FemtoClock™ Crystal-to-HSTL
Frequency Synthesizer
General Description
The ICS8421004I-01 is a 4 output HSTL Synthesizer
optimized to generate Ethernet reference clock
HiPerClockS™
frequencies. Using a 25MHz, 18pF parallel resonant
crystal, the following frequencies can be generated
based on the 2 frequency select pins (F_SEL[1:0]):
156.25MHz, 125MHz and 62.5MHz. The ICS8421004I-01 uses
IDT’s 3
rd
generation low phase noise VCO technology and can
achieve 1ps or lower typical rms phase jitter, easily meeting Ethernet
jitter requirements. The ICS8421004I-01 is packaged in a small
24-pin TSSOP package.
ICS8421004I-01
DATA SHEET
Features
•
•
•
•
•
•
•
•
Four HSTL outputs (V
OH_MAX
= 1.5V)
Selectable crystal oscillator interface or LVCMOS/LVTTL
single-ended input
Supports the following output frequencies: 156.25MHz, 125MHz,
62.5MHz
VCO range: 560MHz - 680MHz
RMS phase jitter @ 156.25MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.44ps (typical)
Power supply modes:
Core/Output
3.3V/1.8V
2.5V/1.8V
-40°C to 85°C ambient operating temperature
Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
ICS
Frequency Select Function Table
Inputs
F_SEL1
0
0
1
1
F_SEL0
0
1
0
1
M Div. Value
25
25
25
25
N Div. Value
4
5
10
not used
M/N Div. Value
6.25
5
2.5
Output Frequency (MHz),
(25MHz Ref.)
156.25
125
62.5
not used
Block Diagram
F_SEL[1:0]
Pulldown
nPLL_SEL
Pulldown
F_SEL[1:0]
0 0 ÷4
(default)
1
01
10
11
÷5
÷10
Not Used
Pin Assignment
Q0
1
nQ0
Q1
nQ1
nQ1
Q1
V
DDO
Q0
nQ0
MR
nPLL_SEL
nc
V
DDA
F_SEL0
V
DD
F_SEL1
2
REF_CLK
Pulldown
25MHz
XTAL_IN
OSC
XTAL_OUT
nXTAL_SEL
Pulldown
0
Phase
Detector
VCO
0
Q2
nQ2
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
nQ2
Q2
V
DDO
Q3
nQ3
GND
nc
nXTAL_SEL
REF_CLK
GND
XTAL_IN
XTAL_OUT
M = 25 (fixed)
Q3
nQ3
MR
Pulldown
ICS421004I-01
24-Lead TSSOP
4.4mm x 7.8mm x 0.92mm
package body
G Package
Top View
ICS8421004AGI-01 REVISION B NOVEMBER 20, 2009
1
©2009 Integrated Device Technology, Inc.
ICS8421004I-01 Data Sheet
FEMTOCLOCK™ CRYSTAL-TO-HSTL FREQUENCY SYNTHESIZER
Table 1. Pin Descriptions
Number
1, 2
3, 22
4, 5
Name
nQ1, Q1
V
DDO
Q0, nQ0
Output
Power
Output
Type
Description
Differential output pair. HSTL interface levels.
Output supply pins.
Differential output pair. HSTL interface levels.
Active HIGH Master Reset. When logic HIGH, the internal dividers are reset
causing the true outputs Qx to go low and the inverted outputs nQx to go high.
When logic LOW, the internal dividers and the outputs are enabled.
LVCMOS/LVTTL interface levels.
PLL select. When LOW, selects PLL (PLL enabled). When HIGH, the PLL is
bypassed. LVCMOS/LVTTL interface levels.
No connect.
Analog supply pin.
Pulldown
Frequency select pins. LVCMOS/LVTTL interface levels.
Core supply pins.
Parallel resonant crystal interface. XTAL_OUT is the output, XTAL_IN is the input.
Power supply ground.
Pulldown
Pulldown
Single-ended reference clock input. LVCMOS/LVTTL interface levels.
Selects between crystal or REF_CLK inputs as the PLL reference source. Selects
XTAL inputs when LOW. Selects REF_CLK when HIGH. LVCMOS/LVTTL
interface levels.
Differential output pair. HSTL interface levels.
Differential output pair. HSTL interface levels.
6
MR
Input
Pulldown
7
8, 18
9
10,
12
11
13,
14
15, 19
16
17
20, 21
23, 24
nPLL_SEL
nc
V
DDA
F_SEL0,
F_SEL1
V
DD
XTAL_OUT,
XTAL_IN
GND
REF_CLK
nXTAL_SEL
nQ3, Q3
Q2, nQ2
Input
Unused
Power
Input
Power
Input
Power
Input
Input
Output
Output
Pulldown
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
Ω
ICS8421004AGI-01 REVISION B NOVEMBER 20, 2009
2
©2009 Integrated Device Technology, Inc.
