September 2005 ASM5P2308A

rev 1.4

Notice: The information in this document is subject to change without notice.
Alliance Semiconductor
2575 Augustine Drive • Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com
3.3V Zero-Delay Buffer
General Features

• Zero input - output propagation delay, adjustable by
capacitive load on FBK input.
• Multiple configurations - Refer “ASM5P2308A
Configurations “ Table.
• Input frequency range: 15MHz to 133MHz
• Multiple low-skew outputs.
• Output-output skew less than 200pS.
• Device-device skew less than 700pS.
• Two banks of four outputs, tri-stateable by two select
inputs.
• Less than 200pS cycle-to-cycle jitter
(-1, -1H,-2, -3, -4, -5H).
• Available in 16 pin SOIC and TSSOP packages.
• 3.3V operation.
• Advanced 0.35µ CMOS technology.
• Industrial temperature available.

Functional Description

ASM5P2308A is a versatile, 3.3V zero-delay buffer
designed to distribute high-speed clocks. It is available in a
16 pin package. The part has an on-chip PLL which locks
to an input clock presented on the REF pin. The PLL
feedback is required to be driven to FBK pin, and can be
obtained from one of the outputs. The input-to-output
propagation delay is guaranteed to be less than 250pS,
and the output-to-output skew is guaranteed to be less than
200pS.

The ASM5P2308A has two banks of four outputs each,
which can be controlled by the select inputs as shown in
the Select Input Decoding Table. The select input also
allows the input clock to be directly applied to the outputs
for chip and system testing purposes.

Multiple ASM5P2308A devices can accept the same input
clock and distribute it. In this case the skew between the
outputs of the two devices is guaranteed to be less than
700pS.

The ASM5P2308A is available in five different
configurations(Refer “ASM5P2308A Configurations” Table).
The ASM5P2308A-1 is the base part, where the output
frequencies equal the reference if there is no counter in the
feedback path. The ASM5P2308A-1H is the high-drive
version of the -1 and the rise and fall times on this device
are much faster.

The ASM5P2308A-2 allows the user to obtain 2X and 1X
frequencies on each output bank. The exact configuration
and output frequencies depends on which output drives the
feedback pin. The ASM5P2308A-3 allows the user to
obtain 4X and 2X frequencies on the outputs.

The ASM5P2308A-4 enables the user to obtain 2X clocks
on all outputs.

The ASM5P2308A-5H is a high-drive version with REF/2
on both banks. Thus, the part is extremely versatile, and
can be used in a variety of applications.