ICS ICS84326

PRELIMINARY
Integrated
Circuit
Systems, Inc.
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
GENERAL DESCRIPTION
FEATURES
The ICS84326 is a Crystal-to-3.3V LVPECL Clock
Synthesizer/Fanout Buffer designed for Serial
HiPerClockS™
Attached SCSI applications and is a member of
the HiperClockS family of High Performance Clock
Solutions from ICS. Using a 25MHz crystal, the
6 LVPECL outputs can be set for either 75MHz or 150MHz
using the frequency select pins. The low jitter/low phase noise
characteristics make it an ideal clock source for use in Serial
Attached SCSI applications or for other applications which
require a 75MHz or 150MHz reference clock.
• 6 LVPECL outputs
,&6
• Crystal oscillator interface
• Output frequency: 75MHz or 150MHz
• Crystal input frequency: 25MHz
• Cycle-to-cycle jitter: 20ps (typical)
• RMS phase jitter at 150MHz, using a 25MHz crystal
(899.8KHz to 20MHz): TBD
• Phase noise:
Offset
100Hz ...............
1KHz ...............
10KHz ...............
100KHz ...............
FUNCTION TABLE
Inputs
Output Frequency
MR
F_SEL
F_OUT
1
X
LOW
0
0
75MHz
0
1
150MHz
ICS84326
Noise Power
TBD
TBD
TBD
TBD
• Full 3.3V or 3.3V core, 2.5V supply mode
• 0°C to 70°C ambient operating temperature
• Industrial temperature information available upon request
BLOCK DIAGRAM
PIN ASSIGNMENT
XTAL1
6
0
OSC
Output
Divider
XTAL2
1
PLL
/
6
/
Q0
nQ0
Q1
nQ1
Q2
nQ2
Q3
nQ3
Q4
nQ4
Q5
nQ5
Q0:Q5
nQ0:nQ5
Feedback
Divider
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
VCCO
F_SEL
nc
MR
XTAL1
XTAL2
nc
VCCA
VCC
PLL_SEL
VEE
VCCO
ICS84326
24-Lead, 300-MIL SOIC
7.5mm x 15.33mm x 2.3mm body package
M Package
Top View
MR
PLL_SEL
F_SEL
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.
84326AM
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1
REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
TABLE 1. PIN DESCRIPTIONS
Number
Name
1, 2
Q0, nQ0
Type
Description
Output
Differential output pair. LVPECL interface levels.
3, 4
Q1, nQ1
Output
Differential output pair. LVPECL interface levels.
5, 6
Q2, nQ2
Output
Differential output pair. LVPECL interface levels.
7, 8
Q3, nQ3
Output
Differential output pair. LVPECL interface levels.
9, 10
Q4, nQ4
Output
Differential output pair. LVPECL interface levels.
11, 12
Q5, nQ5
Output
Differential output pair. LVPECL interface levels.
13, 24
VCCO
Power
Output supply pins.
16
VCC
Power
Core supply pin.
14
VEE
15
PLL_SEL
Input
Negative supply pin.
Selects between the PLL and crystal inputs as the input to the
dividers. When HIGH, selects PLL. When LOW, selects XTAL1, XTAL2.
LVCMOS / LVTTL interface levels.
Analog supply pin.
17
VCCA
Power
18, 22
nc
Unused
19, 20
XTAL2, XTAL1
Input
21
MR
Input
23
F_SEL
Input
Pullup
No connect.
Crystal oscillator interface. XTAL1 is the input. XTAL2 is the output.
Active High Master Reset. When logic HIGH, the internal dividers
are reset causing the true outputs Qx to go low, and the inver ted
Pulldown
outputs nQx to go high. When logic LOW, the internal dividers and
the outputs are enabled. LVCMOS / LVTTL interface levels.
Pullup
Output frequency select pin. LVCMOS / LVTTL interface levels.
