FemtoClock
®
Crystal-to-3.3V LVPECL
Clock Generator
843051
DATA SHEET
General Description
The 843051 is a Gigabit Ethernet Clock Generator. The 843051 can
synthesize 10 Gigabit Ethernet, SONET, or Serial ATA reference
clock frequencies with the appropriate choice of crystal and output
divider. The 843051 has excellent phase jitter performance and 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
Crystal oscillator interface designed for 18pF parallel resonant
crystals
RMS phase jitter at:
155.52MHz (12kHz – 20MHz): 0.74ps (typical)
156.25MHz (1.875MHz – 20MHz): 0.43ps (typical)
161.13MHz (1.933Hz – 20MHz): 0.43ps (typical)
Offset
Noise Power
-95 dBc/Hz
-110 dBc/Hz
-125 dBc/Hz
-125 dBc/Hz
•
•
•
•
Frequency Table
Inputs
Crystal Frequency (MHz)
20.141601
20.141601
19.53125
19.53125
19.44
19.44
18.75
18.75
FREQ_SEL
0
1
0
1
0
1
0
1
100Hz
1kHz
10kHz
100kHz
Full 3.3V output supply mode
0°C to 70°C ambient operating temperature
Available in lead-free (RoHS 6) package
Output Frequency Range (MHz)
161.132812
80.566406
156.25
78.125
155.52
77.76
150
75
Block Diagram
Pin Assignment
V
CCA
V
EE
XTAL_OUT
XTAL_IN
1
2
3
4
8
7
6
5
V
CC
Q0
nQ0
FREQ_SEL
XTAL_IN
OSC
XTAL_OUT
Phase
Detector
VCO
0 ÷4 (default)
1 ÷8
Q0
nQ0
÷32
(fixed)
843051
8 Lead TSSOP
4.40mm x 3.0mm package body
843051 REVISION B 10/15/15
1
©2015 Integrated Device Technology, Inc.
843051 DATA SHEET
Table 1. Pin Descriptions
Number
1
2
3,
4
5
6, 7
8
Name
V
CCA
V
EE
XTAL_OUT
XTAL_IN
FREQ_SEL
nQ0, Q0
V
CC
Power
Power
Input
Input
Output
Power
Pulldown
Type
Description
Analog supply pin
Negative supply pin.
Crystal oscillator interface. XTAL_IN is the input, XTAL_OUT is the output.
Frequency select pin. LVCMOS/LVTTL interface levels.
Differential output pair. LVPECL interface levels.
Core supply pin.
NOTE:
Pulldown
refers to internal input resistors. See Table 2,
Pin Characteristics,
for typical values.
Table 2. Pin Characteristics
Symbol
C
IN
R
PULLDOWN
Parameter
Input Capacitance
Input Pulldown 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
Continuous Current
Surge Current
Package Thermal Impedance,
JA
Storage Temperature, T
STG
Rating
4.6V
-0.5V to V
CC
+ 0.5V
50mA
100mA
101.7C/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
= 0°C to 70°C
Symbol
V
CC
V
CCA
I
CC
I
CCA
I
EE
Parameter
Core Supply Voltage
Analog Supply Voltage
Power Supply Current
Analog Supply Current
Power Supply Current
Test Conditions
Minimum
3.135
3.135
Typical
3.3
3.3
Maximum
3.465
3.465
70
15
85
Units
V
V
mA
mA
mA
FEMTOCLOCK
®
CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
2
REVISION B 10/15/15
843051 DATA SHEET
Table 3B. LVCMOS/LVTTL DC Characteristics,
V
CC
= 3.3V ± 5%, V
EE
= 0V, 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
V
CC
= V
IN
= 3.465V
V
CC
= 3.465V, V
IN
= 0V
-5
Test Conditions
Minimum
2
-0.3
Typical
Maximum
V
CC
+ 0.3
0.8
150
Units
V
V
µA
µA
Table 3C. LVPECL DC Characteristics,
V
CC
= 3.3V ± 5%, V
EE
= 0V, 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
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 4. Crystal Characteristics
Parameter
Mode of Oscillation
Frequency
Equivalent Series Resistance (ESR)
Shunt Capacitance
12
Test Conditions
Minimum
Typical
Fundamental
40
50
7
MHz
Maximum
Units
pF
AC Electrical Characteristics
Table 5. AC Characteristics,
V
CC
= 3.3V ± 5%, V
EE
= 0V, T
A
= 0°C to 70°
Symbol
f
OUT
Parameter
Output Frequency
155.52MHz, Integration Range: 12kHz – 20MHz
156.25MHz, Integration Range: 1.875MHz – 20MHz
tjit(Ø)
RMS Phase Jitter,
Random; NOTE 1
156.25MHz, Integration Range: 12kHz – 20MHz
161.13MHz, Integration Range: 1.933MHz – 20MHz
161.13MHz, Integration Range: 12kHz – 20MHz
t
R
/ t
F
odc
Output Rise/Fall Time
Output Duty Cycle
20% to 80%
325
49
Minimum
Typical
155.52
156.25
161.13
0.74
0.43
0.75
0.43
0.72
600
51
Maximum
Units
MHz
MHz
MHz
ps
ps
ps
ps
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.
REVISION B 10/15/15
3
FEMTOCLOCK
®
CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
843051 DATA SHEET
Typical Phase Noise at 155.52MHz
0
-10
-20
-30
-40
-50
-60
dBc
Hz
-70
-80
-90
-100
155.52MHz
RMS Phase Jitter (Random)
12kHz to 20MHz = 0.74ps (typical)
➝
1k
10k
Filter
Noise Power
➝
-110
-120
-130
-140
-150
-160
-170
-180
-190
100
Raw Phase Noise Data
➝
Phase Noise Result by adding
a filter to raw data
100k
Offset Frequency (Hz)
1M
10M
100M
FEMTOCLOCK
®
CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
4
REVISION B 10/15/15
843051 DATA SHEET
Typical Phase Noise at 156.25MHz
0
-10
-20
-30
-40
-50
-60
dBc
Hz
-70
-80
-90
-100
156.25MHz
RMS Phase Jitter (Random)
1.875MHz to 20MHz = 0.43ps (typical)
➝
➝
Raw Phase Noise Data
1k
10k
100k
Offset Frequency (Hz)
Gb Ethernet Filter
Noise Power
-110
-120
-130
-140
-150
-160
-170
-180
-190
100
➝
Phase Noise Result by adding a
Gb Ethernet filter to raw data
1M
10M
100M
REVISION B 10/15/15
5
FEMTOCLOCK
®
CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
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