General Description

The SY89464U is a low jitter 1:10 LVPECL fanout buffer with a 2:1 differential input multiplexer (MUX) optimized for redundant source switchover applications. Unlike standard multiplexers, the SY89464Uos unique 2:1 Runt Pulse Eliminator (RPE) MUX prevents any short cycles or pruntq pulses during switchover. In addition, a unique Fail Safe Input (FSI) protection prevents metastable output conditions when the selected input clock fails to a DC voltage (voltage between the pins of the differential input drops below 100mV).

The differential input includes Micrelos unique, 3-pin internal termination architecture that allows customers to interface to any differential signal (AC or DC-coupled) as small as 100mV (200mVPP) without any level shifting or termination resistor networks in the signal path. The outputs are 800mV, 100K-compatible LVPECL with fast rise/fall times guaranteed to be less than 220ps.

The SY89464U operates from a 2.5V ~5 or 3.3V ~10 supply and is guaranteed over the full industrial temperature range of ?40†C to +85†C. The SY89464U is part of Micrelos high-speed, Precision Edgeç product line.

Features

• Selects between two sources, and provides 10 precision LVPECL copies

• Guaranteed AC performance over temperature and supply voltage:

- Wide operating frequency: 1kHz to >1.5GHz

- < 1100ps In-to-Out tpd

- < 220ps tr/tf

• Unique, patent-pending MUX input isolation design minimizes adjacent channel crosstalk

• Fail-Safe Input prevents oscillations

• Ultra-low jitter design:

- <1psRMS random jitter

- <1psRMS cycle-to-cycle jitter

- <10psPP total jitter (clock)

- <0.7psRMS MUX crosstalk induced jitter

• Unique patented internal termination and VT pin accepts DC- and AC-coupled inputs (CML, PECL, LVDS)

• 800mV LVPECL output

• 2.5V ±5 or 3.3V ±10 supply voltage

• Output enable

• -40°C to +85°C industrial temperature range

• Available in 44-pin (7mm x 7mm) QFN package

Applications

• Redundant clock switchover

• Fail-safe clock protection

Markets

• LAN/WAN

• Enterprise servers

• ATE

• Test and measurement