SY89809AL Datasheet, PDF (1/8 Pages) Micrel Semiconductor – 3.3V LVPECL/HSTL to HSTL 1:9 High-

SY89809AL
3.3V LVPECL/HSTL to HSTL 1:9 High-
Performance Clock Driver with LVTTL
Clock Select and Enable
General Description
The SY89809AL is a high-performance bus clock driver
with nine differential High-Speed Transceiver Logic (HSTL)
output pairs. The part is designed for use in low-voltage
(3.3V/1.8V) applications, which require a large number of
outputs to drive precisely aligned, ultra-low skew signals to
their destination. The input is multiplexed from either HSTL
or Low-Voltage Positive-Emitter-Coupled Logic (LVPECL)
by the CLK_SEL pin. The Output Enable (OE) is
synchronous so that the outputs will only be
enabled/disabled when they are already in the LOW state.
This avoids any chance of generating a runt clock pulse
when the device is enabled/disabled as can happen with
an asynchronous control.
The SY89809AL features low pin-to-pin skew (15ps
typical) and low part-to-part skew (100ps typical). The
SY89809AL is available in a single space-saving package,
enabling a lower overall cost solution.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Block Diagram
Features
Precision Edge^®
• 3.3V core supply, 1.8V output supply for reduced power
• LVPECL and HSTL inputs
• Nine differential HSTL (low-voltage swing) output pairs
• HSTL outputs drive 50Ω-to-ground with no offset voltage
• 750MHz maximum clock frequency
• Low part-to-part skew (100ps typical)
• Low pin-to-pin skew (15ps typical)
• Available in 32-pin TQFP
Applications
• High-performance PCs
• Workstations
• Parallel processor-based systems
• Other high-performance computing
• Communications
Level
HSTL
HSTL
LVPECL
LVCMOS/LVTTL
Direction
Input
Output
Input
Input
Signal
HSTL_CLK, /HSTL_CLK
Q0 – Q8, /Q0 – /Q8
LVPECL_CLK, /LVPECL_CLK
CLK_SEL, OE
OE⁽¹⁾
0
0
1
1
Table 1. Signal Groups
CLK_SEL Q0 – Q8
/Q0 – /Q8
0
LOW
HIGH
1
LOW
HIGH
0
HSTL_CLK /HSTL_CLK
1
LVPECL_CLK /LVPECL_CLK
Table 2. Truth Table
Note:
1. The OE (output enable) signal is synchronized with the low level of
the HSTL_CLK and LVPECL_CLK signal.
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
July 2010
M9999-070110
[e-mail] or [phone]