ICS ICS844008-16

PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
FEATURES
The ICS844008-16 is an 8 output LVDS
Synthesizer optimized to generate PCI Express
HiPerClockS™ reference clock frequencies and is a member
of the HiPerClocksTM family of high performance
clock solutions from ICS. Using a 25MHz
parallel resonant crystal, the following frequencies can be
generated based on F_SEL pin: 100MHz or 125MHz. The
ICS844008-16 uses ICS’ 3rd generation low phase noise
VCO technology and can achieve <1ps typical rms phase
jitter, easily meeting PCI Express jitter requirements. The
ICS844008-16 is packaged in a 32-pin LQFP package.
• Eight LVDS outputs
ICS
• Crystal oscillator interface
• Supports the following output frequencies:
100MHz or 125MHz
• VCO: 500MHz
• RMS phase jitter @ 125MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.44ps (typical)
• Full 3.3V supply modes
• 0°C to 70°C ambient operating temperature
• Available in both standard and lead-free RoHS compliant
packages
PIN ASSIGNMENT
V DDA
nPLL_SEL
VDD
M/N Divider
Value
5
Output
Frequency
(MHz)
12 5
Q0
1
24
Q7
1
20
5
4
100
nQ0
2
23
nQ7
VDD
3
22
VDD
Q1
4
21
Q6
nQ1
5
20
nQ6
GND
6
19
GND
Q2
7
18
Q5
nQ2
8
17
nQ5
Q0
Pulldown
nQ0
MR
nQ4
Q4
GND
0
÷4
÷5
VDD
(w/25MHz
Reference)
9 10 11 12 13 14 15 16
nQ3
Q2
VCO
500MHz
32-Lead LQFP
7mm x 7mm x 1.4mm
package body
Y Package
Top View
Q3
OSC
Phase
Detector
ICS844008-16
F_SEL
25MHz
32 31 30 29 28 27 26 25
nQ1
1
XTAL_OUT
OE2
N Divider
Value
4
Q1
XTAL_IN
GND
F_SEL
0
M Divider
Value
20
BLOCK DIAGRAM
nPLL_SEL
XTAL_IN
25MHz
OE1
Input
Input
Frequency
(MHz)
25MHz
XTAL_OUT
FREQUENCY SELECT FUNCTION TABLE
nQ2
Q3
nQ3
Q4
M = ÷20 (fixed)
OE1
nQ4
Pullup
Q5
nQ5
Q6
nQ6
Q7
nQ7
MR Pulldown
F_SEL
OE2
Pullup
Pullup
The Preliminary Information presented herein represents a product in prototyping or pre-production. The noted characteristics are based on
initial product characterization. Integrated Circuit Systems, Incorporated (ICS) reserves the right to change any circuitry or specifications
without notice.
844008AY-16
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REV. A FEBRUARY 1, 2006
1
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
TABLE 1. PIN DESCRIPTIONS
Number
Name
1, 2
3, 12,
22, 27
4, 5
6, 13,
19, 29
7, 8
Q0, nQ0
Output
Type
Differential output pair. LVDS interface levels.
Description
VDD
Power
Core supply pin.
Q1, nQ1
Ouput
Differential output pair. LVDS interface levels.
GND
Power
Power supply ground.
Q2, nQ2
Output
9
F_SEL
Input
10, 11
Q3, nQ3
Output
Differential output pair. LVDS interface levels.
14, 15
Q4, nQ4
Output
16
MR
Input
17, 18
nQ5, Q5
Output
Differential output pair. LVDS interface levels.
Active HIGH Master Reset. When logic HIGH, the internal dividers are reset
causing the true outputs Qx to go low and the inver ted outputs nQx
to go high. When logic LOW, the internal dividers and the outputs are
enabled. LVCMOS/LVTTL interface levels.
Differential output pair. LVDS interface levels.
20, 21
nQ6, Q6
Output
Differential output pair. LVDS interface levels.
23, 24
nQ7, Q7
Output
Differential output pair. LVDS interface levels.
25
VDDA
Power
Differential output pair. LVDS interface levels.
Pullup
Pulldown
Frequency select pin LVCMOS/LVTTL interface levels.
Analog supply pin.
Selects between the PLL and REF_CLK as input to the dividers. When LOW,
Pulldselects PLL (PLL Enable). When HIGH, deselects the reference clock (PLL
26
nPLL_SEL
Input
own
Bypass). LVCMOS/LVTTL interface levels.
