CY2304
3.3V Zero Delay Buffer
Cypress Semiconductor Corporation
•
198 Champion Court
•
San Jose
, CA 95134-1709
•
408-943-2600
Document #: 38-07247 Rev. *F
Revised March 12, 2009
Features
■ Zero input-output propagation delay, adjustable by capacitive
load on FBK input
■ Multiple configurations
■ Multiple low-skew outputs
■ 10 MHz to 133 MHz operating range
■ 90 ps typical peak cycle-to-cycle jitter at 15 pF, 66 MHz
■ Space-saving 8-pin 150-mil SOIC package
■ 3.3V operation
■ Industrial temperature available
Functional Description
The CY2304 is a 3.3V zero delay buffer designed to distribute
high-speed clocks in PC, workstation, datacom, telecom, and
other high performance applications.
The part has an on-chip phase-locked loop (PLL) that locks to an
input clock presented on the REF pin. The PLL feedback is
required to be driven into the FBK pin, and can be obtained from
one of the outputs. The input-to-output skew is guaranteed to be
less than 250 ps, and output-to-output skew is guaranteed to be
less than 200 ps.
The CY2304 has two banks of two outputs each.
The CY2304 PLL enters a power down state when there are no
rising edges on the REF input. In this mode, all outputs are
three-stated and the PLL is turned off, resulting in less than
25
μA of current draw.
Multiple CY2304 devices can accept the same input clock and
distribute it in a system. In this case, the skew between the
outputs of two devices is guaranteed to be less than 500 ps.
The CY2304 is available in two different configurations, as
shown in Table 1 on page 1. The CY2304–1 is the base part,
where the output frequencies equal the reference if there is no
counter in the feedback path.
The CY2304–2 allows the user to obtain Ref and 1/2x or 2x
frequencies on each output bank. The exact configuration and
output frequencies depends on which output drives the feedback
pin.
Pinouts
Figure 1. 8-Pin SOIC - Top View
Table 1. Available Configurations
Device
FBK from
Bank A Frequency
Bank B Frequency
CY2304-1
Bank A or B
Reference
Reference
CY2304-2
Bank A
Reference
Reference/2
CY2304-2
Bank B
2 × Reference
Reference
PLL
CLKA1
CLKA2
CLKB1
REF
CLKB2
/2
Extra Divider (-2)
FBK
Logic Block Diagram
1
2
3
4
5
8
7
6
REF
CLKA1
CLKA2
GND
VDD
FBK
CLKB1
CLKB2
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