FemtoClock
®
Crystal-to-3.3V, 2.5V
LVPECL Clock Generator
843021I-01
DATA SHEET
General Description
The 843021I-01 is a Gigabit Ethernet Clock Generator. The
843021I-01 uses a 25MHz crystal to synthesize 125MHz. The
843021I-01 has excellent phase jitter performance, over the
1.875MHz – 20MHz integration range. The 843021I-01 is packaged
in a small 8-pin TSSOP, making it ideal for use in systems with
limited board space.
Features
•
•
•
•
•
•
•
•
One differential 3.3V or 2.5V LVPECL output
Crystal oscillator interface designed for 25MHz,
18pF parallel resonant crystal
Output frequency range: 125MHz, using a 25MHz crystal
VCO range: 490MHz – 640MHz
RMS phase jitter @ 125MHz, using a 25MHz crystal
(1.875MHz – 20MHz): 0.41ps (typical)
Full 3.3V or 2.5V operating supply
-40°C to 85°C ambient operating temperature
Available in lead-free (RoHS 6) package
Block Diagram
OE
Pullup
25MHz
Pin Assignment
V
CC
XTAL_OUT
XTAL_IN
V
EE
1
2
3
4
8
7
6
5
Q
nQ
V
CC
OE
XTAL_IN
OSC
XTAL_OUT
Phase
Detector
VCO
÷4
(fixed)
Q
nQ
÷20
(fixed)
843021I-01
8 Lead TSSOP
4.40mm x 3.0mm x 0.925mm package body
G Package
Top View
843021I-01 Rev A 9/25/15
#
©2015 Integrated Device Technology, Inc.
843021I-01 Data Sheet
FEMTOCLOCK
®
CRYSTAL-TO-3.3V, 2.5V LVPECL CLOCK GENERATOR
Table 1. Pin Descriptions
Number
1, 6
2,
3
4
5
7, 8
Name
V
CC
XTAL_OUT
XTAL_IN
V
EE
OE
nQ, Q
Power
Input
Power
Input
Output
Pullup
Type
Description
Power supply pins.
Crystal oscillator interface. XTAL_IN is the input, XTAL_OUT is the output.
Negative supply pin.
Active high output enable. When logic HIGH, the outputs are enabled and active.
When logic LOW, the outputs are disabled and are in a high impedance state.
LVCMOS/LVTTL interface levels.
Differential output pair. LVPECL interface levels.
NOTE:
Pullup
refers to internal input resistors. See Table 2,
Pin Characteristics,
for typical values.
Table 2. Pin Characteristics
Symbol
C
IN
R
PULLUP
Parameter
Input Capacitance
Input Pullup Resistor
Test Conditions
Minimum
Typical
4
51
Maximum
Units
pF
k
Absolute Maximum Ratings
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 beyond
those listed in the
DC Characteristics or AC Characteristics
is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect product reliability.
Item
Supply Voltage, V
CC
Inputs, V
I
Outputs, I
O
Continuos Current
Surge Current
Package Thermal Impedance,
JA
Storage Temperature, T
STG
Rating
4.6V
-0.5V to V
CC
+ 0.5V
50mA
100mA
129.5C/W (0 mps)
-65C to 150C
DC Electrical Characteristics
Table 3A. Power Supply DC Characteristics,
V
CC
= 3.3V ± 5%, V
EE
= 0V, T
A
= -4
0°C to 85°C
Symbol
V
CC
I
EE
Parameter
Positive Supply Voltage
Power Supply Current
Test Conditions
Minimum
3.135
Typical
3.3
Maximum
3.465
64
Units
V
mA
Table 3B. Power Supply DC Characteristics,
V
CC
= 2.5V ± 5%, V
EE
= 0V, T
A
= -4
0°C to 85°C
Symbol
V
CC
I
EE
Parameter
Positive Supply Voltage
Power Supply Current
Test Conditions
Minimum
2.375
Typical
2.5
Maximum
2.625
62
Units
V
mA
843021I-01 Rev A 9/25/15
2
©2015 Integrated Device Technology, Inc.
