ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR GENERAL DESCRIPTION FEATURES The ICS840021I is a Gigabit Ethernet Clock Generator and a member of the HiPerClocksTM HiPerClockS™ family of high performance devices from ICS. The ICS840021I uses a 25MHz crystal to synthesize 125MHz. The ICS840021I has excellent phase jitter performance, over the 1.875MHz – 20MHz integration range. The ICS840021I is packaged in a small 8-pin TSSOP, making it ideal for use in systems with limited board space. • 1 LVCMOS/LVTTL output, 15Ω output impedence ICS • Crystal oscillator interface designed for 25MHz, 18pF parallel resonant crystal • Output frequency: 125MHz • VCO range: 560MHz to 680MHz • RMS phase jitter @ 125MHz, using a 25MHz crystal (1.875MHz - 20MHz): 0.48ps (typical) (3.3V) Offset Noise Power 100Hz ............... -97.8 dBc/Hz 1kHz .............. -124.6 dBc/Hz 10kHz .............. -132.5 dBc/Hz 100kHz .............. -131.1 dBc/Hz • Voltage supply modes: VDD/VDDA = 3.3V VDD/VDDA = 2.5V • -40°C to 85°C ambient operating temperature • Lead-Free package fully RoHS compliant BLOCK DIAGRAM PIN ASSIGNMENT OE 25MHz XTAL_IN OSC XTAL_OUT Phase Detector VCO Q0 ÷5 VDDA OE XTAL_OUT XTAL_IN 1 2 3 4 8 7 6 5 VDD Q0 GND nc ICS840021I ÷25 (fixed) 840021AGI 8-Lead TSSOP 4.40mm x 3.0mm x 0.925mm package body G Package Top View www.icst.com/products/hiperclocks.html 1 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR TABLE 1. PIN DESCRIPTIONS Number Name 1 VDDA Power Type 2 OE Input 5 XTAL_OUT, XTAL_IN nc Unused 6 GND Power 7 Q0 Output 8 VDD Power 3, 4 Input Description Pullup Analog supply pin. Output enable pin. When HIGH, Q0 output is enabled. When LOW, forces Q0 to HiZ state. LVCMOS/LVTTL interface levels. Crystal oscillator interface. XTAL_IN is the input, XTAL_OUT is the output. No connect. Power supply ground. Single-ended clock output. LVCMOS/LVTTL interface levels. 15Ω output impedence. Core supply pin. NOTE: Pullup refers to internal input resistors. See Table 2, Pin Characteristics, for typical values. TABLE 2. PIN CHARACTERISTICS Symbol Parameter Test Conditions CIN Input Capacitance VDD, VDDA = 3.465V Minimum Typical Maximum Units 4 pF 7 pF CPD Power Dissipation Capacitance 7 pF RPULLUP Input Pullup Resistor 51 kΩ ROUT Output Impedance 15 Ω VDD, VDDA = 2.625V TABLE 3. CONTROL FUNCTION TABLE Control Inputs Output OE Q0 0 Hi-Z 1 Active 840021AGI www.icst.com/products/hiperclocks.html 2 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR ABSOLUTE MAXIMUM RATINGS Supply Voltage, VDD 4.6V Inputs, VI -0.5V to VDD + 0.5 V Outputs, VO -0.5V to VDD + 0.5V Package Thermal Impedance, θJA 101.7°C/W (0 mps) 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 4A. POWER SUPPLY DC CHARACTERISTICS, VDD = VDDA = 3.3V±5%, TA = -40°C TO 85°C Symbol Parameter Minimum Typical Maximum Units VDD Core Supply Voltage Test Conditions 3.135 3.3 3.465 V 3.135 3.3 VDDA Analog Supply Voltage 3.465 V IDD Power Supply Current 65 mA IDDA Analog Supply Current 10 mA TABLE 4B. POWER SUPPLY DC CHARACTERISTICS, VDD = VDDA = 2.5V±5%, TA = -40°C TO 85°C Symbol Parameter Minimum Typical Maximum Units VDD Core Supply Voltage Test Conditions 2.375 2.5 2.625 V 2.375 2.5 VDDA Analog Supply Voltage 2.625 V IDD Power Supply Current 60 mA IDDA Analog Supply Current 10 mA TABLE 4C. LVCMOS/LVTTL DC CHARACTERISTICS, VDD = VDDA = 3.3V±5% OR 2.5V±5%, TA = -40°C TO 85°C Symbol VIH VIL Parameter Input High Voltage Input Low Voltage Test Conditions Minimum Maximum Units VDD = 3.3V 2 Typical VDD + 0.3 V VDD = 2.5V 1.7 VDD + 0.3 V VDD = 3.3V -0.3 0.8 V VDD = 2.5V -0.3 0.7 V 5 µA IIH Input High Current OE VDD = VIN = 3.465V or 2.625V IIL Input Low Current OE VDD = 3.465V or 2.625V, VIN = 0V -150 µA VOH Output High Voltage; NOTE 1 VDD = 3.465V 2.6 V VDD = 2.625V 1. 