FemtoClock
®
Crystal-to-3.3V, 2.5V LVPECL
Clock Generator
G
ENERAL
D
ESCRIPTION
The 843031I-01 is an 10Gb Ethernet Clock Generator. The
843031I-01 uses an 18pF parallel resonant crystal. The 843031I-01
has excellent <1ps phase jitter performance, over the 1.875MHz -
20MHz integration range. The 843031I-01 is packaged in a small
8-pin TSSOP, making it ideal for use in systems with limited board
space.
843031I-01
DATA SHEET
F
EATURES
•
One differential 3.3V or 2.5V LVPECL output
•
Crystal oscillator interface designed for 25MHz,
18pF parallel resonant crystal
•
Output frequencies: 280MHz – 340MHz
•
VCO range: 560MHz - 680MHz
•
RMS phase jitter @ 312.5MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.46ps (typical)
•
Full 3.3V or 2.5V operating supply
•
-40°C to 85°C ambient operating temperature
•
Available in lead-free (RoHS 6) package
C
OMMON
C
ONFIGURATION
T
ABLE
Inputs
Crystal Frequency (MHz)
25
M
25
N
2
Multiplication
Value M/N
12.5
Output Frequency
(MHz)
312.5
B
LOCK
D
IAGRAM
OE
Pullup
P
IN
A
SSIGNMENT
V
CCA
V
EE
XTAL_OUT
XTAL_IN
1
2
3
4
8
7
6
5
V
CC
Q
nQ
OE
XTAL_IN
OSC
XTAL_OUT
Phase
Detector
VCO
N = ÷2
(fixed)
Q
nQ
843031I-01
8-Lead TSSOP
4.40mm x 3.0mm x 0.925mm
package body
G Package
Top View
M = ÷25
(fixed)
843031I-01 REVISION A 10/15/15
1
©2015 Integrated Device Technology, Inc.
843031I-01 DATA SHEET
T
ABLE
1. P
IN
D
ESCRIPTIONS
Number
1
2
3, 4
5
6, 7
8
Name
V
CCA
V
EE
XTAL_OUT,
XTAL_IN
OE
nQ, Q
V
CC
Power
Power
Input
Input
Output
Power
Pullup
Type
Description
Analog supply pin.
Negative supply pin.
Crystal oscillator interface. XTAL_IN is the input,
XTAL_OUT is the output.
Output Enable pin. LVCMOS/LVTTL interface levels.
Differential clock outputs. LVPECL interface levels.
Power supply pin.
NOTE:
Pullup
refers to internal input resistors. See Table 2, Pin Characteristics, for typical values.
T
ABLE
2. P
IN
C
HARACTERISTICS
Symbol
C
IN
R
PULLDOWN
Parameter
Input Capacitance
Input Pullup Resistor
Test Conditions
Minimum
Typical
4
51
Maximum
Units
pF
kΩ
T
ABLE
3. OE F
UNCTION
T
ABLE
Input
OE
0
1
Outputs
Q/nQ
Hi-Z
Enabled
FEMTOCLOCK
®
CRYSTAL-TO-
3.3V, 2.5V LVPECL CLOCK GENERATOR
2
REVISION A 10/15/15
843031I-01 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
101.7°C/W (0 mps)
-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
= 3.3V±5%, T
A
= -40°C
TO
85°C
Symbol
V
CC
V
CCA
I
CCA
I
EE
Parameter
Power Supply Voltage
Analog Supply Voltage
Analog Supply Current
Power Supply Current
Test Conditions
Minimum
3.135
V
CC
– 0.12
Typical
3.3
3.3
Maximum
3.465
3.465
12
105
Units
V
V
mA
mA
T
ABLE
4B. P
OWER
S
UPPLY
DC C
HARACTERISTICS
,
V
CC
= 2.5V±5%, T
A
= -40°C
TO
85°C
Symbol
V
CC
V
CCA
I
CCA
I
EE
Parameter
Power Supply Voltage
Analog Supply Voltage
Analog Supply Current
Power Supply Current
Test Conditions
