SY89467U
Precision LVPECL 1:20 Fanout with 2:1 MUX
and Internal Termination with Fail-Safe Input
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 2008 M9999-040808-C
hbwhelp@micrel.com or (408) 955-1690
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 dierential input drops
signicantly 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 (200mVPP) 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:
– <1psRMS random jitter
– <1psRMS cycle-to-cycle jitter
– <10psPP total jitter (clock)
– <0.7psRMS 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: VCC 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.
