FemtoClock
®
Crystal-to-HSTL
Frequency Synthesizer
G
ENERAL
D
ESCRIPTION
The 8421002I-01 is a 2 output HSTL Synthesizer optimized to
generate Ethernet reference clock frequencies and is a member of
the HiPerClocks
TM
family of high performance clock solutions from
IDT. 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 8421002I-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 8421002I-01 is packaged in a small 20-pin
TSSOP package.
8421002I-01
DATA SHEET
F
EATURES
• Two HSTL outputs (VOHmax = 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 lead-free (RoHS 6) compliant package
F
REQUENCY
S
ELECT
F
UNCTION
T
ABLE
Output Frequency
(25MHz Ref.)
156.25
125
62.5
not used
P
IN
A
SSIGNMENT
nc
V
DDO
Q0
nQ0
MR
nPLL_SEL
nc
V
DDA
F_SEL0
V
DD
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
DDO
Q1
nQ1
GND
V
DD
nXTAL_SEL
REF_CLK
XTAL_IN
XTAL_OUT
F_SEL1
F_SEL1
0
0
1
1
F_SEL0
0
1
0
1
M Divider
Value
25
25
25
N Divider
Value
4
5
10
not used
8421002I-01
B
LOCK
D
IAGRAM
F_SEL[1:0]
nPLL_SEL
Pulldown
Pulldown
2
Q0
20-Lead TSSOP
6.5mm x 4.4mm x 0.92mm
package body
G Package
Top View
F_SEL[1:0]
0 0 ÷4
(default)
1
01
10
11
÷5
÷10
Not Used
REF_CLK
Pulldown
1
25MHz
nQ0
XTAL_IN
OSC
XTAL_OUT
nXTAL_SEL
Pulldown
0
Phase
Detector
VCO
Q1
nQ1
0
M = 25 (fixed)
MR
Pulldown
8421002I-01 REVISION B 8/14/15
1
©2015 Integrated Device Technology, Inc.
8421002I-01 DATA SHEET
T
ABLE
1. P
IN
D
ESCRIPTIONS
Number
1, 7
2, 20
3, 4
5
Name
nc
V
DDO
Q0, nQ0
MR
Unused
Power
Ouput
Input
Type
Description
No connect.
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
Pulldown
to go high. When logic LOW, the internal dividers and the outputs are en-
abled. LVCMOS/LVTTL interface levels.
Selects between the PLL and REF_CLK as input to the dividers. When LOW,
Pulldown selects PLL (PLL Enable). When HIGH, deselects the reference clock (PLL
Bypass). LVCMOS/LVTTL interface levels.
Analog supply pin.
Pulldown Frequency select pins. LVCMOS/LVTTL interface levels.
Core supply pin.
Parallel resonant crystal interface. XTAL_OUT is the output,
XTAL_IN is the input.
Pulldown LVCMOS/LVTTL reference clock input.
Selects between crystal or REF_CLK inputs as the the PLL Reference
Pulldown source. Selects XTAL inputs when LOW. Selects REF_CLK when HIGH.
LVCMOS/LVTTL interface levels.
Power supply ground.
Differential output pair. HSTL interface levels.
6
8
9, 11
10, 16
12, 13
14
15
17
18, 19
nPLL_SEL
V
DDA
F_SEL0,
F_SEL1
V
DD
XTAL_OUT,
XTAL_IN
REF_CLK
nXTAL_SEL
GND
nQ1, Q1
Input
Power
Input
Power
Input
Input
Input
Power
Output
NOTE:
Pulldown
refers to internal input resistors. See Table 2, Pin Characteristics, for typical values.
T
ABLE
2. P
IN
C
HARACTERISTICS
Symbol
C
IN
R
PULLDOWN
Parameter
Input Capacitance
Input Pulldown Resistor
Test Conditions
Minimum
Typical
4
51
Maximum
Units
pF
kΩ
FEMTOCLOCKS™ CRYSTAL-TO-HSTL
FREQUENCY SYNTHESIZER
2
REVISION B 8/14/15
8421002I-01 DATA SHEET
A
BSOLUTE
M
AXIMUM
R
ATINGS
Supply Voltage, V
DD
Inputs, V
I
Outputs, I
O
Continuous Current
Surge Current
Package Thermal Impedance,
θ
JA
Storage Temperature, T
STG
4.6V
-0.5V to V
DD
+ 0.5V
50mA
100mA
73.2°C/W (0 lfpm)
-65°C to 150°C
N OT E : S t r e s s e s b eyo n d t h o s e l i s t e d u n d e r A b s o l u t e
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 ex-
tended periods may affect product reliability.
