FemtoClock
®
Crystal-to-3.3V
LVPECL Frequency Synthesizer
G
ENERAL
D
ESCRIPTION
The 8430252I-45 is a 2 output LVPECL and LVCMOS/LVTTL
Synthesizer optimized to generate Ethernet reference clock
frequencies. Using a 25MHz, 18pF parallel resonant crystal, the
following fre-quencies can be generated: 156.25MHz LVPECL
output and, 125MHz LVCMOS output. The 8430252I-45 uses IDT’s
3
RD
generation low phase noise VCO technology and can achieve
1ps or lower typical rms phase jitter, easily meeting Ethernet jitter
requirements. The 8430252I-45 is packaged in a small 16-pin
TSSOP package.
8430252I-45
DATASHEET
F
EATURES
• One differential 3.3V LVPECL output and
One LVCMOS/LVTTL output
• Crystal oscillator interface designed for a 25MHz,
18pF parallel resonant crystal
• A 25MHz crystal generates both an output frequency of
156.25MHz (LVPECL) and 125MHz (LVCMOS)
• VCO frequency: 625MHz
• RMS phase jitter @ 156.25MHz (1.875MHz - 20MHz) using a
25MHz crystal: 0.39ps (typical)
• Full 3.3V supply mode
• -40°C to 85°C ambient operating temperature
• Available in lead-free (RoHS 6) package
B
LOCK
D
IAGRAM
P
IN
A
SSIGNMENT
OE
V
EE
QA
V
CCO
_
A
nc
nc
V
CCA
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
CLK_EN
V
EE
QB
nQB
V
CCO
_
B
XTAL_IN
XTAL_OUT
V
EE
8430252I-45
16-Lead TSSOP
4.4mm x 5.0mm x 0.92mm
package body
G Package
Top View
8430252I-45 REVISION B DECEMBER 9, 2014
1
©2014 Integrated Device Technology, Inc.
8430252I-45 DATA SHEET
T
ABLE
1. P
IN
D
ESCRIPTIONS
Number
1
2, 9, 15
3
4
5, 6
7
8
10, 11
12
13, 14
16
Name
OE
V
V
EE
Type
Input
Power
Output
Power
Unused
Power
Power
Input
Power
Output
Input
Pullup
Pullup
Description
Output enable pin. LVCMOS/LVTTL interface levels.
See Table 3A Function Table.
Negative supply pins.
LVCMOS/LVTTL clock output.
Output supply pin for QA output.
No connect.
Analog supply pin.
Core supply pin.
Crystal oscillator interface. XTAL_IN is the input, XTAL_OUT is the output.
Output supply pin for QB, nQB outputs.
Differential clock outputs. LVPECL interface levels.
Clock enable pin. LVCMOS/LVTTL interface levels.
See Table 3B Function Table.
QA
CCO_A
nc
V
CCA
V
CC
XTAL_OUT,
XTAL_IN
V
CCO_B
nQB, QB
CLK_EN
NOTE: Pullup refers to internal input resistors. See Table 2, Pin Characterisitcs, for typical values.
T
ABLE
2. P
IN
C
HARACTERISTICS
Symbol
C
IN
C
PD
R
PULLUP
R
OUT
Parameter
Input Capacitance
Power Dissipation Capacitance
Input Pullup Resistor
Output Impedance
QA
V
CCO_A
= 3.3V
V
CC
, V
CCA
, V
CCO_A,
V
CCO_B
= 3.465V
Test Conditions
Minimum
Typical
4
18
51
20
Maximum
Units
pF
pF
kΩ
Ω
T
ABLE
3A. OE S
ELECT
F
UNCTION
T
ABLE
Input
OE
0
1
Output
QA
Hi-Z
Active
T
ABLE
3B. CLK_EN S
ELECT
F
UNCTION
T
ABLE
Input
CLK_EN
0
1
QB
Low
Active
Outputs
nQB
High
Active
FEMTOCLOCK® CRYSTAL-TO-
3.3V LVPECL FREQUENCY SYNTHESIZER
2
REVISION B 12/9/14
8430252I-45 DATA SHEET
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
89°C/W (0 lfpm)
-65°C to 150°C
N OT E : S t r e s s e s b eyo n d t h o s e l i s t e d u n d e r A b s o l u t e
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 beyond
those listed in the
DC Characteristics
or
AC Characteristics
is not
implied. Exposure to absolute maximum rating conditions for ex-
tended periods may affect product reliability.
