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
Cypress Semiconductor Corporation
Document #: 38-07575 Rev. *E
•
198 Champion Court
•
San Jose
,
CA 95134-1709
•
408-943-2600
Revised January 27, 2006
PRELIMINARY
Pin Description
Pin No.
G1
H1
E1, F1
E6, F6
H6, G6
AGND
AVDD
FB_INT, FB_INC
FB_OUTT,
FB_OUTC
Name
1.8V analog supply
Feedback differential clock input
Feedback differential clock output
Ground
Description
Ground for 1.8V analog supply
CY2SSTU877
CLK_INT, CLK_INC Differential clock input with a (10K–100KΩ) pull-down resistor
B2, B3, B4, B5, C2, C5, H2, H5, J2, J3, J4, GND
J5
F5
D5
D2, D3, D4, E2, E5, F2, G2, G3, G4, G5
A2, A1, D1, J1, K3, A5, A6, D6, J6, K4,
A3, B1, C1, K1, K2, A4, B6, C6, K6, K5
Table 1. Function Table
Inputs
AVDD
GND
GND
GND
GND
VDD
VDD
VDD
VDD
VDD
X
OE
H
H
L
L
L
L
H
H
X
X
OS
X
X
H
L
H
L
X
X
X
X
CLK_INT CLK_INC
L
H
L
H
L
H
L
H
L
H
H
L
H
L
H
L
H
L
L
H
OE
OS
VDDQ
CLKT [0:9]
CLKC [0:9]
Output enable (ASYNC) for CLKT[0:9] and CLKC [0:9]
Output Select (Tied to GND or VDDQ)
1.8V supply
Buffered output of input clock, CLK
Buffered output of input clock, CLK
Outputs
CLKT
L
H
Lz
Lz,CLKT7
Active
Lz
Lz,CLKT7
Active
L
H
Lz
CLKC
H
L
Lz
Lz,CLKC7
Active
Lz
Lz,CLKC7
Active
H
L
Lz
FB_OUTT FB_OUTC
L
H
L
H
L
H
L
H
Lz
Reserved
H
L
H
L
H
L
H
L
Lz
PLL
Bypassed/Off
Bypassed/Off
Bypassed/Off
Bypassed/Off
On
On
On
On
Off
Recommended Operating Conditions
Parameter
T
A
(Com.)
V
DD
, AV
DD
Description
Ambient Operating Temp
Operating Voltage
Condition
Min.
0
1.7
Max.
70
1.9
Unit
°C
V
Document #: 38-07575 Rev. *E
Page 2 of 9
PRELIMINARY
Absolute Maximum Conditions
Parameter
V
IN
V
OUT
T
S
V
CC,
AV
CC
I
IK
I
OK
I
O
Description
Input Voltage Range
Output Voltage Range
Storage Temperature
Supply Voltage Range
Input Clamp Current
Output Clamp Current
Continuous Output Current
Continuous Current through V
DD
/GND
Condition
Min.
–0.5
–0.5
–65
–0.5
–50
–50
–50
–100
CY2SSTU877
Max.
V
DDQ
+ 0.5
V
DDQ
+ 0.5
150
2.5
50
50
50
100
Unit
V
V
°C
V
mA
mA
mA
mA
DC Electrical Specifications
Parameter
V
IK
V
OD
V
OX
V
IX
V
ID
DC
V
ID
AC
V
IL
V
IH
V
OL
V
OH
I
IH
I
IL
I
ODL
I
DDLD
I
DD
I
OH
I
OL
C
IN
C
OUT
C
IN(DELTA)
Description
Input Clamping Voltage
Output Differential Voltage
Output Differential Crossing Voltage
Input Differential Crossing Voltage
Input Differential Voltage (DC Values)
Input Differential Voltage (AC Values)
Input Low Voltage
Input High Voltage
Output Low Voltage
Output High Voltage
Input High Current
Input Low Current
Output disabled low current
Static Supply current
Dynamic Supply Current
Output High Current
Output Low Current
Input Capacitance
(Input Capacitance of
CLK_INT, CLK_INC,
FB_INT, FB_INC) V
I
=
V
DDQ
or GND
Ci(delta) (CLK_INT,
CLK_INC, FB_INT,
FB_INC) V
I
= V
DDQ
or
GND
2
(OE, OS, CLK_INT,
CLK_INC)
(OE, OS, CLK_INT,
CLK_INC)
I
OL
= 100
µA
I
OL
= 9 mA
I
OH
= –100
µA
I
OH
= –9 mA
V
IN
= V
DDQ
or GND
V
IN
= V
DDQ
or GND
V
ODL
= 100 mV
OE = GND
I
DDQ
+ I
ADD,
CLK_INT =
CLK_INC = GND
C
L
= 0 @ 270 MHz
V
DDQ
– 0.2
1.1
–250
–10
100
500
300
–9
9
3
250
10
0.65 * V
DDQ
0.1
0.6
Conditions
I
I
= –18 mA
0.5
V
DDQ
/2 – 0.08
(V
DDQ
/2) – 0.15
0.3
0.6
V
DDQ
/2 + 0.08
(V
DDQ
/2) + 0.15
V
DDQ
+ 0.4
V
DDQ
+ 0.4
0.35 * V
DDQ
Min.
Max.
–1.2
Unit
V
V
V
V
V
V
V
V
V
V
V
V
µA
µA
µA
µA
mA
mA
mA
pF
pF
–0.25
0.25
pF
Document #: 38-07575 Rev. *E
Page 3 of 9
PRELIMINARY
AC Timing Specifications
Parameter
F
CLK
T
DC
T
ODC
T
LOCK
T
OENB
T
ODIS
Tjitt (cc)
Tjit (Period)
Tjit (H-Period)
T
(φ)
T
(φ)DYN
T
SKEW
S
LR(O)
S
LR(I)
[1,2]
CY2SSTU877
Min.
125
250
40
48
–
Max.
500
500
60
52
15
8
8
40
30
45
60
50
40
40
4
4
Unit
MHz
MHz
%
%
µs
ns
ns
ps
ps
ps
ps
ps
ps
ps
V/ns
V/ns
V/ns
Description
Clock Frequency (Max)
Clock Frequency (Application)
Input Duty Cycle
Output Duty Cycle
PLL Lock Time
Output Enable Time
Output Disable Time
Cycle-to-cycle jitter
Period jitter
Half Period Cycle-to-cycle jitter
Static Phase Offset
Dynamic Phase Offset
Clock Skew
Output Slew Rate
Input Slew Rate
Conditions
Room temp and nominal V
DDQ
Room temp and nominal V
DDQ
OE to any CLKT/ CLKC[0:9]
OE to any CLKT/ CLKC[0:9]
–
–
–40
–30
Above 270 MHz
Below 270 MHz
Average 1000 cycles
–45
–60
–50
–40
–
CLKT/ CLKC[0:9], FB_OUTT,
FB_OUTC
CLK_INT, CLK_INC, FB_INT,
FB_INC
OE
1.5
1
0.5
Figure 1. Test Loads for Timing Measurement
Notes:
1. Operating clock frequency indicates a range over which the PLL must be able to lock, but in which it is not required to meet the other timing parameters (used for
low speed system debug).
2. Application clock frequency indicates a range over which the PLL must meet all timing requirements.
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