL, and LVCMOS.

The 8T49N240 accepts up to two differential or single-ended input clocks and one fundamental-mode crystal input. The internal PLL can lock to either input reference clock or to the crystal alone, functioning as a frequency synthesizer. The PLL can use a second input as a redundant backup for the primary input reference; however, in this case the two input clock references must have an integer frequency relationship.

The device supports hitless reference switching between input clocks. It monitors loss of signal (LOS) on both input clocks and generates an alarm upon detection of an input clock failure. Both automatic and manual hitless reference switching options are supported. LOS behavior is configurable to support gapped or non-gapped clocks.

The 8T49N240 supports holdover state. Upon detection of loss of all applicable input references, holdover is entered with an initial accuracy of ±50ppb. It maintains the historical average operating point of the PLL, which can be restored during holdover with a limited phase slope.

The PLL features register-selectable loop bandwidth ranging from 0.2Hz to 6.4kHz.

The device supports output enable and clock select inputs, as well as lock, holdover state, and LOS status outputs.

The device is programmable via I2C interface. It also supports I2C master functionality, allowing register configuration to be read from an external EEPROM.

Factory pre-programmed devices using on-chip one-time programmable (OTP) memory are also available.

• OTN, including ITU-T G.709 (2009) FEC CPRI interface
• Fiber optics
• 40G/100G Ethernet, Gb Ethernet, terabit IP switches/routers