LVPECL Frequency VCXO
IDT8CA3V76-0137
DATA SHEET
General Description
The IDT8CA3V76-0137 is a single output (155.52MHz) LVPECL
VCXO. The device uses IDT’s fourth generation FemtoClock® NG
technology for an optimum of high clock frequency and low phase
noise performance and (<0.5 ps RMS 12kHz - 20MHz). The device
accepts 3.3V supply and is packaged in a small, lead-free (RoHS 6)
6-lead ceramic 5mm x 7mm x 1.55mm package.
The extended temperature range supports wireless infrastructure,
telecommunication and networking end equipment requirements.
The device is a member of the high-performance clock family from
IDT.
Features
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Fourth generation FemtoClock® NG technology
Output Frequency 155.52MHz
VCXO Absolute Pull Range (APR) ±200ppm
One 3.3V LVPECL clock output
Output enable control input, LVCMOS/LVTTL compatible
RMS phase jitter @ 155.52MHz (12kHz - 20MHz): 0.5ps (typical)
RMS phase jitter @ 155.52MHz (1kHz - 40MHz): 0.9ps (typical)
3.3V supply voltage
-40°C to 85°C ambient operating temperature
Available in lead-free (RoHS 6) 6-lead ceramic 5mm x 7mm x
1.55mm package
Block Diagram
Pin Assignment
VC 1
6 V
CC
5 nQ
4 Q
OSC
114.285 MHz
2
÷P
PFD
&
LPF
FemtoClock® NG
VCO
1950-2600MHz
÷N
Q
nQ
nOE 2
V
EE
3
÷MINT,
MFRAC
7
VC
A/D
25
Configuration Register (ROM)
(Frequency, Pull-range, Polarity)
7
IDT8CA3V76-0137
6-lead ceramic 5mm x 7mm x 1.55mm
package body
CD Package
Top View
nOE
Pulldown
IDT8N3SV76EC-0137CDI
MARCH 22, 2012
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©2012 Integrated Device Technology, Inc.
IDT8CA3V76-0137 Data Sheet
LVPECL FREQUENCY VCXO
Pin Description and Characteristic Tables
Table 1. Pin Descriptions
Number
1
2
3
4, 5
6
Name
VC
nOE
V
EE
Q, nQ
V
CC
Input
Input
Power
Output
Power
Pulldown
Type
Description
VCXO Control Voltage input.
Output enable pin. See Table 3 for function. LVCMOS/LVTTL interface levels.
Negative power supply.
Differential clock output. LVPECL interface levels.
Power supply pin.
NOTE:
Pulldown
refers to an internal input resistors. See Table 2,
Pin Characteristics,
for typical values.
Table 2. Pin Characteristics
Symbol
C
IN
R
PULLDOWN
Parameter
Input Capacitance
nOE
VC
Test Conditions
Minimum
Typical
5.5
10
50
Maximum
Units
pF
pF
k
Input Pulldown Resistor
IDT8N3SV76EC-0137CDI
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©2012 Integrated Device Technology, Inc.
IDT8CA3V76-0137 Data Sheet
LVPECL FREQUENCY VCXO
Function Tables
Table 3. nOE Configuration
Input
nOE
0 (default)
1
Q, nQ outputs are enabled
Q, nQ outputs are in high-impedance state
Output Enable
Principles of Operation
The IDT8CA3V76-0137 uses a fractional feedback-divider
synthesizer core with a Delta-Sigma modulator for noise shaping and
is very robust in its frequency synthesis capability. The output
frequency is synthesized from an internal 114.285MHz third overtone
crystal in order to minimize phase noise generation by frequency
multiplication. The higher frequency reference crystal also allows
more efficient “shaping” of noise by the Delta-Sigma modulator. The
device contains a 25-bit PLL feedback divider with a 2-bit
pre-scaler(P), a 7-bit integer portion (MINT), a 18-bit fractional
portion (MFRAC) and a 7-bit output divider (N) for high-resolution
frequency generation. The resolution (frequency increment for one
MFRAC increment) is equal to 114.285MHz ÷ (2
18
· N) or
435.9Hz ÷ N (N = 2 to 126).
This device is a digital VCXO. In a traditional, “analog” VCXO,
variation of the output frequency is achieved by “pulling” the resonant
frequency of the crystal. A digital VCXO operates with a fixed crystal
frequency. Variation of the output frequency is achieved by modifying
the fractional portion (MFRAC) of the PLL feedback loop divider. A
fixed-frequency crystal features a comparatively higher Q factor than
a pullable crystal, which enables better phase-noise performance.
The operating frequency and pull range of the 8CA3V76-0137 are
factory-programmed by IDT to a center frequency of 155.52 MHz and
a pull range of +/- 237 MHz. The data given in this datasheet are valid
for this particular programming only.
More devices with different programming are available on request.
Please refer to the FemtoClock NG Ceramic-Package XO and VCXO
Ordering Product Information document and/or contact IDT.
IDT8N3SV76EC-0137CDI
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©2012 Integrated Device Technology, Inc.
IDT8CA3V76-0137 Data Sheet
LVPECL FREQUENCY VCXO
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
Other Inputs
Outputs, I
O
(LVPECL)
Continuous Current
Surge Current
Package Thermal Impedance,
JA
Storage Temperature, T
STG
Rating
3.63V
-0.5V to V
CC
+ 0.5V
50mA
100mA
41.4C/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
CC
Parameter
Power Supply Voltage
Power Supply Current
Test Conditions
Minimum
3.135
Typical
3.3
Maximum
3.465
148
Units
V
mA
Table 4B. 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
– 1.3
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 4C. LVCMOS/LVTTL DC Characteristic, V
CC
=
3.3V ± 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
nOE
nOE
V
CC
= V
IN
= 3.465V or 2.625V
V
CC
= 3.465V or 2.625V, V
IN
= 0V
-5
Minimum
2
1.7
-0.3
-0.3
Typical
Maximum
V
CC
+ 0.3
V
CC
+ 0.3
0.8
0.7
150
Units
V
V
V
V
µA
µA
Input Low Voltage
Input High Current
Input Low Current
IDT8N3SV76EC-0137CDI
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©2012 Integrated Device Technology, Inc.
IDT8CA3V76-0137 Data Sheet
LVPECL FREQUENCY VCXO
AC Electrical Characteristics
Table 5A. VCXO Control Voltage Input (V
C
) Characteristics,
V
CC
=
3.3V ± 5% , V
EE
=
0V, T
A
= -40°C to 85°C
Symbol
K
V
L
VC
BW
Z
VC
VC
NOM
V
C
Parameter
Oscillator Gain, NOTE 1, 2,
Control Voltage Linearity; NOTE 4
Modulation Bandwidth
VC Input Impedance
Nominal Control Voltage
Control Voltage Tuning Range;
NOTE 3
0
Test Conditions
V
CC
= 3.3V
BSL Variation
Minimum
503.81
-1
Typical
524.60
±0.1
100
500
V
CC
/2
V
CC
Maximum
552.14
+1
Units
ppm/V
%
kHz
k
V
V
NOTE 1: V
C
= 0V to V
CC
.
NOTE 2: For best phase noise performance, use the lowest K
V
that meets the requirements of the application.
NOTE 3: BSL = Best Straight Line Fit: Variation of the output frequency vs. control voltage V
C
, in percent. V
C
ranges from 10% to 90% V
CC
.
IDT8N3SV76EC-0137CDI
MARCH 22, 2012
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©2012 Integrated Device Technology, Inc.
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