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
TABLE 2. PIN CHARACTERISTICS
Symbol
Parameter
CIN
Input Capacitance
Test Conditions
Minimum
Typical
Maximum
Units
4
pF
RPULLUP
Input Pullup Resistor
51
KΩ
RPULLDOWN
Input Pulldown Resistor
51
KΩ
84326AM
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REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC
4.6V
Inputs, VI
-0.5V to VCC + 0.5 V
Outputs, VO
-0.5V to VCCO + 0.5V
Package Thermal Impedance, θJA
50°C/W (0 lfpm)
Storage Temperature, TSTG
-65°C to 150°C
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.
TABLE 3A. POWER SUPPLY DC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = 0°C TO 70°C
Symbol
Parameter
Minimum
Typical
Maximum
Units
VCC
Core Supply Voltage
Test Conditions
3.135
3.3
3.465
V
VCCA
Analog Supply Voltage
3.135
3.3
3.465
V
3.135
3.3
3.465
VCCO
Output Supply Voltage
IEE
Power Supply Current
140
mA
V
ICCA
Analog Supply Current
20
mA
TABLE 3B. LVCMOS / LVTTL DC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = 0°C TO 70°C
Symbol
Parameter
VIH
Input High Voltage
VIL
Input Low Voltage
IIH
Input High Current
IIL
Input Low Current
Test Conditions
PLL_SEL, MR,
F_SEL
PLL_SEL, MR,
F_SEL
MR
PLL_SEL, F_SEL
Minimum
Typical
Maximum
Units
2
VCC + 0.3
V
-0.3
0.8
V
150
µA
5
µA
VCC = VIN = 3.465V
VCC = VIN = 3.465V
MR
VCC = 3.465V, VIN = 0V
-5
µA
PLL_SEL, F_SEL
VCC = 3.465V, VIN = 0V
-150
µA
TABLE 3C. LVPECL DC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = 0°C TO 70°C
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
VOH
Output High Voltage; NOTE 1
VCCO - 1.4
VCCO - 1.0
V
VOL
Output Low Voltage; NOTE 1
VCCO - 2.0
VCCO - 1.7
V
VSWING
Peak-to-Peak Output Voltage Swing
0.6
1.0
V
NOTE 1: Outputs terminated with 50Ω to VCCO - 2V.
84326AM
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3
REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
TABLE 3D. POWER SUPPLY DC CHARACTERISTICS, VCC = VCCA = 3.3V±5%, VCCO = 2.5V±5%, TA = 0°C TO 70°C
Symbol
Parameter
Test Conditions
VCC
Core Supply Voltage
Minimum
Typical
Maximum
Units
3.135
3.3
3.465
V
VCCA
Analog Supply Voltage
3.135
3.3
3.465
V
VCCO
Output Supply Voltage
2.375
2.5
2.625
V
IEE
Power Supply Current
140
mA
ICCA
Analog Supply Current
20
mA
TABLE 3E. LVCMOS / LVTTL DC CHARACTERISTICS, VCC = VCCA = 3.3V±5%, VCCO = 2.5V±5%, TA = 0°C TO 70°C
Symbol
Parameter
VIH
Input High Voltage
VIL
Input Low Voltage
IIH
Input High Current
IIL
Input Low Current
Test Conditions
Minimum
Typical
Maximum
Units
2
VCC + 0.3
V
-0.3
0.8
V
PLL_SEL, MR,
F_SEL
PLL_SEL, MR,
F_SEL
MR
VCC = VIN = 3.465V
150
µA
PLL_SEL, F_SEL
VCC = VIN = 3.465V
5
µA
MR
VCC = 3.465V, VIN = 0V
-5
µA
PLL_SEL, F_SEL
VCC = 3.465V, VIN = 0V
-150
µA
TABLE 3F. LVPECL DC CHARACTERISTICS, VCC = VCCA = 3.3V±5%, VCCO = 2.5V±5%, TA = 0°C TO 70°C
Symbol
Parameter
Maximum
Units
VOH
Output High Voltage; NOTE 1
Test Conditions
Minimum
VCCO - 1.4
Typical
VCCO - 1.0
V
VOL
Output Low Voltage; NOTE 1
VCCO - 2.0
VCCO - 1.7
V
VSWING
Peak-to-Peak Output Voltage Swing
0.6
1.0
V
NOTE 1: Outputs terminated with 50Ω to VCCO - 2V.
