2.5 V/3.3 V PECL/ECL 1:5 clock distribution chip
Rev. 01 — 14 October 2002
The PCKEL14 is a low skew 1:5 clock distribution chip designed explicitly for low
skew clock distribution applications. The device can be driven by either a differential
or single-ended ECL, or if positive power supplies are used, PECL input signal. The
PCKEL14 is designed to operate in ECL or PECL mode for a voltage supply range of
−2.375 V to −3.8 V (or 2.375 V to 3.8 V).
The PCKEL14 features a multiplexed clock input to allow for the distribution of a lower
speed scan or test clock along with the high speed system clock. When LOW (or left
open and pulled LOW by the input pull-down resistor), the SEL pin will select the
differential clock input.
The common enable (EN) 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 internal ﬂip-ﬂop is clocked on the falling edge of
the input clock, therefore all associated speciﬁcation limits are referenced to the
negative edge of the clock input.
The VBB pin (an internally generated voltage supply) is available to this device only.
For single-ended conditions, the unused differential input is connected to VBB as a
switching reference voltage. VBB may also rebias AC-coupled inputs. When used,
decouple VBB and VCC via a 0.01 µF capacitor and limit current sourcing or sinking to
0.1 mA. When not used, VBB should be left open.
s 50 ps output-to-output skew at 3.3 V
s Synchronous enable/disable
s Multiplexed clock input
s ESD protection: > 2.5 kV HBM
s The PCK series contains temperature compensation
s PECL mode operating range: VCC = 2.375 V to 3.8 V, with VEE = 0 V
s NECL mode operating range: VCC = 0 V, with VEE = −2.375 V to −3.8 V
s Internal 75 kΩ pull-down resistors on all inputs, plus a 37.5 kΩ pull-up on CLK
s Q output will default LOW with inputs open or at VEE
s Meets or exceeds JEDEC spec EIA/JESD78 IC latch-up test
s Moisture sensitivity level 1
s Flammability rating: UL-94 code V-0 @ 1/8”
Datasheet pdf - http://www.DataSheet4U.net/