ICS84325
C
RYSTAL
-
TO
-3.3V LVPECL
F
REQUENCY
S
YNTHESIZER WITH
F
ANOUT
B
UFFER
G
ENERAL
D
ESCRIPTION
The ICS84325 is a Crystal-to-3.3 VLVPECL Frequency
Synthesizer with Fanout Buffer. The output frequency can be
programmed using frequency select pins. The low phase
noise characteristics of the ICS84325 make it an ideal
clocksource for Fibre Channel 1, Fibre Channel 2, Infiniband
and Gigabit Ethernet applications.
F
EATURES
•
6 differential 3.3V LVPECL outputs
•
Crystal oscillator interface
•
Output frequency range: 106.25MHz to 250MHz
•
Crystal input frequency: 25MHz and 25.5MHz
•
Output skew: 60ps (maximum)
•
RMS phase jitter at 212.5MHz, using a 25.5MHz crystal
(637KHz to 10MHz): 2.76ps
•
Phase noise: Typical at 212.5MHz
Offset
Noise Power
100Hz ................. -92 dBc/Hz
1KHz ................. -112 dBc/Hz
10KHz ................. -120 dBc/Hz
100KHz ................. -122 dBc/Hz
•
3.3V supply voltage
•
0°C to 70°C ambient operating temperature
•
Lead-Free package available.
F
UNCTION
T
ABLE
Inputs
MR
1
0
0
0
0
F_SEL1
X
0
0
1
1
F_SEL0
X
0
1
0
1
25.5MHz
25.5MHz
25MHz
25MHz
XTAL
Output Frequency
F_OUT
LOW
106.25MHz
212.5MHz
125MHz
250MHz
•
Industrial temperature information available upon request
B
LOCK
D
IAGRAM
P
IN
A
SSIGNMENT
Q0
nQ0
Q1
nQ1
Q2
nQ2
Q3
nQ3
Q4
nQ4
Q5
nQ5
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
V
CCO
F_SEL0
F_SEL1
MR
XTAL1
XTAL2
V
EE
V
CCA
V
CC
PLL_SEL
V
EE
V
CCO
XTAL1
OSC
XTAL2
0
1
6
Output
Divider
PLL
/
6
/
Q0:Q5
nQ0:nQ5
Feedback
Divider
ICS84325
24-Lead, 300-MIL SOIC
7.5mm x 15.33mm x 2.3mm body package
M Package
Top View
F_SEL1
MR
PLL_SEL
F_SEL0
84325EM
www.idt.com
1
REV. C JULY 21, 2010
ICS84325
C
RYSTAL
-
TO
-3.3V LVPECL
F
REQUENCY
S
YNTHESIZER WITH
F
ANOUT
B
UFFER
T
ABLE
1. P
IN
D
ESCRIPTIONS
Number
1, 2
3, 4
5, 6
7, 8
9, 10
11, 12
1 3, 24
16
14, 18
15
17
19, 20
21
22
23
Name
Q0, nQ0
Q1, nQ1
Q2, nQ2
Q3, nQ3
Q4, nQ4
Q5, nQ5
V
CCO
V
CC
V
EE
PLL_SEL
V
CCA
XTAL2, XTAL1
MR
F_SEL1
F_SEL0
Input
Power
Input
Input
Input
Input
Pullup
Type
Output
Output
Output
Output
Output
Output
Power
Power
Description
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Output supply pins.
Core supply pin.
Negative supply pins.
Selects between the PLL and cr ystal inputs as the input to the dividers.
When HIGH, selects PLL. When LOW, selects XTAL1, XTAL2.
LVCMOS / LVTTL interface levels.
Analog supply pin.
Cr ystal oscillator interface. XTAL1 is the input. XTAL2 is the output.
Active High Master Reset. When logic HIGH, the internal dividers are
reset causing the true outputs Qx to go low and the inver ted outputs
Pulldown
nQx to go high. When logic LOW, the internal dividers and the outputs
are enabled. LVCMOS / LVTTL interface levels.
Pulldown Feedback frequency select pin. LVCMOS / LVTTL interface levels.
Pullup
Output select pin. LVCMOS / LVTTL interface levels.
NOTE:
Pullup
and
Pulldown
refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
T
ABLE
2. P
IN
C
HARACTERISTICS
Symbol
C
IN
R
PULLUP
R
PULLDOWN
Parameter
Input Capacitance
Input Pullup Resistor
Input Pulldown Resistor
Test Conditions
Minimum
Typical
4
51
51
Maximum
Units
pF
KΩ
KΩ
84325EM
www.idt.com
2
REV. C JULY 21, 2010
ICS84325
C
RYSTAL
-
TO
-3.3V LVPECL
F
REQUENCY
S
YNTHESIZER WITH
F
ANOUT
B
UFFER
A
BSOLUTE
M
AXIMUM
R
ATINGS
Supply Voltage, V
CC
Inputs, V
I
Outputs, I
O
Continuous Current
Surge Current
Package Thermal Impedance,
θ
JA
Storage Temperature, T
STG
4.6V
-0.5V to V
CC
+ 0.5V
50mA
100mA
50°C/W (0 lfpm)
-65°C to 150°C
NOTE: Stresses beyond those listed under Absolute
Maximum Ratings may cause permanent damage to the
device. These ratings are stress specifications only. Functional
operation of product at these conditions or any conditions be-
yond those listed in the
DC Characteristics
or
AC Character-
istics
is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect product reliability.