T
ABLE
3A. P
OWER
S
UPPLY
DC C
HARACTERISTICS
,
V
DD
= V
DDA
= 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
110
12
Units
V
V
V
mA
mA
mA
T
ABLE
3B. P
OWER
S
UPPLY
DC C
HARACTERISTICS
,
V
DD
= V
DDA
= 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
Power 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
96
12
Units
V
V
V
mA
mA
mA
T
ABLE
3C. LVCMOS / LVTTL DC C
HARACTERISTICS
,
V
DD
= V
DDA
= 3.3V±5%
OR
2.5V±5%, V
DDO
= 1.8V±0.2V, T
A
= -40°C
TO
85°C
Symbol
V
IH
V
IL
I
IH
Parameter
Input High Voltage
Input
Low Voltage
Input
High Current
Input
Low Current
REF_CLK, MR,
F_SEL0, F_SEL1,
nPLL_SEL, nXTAL_SEL
REF_CLK, MR,
F_SEL0, F_SEL1,
nPLL_SEL, nXTAL_SEL
Test Conditions
V
DD
= 3.3V
V
DD
= 2.5V
V
DD
= 3.3V
V
DD
= 2.5V
V
DD
= V
IN
= 3.465V
or 2.5V
V
DD
= 3.465V or 2.5V,
V
IN
= 0V
-150
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
I
IL
µA
REVISION B 8/14/15
3
FEMTOCLOCKS™ CRYSTAL-TO-HSTL
FREQUENCY SYNTHESIZER
8421002I-01 DATA SHEET
T
ABLE
3D. HSTL DC C
HARACTERISTICS
,
V
DD
= V
DDA
= 3.3V±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
1.0
0
40
0.6
Typical
Maximum
1.5
0.5
60
1.3
Units
V
V
%
V
NOTE 1: Outputs terminated with 50Ω to ground.
NOTE 2: Defined with respect to output voltage swing at a given condition.
T
ABLE
3E. HSTL DC C
HARACTERISTICS
,
V
DD
= V
DDA
= 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
0.8
0
40
0.5
Typical
Maximum
1.5
0.6
60
1.5
Units
V
V
%
V
NOTE 1: Outputs terminated with 50Ω to ground.
NOTE 2: Defined with respect to output voltage swing at a given condition.
T
ABLE
4. C
RYSTAL
C
HARACTERISTICS
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
25
Maximum
27.2
50
7
1
Units
MHz
Ω
pF
mW
Fundamental
FEMTOCLOCKS™ CRYSTAL-TO-HSTL
FREQUENCY SYNTHESIZER
4
REVISION B 8/14/15
8421002I-01 DATA SHEET
T
ABLE
5A. AC C
HARACTERISTICS
,
V
DD
= V
DDA
= 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, 3
156.25MHz, (1.875MHz - 20MHz)
RMS Phase Jitter (Random);
NOTE 2
Output Rise/Fall Time
Output Duty Cycle
125MHz, (1.875MHz - 20MHz)
62.5MHz,(1.875MHz - 20MHz)
20% to 80%
215
48
0.44
0.48
0.49
815
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
20
Units
MHz
MHz
MHz
ps
ps
ps
ps
ps
%
NOTE 1: Defined as skew between outputs at the same supply voltages and with equal load conditions.
Measured at V
DDO
/2.
NOTE 2: Please refer to the Phase Noise Plot.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
T
ABLE
5B. AC C
HARACTERISTICS
,
V
DD
= V
DDA
= 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
Parameter
Output Frequency
Output Skew; NOTE 1, 3
156.25MHz, (1.875MHz - 20MHz)
RMS Phase Jitter (Random);
NOTE 2
Output Rise/Fall Time
125MHz, (1.875MHz - 20MHz)
62.5MHz,(1.875MHz - 20MHz)
20% to 80%
315
0.41
0.49
0.50
715
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
20
Units
MHz
MHz
MHz
ps
ps
ps
ps
ps
%
odc
Output Duty Cycle
48
NOTE 1: Defined as skew between outputs at the same supply voltages and with equal load conditions.
Measured at V
DDO
/2.
NOTE 2 Please refer to the Phase Noise Plot.
NOTE 3 This parameter is defined in accordance with JEDEC Standard 65.
REVISION B 8/14/15
5
FEMTOCLOCKS™ CRYSTAL-TO-HSTL
FREQUENCY SYNTHESIZER
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