Output enable for Q5/nQ5:Q7/nQ7 outputs.
28
OE2
Input
Pullup
LVCMOS/LVTTL interface levels.
Parallel resonant cr ystal interface. XTAL_OUT is the output,
XTAL_OUT,
30, 31
Input
XTAL_IN is the input.
XTAL_IN
Output enable for Q0/nQ0:Q4/nQ4 outputs.
32
OE1
Input
Pullup
LVCMOS/LVTTL interface levels.
NOTE: Pullup refers to internal input resistors. See Table 2, Pin Characteristics, for typical values.
TABLE 2. PIN CHARACTERISTICS
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
CIN
Input Capacitance
4
pF
RPULLDOWN
Input Pulldown Resistor
51
kΩ
RPULLUP
Input PullUP Resistor
51
kΩ
TABLE 3A. OE1 FUNCTION TABLE
Input
OE1
TABLE 3B. OE2 FUNCTION TABLE
Outputs
Input
Q0:Q4, nQ0:nQ4
OE2
Outputs
Q5:Q7, nQ5:nQ7
0
Places outputs in Hi-Z state
0
Places outputs in Hi-Z state
1
Normal operation
1
Normal operation
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PRELIMINARY
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VDD
4.6V
Inputs, VI
-0.5V to VDD + 0.5V
Outputs, IO
Continuous Current
Surge Current
10mA
15mA
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.
Package Thermal Impedance, θJA 47.9°C/W (0 lfpm)
Storage Temperature, TSTG
-65°C to 150°C
TABLE 4A. POWER SUPPLY DC CHARACTERISTICS, VDD = 3.3V±5%, TA = 0°C TO70°C
Symbol
Parameter
Minimum
Typical
Maximum
Units
VDD
Core Supply Voltage
Test Conditions
3.135
3.3
3.465
V
VDDA
Analog Supply Voltage
3.135
3.3
3.465
V
IDD
Power Supply Current
285
mA
IDDA
Analog Supply Current
12
mA
TABLE 4B. LVCMOS / LVTTL DC CHARACTERISTICS, VDD = 3.3V±5%, TA = 0°C TO70°C
Symbol
VIH
Parameter
Input High Voltage
Test Conditions
VDD = 3.3V
VIL
Input Low Voltage
VDD = 3.3V
IIH
Input
High Current
MR, nPLL_SEL
Input
Low Current
MR, nPLL_SEL
VDD = 3.465V, VIN = 0V
-5
µA
OE1, OE2, F_SEL
VDD = 3.465V, VIN = 0V
-150
µA
IIL
Minimum Typical
2
-0.3
VDD = VIN = 3.465
OE1, OE2, F_SEL
VDD = VIN = 3.465
Maximum
VDD + 0.3
Units
V
0.8
V
150
µA
5
µA
TABLE 4C. LVDS DC CHARACTERISTICS, VDD = 3.3V±5%, TA = 0°C TO70°C
Symbol
Parameter
VOD
Differential Output Voltage
440
mV
Δ VOD
VOD Magnitude Change
40
mV
VOS
Offset Voltage
1.4
V
Δ VOS
VOS Magnitude Change
50
mV
844008AY-16
Test Conditions
Minimum
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3
Typical
Maximum
Units
REV. A FEBRUARY 1, 2006
PRELIMINARY
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
TABLE 5. CRYSTAL CHARACTERISTICS
Parameter
Test Conditions
Minimum
Maximum
Units
27.2
MH z
Par ts per Million (ppm); NOTE 1
100
ppm
Equivalent Series Resistance (ESR)
50
Ω
Shunt Capacitance
7
pF
Mode of Oscillation
Typical
Fundamental
Frequency
22.4
25
Drive Level
100
NOTE: Characterized using an18pF parallel resonant crystal.
NOTE 1: When used with recommended 50ppm crystal and external trim caps adjusted for user PC board.
µW
TABLE 6. AC CHARACTERISTICS, VDD = 3.3V±5%, TA = 0°C TO70°C
Symbol
Parameter
fOUT
Output Frequency
tsk(o)
Output Skew; NOTE 1, 2
tjit(cc)
Cycle-to-Cycle Jitter
tjit(Ø)
RMS Phase Jitter (Random);
NOTE 3
t R / tF
Output Rise/Fall Time
Test Conditions
Minimum
FSEL = 0
FSEL = 1
Typical
Units
MHz
100
MHz
TBD
ps
40
ps
125MHz, (1.875MHz - 20MHz)
0.44
ps
100MHz, (1.875MHz - 20MHz)
0.44
ps
20% to 80%
450
ps
odc
Output Duty Cycle
50
NOTE 1: Defined as skew between outputs at the same supply voltages and with equal load conditions.
