FEMTOCLOCKS™ CRYSTAL-TO-3.3V LVPECL
CLOCK GENERATOR
ICS843021-57
General Description
The ICS843021-57 is a Gigabit Ethernet Clock
Generator and a member of the HiPerClocks
TM
HiPerClockS™
family of high performance devices from IDT. The
ICS843021-57 uses a 25MHz crystal to synthesize
125MHz. The ICS843021-57 has excellent phase
jitter performance, over the 1.875MHz – 20MHz integration range.
The ICS843021-57 is packaged in a small 8-pin TSSOP, making it
ideal for use in systems with limited board space.
Features
•
•
•
•
•
•
•
•
•
One differential 3.3V LVPECL output
Output frequency range: 100MHz – 140MHz
VCO range: 500MHz – 700MHz
Output duty cycle range: 47% – 53%
RMS phase jitter at 125MHz, using a 25MHz crystal
(1.875MHz – 20MHz): 0.40ps (typical)
Full 3.3V output supply mode
0°C to 70°C ambient operating temperature
Available in lead-free (RoHS 6) package
Industrial temperature information available upon request
ICS
Table 1. Frequency Table
Inputs
Crystal Frequency (MHz)
25
26.6
Output Frequency Range
(MHz)
125
133
Block Diagram
XTAL_IN
Pin Assignment
Phase
Detector
VCO
÷5
Q
nQ
V
CCA
V
EE
XTAL_OUT
XTAL_IN
1
2
3
4
8
7
6
5
V
CC
Q
nQ
nc
OSC
XTAL_OUT
÷25
(fixed)
ICS843021-57
8 Lead TSSOP
4.40mm x 3.0mm x 0.925
package body
G Package
Top View
IDT™ / ICS™
3.3V LVPECL CLOCK GENERATOR
1
ICS843021AG-57
REV. AJUNE 19, 2007
ICS843021-57
FEMTOCLOCK™CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
Table 2. Pin Descriptions
Number
1
2
3,
4
5
6, 7
8
Name
V
CCA
V
EE
XTAL_OUT
XTAL_IN
nc
nQ, Q
V
CC
Power
Power
Input
Unused
Output
Power
Type
Description
Analog supply pin
Negative supply pin.
Crystal oscillator interface. XTAL_IN is the input, XTAL_OUT is the output.
No connect.
Differential output pair. LVPECL interface levels.
Core supply pin.
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
Continuous Current
Surge Current
Package Thermal Impedance,
θ
JA
Storage Temperature, T
STG
Rating
4.6V
-0.5V to V
CC
+ 0.5V
50mA
100mA
112.4°C/W (0 mps)
-65°C to 150°C
DC Electrical Characteristics
Table 3A. Power Supply DC Characteristics,
V
CC
= 3.3V ± 10%, V
EE
= 0V, T
A
= 0°C to 70°C
Symbol
V
CC
V
CCA
I
CC
I
CCA
I
EE
Parameter
Power Supply Voltage
Analog Supply Voltage
Power Supply Current
Analog Supply Current
Power Supply Current
Test Conditions
Minimum
2.97
V
CC
– 0.09
Typical
3.3
3.3
Maximum
3.63
V
CC
57
9
66
Units
V
V
mA
mA
mA
IDT™ / ICS™
3.3V LVPECL CLOCK GENERATOR
2
ICS843021AG-57
REV. AJUNE 19, 2007
ICS843021-57
FEMTOCLOCK™CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
Table 3B. LVPECL DC Characteristics,
V
CC
= 3.3V ± 10%, V
EE
= 0V, T
A
= 0°C to 70°C
Symbol
V
OH
V
OL
V
SWING
Parameter
Output High Current; NOTE 1
Output Low Current; 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
µA
µA
V
NOTE 1: Outputs termination with 50Ω to V
CC
– 2V.
AC Electrical Characteristics
Table 4. AC Characteristics,
V
CC
= 3.3V ± 10%, V
EE
= 0V, T
A
= 0°C to 70°
Parameter Symbol
f
OUT
tjit(Ø)
t
R
/ t
F
odc
Output Frequency
RMS Phase Jitter, Random;
NOTE 1
Output Rise/Fall Time
Output Duty Cycle
125MHz,
Integration Range: 1.875MHz – 20MHz
20% to 80%
200
47
Test Conditions
Minimum
100
0.40
550
53
Typical Maximum
140
Units
MHz
ps
ps
%
NOTE 1: Please refer to Phase Noise Plot.
IDT™ / ICS™
3.3V LVPECL CLOCK GENERATOR
3
ICS843021AG-57 REV. A JUNE 19, 2007
ICS843021-57
FEMTOCLOCK™CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
Typical Phase Noise at 125MHz
➝
Gigabit Ethernet Filter
125MHz
RMS Phase Jitter (Random)
1.875Hz to 20MHz = 0.40ps (typical)
dBc
Hz
Noise Power
➝
Offset Frequency (Hz)
IDT™ / ICS™
3.3V LVPECL CLOCK GENERATOR
4
➝
Raw Phase Noise Data
Phase Noise Result by adding a
Gigabit Ethernet filter to raw data
ICS843021AG-57
REV. AJUNE 19, 2007
ICS843021-57
FEMTOCLOCK™CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
Parameter Measurement Information
2V
2V
Noise Power
Phase Noise Plot
V
CC
V
CCA
Qx
SCOPE
Phase Noise Mask
LVPECL
nQx
V
EE
f
1
Offset Frequency
f
2
RMS Jitter = Area Under the Masked Phase Noise Plot
-1.3V±0.33V
-
-
3.3V LVPECL Output Load AC Test Circuit
RMS Phase Jitter
nQ
80%
Q
80%
V
SW I N G
t
PW
t
PERIOD
Clock
Outputs
x 100%
20%
t
R
t
F
20%
odc =
t
PW
t
PERIOD
Output Duty Cycle/Pulse Width/Period
Output Rise/Fall Time
IDT™ / ICS™
3.3V LVPECL CLOCK GENERATOR
5
ICS843021AG-57 REV. A JUNE 19, 2007
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