T
ABLE
4A. P
OWER
S
UPPLY
DC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO_A,
V
CCO_B
= 3.3V±5%, T
A
= -40°C
TO
85°C
Symbol
V
CC
V
CCA
V
CCO_A,
V
CCO_B
I
EE
I
CCA
Parameter
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Test Conditions
Minimum
3.135
V
CC
– 0.10
3.135
Typical
3.3
3.3
3.3
Maximum
3.465
V
CC
3.465
95
10
Units
V
V
V
mA
mA
T
ABLE
4B. LVCMOS / LVTTL DC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO_A
= 3.3V±5%, T
A
= -40°C
TO
85°C
Symbol
V
IH
V
IL
I
IH
Parameter
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
OE, CLK_EN
OE, CLK_EN
V
CC
= V
IN
= 3.465V
V
CC
= 3.465V, V
IN
= 0V
-150
2.6
0.5
V
V
Test Conditions
Minimum
2
-0.3
Typical
Maximum
V
CC
+ 0.3
0.8
5
Units
V
V
I
IL
V
OH
V
OL
Output High Voltage; NOTE 1
Output Low Voltage; NOTE 1
NOTE 1: Outputs terminated with 50Ω to V
CCO_A
/2. See Parameter Measurement Information Section,
“3.3V Output Load Test Circuit”.
T
ABLE
4C. LVPECL DC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO_B
= 3.3V±5%, T
A
= -40°C
TO
85°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_B
- 1.4
V
CCO_B
- 2.0
0.6
Typical
Maximum
V
CCO_B
- 0.9
V
CCO_B
- 1.7
1.0
Units
V
V
V
NOTE 1: Outputs terminated with 50Ω to V
CCO_B
- 2V.
REVISION B 12/9/14
3
FEMTOCLOCK® CRYSTAL-TO-
3.3V LVPECL FREQUENCY SYNTHESIZER
8430252I-45 DATA SHEET
T
ABLE
5. C
RYSTAL
C
HARACTERISTICS
Parameter
Mode of Oscillation
Frequency
Equivalent Series Resistance (ESR)
Shunt Capacitance
Drive Level
NOTE: Characterized using an 18pF parallel resonant crystal.
Test Conditions
Minimum
Typical
Fundamental
25
50
7
1
MHz
Ω
pF
mW
Maximum
Units
T
ABLE
6. AC C
HARACTERISTICS
,
V
CC
= V
CCA
= V
CCO_A,
V
CCO_B
= 3.3V±5%, T
A
= -40°C
TO
85°C
Symbol
f
OUT
tjit(Ø)
t
R
/ t
F
odc
Parameter
Output Frequency Range
RMS Phase Jitter
(Random); NOTE 1
Output
Rise/Fall Time
Output Duty Cycle
QA
QB, nQB
QA
QB, nQB
QA
125MHz (1.875MHz - 20MHz)
156.25MHz (1.875MHz - 20MHz)
20% to 80%
500
300
47
Test Conditions
Minimum
Typical
156.25
125
0.41
0.39
1200
700
53
Maximum
Units
MHz
MHz
ps
ps
ps
ps
%
QB, nQB
48
52
%
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established
when the device is mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet
specifications after thermal equilibrium has been reached under these conditions.
NOTE 1: Please refer to the Phase Noise Plots.
FEMTOCLOCK® CRYSTAL-TO-
3.3V LVPECL FREQUENCY SYNTHESIZER
4
REVISION B 12/9/14
8430252I-45 DATA SHEET
T
YPICAL
P
HASE
N
OISE AT
156.25MH
Z
0
-10
-20
-30
-40
-50
-60
-70
➤
10Gb Ethernet Filter
156.25MHz
RMS Phase Jitter (Random)
1.875Mhz to 20MHz = 0.39ps (typical)
N
OISE
P
OWER
dBc
Hz
-80
-90
-100
-110
-120
-130
-140
-150
-160
-170
-180
-190
1k
10k
Raw Phase Noise Data
➤
Phase Noise Result by adding
10Gb Ethernet Filterto raw data
100k
1M
10M
100M
T
YPICAL
P
HASE
N
OISE AT
125MH
Z
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
-160
-170
-180
-190
1k
10k
100k
➤
10Gb Ethernet Filter
125MHz
RMS Phase Jitter (Random)
1.875Mhz to 20MHz = 0.41ps (typical)
➤
O
FFSET
F
REQUENCY
(H
Z
)
N
OISE
P
OWER
dBc
Hz
Raw Phase Noise Data
➤
Phase Noise Result by adding
10Gb Ethernet Filterto raw data
1M
10M
100M
➤
O
FFSET
F
REQUENCY
(H
Z
)
REVISION B 12/9/14
5
FEMTOCLOCK® CRYSTAL-TO-
3.3V LVPECL FREQUENCY SYNTHESIZER
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