SY89221U_0708 Datasheet, PDF (1/17 Pages) Micrel Semiconductor – Precision 1:15 LVPECL Fanout Buffer with

SY89221U
Precision 1:15 LVPECL Fanout Buffer with
2:1 MUX and Four ÷1/÷2/÷4 Clock Divider
Output Banks
General Description
The SY89221U is a 2.5/3.3V precision, high-speed,
integrated clock divider and LVPECL fanout buffer
capable of handling clocks up to 1.5GHz. Optimized
for communications applications, the four
independently controlled output banks are phase-
matched and can be configured for pass through ÷1,
÷2 or ÷4 divider ratios.
The differential input includes Micrel’s unique, 3-pin
input termination architecture that allows the user 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 low-skew, low-jitter outputs are LVPECL
compatible with extremely fast rise/fall times that are
guaranteed to be less than 220ps.
The /MR (master reset) input asynchronously resets
the outputs. A four-clock delay after de-asserting /MR
allows the counters to synchronize and start the
outputs from the same state without any runt pulse.
The SY89221U is part of Micrel’s Precision Edge^®
product family. All support documentation can be
found at Micrel's web site at: www.micrel.com.
Features
• Four low-skew LVPECL output banks with
independently programmable ÷1, ÷2 and ÷4 divider
options
• Four output banks, 15 total outputs
• Guaranteed AC performance over temperature and
voltage:
– Accepts a clock frequency up to 1.5GHz
– <1600ps IN-to-OUT propagation delay
– <270ps rise/fall time
– <35 ps within-bank skew
• Fail Safe Input
– Prevents outputs from oscillating
• Ultra-low jitter design:
– <1ps_RMS random jitter
– <10ps_PP total jitter (clock)
• Patent-pending input termination and VT pin
accepts DC- and AC-coupled inputs (CML, PECL,
LVDS)
• CMOS/TTL-compatible output enable (EN) and
divider select control
• 2.5V ±5% or 3.3V ±10% power supply
• –40°C to +85°C temperature range
• Available in 64-pin TQFP
Applications
• All SONET/SDH applications
• All Fibre Channel applications
• All Gigabit Ethernet applications
Markets
• LAN/WAN routers/switches
• Enterprise servers
• Storage
• ATE
• Test and measurement
Precision Edge is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
August 2007
M9999-082407-C
[e-mail] or [phone]