TABLE 4. CRYSTAL CHARACTERISTICS
Parameter
Test Conditions
Minimum
Maximum
Units
Frequency
25
MHz
Equivalent Series Resistance (ESR)
70
Ω
Shunt Capacitance
7
pF
Mode of Oscillation
Typical
Fundamental
NOTE: Characterized using an 18pf parallel resonant crystal.
84326AM
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4
REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
TABLE 5A. AC CHARACTERISTICS, VCC = VCCA = VCCO = 3.3V±5%, TA = 0°C TO 70°C
Symbol Parameter
FOUT
Test Conditions
Output Frequency
tjit(cc)
Cycle-to-Cycle Jitter ; NOTE 2
tjit(per)
Period Jitter, RMS
tsk(o)
Output Skew; NOTE 1, 2
tR / t F
Output Rise/Fall Time
odc
Output Duty Cycle
Minimum
Typical
Maximum
Units
150
MHz
75
20% to 80%
20
ps
TBD
ps
50
ps
200
700
50
ps
%
tLOCK
PLL Lock Time
See Parameter Measurement Information section.
NOTE 1: Defined as skew between outputs at the same supply voltage and with equal load conditions.
Measured at the output differential crossing points.
NOTE 2: This parameter is defined in accordance with JEDEC Standard 65.
1
ms
Maximum
Units
150
MHz
TABLE 5B. AC CHARACTERISTICS, VCC = VCCA = 3.3V±5%, VCCO = 2.5V±5%, TA = 0°C TO 70°C
Symbol Parameter
FOUT
Output Frequency
tjit(cc)
Cycle-to-Cycle Jitter ; NOTE 2
tjit(per)
Period Jitter, RMS
tsk(o)
Output Skew; NOTE 1, 2
tR / tF
Output Rise/Fall Time
odc
Output Duty Cycle
Test Conditions
Minimum
Typical
75
20
20% to 80%
TBD
ps
35
ps
200
700
ps
1
ms
50
tLOCK
PLL Lock Time
See Parameter Measurement Information section.
NOTE 1: Defined as skew between outputs at the same supply voltage and with equal load conditions.
Measured at the output differential crossing points.
NOTE 2: This parameter is defined in accordance with JEDEC Standard 65.
84326AM
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5
%
REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
PARAMETER MEASUREMENT INFORMATION
2V
VCC, VCCA, VCCO = 2V
2.8V
Qx
SCOPE
VCC,
V CCA
LVPECL
SCOPE
Qx
VCCO
LVPECL
nQx
nQx
VEE = -1.3V ± 0.165V
VEE = -0.5V ± 0.165V
3.3V OUTPUT LOAD AC TEST CIRCUIT
3.3V/2.5V OUTPUT LOAD AC TEST CIRCUIT
VOH
nQx
VREF
Qx
VOL
1σ contains 68.26% of all measurements
2σ contains 95.4% of all measurements
3σ contains 99.73% of all measurements
4σ contains 99.99366% of all measurements
6σ contains (100-1.973x10-7)% of all measurements
nQy
Qy
Histogram
Reference Point
tsk(o)
Mean Period
(Trigger Edge)
(First edge after trigger)
PERIOD JITTER
OUTPUT SKEW
nQ0:nQ5
80%
80%
V
Q0:Q5
SW I N G
20%
20%
➤
tcycle
➤
n
tcycle n+1
➤
Clock Outputs
➤
t
R
t
F
t jit(cc) = tcycle n –tcycle n+1
1000 Cycles
CYCLE-TO-CYCLE JITTER
OUTPUT RISE/FALL TIME
nQ0:nQ5
Q0:Q5
Pulse Width
t
odc =
PERIOD
t PW
t PERIOD
odc & tPERIOD
84326AM
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REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
APPLICATION INFORMATION
POWER SUPPLY FILTERING TECHNIQUES
As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS84326 provides separate power supplies to isolate any high switching
noise from the outputs to the internal PLL. VCC, VCCA and VCCO
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 20Ω resistor along
with a 10µF and a .01µF bypass capacitor should be connected to each VCCA pin.