8 VOL Output Low Voltage; NOTE 1 VDD = 3.465V or 2.625V V 0.5 V NOTE 1: Outputs terminated with 50Ω to VDD/2. See Parameter Measurement Information Section, "Output Load Test Circuit" diagrams. 840021AGI www.icst.com/products/hiperclocks.html 3 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR TABLE 5. CRYSTAL CHARACTERISTICS Parameter Test Conditions Minimum Mode of Oscillation Typical Maximum Units Fundamental Frequency 25 MHz Ω Equivalent Series Resistance (ESR) 50 Shunt Capacitance 7 pF Drive Level 1 mW Maximum Units TABLE 6A. AC CHARACTERISTICS, VDD = VDDA = 3.3V±5%, TA = -40°C TO 85°C Symbol Parameter fOUT Output Frequency RMS Phase Jitter (Random); NOTE 1 Output Rise/Fall Time tjit(Ø) tR / tF Test Conditions Minimum Integration Range: 1.875MHz to 20MHz 20% to 80% odc Output Duty Cycle NOTE 1: Please refer to the Phase Noise Plot. Typical 125 MHz 0.48 ps 200 500 ps 48 52 % Maximum Units TABLE 6A. AC CHARACTERISTICS, VDD = VDDA = 2.5V±5%, TA = -40°C TO 85°C Symbol Parameter fOUT Output Frequency RMS Phase Jitter (Random); NOTE 1 Output Rise/Fall Time tjit(Ø) tR / tF Test Conditions Integration Range: 1.875MHz to 20MHz 20% to 80% odc Output Duty Cycle NOTE 1: Please refer to the Phase Noise Plot. 840021AGI Minimum www.icst.com/products/hiperclocks.html 4 Typical 125 MHz 0.50 ps 250 550 ps 48 52 % REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR TYPICAL PHASE NOISE AT 125MHZ (3.3V OR 2.5V) ➤ 0 -10 -20 Gigabit Ethernet Filter -30 125MHz -50 -60 RMS Phase Jitter (Random) 1.875MHz to 20MHz (3.3V) = 0.48ps (typical) 1.875MHz to 20MHz (2.5V) = 0.50ps (typical) -70 -80 -90 Raw Phase Noise Data -100 -110 ➤ NOISE POWER dBc Hz -40 -120 -130 -140 -150 -160 ➤ -170 -180 -190 100 1k 10k Phase Noise Result by adding Gigabit Ethernet Filter to raw data 100k 1M 10M 100M OFFSET FREQUENCY (HZ) 840021AGI www.icst.com/products/hiperclocks.html 5 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR PARAMETER MEASUREMENT INFORMATION 1.25V ± 5% 1.65V ± 5% SCOPE VDD, VDDA Qx LVCMOS SCOPE VDD, VDDA Qx LVCMOS GND GND -1.25V ± 5% -1.65V ± 5% 3.3V OUTPUT LOAD AC TEST CIRCUIT 2.5V OUTPUT LOAD AC TEST CIRCUIT Noise Power Phase Noise Plot 80% 80% Phase Noise Mask Clock Outputs f1 Offset Frequency 20% 20% tR tF f2 RMS Jitter = Area Under the Masked Phase Noise Plot RMS PHASE JITTER OUTPUT RISE/FALL TIME V DD 2 Q0 t PW t odc = PERIOD t PW x 100% t PERIOD OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD 840021AGI www.icst.com/products/hiperclocks.html 6 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR APPLICATION INFORMATION POWER SUPPLY FILTERING TECHNIQUES As in any high speed analog circuitry, the power supply pins are vulnerable to random noise. The ICS840021I 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 pin. 3.3V or 2.5V VDD .01μF 10 Ω VDDA .01μF 10μF FIGURE 1. POWER SUPPLY FILTERING CRYSTAL INPUT INTERFACE The ICS840021I has been characterized with 18pF parallel resonant crystals. The capacitor