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SY89843U_10 Datasheet, PDF (1/17 Pages) Micrel Semiconductor – Precision LVPECL Runt Pulse Eliminator 2:1 | |||
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SY89843U
Precision LVPECL Runt Pulse Eliminator 2:1
MUX with 1:2 Fanout and Internal Termination
General Description
The SY89843U is a low jitter PECL, 2:1 differential input
multiplexer (MUX) optimized for redundant source
switchover applications. Unlike standard multiplexers,
the SY89843U unique 2:1 Runt Pulse Eliminator (RPE)
MUX prevents any short cycles or âruntâ pulses during
switchover. In addition, a unique Fail-Safe Input
protection prevents metastable 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 Micrelâs unique, 3-pin
input 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
output is 800mV, 100K compatible LVPECL with fast
rise/fall times guaranteed to be less than 190ps.
The SY89843U operates from a 2.5V ±5% or 3.3V
±10% supply and is guaranteed over the full industrial
temperature range of â40°C to +85°C. The SY89843U is
part of Micrelâs high-speed, Precision Edge® product
line. All support documentation can be found on Micrelâs
web site at: www.micrel.com.
Features
Precision Edge ®
⢠Selects between two sources, and provides a
glitch-free, stable LVPECL output
⢠Guaranteed AC performance over temperature
and supply voltage:
⢠â Wide operating frequency: 1kHz to >1.5GHz
⢠â < 880ps In-to-Out tpd
⢠â < 190ps tr/tf
⢠Unique patent-pending input isolation design
minimizes crosstalk
⢠Fail-Safe Input prevents oscillations
⢠Ultra-low jitter design:
â <1psRMS random jitter
â <1psRMS cycle-to-cycle jitter
â <10psPP total jitter (clock)
â <0.7psRMS MUX crosstalk induced jitter
⢠Unique patent-pending input termination and VT
pin accepts DC- and AC-coupled inputs (CML,
PECL, LVDS)
⢠800mV LVPECL output swing
⢠2.5V ±5% or 3.3V ±10% supply voltage
⢠â40°C to +85°C industrial temperature range
⢠Available in 24-pin (4mm x 4mm) QFN package
Applications
⢠Redundant clock switchover
⢠Failsafe clock protection
Markets
⢠LAN/WAN
⢠Enterprise servers
⢠ATE
⢠Test and measurement
Precision Edge is a registered trademark of Micrel, Inc.
Micrel Inc. ⢠2180 Fortune Drive ⢠San Jose, CA 95131 ⢠USA ⢠tel +1 (408) 944-0800 ⢠fax + 1 (408) 474-1000 ⢠http://www.micrel.com
May 2007
M9999-052207-B
hbwhelp@micrel.com or (408) 955-1690
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