CY2SSTU877
1.8V, 500 MHz, 10-Output JEDEC-Compliant Zero Delay Buffer
Features
• Operating frequency: 125 MHz to 500 MHz
• Supports DDRII SDRAM
• 1 to 10 differential clock buffer (SSTL_18)
• Spread-Spectrum-compatible
• Low jitter (cycle-to-cycle): 40 ps
• Very low output-to-output skew: 40 ps
• Auto power-down feature when input is low
• 1.8V operation
• Fully JEDEC-compliant (JESD 82-8)
• 52-ball BGA
distributes a differential clock input pair (CK, CK#) to ten differ-
ential pair of clock outputs (Y[0:9], Y#[0:9]) and one differential
pair of feedback clock outputs (FBOUT, FBOUT#).
The input clocks (CK, CK#), the feedback clocks (FBIN,
FBIN#), the LVCMOS (OE, OS), and the analog power input
(AVDD) control the clock outputs.
The PLL in the CY2SSTU877 clock driver uses the input
clocks (CK, CK#) and the feedback clocks (FBIN, FBIN#) to
provide high-performance, low-skew, low-jitter output differ-
ential clocks (Y[0:9], Y#[0:9]). The CY2SSTU877 is also able
to track Spread Spectrum Clocking (SSC) for reduced EMI.
When AVDD is grounded, the PLL is turned off and bypassed
for test purposes. When both clock signals (CK, CK#) are logic
low, the device will enter a low-power mode. An input logic
detection circuit on the differential inputs, independent from
the input buffers, will detect the logic low level and perform a
low-power state where all outputs, the feedback, and the PLL
are OFF. When the inputs transition from both being logic low
to being differential signals, the PLL will be turned back on, the
inputs and outputs will be enabled and the PLL will obtain
phase lock between the feedback clock pair (FBIN, FBIN#)
and the input clock pair (CK, CK#) within the specified stabili-
zation time t
L
.
Functional Description
The CY2SSTU877 is a high-performance, low-skew, low-jitter
zero delay buffer designed to distribute differential clocks in
high-speed applications.
This phase-locked loop (PLL) clock buffer is designed for a
V
DD
of 1.8V, an AV
DD
of 1.8V and SSTL18 differential data
input and output levels. This device is a zero delay buffer that
Block Diagram
Pin Configuration
1
A
B
C
D
E
F
G
H
J
K
CLKT1
CLKC1
CLKC2
CLKT2
CLK_INT
CLK_INC
AGND
AVDD
CLKT3
CLKC3
2
CLKT0
GND
GND
VDDQ
VDDQ
VDDQ
VDDQ
GND
GND
CLKC4
3
CLKC0
GND
NB
VDDQ
NB
NB
VDDQ
NB
GND
CLKT4
4
CLKC5
GND
NB
VDDQ
NB
NB
VDDQ
NB
GND
CLKT9
5
CLKT5
GND
GND
OS
VDDQ
OE
VDDQ
GND
GND
CLKC9
6
CLKT6
CLKC6
CLKC7
CLKT7
FB_INT
FB_INC
FB_OUTC
FB_OUTT
CLKT8
CLKC8
52 BGA
Rev 1.0, November 21, 2006
2200 Laurelwood Road, Santa Clara, CA 95054
Tel:(408) 855-0555
Fax:(408) 855-0550
Page 1 of 8
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