SY89467U Datasheet, PDF (1/15 Pages) Micrel Semiconductor – Precision LVPECL 1:20 Fanout with 2:1 MUX and Internal Termination with Fail-Safe Input

SY89467U
Precision LVPECL 1:20 Fanout with 2:1 MUX
and Internal Termination with Fail-Safe Input
General Description
The SY89467U is a 2.5/3.3V, 1:20 LVPECL fanout
buffer with a 2:1 differential input multiplexer (MUX).
A unique Fail-Safe Input (FSI) protection prevents
metastable output conditions when the selected
input clock fails to a DC voltage (when voltage
between the pins of the differential input drops
significantly below 100mV).
The differential input includes Micrel’s unique, 3-pin
internal termination architecture that can 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, LVPECL with fast rise/fall times
guaranteed to be less than 270ps.
The SY89467U 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
SY89467U 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.
Functional Block Diagram
Precision Edge^®
Features
• Selects between two inputs, and provides 20
precision LVPECL copies
• Fail-Safe Input
– Prevents outputs from oscillating when input is
invalid
• Guaranteed AC performance over temperature and
supply voltage:
– DC-to >1.5 GHz throughput
– < 1200ps Propagation Delay (In-to-Q)
– 270ps Rise/Fall times
• 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 MUX input isolation design
minimizes adjacent channel crosstalk
• Unique patented internal termination and VT pin
accepts DC- and AC-coupled inputs (CML, PECL,
LVDS)
• Wide input voltage range: V_CC to GND
• 2.5V ±5% or 3.3V ±10% supply voltage
• -40°C to +85°C industrial temperature range
• Available in 64-pin TQFP package
Applications
• Fail-safe clock protection
• SONET clock distribution
• Backplane distribution
Markets
• LAN/WAN
• Enterprise servers
• ATE
• Test and measurement
Precision Edge is a registered trademark of Micrel, Inc.
MicroLeadFrame and MLF are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
April 2008
M9999-040808-C
[e-mail] or [phone]