SY89474U
Precision LVDS 2:1 Multiplexer with 1:2
Fanout and Internal Termination
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
August 2005 M9999-081105
hbwhelp@micrel.com or (408) 955-1690
General Description
The SY89474U is a 2.5V precision, high-speed 2:1
differential MUX capable of processing clocks up to
2.5GHz and data up to 2.5Gbps.
The differential input includes Micrel’s unique, 3-pin input
termination architecture that directly interfaces 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
output is 325mV LVDS with fast rise/fall times guaranteed
to be less than 150ps.
The SY89474U operates from a 2.5V ±5% supply and is
guaranteed over the full industrial temperature range of
-40°C to +85°C. The SY89474U is part of Micrel’s high-
speed, Precision Edge® product line. For multiple clock
switchover solutions, please refer to the SY89840U–
SY89845U fa mily.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Functional Block Diagram
Precision Edge®
Features
•Selects between two input channels and provides two
copies of the selected input
•Guaranteed AC performance over temperature and
supply voltage:
−DC to 2.5Gbps data throughput
−DC to 2.5GHz fMAX (clock)
−<470ps In-to-Out tpd
−<150ps tr/tf
−<20ps output-to-output skew
•Unique, patent-pending input isolation design
minimizes crosstalk
•Ultra-low jitter design:
−<1psRMS random jitter
−<10psPP deterministic jitter
−<1psRMS cycle-to-cycle jitter
−<10psPP total jitter (clock)
−<0.7psRMS crosstalk induced jitter
•Unique patent-pending input termination and VT pin
accepts DC- and AC-coupled inputs (CML, PECL,
LVDS)
•325mV LVDS output swing
•2.5V ±5% supply voltage
•−40°C to +85°C industrial temperature range
•Available in 24-pin (4mm x 4mm) QFN package
Applications
•Clock switchover
•Data distribution
Markets
•LAN/WAN
•Enterprise Servers
•ATE
•Test and Measurement
Precision Edge is a registered trademark of Micrel, Inc.