7B991 Datasheet, PDF (1/17 Pages) Maxwell Technologies – Programmable Skew Clock Buffer (PSCB)

7B991
Programmable Skew
Clock Buffer (PSCB)
FEATURES:
• All output pair skew < 100 ps typical (250 max.)
• 3.75 to 80 MHz output operation
• User-selectable output functions
• Selectable skew to 18 ns
• Inverted and non-inverted
• Operation at ½ and ¼ input frequency
• Operation at 2x and 4x input frequency (input as low as
3.75 MHz)
• Zero input to output delay
• 50% duty-cycle outputs
• Outputs drive 50Ω terminated lines
• Low operating current
• Package: 32-pin RAD-PAK® flat package
• Jitter < 200 ps peak-to-peak (< 25 ps RMS)
• Compatible with Pentium™-based processor
• Total dose hardness:
- >100 krads (Si), depending upon space mission
• Excellent Single Event Effects:
- SEL > 116MeV/mg/cm²
- SEU_TH -3 MeV/mg/cm²
- SEU sat cross section: 1E-3/device
Logic Diagram
DESCRIPTION:
Maxwell Technologies’ 7B991 Programmable Skew Clock
Buffers (PSCB) offer user-selectable control over system
clock functions. These multiple-output clock drivers provide
the system integrator with functions necessary to optimize tim-
ing of high-performance computer systems. Eight individual
drivers, arranged as four pairs of user-controllable outputs,
can each drive terminated transmission lines with impedances
as low as 50Ω while delivering minimal and specified output
skews and full-swing logic levels.
Each output can be hardwired to one of nine delay or function
configurations. Delay increments of 0.7 to 1.5 ns are deter-
mined by the operating frequency with outputs able to skew up
to ± 6 time units from their nominal “zero” skew position. The
completely integrated PLL allows external load and transmis-
sion line delay effects to be canceled. When this “zero delay”
capability of the PSCB is combined with the selectable output
skew functions, the user can create output-to-output delays of
up to ±12 time units.
Maxwell Technologies' patented RAD-PAK® packaging technol-
ogy incorporates radiation shielding in the microcircuit pack-
age. It eliminates the need for box shielding while providing
the required radiation shielding for a lifetime in orbit or space
mission. In a GEO orbit, RAD-PAK provides greater than 100
krad (Si) radiation dose tolerance. This product is available
with screening up to Class S.
09.23.02 Rev 4
[phone] - Fax: [phone] - www.maxwell.com
All data sheets are subject to change without notice 1
©2002 Maxwell Technologies.
All rights reserved.