ICS8421004I-01 Data Sheet
FEMTOCLOCK™ CRYSTAL-TO-HSTL FREQUENCY SYNTHESIZER
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
DD
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
DD
+ 0.5V
50mA
100mA
70°C/W (0 mps)
-65°C to 150°C
DC Electrical Characteristics
Table 3A. Power Supply DC Characteristics,
V
DD
= 3.3V ± 5%, V
DDO
= 1.8V ±0.2V, T
A
= -40°C to 85°C
Symbol
V
DD
V
DDA
V
DDO
I
DD
I
DDA
I
DDO
Parameter
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Output Supply Current
No Load
0
Test Conditions
Minimum
3.135
3.135
1.6
Typical
3.3
3.3
1.8
Maximum
3.465
3.465
2.0
113
13
Units
V
V
V
mA
mA
mA
Table 3B. Power Supply DC Characteristics,
V
DD
= 2.5V ± 5%, V
DDO
= 1.8V ±0.2V, T
A
= -40°C to 85°C
Symbol
V
DD
V
DDA
V
DDO
I
DD
I
DDA
I
DDO
Parameter
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Core Supply Current
Analog Supply Current
Output Supply Current
No Load
0
Test Conditions
Minimum
2.375
2.375
1.6
Typical
2.5
2.5
1.8
Maximum
2.625
2.625
2.0
100
13
Units
V
V
V
mA
mA
mA
ICS8421004AGI-01 REVISION B NOVEMBER 20, 2009
3
©2009 Integrated Device Technology, Inc.
ICS8421004I-01 Data Sheet
FEMTOCLOCK™ CRYSTAL-TO-HSTL FREQUENCY SYNTHESIZER
Table 3C. LVCMOS/LVTTL DC Characteristics,
T
A
= -40°C to 85°C
Symbol
V
IH
Parameter
Input High Voltage
Test Conditions
V
DD
= 3.3V
V
DD
= 2.5V
Input Low Voltage
Input
High Current
Input
Low Current
REF_CLK, MR, F_SEL[0:1],
nPLL_SEL, nXTAL_SEL
REF_CLK, MR, F_SEL[0:1],
nPLL_SEL, nXTAL_SEL
V
DD
= 3.3V
V
DD
= 2.5V
V
DD
= V
IN
= 3.465V or
2.625V
V
DD
= 3.465V or 2.625V,
V
IN
= 0V
-5
Minimum
2
1.7
-0.3
-0.3
Typical
Maximum
V
DD
+ 0.3
V
DD
+ 0.3
0.8
0.7
150
Units
V
V
V
V
µA
µA
V
IL
I
IH
I
IL
Table 3D. HSTL DC Characteristics,
V
DD
= 3.3V ± 5% or 2.5V ± 5%, V
DDO
= 1.8V ±0.2V, T
A
= -40°C to 85°C
Symbol
V
OH
V
OL
V
OX
V
SWING
Parameter
Output High Voltage; NOTE 1
Output Low Voltage; NOTE 1
Output Crossover Voltage; NOTE 2
Peak-to-Peak Output Voltage Swing
Test Conditions
Minimum
0.95
0
0.40
0.6
Typical
Maximum
1.5
0.4
0.60
1.4
Units
V
V
V
V
NOTE 1: Outputs termination with 50Ω to ground.
NOTE 2: Defined with respect to output voltage swing at a given condition.
Table 4. Crystal Characteristics
Parameter
Mode of Oscillation
Frequency
Equivalent Series Resistance (ESR)
Shunt Capacitance
Drive Level
NOTE: Characterized using an 18pF parallel resonant crystal.
22.4
Test Conditions
Minimum
Typical
Fundamental
25
27.2
50
7
1
MHz
Maximum
Units
Ω
pF
mW
ICS8421004AGI-01 REVISION B NOVEMBER 20, 2009
4
©2009 Integrated Device Technology, Inc.
ICS8421004I-01 Data Sheet
FEMTOCLOCK™ CRYSTAL-TO-HSTL FREQUENCY SYNTHESIZER
AC Electrical Characteristics
Table 5A. AC Characteristics,
V
DD
= 3.3V ± 5%, V
DDO
= 1.8V ±0.2V, T
A
= -40°C to 85°C
Symbol
f
OUT
tsk(o)
tjit(Ø)
t
R
/ t
F
odc
Parameter
Output Frequency
Output Skew; NOTE 1, 2
156.25MHz, (1.875MHz – 20MHz)
RMS Phase Jitter (Random);
NOTE 3
Output Rise/Fall Time
Output Duty Cycle
125MHz, (1.875MHz – 20MHz)
62.5MHz, (1.875MHz – 20MHz)
20% to 80%
200
48
0.44
0.48
0.49
800
52
Test Conditions
F_SEL[1:0] = 00
F_SEL[1:0] = 01
F_SEL[1:0] = 10
Minimum
140
112
56
Typical
Maximum
170
136
68
30
Units
MHz
MHz
MHz
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: Defined as skew between outputs at the same supply voltages and with equal load conditions. Measured at the differential cross
points.
NOTE 2: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 3: Please refer to the Phase Noise Plot.
Table 5B. AC Characteristics,
V
DD
= 2.5V ± 5%, V
DDO
= 1.8V ±0.2V, T
A
= -40°C to 85°C
Symbol
f
OUT
tsk(o)
tjit(Ø)
t
R
/ t
F
odc
Parameter
Output Frequency
Output Skew; NOTE 1, 2
156.25MHz, (1.875MHz – 20MHz)
RMS Phase Jitter (Random);
NOTE 3
Output Rise/Fall Time
Output Duty Cycle
125MHz, (1.875MHz – 20MHz)
62.5MHz, (1.875MHz – 20MHz)
20% to 80%
200
48
0.41
0.49
0.50
800
52
Test Conditions
F_SEL[1:0] = 00
F_SEL[1:0] = 01
F_SEL[1:0] = 10
Minimum
140
112
56
Typical
Maximum
170
136
68
30
Units
MHz
MHz
MHz
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: Defined as skew between outputs at the same supply voltages and with equal load conditions. Measured at the differential cross
points.
NOTE 2: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 3: Please refer to the Phase Noise Plot.
ICS8421004AGI-01 REVISION B NOVEMBER 20, 2009
5
©2009 Integrated Device Technology, Inc.
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