values, C1 and C2, shown in Figure 2 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 22p Figure 2. CRYSTAL INPUt INTERFACE 840021AGI www.icst.com/products/hiperclocks.html 7 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR APPLICATION SCHEMATIC Figure 3A shows a schematic example of the ICS840021I. An example of LVCMOS termination is shown in this schematic. Additional LVCMOS termination approaches are shown in the LVCMOS Termination Application Note. In this example, an 18pF parallel resonant 25MHz crystal is used for generating 125MHz VDD output frequency. The C1 = 22pF and C2 = 33pF are recommended for frequency accuracy. For different board layout, the C1 and C2 values may be slightly adjusted for optimizing frequency accuracy. VDDA R2 10 C3 C4 10uF 0.1u U1 OE C2 33pF 1 2 3 4 VDDA OE XTAL_OUT XTAL_IN VDD Q0 GND NC 8 7 6 5 R3 33 VDD Q Zo = 50 Ohm X1 C5 0.1u ICS840021i C1 22pF LVCMOS VDD=3.3V FIGURE 3A. ICS840021I SCHEMATIC EXAMPLE PC BOARD LAYOUT EXAMPLE Figure 3B shows an example of ICS840021I P.C. board layout. The crystal X1 footprint shown in this example allows installation of either surface mount HC49S or through-hole HC49 package. The footprints of other components in this example are listed in the Table 7. There should be at least one decoupling capacitor per power pin. The decoupling capacitors should be located as close as possible to the power pins. The layout assumes that the board has clean analog power ground plane. TABLE 7. FOOTPRINT TABLE Reference Size C1, C2 0402 C3 0805 C4, C5 0603 R2, R3 0603 NOTE: Table 7, lists component sizes shown in this layout example. FIGURE 3B. ICS840021I PC BOARD LAYOUT EXAMPLE 840021AGI www.icst.com/products/hiperclocks.html 8 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR RELIABILITY INFORMATION TABLE 8. θJAVS. AIR FLOW TABLE FOR 8 LEAD TSSOP θJA by Velocity (Meters per Second) Multi-Layer PCB, JEDEC Standard Test Boards 0 1 2.5 101.7°C/W 90.5°C/W 89.8°C/W TRANSISTOR COUNT The transistor count for ICS840021I is: 1961 840021AGI www.icst.com/products/hiperclocks.html 9 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. PACKAGE OUTLINE - G SUFFIX FOR FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR 8 LEAD TSSOP TABLE 9. PACKAGE DIMENSIONS SYMBOL Millimeters Minimum N A Maximum 8 -- 1.20 A1 0.05 0.15 A2 0.80 1.05 b 0.19 0.30 c 0.09 0.20 D 2.90 3.10 E E1 6.40 BASIC 4.30 e 4.50 0.65 BASIC L 0.45 0.75 α 0° 8° aaa -- 0.10 Reference Document: JEDEC Publication 95, MO-153 840021AGI www.icst.com/products/hiperclocks.html 10 REV. A MAY 19, 2005 ICS840021I Integrated Circuit Systems, Inc. FEMTOCLOCKS™CRYSTAL-TOLVCMOS/LVTTL CLOCK GENERATOR TABLE 10. ORDERING INFORMATION Part/Order Number Marking Package Shipping Packaging Temperature ICS840021AGI 021AI 8 lead TSSOP tube -40°C to 85°C ICS840021AGIT 021AI 8 lead TSSOP 2500 tape & reel -40°C to 85°C ICS840021AGILF TBD 8 lead "Lead-Free" TSSOP tube -40°C to 85°C ICS840021AGILFT TBD 8 lead "Lead-Free" TSSOP 2500 tape & reel -40°C to 85°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 aforementioned trademarks, HiPerClockS™ and FemtoClocks™ 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 and industrial applications. Any other applications such as those requiring 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. 840021AGI www.icst.com/products/hiperclocks.html 11 REV. A MAY 19, 2005