LVPECL Frequency-Programmable
Crystal Oscillator
IDT8N3S271
DATA SHEET
General Description
The IDT8N3S271 is a Frequency-Programmable Crystal Oscillator
with very flexible frequency programming capabilities. The device
uses IDT’s fourth generation FemtoClock® NG technology for an
optimum of high clock frequency and low phase noise performance.
The device accepts 2.5V or 3.3V supply and is packaged in a small,
lead-free (RoHS 6) 6-lead ceramic 5mm x 7mm x 1.55mm package.
The device can be factory programmed to any frequency in the range
from 15.476MHz to 866.67MHz and from 975MHz to 1,300MHz and
supports a very high degree of frequency precision of 218Hz or
better. The extended temperature range supports wireless
infrastructure, telecommunication and networking end equipment
requirements.
Features
•
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•
•
•
•
•
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Fourth generation FemtoClock® NG technology
Factory-programmable clock output frequency from 15.476MHz to
866.67MHz and from 975MHz to 1,300MHz
Frequency programming resolution is 218Hz and better
One 2.5V or 3.3V LVPECL clock output
Output enable control (positive polarity), LVCMOS/LVTTL
compatible
RMS phase jitter @ 156.25MHz (12kHz - 20MHz): 0.24ps
(typical), integer PLL feedback configuration
RMS phase jitter @ 156.25MHz (1kHz - 40MHz): 0.27ps (typical),
integer PLL feedback configuration
2.5V or 3.3V supply
-40°C to 85°C ambient operating temperature
Available in a lead-free (RoHS 6) 6-pin ceramic package
Block Diagram
PFD
&
LPF
FemtoClock® NG
VCO
1950-2600MHz
Pin Assignment
DNU
1
2
3
6
5
4
V
CC
nQ
Q
OSC
f
XTAL
2
÷P
÷N
Q
nQ
OE
V
EE
÷MINT,
MFRAC
25
Configuration Register (ROM)
OE
Pullup
7
IDT8N3S271
6-lead ceramic 5mm x 7mm x 1.55mm
package body
CD Package
Top View
IDT8N3S271CCD
REVISION A DECEMBER 17, 2012
1
©2012 Integrated Device Technology, Inc.
IDT8N3S271 Data Sheet
LVPECL FREQUENCY-PROGRAMMABLE CRYSTAL OSCILLATOR
Pin Description and Characteristic Tables
Table 1. Pin Descriptions
Number
1
2
3
4, 5
6
Name
DNU
OE
V
EE
Q, nQ
V
CC
Input
Power
Output
Power
Pullup
Type
Description
Do not use (factory use only).
Output enable pin. See Table 3A for function. LVCMOS/LVTTL interface levels.
Negative power supply.
Differential clock output. LVPECL interface levels.
Positive power supply.
NOTE:
Pullup
refers to internal input resistor. See Table 2,
Pin Characteristics,
for typical values.
Table 2. Pin Characteristics
Symbol
C
IN
R
PULLUP
Parameter
Input Capacitance
Input Pullup Resistor
OE
Test Conditions
Minimum
Typical
5.5
50
Maximum
Units
pF
k
Function Tables
Table 3A. OE Configuration
Input
OE
0
1 (default)
Output Enable
Outputs Q, nQ are in high-impedance state.
Outputs are enabled.
NOTE: OE is an asynchronous control.
Table 3B. Output Frequency Range
15.476MHz to 866.67MHz
975MHz to 1,300MHz
NOTE: Supported output frequency range. The output frequency can be programmed to any frequency in this range and to a precision of
218Hz or better.
IDT8N3S271CCD
REVISION A DECEMBER 17, 2012
2
©2012 Integrated Device Technology, Inc.
IDT8N3S271 Data Sheet
LVPECL FREQUENCY-PROGRAMMABLE CRYSTAL OSCILLATOR
Principles of Operation
The block diagram consists of the internal 3rd overtone crystal and
oscillator which provide the reference clock f
XTAL
of either
114.285MHz or 100MHz. The PLL includes the FemtoClock NG VCO
along with the Pre-divider (P), the feedback divider (M) and the post
divider (N). The
P, M,
and
N
dividers determine the output frequency
based on the f
XTAL
reference. The feedback divider is fractional
supporting a huge number of output frequencies. The configuration
of the feedback divider to integer-only values results in an improved
output phase noise characteristics at the expense of the range of
output frequencies. Internal registers are used to hold one factory
pre-set
P, M,
and
N
configuration setting. The
P, M,
and
N
frequency
configuration supports an output frequency range from 15.476MHz to
866.67MHz and from 975MHz to 1,300MHz.