T
ABLE
3A. P
OWER
S
UPPLY
DC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO
= 3.3V±5%, T
A
= 0°C
TO
70°C
Symbol
V
CC
V
CCA
I
EE
I
CCA
Parameter
Core Supply Voltage
Analog Supply Voltage
Power Supply Current
Analog Supply Current
Test Conditions
Minimum
3.135
3.135
Typical
3.3
3.3
Maximum
3.465
3.465
210
27
Units
V
V
mA
mA
T
ABLE
3B. LVCMOS / LVTTL DC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO
= 3.3V±5%, T
A
= 0°C
TO
70°C
Symbol
V
IH
V
IL
I
IH
I
IL
Parameter
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
PLL_SEL, MR,
F_SEL0, F_SEL1
PLL_SEL, MR,
F_SEL0, F_SEL1
MR, F_SEL1
PLL_SEL, F_SEL0
MR, F_SEL1
PLL_SEL, F_SEL0
Test Conditions
Minimum
2
-0.3
V
CC
= V
IN
= 3.465V
V
CC
= V
IN
= 3.465V
V
CC
= 3.465V, V
IN
= 0V
V
CC
= 3.465V, V
IN
= 0V
-5
-150
Typical
Maximum
V
CC
+ 0.3
0.8
150
5
Units
V
V
µA
µA
µA
µA
T
ABLE
3C. LVPECL DC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO
= 3.3V±5%, T
A
= 0°C
TO
70°C
Symbol
V
OH
V
OL
V
SWING
Parameter
Output High Voltage; NOTE 1
Output Low Voltage; NOTE 1
Peak-to-Peak Output Voltage Swing
Test Conditions
Minimum
V
CCO
- 1.4
V
CCO
- 2.0
0.6
Typical
Maximum
V
CCO
- 0.8
V
CCO
- 1.7
1.2
Units
V
V
V
NOTE 1: Outputs terminated with 50
Ω
to V
CCO
- 2V.
84325EM
www.idt.com
3
REV. C JULY 21, 2010
ICS84325
C
RYSTAL
-
TO
-3.3V LVPECL
F
REQUENCY
S
YNTHESIZER WITH
F
ANOUT
B
UFFER
T
ABLE
4. C
RYSTAL
C
HARACTERISTICS
Parameter
Mode of Oscillation
Frequency
Equivalent Series Resistance (ESR)
Shunt Capacitance
25
Test Conditions
Minimum
Typical Maximum
25.5
50
7
Units
MHz
Ω
pF
Fundamental
T
ABLE
5. AC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO
= 3.3V±5%, T
A
= 0°C
TO
70°C
Symbol Parameter
F
OUT
Output Frequency
Output Skew; NOTE 1, 2
Output Rise/Fall Time
20% to 80%
fOUT = 106.25MHz
odc
Output Duty Cycle
fOUT = 125MHz
fOUT = 212.5MHz
fOUT = 250MHz
300
48
46
43
40
Test Conditions
Minimum
106.25
Typical
Maximum
250
60
800
52
54
57
60
1
Units
MHz
ps
ps
%
%
%
%
ms
t
sk(o)
t
R
/ t
F
t
LOCK
PLL Lock Time
See Parameter Measurement Information section.
NOTE 1: Defined as skew between outputs at the same supply voltage and with equal load conditions.
Measured at V
CCO
/2.
NOTE 2: This parameter is defined in accordance with JEDEC Standard 65.
84325EM
www.idt.com
4
REV. C JULY 21, 2010
ICS84325
C
RYSTAL
-
TO
-3.3V LVPECL
F
REQUENCY
S
YNTHESIZER WITH
F
ANOUT
B
UFFER
T
YPICAL
P
HASE
N
OISE
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
-160
-170
-180
-190
100
1k
10k
100k
➚
Fibre Channel 1
Bandpass Filter
Jitter BW
Source
Mode
Jitter Filter
Process Result
Noise only
106.250M Hz
Stop Freq.
40.000M Hz
Jitter
2.62 ps
Diff. Jitter
P
HASE
N
OISE
Freq. carrier
Start Freq.
10.000
(
dBc
)
H
Z
O
FFSET
F
REQUENCY
(H
Z
)
0
-10
-20
-30
-40
-50
-60
-70
P
HASE
N
OISE
( )
dBc
H
Z
-80
-90
-100
-130
-140
-150
-160
-170
-180
-190
100
1k
10k
O
FFSET
F
REQUENCY
(H
Z
)
84325EM
www.idt.com
5
➚
-110
-120
Raw phase noise data
➚
Raw phase noise data
➚
Phase noise result by adding
Bandpass Filter to raw data
1M
10M
100M
➚
Fibre Channel 2
Bandpass Filter
Jitter BW
Source
Mode
Jitter Filter
Process Result
Noise only
212.500M Hz
Stop Freq.
40.000M Hz
Jitter
2.76 ps
Diff. Jitter
Freq. carrier
Start Freq.
10.000
➚
Phase noise result by adding
Bandpass Filter to raw data
100k
1M
10M
100M
REV. C JULY 21, 2010
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