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PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR
FEATURES
* 1 differential 3.3V LVPECL output * Crystal oscillator interface designed for 25MHz, 18pF parallel resonant crystal * Maximum output frequency: 250MHz, using a 25MHz crystal * VCO range: 490MHz - 640MHz * RMS phase jitter @ 250MHz, using a 25MHz crystal (12KHz - 20MHz): 0.33ps (typical) * 3.3V operating supply * 0C to 70C ambient operating temperature
GENERAL DESCRIPTION
The ICS843023 is a Gigabit Ethernet Clock Generator and a member of the HiPerClocksTM HiPerClockSTM family of high performance devices from ICS. The ICS843023 uses a 25MHz crystal to synthesize 250MHz. The ICS843023 has excellent phase jitter performance, over the 1.875MHz - 20MHz integration range. The ICS843023 is packaged in a small 8-pin TSSOP, making it ideal for use in systems with limited board space.
ICS
BLOCK DIAGRAM
OE 25MHz XTAL_IN
PIN ASSIGNMENT
VCC XTAL_OUT XTAL_IN VEE 1 2 3 4 8 7 6 5 Q0 nQ0 VCC OE
OSC
XTAL_OUT
Phase Detector
VCO
/2 (fixed)
Q0 nQ0
ICS843023
/20 (fixed)
8-Lead TSSOP 4.40mm x 3.0mm x 0.925mm package body G Package Top View
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. 843023AG www.icst.com/products/hiperclocks.html REV. A NOVEMBER 30, 2004
1
PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR
Type Description Core supply pin. Cr ystal oscillator interface. XTAL_IN is the input, XTAL_OUT is the output. Negative supply pin. Active high output enable. When logic HIGH, the outputs are enabled and active. When logic LOW, the outputs are disabled and are in a high impedance state. LVCMOS/LVTTL interface levels. Differential clock outputs. LVPECL interface levels.
TABLE 1. PIN DESCRIPTIONS
Number 1, 6 2, 3 4 5 7, 8 Name VCC XTAL_OUT, XTAL_IN V EE OE nQ0, Q0 Power Input Power Input Output Pullup
Pullup refers to internal input resistors. See Table 2, Pin Characteristics, for typical values.
TABLE 2. PIN CHARACTERISTICS
Symbol CIN RPULLUP Parameter Input Capacitance Input Pullup Resistor Test Conditions Minimum Typical 4 51 Maximum Units pF K
843023AG
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REV. A NOVEMBER 30, 2004
PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR
4.6V -0.5V to VCC + 0.5V 50mA 100mA 101.7C/W (0 mps) -65C to 150C 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.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC Inputs, VI Outputs, IO Continuous Current Surge Current Package Thermal Impedance, JA Storage Temperature, TSTG
TABLE 3A. POWER SUPPLY DC CHARACTERISTICS, VCC = 3.3V5%, TA=0C TO 70C
Symbol VCC VCCA IEE Parameter Core Supply Voltage Analog Supply Voltage Power Supply Current Test Conditions Minimum 3.135 3.135 Typical 3.3 3.3 65 Maximum 3.465 3.465 Units V V mA
TABLE 4B. LVCMOS/LVTTL DC CHARACTERISTICS, VCC = 3.3V5%, TA = 0C TO 70C
Symbol VIH VIL IIH IIL Parameter Input High Voltage Input Low Voltage Input High Current Input Low Current OE OE VCC = VIN = 3.465V VCC = 3.465V, VIN = 0V -150 Test Conditions Minimum 2 -0.3 Typical Maximum VCC + 0.3 0.8 5 Units V V A A
TABLE 3C. LVPECL DC CHARACTERISTICS, VCC = 3.3V5%, TA=0C TO 70C
Symbol VOH VOL VSWING Parameter Output High Voltage; NOTE 1 Output Low Voltage; NOTE 1 Peak-to-Peak Output Voltage Swing Test Conditions Minimum VCC - 1.4 VCC - 2.0 0.6 Typical Maximum VCC - 0.9 VCC - 1.7 1.0 Units V V V
NOTE 1: Outputs terminated with 50 to VCC - 2V.
TABLE 4. CRYSTAL CHARACTERISTICS
Parameter Mode of Oscillation Frequency Equivalent Series Resistance (ESR) Shunt Capacitance Test Conditions Minimum Typical Fundamental 25 50 7 MHz pF Maximum Units
TABLE 5. AC CHARACTERISTICS, VCC = 3.3V5%, TA=0C TO 70C
Symbol fOUT Parameter Output Frequency RMS Phase Jitter (Random); NOTE 1 Output Rise/Fall Time Test Conditions Minimum Typical Maximum 250 Integration Range: 1.875MHz - 20MHz 20% to 80% 0.33 400 50 Units MHz ps ps %
REV. A NOVEMBER 30, 2004
tjit(O)
tR / tF
odc Output Duty Cycle NOTE 1: Please refer to the Phase Noise Plot.
843023AG
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PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR
PARAMETER MEASUREMENT INFORMATION
2V
Phase Noise Plot
Noise Power
VCC
Qx
SCOPE
LVPECL
nQx
Phase Noise Mask
VEE
f1 Offset Frequency f2
-1.3V 0.165V
RMS Jitter = Area Under the Masked Phase Noise Plot
3.3V OUTPUT LOAD AC TEST CIRCUIT
RMS PHASE JITTER
nQ0 Q0
Pulse Width t
PERIOD
80% Clock Outputs
80% VSW I N G
20% tR tF
20%
odc =
t PW t PERIOD
OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
OUTPUT RISE/FALL TIME
843023AG
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REV. A NOVEMBER 30, 2004
PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR APPLICATION INFORMATION
CRYSTAL INPUT INTERFACE
The ICS843023 has been characterized with 18pF parallel resonant crystals. The capacitor values, C1 and C2, shown in Figure 1 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.