843021I-01 Data Sheet
FEMTOCLOCK
®
CRYSTAL-TO-3.3V, 2.5V LVPECL CLOCK GENERATOR
Table 3C. LVCMOS/LVTTL DC Characteristics,
V
CC
= 3.3V ± 5% or 2.5V ± 5%, V
EE
= 0V, T
A
=
0°C to 70°C
Symbol
V
IH
Parameter
Input High Voltage
Test Conditions
V
CC
= 3.3V
V
CC
= 2.5V
Input Low Voltage
Input High Current
Input Low Current
V
CC
= 3.3V
V
CC
= 2.5V
V
CC
= V
IN
= 3.465 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
V
IL
I
IH
I
IL
Table 3D. LVPECL DC Characteristics,
V
CC
= 3.3V ± 5%, V
EE
= 0V, T
A
= -4
0°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 termination with 50 to V
CC
– 2V.
Table 3E. LVPECL DC Characteristics,
V
CC
= 2.5V ± 5%, V
EE
= 0V, T
A
= -4
0°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
0.4
Typical
Maximum
V
CC
– 0.9
V
CC
– 1.5
1.0
Units
V
V
V
NOTE 1: Outputs termination with 50 to V
CC
– 2V.
Table 4. Crystal Characteristics
Parameter
Mode of Oscillation
Frequency; NOTE 1
Equivalent Series Resistance (ESR)
Shunt Capacitance
Drive Level
Test Conditions
Minimum
Typical
Fundamental
25
90
7
300
MHz
Maximum
Units
pF
µW
843021I-01 Rev A 9/25/15
3
©2015 Integrated Device Technology, Inc.
843021I-01 Data Sheet
FEMTOCLOCK
®
CRYSTAL-TO-3.3V, 2.5V LVPECL CLOCK GENERATOR
AC Electrical Characteristics
Table 5A. AC Characteristics,
V
CC
= 3.3V ± 5%, V
EE
= 0V, T
A
= -4
0°C to 85°C
Symbol
f
OUT
tjit(Ø)
t
R
/ t
F
odc
Parameter
Output Frequency
RMS Phase Jitter, Random;
NOTE 1
Output Rise/Fall Time
Output Duty Cycle
125MHz,
( Integration Range: 1.875MHz – 20MHz)
20% to 80%
250
49
Test Conditions
Minimum
122.5
Typical
125
0.41
600
51
Maximum
160
Units
MHz
ps
ps
%
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 Phase Noise Plot.
Table 5B. AC Characteristics,
V
CC
= 2.5V ± 5%, V
EE
= 0V, T
A
= -4
0°C to 85°C
Symbol
f
OUT
tjit(Ø)
t
R
/ t
F
odc
Parameter
Output Frequency
RMS Phase Jitter, Random;
NOTE 1
Output Rise/Fall Time
Output Duty Cycle
125MHz,
( Integration Range: 1.875MHz – 20MHz)
20% to 80%
250
49
Test Conditions
Minimum
122.5
Typical
125
0.42
600
51
Maximum
160
Units
MHz
ps
ps
%
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 Phase Noise Plot.
843021I-01 Rev A 9/25/15
4
©2015 Integrated Device Technology, Inc.
843021I-01 Data Sheet
FEMTOCLOCK
®
CRYSTAL-TO-3.3V, 2.5V LVPECL CLOCK GENERATOR
Typical Phase Noise at 125MHz (3.3V or 2.5V)
Noise Power
dBc
Hz
125MHz
RMS Phase Jitter (Random)
1.875MHz to 20MHz (3.3V)= 0.41ps (typical)
1.875MHz to 20MHz (2.5V)= 0.42ps (typical)
Raw Phase Noise Data
Offset Frequency (Hz)
843021I-01 Rev A 9/25/15
5
➝
Phase Noise Result by adding a
Gigabit Ethernet filter to raw data
➝
Gigabit Ethernet Filter
➝
©2015 Integrated Device Technology, Inc.
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