LVDS Dual Frequency Programmable
Crystal Oscillator
IDT8N4D085
DATASHEET
General Description
The IDT8N4D085 is an LVDS Dual Frequency-Programmable Crys-
tal Oscillator with very flexible frequency programming capabilities.
The device uses IDT’s fourth generation FemtoClock
®
NG technolo-
gy for an optimum of high clock frequency and low phase noise per-
formance. 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 programmed to any 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. One of two
pre-set output frequencies is selected by the FSEL pin.The extended
temperature range supports wireless infrastructure, telecommunica-
tion and networking end equipment requirements.
Features
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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, 3.3V LVDS clock output
Output enable control (negative polarity), LVCMOS/LVTTL
compatible
LVCMOS compatible control inputs
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
OE 1
6 V
DD
5 nQ
4 Q
OSC
f
REF
2
÷P
÷N
Q
nQ
FSEL 2
GND 3
÷MINT,
MFRAC
25
FSEL
OE
Pulldown
Pullup
7
IDT8N4D085
6-lead ceramic 5mm x 7mm x 1.55mm
package body
CD Package
Top View
Configuration Register (ROM)
IDT8N4D085CCD
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©2012 Integrated Device Technology, Inc.
IDT8N4D085 Data Sheet
LVDS DUAL FREQUENCY PROGRAMMBLE CRYSTAL OSCILLATOR
Pin Description and Characteristic Tables
Table 1. Pin Descriptions
Number
1
2
3
4, 5
6
Name
OE
FSEL
GND
Q, nQ
V
DD
Input
Input
Power
Output
Power
Type
Pullup
Description
Output enable pin. See table 33A for function. LVCMOS/LVTTL interface levels.
Pulldown Frequency select pin. See table 33B for function. LVCMOS/LVTTL interface levels.
Power supply ground.
Differential clock output pair. LVDS interface levels.
Power supply pin.
NOTE:
Pullup and pulldown
refer to internal input resistors. See Table 2,
Pin Characteristics,
for typical values.
Table 2. Pin Characteristics
Symbol
C
IN
R
PULLDOWN
R
PULLUP
Parameter
Input Capacitance
Input Pulldown Resistor
Input Pullup Resistor
Test Conditions
Minimum
Typical
5.5
50
50
Maximum
Units
pF
k
k
Function Tables
Table 3A. OE Configuration
Input
OE
0
1 (default)
Output Enable
Output Q, nQ is in high-impedance state
Output Q, nQ is enabled
NOTE: OE is an asynchronous control.
Table 3B. Frequency Selection
Input
FSEL
0 (default)
1
Operation
Frequency 0
Frequency 1
NOTE: Frequency 0 and 1 are factory-programmed by IDT. Any frequency combination within the available
frequency range (see table 33C) can be ordered. For order information, see
FemtoClock NG Ceramic-Package
XO and VCXO Ordering Product Information
document.
Table 3C. Output Frequency Range
Output Frequency Range (MHz)
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.
2
©2012 Integrated Device Technology, Inc.
IDT8N4D085CCD
NOVEMBER 29, 2012
IDT8N4D085 Data Sheet
LVDS DUAL FREQUENCY PROGRAMMBLE 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 114.285
MHz or 100 MHz. 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 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 up to two different factory pre-set
configuration settings. The configuration is selected via the the FSEL
pin. Changing the FSEL control results in an immediate change of the
output frequency to the selected register values. The
P, M,
and
N
frequency configurations support 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
Table 4. Frequency Selection
Input
FSEL
0 (default)
1
Selects
Frequency 0
Frequency 1
Frequency Configuration
An order code is assigned to each frequency configuration and the
VCXO pull-range 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.
(1)
IDT8N4D085CCD
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©2012 Integrated Device Technology, Inc.
IDT8N4D085 Data Sheet
LVDS DUAL FREQUENCY PROGRAMMBLE 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
DD
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 reliabilit
y.
Rating
3.63V
-0.5V to V
DD
+ 0.5V
10mA
15mA
41.4C/W (0 mps)
-65C to 150C
DC Electrical Characteristics
Table 5A. Power Supply DC Characteristics, V
DD
=
3.3V ± 5%, T
A
= -40°C to 85°C
Symbol
V
DD
I
DD
Parameter
Power Supply Voltage
Power Supply Current
Test Conditions
Minimum
3.135
Typical
3.3
134
Maximum
3.465
160
Units
V
mA
Table 5B. Power Supply DC Characteristics, V
DD
=
2.5V ± 5%, T
A
= -40°C to 85°C
Symbol
V
DD
I
DD
Parameter
Power Supply Voltage
Power Supply Current
Test Conditions
Minimum
2.375
Typical
2.5
129
Maximum
2.625
155
Units
V
mA
Table 5C. LVCMOS/LVTTL DC Characteristic, V
CC
= 3.3V ± 5% or 2.5V ± 5%, T
A
= -40°C to 85°C
Symbol
V
IH
Parameter
Input High Voltage
OE
FSEL
V
IL
Input Low Voltage
OE
FSEL
OE
I
IH
Input High Current
FSEL
OE
I
IL
Input Low Current
FSEL
Test Conditions
V
DD
= 3.3V
V
DD
= 2.5V
V
DD
= 3.3V
V
DD
= 3.3V
V
DD
= 2.5V
V
DD
= 2.5V
V
DD
= V
IN
= 3.465V or 2.625V
V
DD
= V
IN
= 3.465V or 2.625V
V
DD
= 3.465V or 2.625V, V
IN
= 0V
V
DD
= 3.465V or 2.625V, V
IN
= 0V
-150
-5
Minimum
2
1.7
-0.3
-0.3
-0.3
-0.3
Typical
Maximum
V
DD
+ 0.3
V
DD
+ 0.3
0.8
0.5
0.7
0.5
10
150
Units
V
V
V
V
V
V
µA
µA
µA
µA
IDT8N4D085CCD
NOVEMBER 29, 2012
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©2012 Integrated Device Technology, Inc.
IDT8N4D085 Data Sheet
LVDS DUAL FREQUENCY PROGRAMMBLE CRYSTAL OSCILLATOR
Table 5D. LVDS DC Characteristics, V
DD
=
3.3V ± 5%, T
A
= -40°C to 85°C
Symbol
V
OD
V
OD
V
OS
V
OS
.
Parameter
Differential Output Voltage
V
OD
Magnitude Change
Offset Voltage
V
OS
Magnitude Change
1.125
1.22
Test Conditions
Minimum
247
Typical
370
Maximum
454
50
1.375
50
Units
mV
mV
V
mV
Table 5E. LVDS DC Characteristics, V
DD
=
2.5V ± 5%, T
A
= -40°C to 85°C
Symbol
V
OD
V
OD
V
OS
V
OS
Parameter
Differential Output Voltage
V
OD
Magnitude Change
Offset Voltage
V
OS
Magnitude Change
1.125
1.21
Test Conditions
Minimum
247
Typical
360
Maximum
454
50
1.375
50
Units
mV
mV
V
mV
IDT8N4D085CCD
NOVEMBER 29, 2012
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©2012 Integrated Device Technology, Inc.
Analog electronics
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