XTAL_OUT C1 33p X1 18pF Parallel Crystal XTAL_IN C2 27p
Figure 1. CRYSTAL INPUt INTERFACE
TERMINATION FOR 3.3V LVPECL OUTPUT
The clock layout topology shown below is a typical termination for LVPECL outputs. The two different layouts mentioned are recommended only as guidelines. 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 designed to drive 50 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.
3.3V
Zo = 50 FOUT FIN
125 Zo = 50 FOUT
50 50 VCC - 2V RTT
125
Zo = 50
FIN
Zo = 50 84 84
RTT =
1 Zo (VOH + VOL / VCC - 2) - 2
FIGURE 2A. LVPECL OUTPUT TERMINATION
843023AG
FIGURE 2B. LVPECL OUTPUT TERMINATION
REV. A NOVEMBER 30, 2004
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PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR POWER CONSIDERATIONS
This section provides information on power dissipation and junction temperature for the ICS843023. Equations and example calculations are also provided.
1. Power Dissipation. The total power dissipation for the ICS843023 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 * 65mA= 225.2mW Power (outputs)MAX = 30mW/Loaded Output pair
Total Power_MAX (3.465V, with all outputs switching) = 225.2mW + 30mW = 255.2mW
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 125C.
The equation for Tj is as follows: Tj = JA * Pd_total + TA Tj = Junction Temperature JA = 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 JA must be used. Assuming a moderate air flow of 1 meter per second and a multi-layer board, the appropriate value is 90.5C/W per Table 6 below. Therefore, Tj for an ambient temperature of 70C with all outputs switching is: 70C + 0.255W * 90.5C/W = 93.1C. This is well below the limit of 125C. 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 JA
FOR
8-PIN SOIC, FORCED CONVECTION
JA by Velocity (Meter per Second)
0
Multi-Layer PCB, JEDEC Standard Test Boards 101.7C/W
1
90.5C/W
2.5
89.8C/W
843023AG
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REV. A NOVEMBER 30, 2004
PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR
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 3.
VCC
Q1
VOUT RL 50 VCC - 2V
FIGURE 3. LVPECL DRIVER CIRCUIT
AND
TERMINATION
To calculate worst case power dissipation into the load, use the following equations which assume a 50 load, and a termination voltage of V - 2V.
CC
*
For logic high, VOUT = V (V
CCO_MAX
OH_MAX
=V
CC_MAX
- 0.9V
-V
OH_MAX
) = 0.9V =V - 1.7V
*
For logic low, VOUT = V (V
CCO_MAX
OL_MAX
CC_MAX
-V
OL_MAX
) = 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
CC_MAX
- 2V))/R ] * (V
L
CC_MAX
-V
OH_MAX
) = [(2V - (V
CC_MAX
-V
OH_MAX
))/R ] * (V
L
CC_MAX
-V
OH_MAX
)=
[(2V - 0.9V)/50] * 0.9V = 19.8mW
Pd_L = [(V
OL_MAX
- (V
CC_MAX
- 2V))/R ] * (V
L
CC_MAX
-V
OL_MAX
) = [(2V - (V
CC_MAX
-V
OL_MAX
))/R ] * (V
L
CC_MAX
-V
OL_MAX
)=
[(2V - 1.7V)/50] * 1.7V = 10.2mW Total Power Dissipation per output pair = Pd_H + Pd_L = 30mW
843023AG
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7
REV. A NOVEMBER 30, 2004
PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR RELIABILITY INFORMATION
TABLE 7. JAVS. AIR FLOW TABLE
FOR
8 LEAD TSSOP
JA by Velocity (Meter per Second)
0
Multi-Layer PCB, JEDEC Standard Test Boards 101.7C/W
1
90.5C/W
2.5
89.8C/W
TRANSISTOR COUNT
The transistor count for ICS843023 is: 2360
843023AG
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REV. A NOVEMBER 30, 2004
PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR
8 LEAD TSSOP
PACKAGE OUTLINE - G SUFFIX
FOR
TABLE 8. PACKAGE DIMENSIONS
SYMBOL N A A1 A2 b c D E E1 e L aaa 0.45 0 -4.30 0.65 BASIC 0.75 8 0.10 -0.05 0.80 0.19 0.09 2.90 6.40 BASIC 4.50 Millimeters Minimum 8 1.20 0.15 1.05 0.30 0.20 3.10 Maximum
Reference Document: JEDEC Publication 95, MO-153
843023AG
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REV. A NOVEMBER 30, 2004
PRELIMINARY
Integrated Circuit Systems, Inc.
ICS843023
FEMTOCLOCKSTM CRYSTAL-TO3.3V, 250MHZ LVPECL CLOCK GENERATOR
Marking 3023A 3023A Package 8 lead TSSOP 8 lead TSSOP on Tape and Reel Count 100 per tube 2500 Temperature 0C to 70C 0C to 70C
TABLE 9. ORDERING INFORMATION
Part/Order Number ICS843023AG ICS843023AGT
The aforementioned trademarks, HiPerClockSTM
and FemtoClocksTM
are a trademark of Integrated Circuit Systems, Inc. or its subsidiaries in the United States and/or other countries.
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. 843023AG
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REV. A NOVEMBER 30, 2004

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