Measured at VDD/2.
NOTE 2: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 3: Please refer to the Phase Noise Plot.
844008AY-16
Maximum
125
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4
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PRELIMINARY
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
TYPICAL PHASE NOISE
AT
125MHZ AT 3.3V
➤
0
-10
-20
PCI Express Jitter Filter
-30
125MHz
RMS Phase Jitter (Random)
1.875Mhz to 20MHz = 0.44ps (typical)
-70
-80
-90
-100
Raw Phase Noise Data
-110
➤
NOISE POWER dBc
Hz
-40
-50
-60
-120
-130
-140
-150
➤
-160
-170
-180
Phase Noise Result by adding
PCI Express Filter to raw data
-190
1k
10k
100k
1M
10M
100M
OFFSET FREQUENCY (HZ)
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REV. A FEBRUARY 1, 2006
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
PARAMETER MEASUREMENT INFORMATION
Phase Noise Plot
SCOPE
Noise Power
Qx
3.3V±5%
POWER SUPPLY
+ Float GND -
LVDS
Phase Noise Mask
nQx
f1
Offset Frequency
f2
RMS Jitter = Area Under the Masked Phase Noise Plot
RMS PHASE JITTER
nQx
nQ0:nQ7
Qx
Q0:nQ7
➤
nQy
Qy
tcycle n
➤
3.3V CORE/3.3V OUTPUT LOAD AC TEST CIRCUIT
➤
tcycle
➤
n+1
t jit(cc) = tcycle n –tcycle n+1
tsk(o)
1000 Cycles
OUTPUT SKEW
CYCLE-TO-CYCLE JITTER
nQ0:nQ7
80%
80%
Q0:Q7
VSW I N G
t PW
t
odc =
Clock
Outputs
PERIOD
t PW
20%
20%
tR
tF
x 100%
t PERIOD
OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
OUTPUT RISE/FALL TIME
VDD
out
➤
DC Input
LVDS
100
VOD/Δ VOD
➤
out
out
VOS/Δ VOS
➤
LVDS
➤
DC Input
out
➤
VDD
➤
DIFFERENTIAL OUTPUT VOLTAGE SETUP
OFFSET VOLTAGE SETUP
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REV. A FEBRUARY 1, 2006
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
APPLICATION INFORMATION
POWER SUPPLY FILTERING TECHNIQUES
As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS844008-16 provides separate power supplies to isolate any high switching noise from the outputs to the internal PLL. VDD and VDDA
should be individually connected to the power supply
plane through vias, and bypass capacitors should be
used for each pin. To achieve optimum jitter performance,
power supply isolation is required. Figure 1 illustrates how
a 10Ω resistor along with a 10µF and a .01μF bypass
capacitor should be connected to each VDDA.
3.3V
VDD
.01μF
10Ω
VDDA
.01μF
10μF
FIGURE 1. POWER SUPPLY FILTERING
CRYSTAL INPUT INTERFACE
Figure 2 below were determined using a 25MHz parallel
resonant crystal and were chosen to minimize the ppm error.
The ICS844008-16 has been characterized with 18pF
parallel resonant crystals. The capacitor values shown in
XTAL_OUT
C1
27p
X1
18pF Parallel Crystal
XTAL_IN
C2
27p
Figure 2. CRYSTAL INPUt INTERFACE
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
RECOMMENDATIONS FOR UNUSED INPUT AND OUTPUT PINS
INPUTS:
OUTPUTS:
LVCMOS CONTROL PINS:
All control pins have internal pull-ups or pull-downs; additional
resistance is not required but can be added for additional
protection. A 1kΩ resistor can be used.
LVDS
All unused LVDS output pairs can be either left floating or
terminated with 100Ω across. If they are left floating, we
recommend that there is no trace attached.
3.3V LVDS DRIVER TERMINATION
A general LVDS interface is shown in Figure 3. In a 100Ω
differential transmission line environment, LVDS drivers
require a matched load termination of 100Ω across near
the receiver input. For a multiple LVDS outputs buffer, if
only partial outputs are used, it is recommended to terminate the unused outputs.