3.3V
VCC
.01µF
20 Ω
VCCA
.01µF
10 µF
FIGURE 1. POWER SUPPLY FILTERING
TERMINATION FOR 3.3V LVPECL OUTPUTS
The clock layout topology shown below is a typical termination for 3.3V LVPECL outputs. The two different layouts
mentioned are recommended only as guidelines.
designed to drive 50Ω transmission lines. Matched impedance
techniques should be used to maximize operating
frequency and minimize signal distortion. Figures 2A and 2B
show two different layouts which are recommended only
as guidelines. Other suitable clock layouts may exist and it
would be recommended that the board designers simulate to
guarantee compatibility across all printed circuit and clock
component process variations.
FOUT and nFOUT are low impedance follower outputs that
generate ECL/LVPECL compatible outputs. Therefore, terminating resistors (DC current path to ground) or current
sources must be used for functionality. These outputs are
3.3V
Zo = 50Ω
5
2 Zo
FIN
FOUT
Zo = 50Ω
Zo = 50Ω
FOUT
50 Ω
1
(VOH + VOL / VCC –2) –2
Zo = 50Ω
VCC - 2V
RTT
3
2 Zo
Zo
FIGURE 2A. LVPECL OUTPUT TERMINATION
84326AM
FIN
50Ω
➤
RTT =
5
2 Zo
3
2 Zo
FIGURE 2B. LVPECL OUTPUT TERMINATION
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REV. A MARCH 10, 2003
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Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
TERMINATION FOR 2.5V LVPECL OUTPUT
Figure 3A and Figure 3B show examples of termination for 2.5V
LVPECL driver. These terminations are equivalent to terminating 50Ω to VCC - 2V. For VCC = 2.5V, the VCC - 2V is very close to
ground level. The R3 in Figure 3B can be eliminated and the
termination is shown in Figure 3C.
2.5V
2.5V
2.5V
R1
250
R3
250
Zo = 50 Ohm
+
Zo = 50 Ohm
2,5V LVPECL
Driver
R2
62.5
R4
62.5
FIGURE 3A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
2.5V
2.5V
Zo = 50 Ohm
+
Zo = 50 Ohm
2,5V LVPECL
Driver
R1
50
R2
50
R3
18
FIGURE 3B. 2.5V LVPECL DRIVER TERMINATION EXAMPLE
2.5V
2.5V
Zo = 50 Ohm
+
Zo = 50 Ohm
2,5V LVPECL
Driver
R1
50
R2
50
FIGURE 3C. 2.5V LVPECL TERMINATION EXAMPLE
84326AM
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REV. A MARCH 10, 2003
PRELIMINARY
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Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
CRYSTAL INPUT INTERFACE
The ICS84326 has been characterized with 18pF parallel
resonant crystals. The capacitor values, C1 and C2, shown
in Figure 4 below were determined using a 25MHz, 18pF
parallel resonant crystal and were chosen to minimize the
ppm error. The optimum C1 and C2 values can be slightly
adjusted for different board layouts.
19
XTAL2
C1
18pF
25MHz X1
20
XTAL1
C2
22pF
ICS84326
Figure 4. CRYSTAL INPUt INTERFACE
SCHEMATIC EXAMPLE
Figure 5A shows a schematic example of using an ICS84326. In
this example, the input is a 25MHz parallel resonant crystal with
load capacitor CL=18pF. The frequency fine tuning capacitors C1
and C2 is 22pF and 18pF respectively. This example also shows
logic control input handling. The configuration is set at F_SEL=0,
therefore, the output frequency is 150MHz. It is recommended to
have one decouple capacitor per power pin. Each decoupling capacitor should be located as close as possible to the power pin.
