SY89464U_10 Datasheet, PDF (1/19 Pages) Micrel Semiconductor – Precision LVPECL 1:10 Fanout with 2:1 Runt

SY89464U
Precision LVPECL 1:10 Fanout with 2:1 Runt
Pulse Eliminator MUX and Internal Termination
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
SY89464U’s unique 2:1 Runt Pulse Eliminator
(RPE) MUX prevents any short cycles or “runt”
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 Micrel’s unique, 3-pin
internal termination architecture that allows
customers to interface to any differential signal (AC-
or DC-coupled) as small as 100mV (200mV_PP)
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 Micrel’s high-speed, Precision
Edge^® product line.
All support documentation can be found on Micrel’s
web site at: www.micrel.com.
Precision Edge is a registered trademark of Micrel, Inc.
Features
Precision Edge^®
• 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 t_pd
– < 220ps t_r/t_f
• Unique, patent-pending MUX input isolation design
minimizes adjacent channel crosstalk
• Fail-Safe Input prevents oscillations
• Ultra-low jitter design:
– <1ps_RMS random jitter
– <1ps_RMS cycle-to-cycle jitter
– <10ps_PP total jitter (clock)
– <0.7ps_RMS 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
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
December 2007
M9999-120607-C
[e-mail] or [phone]