The devices use the fractional feedback divider with a delta-sigma
modulator for noise shaping and robust frequency synthesis
capability. The relatively high reference frequency minimizes phase
noise generated by frequency multiplication and allows more efficient
shaping of noise by the delta-sigma modulator.
The output frequency is determined by the 2-bit pre-divider (P), the
feedback divider (M) and the 7-bit post divider (N). The feedback
divider (M) consists of both a 7-bit integer portion (MINT) and an
18-bit fractional portion (MFRAC) and provides the means for
high-resolution frequency generation. The output frequency f
OUT
is
calculated by:
1
f OUT
=
f XTAL
------------
MINT
+
MFRAC
+ 0.5
------------------------------------
-
P
N
18
2
Frequency Configuration
An order code is assigned to each frequency configuration
programmed by the factory (default frequencies). For more
information on the available default frequencies and order codes,
please see the Ordering Information section in this document. For
available order codes, see the
FemtoClock NG Ceramic-Package XO
and VCXO Ordering Product Information
document.
For more information on programming capabilities of the device for
custom frequency and pull-range configurations, see the
FemtoClock
NG Ceramic 5x7 Module Programming Guide.
IDT8N3S271CCD
REVISION A DECEMBER 17, 2012
3
©2012 Integrated Device Technology, Inc.
IDT8N3S271 Data Sheet
LVPECL FREQUENCY-PROGRAMMABLE CRYSTAL OSCILLATOR
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
Item
Supply Voltage, V
CC
Inputs, V
I
Outputs, I
O
Continuous Current
Surge Current
Package Thermal Impedance,
JA
Storage Temperature, T
STG
Characteristics or AC Characteristics
is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect
product reliability.
Rating
3.63V
-0.5V to V
CC
+ 0.5V
50mA
100mA
49.4C/W (0 mps)
-65C to 150C
DC Electrical Characteristics
Table 4A. Power Supply DC Characteristics, V
CC
=
3.3V ± 5%, V
EE
=
0V, T
A
= -40°C to 85°C
Symbol
V
CC
I
EE
Parameter
Power Supply Voltage
Power Supply Current
Test Conditions
Minimum
3.135
Typical
3.3
123
Maximum
3.465
148
Units
V
mA
Table 4B. Power Supply DC Characteristics, V
CC
=
2.5V ± 5%, V
EE
=
0V, T
A
= -40°C to 85°C
Symbol
V
CC
I
EE
Parameter
Power Supply Voltage
Power Supply Current
Test Conditions
Minimum
2.375
Typical
2.5
119
Maximum
2.625
143
Units
V
mA
Table 4C. LVPECL DC Characteristics, V
CC
= 3.3V ± 5%, V
EE
=
0V, 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
– 0.8
V
CC
– 1.6
1.0
Units
V
V
V
NOTE 1: Outputs terminated with 50
to V
CC
– 2V.
Table 4D. LVPECL DC Characteristics, V
CC
= 2.5V ± 5%, V
EE
=
0V, 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
0.4
Typical
Maximum
V
CC
– 0.8
V
CC
– 1.5
1.0
Units
V
V
V
NOTE 1: Outputs terminated with 50
to V
CC
– 2V.
IDT8N3S271CCD
REVISION A DECEMBER 17, 2012
4
©2012 Integrated Device Technology, Inc.
IDT8N3S271 Data Sheet
LVPECL FREQUENCY-PROGRAMMABLE CRYSTAL OSCILLATOR
Table 4E. LVCMOS/LVTTL DC Characteristic, V
CC
= 3.3V ± 5% or 2.5V ± 5%, V
EE
=
0V, T
A
= -40°C to 85°C
Symbol
V
IH
V
IL
I
IH
I
IL
Parameter
Input High Voltage
Test Conditions
V
CC
= 3.3V
V
CC
= 2.5V
V
CC
= V
IN
= 3.465V
V
CC
= V
IN
= 2.5V
OE
OE
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
10
Units
V
V
V
V
µA
µA
Input Low Voltage
Input High Current
Input Low Current
IDT8N3S271CCD
REVISION A DECEMBER 17, 2012
5
©2012 Integrated Device Technology, Inc.
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