3.3V
3.3V
LVDS
+
R1
100
-
100 Ohm Differential Transmission Line
FIGURE 3. TYPICAL LVDS DRIVER TERMINATION
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REV. A FEBRUARY 1, 2006
PRELIMINARY
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
POWER CONSIDERATIONS
This section provides information on power dissipation and junction temperature for the ICS844008-16.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS844008-16 is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for VDD = 3.3V + 5% = 3.465V, which gives worst case results.
•
Power (core)MAX = VDD_MAX * (IDD_MAX + IDDA_MAX) = 3.465V * (285mA + 12mA) = 1029mW
2. Junction Temperature.
Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad and directly affects the reliability of
the device. The maximum recommended junction temperature for HiPerClockSTM devices is 125°C.
The equation for Tj is as follows: Tj = θJA * Pd_total + TA
Tj = Junction Temperature
θJA = Junction-to-Ambient Thermal Resistance
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
TA = Ambient Temperature
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θJA must be used.
Assuming a moderate air flow of 200 linear feet per minute and a multi-layer board, the appropriate value is 42.1°C/W per
Table 7 below.
Therefore, Tj for an ambient temperature of 70°C with all outputs switching is:
70°C + 1.029W * 42.1°C/W = 113.3°C. This is below the limit of 125°C.
This calculation is only an example. Tj will obviously vary depending on the number of loaded outputs, supply voltage, air
flow, and the type of board (single layer or multi-layer).
TABLE 7. THERMAL RESISTANCE θJA FOR 32-LEAD LQFP, FORCED CONVECTION
θJA by Velocity (Linear Feet per Minute)
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
0
200
500
67.8°C/W
47.9°C/W
55.9°C/W
42.1°C/W
50.1°C/W
39.4°C/W
NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs.
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
RELIABILITY INFORMATION
TABLE 8. θJAVS. AIR FLOW TABLE FOR 32 LEAD LQFP
θJA by Velocity (Linear Feet per Minute)
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
0
200
500
67.8°C/W
47.9°C/W
55.9°C/W
42.1°C/W
50.1°C/W
39.4°C/W
NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs.
TRANSISTOR COUNT
The transistor count for ICS844008-16 is: 2597
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
PACKAGE OUTLINE - Y SUFFIX FOR 32 LEAD LQFP
TABLE 9. PACKAGE DIMENSIONS
JEDEC VARIATION
ALL DIMENSIONS IN MILLIMETERS
BBA
SYMBOL
MINIMUM
NOMINAL
MAXIMUM
32
N
A
--
--
1.60
A1
0.05
--
0.15
A2
1.35
1.40
1.45
b
0.30
0.37
0.45
c
0.09
--
0.20
D
9.00 BASIC
D1
7.00 BASIC
D2
5.60 Ref.
E
9.00 BASIC
E1
7.00 BASIC
E2
5.60 Ref.
e
0.80 BASIC
0.60
0.75
L
0.45
θ
0°
--
7°
ccc
--
--
0.10
Reference Document: JEDEC Publication 95, MS-026
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ICS844008-16
FEMTOCLOCKS™ CRYSTAL-TOLVDS FREQUENCY SYNTHESIZER
TABLE 10. ORDERING INFORMATION
Part/Order Number
Marking
Package
Shipping Packaging
Temperature
ICS844008AY-16
ICS844008A16
32 Lead LQFP
tube
0°C to 70°C
ICS844008AY-16T
ICS844008A16
32 Lead LQFP
1000 tape & reel
0°C to 70°C
ICS844008AY-16LF
TBD
32 Lead "Lead-Free" LQFP
tube
0°C to 70°C
ICS844008AY-16LFT
TBD
32 Lead "Lead-Free" LQFP
1000 tape & reel
0°C to 70°C
NOTE: par ts that are ordered with an "LF" suffix to the par t number are the Pb-Free configuration and are RoHS compliant.
The ICS logo is a registered trademark, and HiPerClockS is a trademark of Integrated Circuit Systems, Inc. All other trademarks are the property of their respective owners and may be registered
in certain jurisdictions.
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems, Incorporated (ICS) assumes no responsibility for either its use or for infringement
of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications.
Any other applications such as those requiring extended temperature range, high reliability or other extraordinary environmental requirements are not recommended without additional processing by
ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or critical medical instruments.
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