SY89228U Datasheet, PDF (1/16 Pages) Micrel Semiconductor – 1GHz Precision, LVPECL ÷3, ÷5 Clock Divider with Fail-Safe Input and Internal Termination

SY89228U
1GHz Precision, LVPECL ÷3, ÷5 Clock Divider
with Fail-Safe Input and Internal Termination
General Description
The SY89228U is a precision, low jitter 1GHz ÷3, ÷5
clock divider with an LVPECL output. A unique Fail-
Safe Input (FSI) protection prevents metastable
output conditions when the input clock voltage swing
drops significantly below 100mV or input is removed.
The differential input includes Micrel’s unique, 3-pin
internal termination architecture that allows the input
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 270ps.
The SY89228U 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
SY89228U 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.
Block Diagram
Features
Precision Edge^®
• Accepts a high-speed input and provides a precision
÷3 and ÷5 sub-rate, LVPECL output
• Fail-Safe Input
– Prevents oscillations when input is invalid
• Guaranteed AC performance over temperature and
supply voltage:
– DC-to >1.0GHz throughput
– < 1500ps 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 internal termination and VT pin
accepts DC- and AC-coupled inputs (CML, PECL,
LVDS)
• Wide input voltage range VCC to GND
• 800mV LVPECL output
• 46% to 54% Duty Cycle(÷ 3)
• 47% to 53% Duty Cycle(÷ 5)
• 2.5V ±5% or 3.3V ±10% supply voltage
• -40°C to +85°C industrial temperature range
• Available in 16-pin (3mm x 3mm) MLF^® package
Applications
• Fail-safe clock protection
Markets
• LAN/WAN
• Enterprise servers
• ATE
• Test and measurement
Precision Edge is a registered trademark of Micrel, Inc.
MLF and MicroLeadFrame are registered trademarks of Amkor Technology.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
August 2007
M9999-080707-A
[e-mail] or [phone]