The low pass filter R7, C11 and C16 for clean analog supply should
also be located as close to the VCCA pin as possible.
VCC
VCC
R4
1K
Zo = 50
13
14
15
16
17
18
19
20
21
22
23
24
R7
24
VCCA
22p
C11
0.1u
C16
10u
C1
X1
25MHz,18pF
U1
VCC
R5
1K
C2
18p
VCCO
VEE
PLL_SEL
VCC
VCCA
nc
XTAL2
XTAL1
MR
nc
F_SEL
VCCO
nQ5
Q5
nQ4
Q4
nQ3
Q3
nQ2
Q2
nQ1
Q1
nQ0
Q0
12
11
10
9
8
7
6
5
4
3
2
1
Zo = 50
+
R2
50
R1
50
R3
50
R6
1K
ICS84326
(U1,13)
VCC=3.3V
VCC
C6
0.1u
(U1,16)
(U1,24)
C5
0.1u
C3
0.1u
FIGURE 5A. ICS84326 SCHEMATIC EXAMPLE
84326AM
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REV. A MARCH 10, 2003
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ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
The following component footprints are used in this layout
example:
• The differential 50Ω output traces should have the
same length.
All the resistors and capacitors are size 0603.
• Avoid sharp angles on the clock trace. Sharp angle
turns cause the characteristic impedance to change on
the transmission lines.
POWER
AND
GROUNDING
Place the decoupling capacitors C5, C6 and C3, as close as
possible to the power pins. If space allows, placement of the
decoupling capacitor on the component side is preferred. This
can reduce unwanted inductance between the decoupling capacitor and the power pin caused by the via.
• Keep the clock traces on the same layer. Whenever possible, avoid placing vias on the clock traces. Placement
of vias on the traces can affect the trace characteristic
impedance and hence degrade signal integrity.
Maximize the power and ground pad sizes and number of vias
capacitors. This can reduce the inductance between the power
and ground planes and the component power and ground pins.
• To prevent cross talk, avoid routing other signal traces in
parallel with the clock traces. If running parallel traces is
unavoidable, allow a separation of at least three trace
widths between the differential clock trace and the other
signal trace.
The RC filter consisting of R7, C11, and C16 should be placed
as close to the VCCA pin as possible.
• Make sure no other signal traces are routed between the
clock trace pair.
CLOCK TRACES
• The matching termination resistors should be located as
close to the receiver input pins as possible.
AND
TERMINATION
Poor signal integrity can degrade the system performance or
cause system failure. In synchronous high-speed digital systems,
the clock signal is less tolerant to poor signal integrity than other
signals. Any ringing on the rising or falling edge or excessive ring
back can cause system failure. The shape of the trace and the
trace delay might be restricted by the available space on the board
and the component location. While routing the traces, the clock
signal traces should be routed first and should be locked prior to
routing other signal traces.
CRYSTAL
The crystal X1 should be located as close as possible to the pins
20 (XTAL1) and 19 (XTAL2). The trace length between the X1
and U1 should be kept to a minimum to avoid unwanted parasitic
inductance and capacitance. Other signal traces should not be
routed near the crystal traces.
C6
GND
VCC
C5
C1
Signals
R7
C16
VIA
C11
X1
C2
C3
U1
ICS84326
Pin1
50 Ohm Traces
FIGURE 5B. ICS84326 P.C. BOARD LAYOUT EXAMPLE
84326AM
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REV. A MARCH 10, 2003
PRELIMINARY
Integrated
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Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
POWER CONSIDERATIONS
This section provides information on power dissipation and junction temperature for the ICS84326.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS84326 is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for VCC = 3.3V + 5% = 3.465V, which gives worst case results.
NOTE: Please refer to Section 3 for details on calculating power dissipated in the load.
•
•
Power (core)MAX = VCC_MAX * IEE_MAX = 3.465V * 140mA = 485mW
Power (outputs)MAX = 30.2mW/Loaded Output pair
If all outputs are loaded, the total power is 6 * 30.2mW = 181mW
Total Power_MAX (3.465V, with all outputs switching) = 485mW + 181mW = 666mW
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 43°C/W per Table 6 below.
