SY89808L 3.3V, 500MHz, 1:9 Differential HSTL (1.5V) Fanout Buffer/Translato0 pages

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Precision Edge®
Micrel, Inc. SY89808L
M9999-091405
hbwhelp@micrel.com or (408) 955-1690
FEATURES
9 differential HSTL (1.5V compatible) output pairs
500MHz maximum clock frequency
Triple-buffered enable function
3.3V core supply, 1.8V output supply for reduced
power
LVPECL and HSTL inputs
HSTL outputs drive 50Ù to ground with no
offset voltage
Low pin-to-pin skew (25ps max.)
Guaranteed over industrial –40°C to +85°C
temperature range
Available in 32-pin TQFP package
The SY89808L is a High-Performance Bus Clock Driver with
9 differential HSTL (High-Speed Transceiver Logic) 1.5V
compatible output pairs. The part is designed for use in lowvoltage
(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
LVPECL (Low-Voltage Positive-Emitter-Coupled Logic) by the
CLK_SEL pin.
The Output Enable (OE) is synchronous and triple-buffered
so that the outputs will only be enabled/disabled when they are
already in the LOW state. This avoids any potential of generating
a runt clock pulse when the device is enabled/disabled, as can
occur with an asynchronous control. The triple-buffering feature
provides a three-clock delay from the time the OE input is
asserted/de-asserted to when the clock appears at the outputs.
The SY89808L features an ultra-low pin-to-pin skew of less
than 25ps. The SY89808L is available in a 32-TQFP space
saving package, enabling a lower overall cost solution.
3.3V, 500MHz, 1:9 DIFFERENTIAL
HSTL (1.5V) FANOUT BUFFER/
TRANSLATOR
DESCRIPTION
Precision Edge®
SY89808L
LOGIC SYMBOL
APPLICATIONS
Workstations
Parallel processor-based systems
High-performance computing
Communications
CLK_SEL
HSTL_CLK
/HSTL_CLK
LVPECL_CLK
/LVPECL_CLK
OE
0
1
9
9
Q0 — Q8
/Q0 — /Q8
EN
ENABLE
LOGIC
Rev.: E Amendment: /0
Issue Date: September 2005
Precision Edge®
TYPICAL PERFORMANCE
200
300
400
500
600
700
800
900
0
200
400
600
800
1000
1200
1400
1600
AMPLITUDE (mV)
FREQUENCY (MHz)
Output Amplitude
vs. Frequency
Precision Edge is a registered trademark of Micrel, Inc.
TRUTH TABLE
OE(1) CLK_SEL Q0 – Q8 /Q0 – /Q8
0 0 LOW HIGH
0 1 LOW HIGH
1 0 HSTL_CLK /HSTL_CLK
1 1 LVPECL_CLK /LVPECL_CLK
Notes:
1. The OE (output enable) signal is synchronized with the low level of the
HSTL_CLK and LVPECL_CLK signal.