Minimum
2.375
V
CC
– 0.12
Typical
2.5
2.5
Maximum
2.625
2.625
12
90
Units
V
V
mA
mA
T
ABLE
4C. LVCMOS/LVTTL DC C
HARACTERISTICS
,
V
CC
= 3.3V±5%
OR
2.5V±5%, T
A
= -40°C
TO
85°C
Symbol
V
IH
V
IL
I
IH
I
IL
Parameter
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
Test Conditions
V
CC
= 3.3V
V
CC
= 2.5V
V
CC
= 3.3V
V
CC
= 2.5V
V
CC
= V
IN
= 3.465V or 2.625V
V
CC
= 3.465V or 2.625V, V
IN
= 0V
-150
Minimum
2
1.7
-0.3
-0.3
Typical
Maximum
V
CC
+ 0.3
V
CC
+ 0.3
0.8
0.7
5
Units
V
V
V
V
µA
µA
REVISION A 10/15/15
3
FEMTOCLOCK
®
CRYSTAL-TO-
3.3V, 2.5V LVPECL CLOCK GENERATOR
843031I-01 DATA SHEET
T
ABLE
4D. LVPECL DC C
HARACTERISTICS
,
V
CC
= 3.3V±5%
OR
2.5V±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
CC
- 1.4
V
CC
- 2.0
0.6
Typical
Maximum
V
CC
- 0.9
V
CC
- 1.7
1.0
Units
V
V
V
NOTE 1: Outputs terminated with 50Ω to V
CC
- 2V.
T
ABLE
5. C
RYSTAL
C
HARACTERISTICS
Parameter
Mode of Oscillation
Frequency
Equivalent Series Resistance (ESR)
Shunt Capacitance
Drive Level
NOTE: It is not recommended to overdrive the crystal input with an external clock.
22.4
Test Conditions
Minimum
Typical
Fundamental
25
27.2
40
7
300
MHz
Ω
pF
mW
Maximum
Units
T
ABLE
6A. AC C
HARACTERISTICS
,
V
CC
= 3.3V±5%, T
A
= -40°C
TO
85°C
Symbol
f
OUT
tjit(Ø)
t
R
/ t
F
Parameter
Output Frequency
RMS Phase Jitter ( Random);
NOTE 1
Output Rise/Fall Time
312.5MHz @ Integration Range:
1.875MHz - 20MHz
20% to 80%
150
Test Conditions
Minimum
280
Typical
312.5
0.46
500
Maximum
340
Units
MHz
ps
ps
odc
Output Duty Cycle
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 conditons.
NOTE 1: Please refer to the Phase Noise Plots following this section.
T
ABLE
6B. AC C
HARACTERISTICS
,
V
CC
= 2.5V±5%, T
A
= -40°C
TO
85°C
Symbol
f
OUT
tjit(Ø)
t
R
/ t
F
Parameter
Output Frequency
RMS Phase Jitter ( Random);
NOTE 1
Output Rise/Fall Time
312.5MHz @ Integration Range:
1.875MHz - 20MHz
20% to 80%
150
Test Conditions
Minimum
280
Typical
312.5
0.48
500
Maximum
340
Units
MHz
ps
ps
odc
Output Duty Cycle
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 conditons.
NOTE 1: Please refer to the Phase Noise Plots following this section.
FEMTOCLOCK
®
CRYSTAL-TO-
3.3V, 2.5V LVPECL CLOCK GENERATOR
4
REVISION A 10/15/15
843031I-01 DATA SHEET
T
YPICAL
P
HASE
N
OISE AT
312.5MH
Z
A
T
3.3V
0
-10
-20
-30
-40
-50
312.5MHz
RMS Phase Jitter (Random)
1.875Mhz to 20MHz = 0.46ps (typical)
10Gb Ethernet Filter
N
OISE
P
OWER
dBc
Hz
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
-160
-170
-180
-190
100
1K
10K
100K
1M
10M
100M
Raw Phase Noise Data
Phase Noise result by adding
10Gb Ethernet Filter to raw data
O
FFSET
F
REQUENCY
(H
Z
)
REVISION A 10/15/15
5
FEMTOCLOCK
®
CRYSTAL-TO-
3.3V, 2.5V LVPECL CLOCK GENERATOR
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EEWORLD