Therefore, Tj for an ambient temperature of 70°C with all outputs switching is:
70°C + 0.666W * 43°C/W = 98.6°C. This is well 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 6. THERMAL RESISTANCE qJA
FOR
24-PIN SOIC, FORCED CONVECTION
qJA by Velocity (Linear Feet per Minute)
Multi-Layer PCB, JEDEC Standard Test Boards
0
200
500
50°C/W
43°C/W
38°C/W
NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs.
84326AM
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REV. A MARCH 10, 2003
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ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
3. Calculations and Equations.
The purpose of this section is to derive the power dissipated into the load.
LVPECL output driver circuit and termination are shown in Figure 6.
VCC
Q1
VOUT
RL
50
VCC - 2V
FIGURE 6. LVPECL DRIVER CIRCUIT
TERMINATION
AND
To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination
voltage of V - 2V.
CCO
•
For logic high, VOUT = VOH_MAX = VCCO_MAX – 1.0V
(V
CCO_MAX
•
-V
OH_MAX
) = 1.0V
For logic low, VOUT = V
OL_MAX
(V
CCO_MAX
-V
OL_MAX
=V
CCO_MAX
– 1.7V
) = 1.7V
Pd_H is power dissipation when the output drives high.
Pd_L is the power dissipation when the output drives low.
Pd_H = [(V
OH_MAX
– (V
CCO_MAX
- 2V))/R ] * (V
CCO_MAX
L
-V
) = [(2V - (V
OH_MAX
CCO_MAX
-V
OH_MAX
))/R ] * (V
CCO_MAX
L
-V
OH_MAX
)=
[(2V - 1V)/50Ω] * 1V = 20.0mW
Pd_L = [(V
OL_MAX
– (V
CCO_MAX
- 2V))/R ] * (V
L
CCO_MAX
-V
OL_MAX
) = [(2V - (V
CCO_MAX
-V
OL_MAX
))/R ] * (V
L
CCO_MAX
-V
OL_MAX
)=
[(2V - 1.7V)/50Ω] * 1.7V = 10.2mW
Total Power Dissipation per output pair = Pd_H + Pd_L = 30.2mW
84326AM
www.icst.com/products/hiperclocks.html
12
REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
RELIABILITY INFORMATION
TABLE 7. θJAVS. AIR FLOW TABLE
qJA by Velocity (Linear Feet per Minute)
Multi-Layer PCB, JEDEC Standard Test Boards
0
200
500
50°C/W
43°C/W
38°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 ICS84326 is: 2804
84326AM
www.icst.com/products/hiperclocks.html
13
REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
PACKAGE OUTLINE - M SUFFIX
TABLE 8. PACKAGE DIMENSIONS
Millimeters
SYMBOL
Minimum
Maximum
N
A
24
--
2.65
A1
0.10
--
A2
2.05
2.55
B
0.33
0.51
C
0.18
0.32
D
15.20
15.85
E
7.40
e
H
7.60
1.27 BASIC
10.00
10.65
h
0.25
0.75
L
0.40
1.27
α
0°
8°
Reference Document: JEDEC Publication 95, MS-013, MO-119
84326AM
www.icst.com/products/hiperclocks.html
14
REV. A MARCH 10, 2003
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS84326
CRYSTAL-TO-3.3V LVPECL
SERIAL ATTACHED SCSI CLOCK SYNTHESIZER/FANOUT BUFFER
TABLE 9. ORDERING INFORMATION
Part/Order Number
Marking
Package
Count
Temperature
ICS84326AM
ICS84326AM
24 Lead SOIC
30 per tube
0°C to 70°C
ICS84326AMT
ICS84326AM
24 Lead SOIC on Tape and Reel
1000
0°C to 70°C
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.
84326AM
www.icst.com/products/hiperclocks.html
15
REV. A MARCH 10, 2003