PRELIMINARY ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/ CLOCK GENERATOR FOR PCI EXPRESS™ AND ETHERNET General Description Features The ICS8743008I is Zero-Delay Buffer/Frequency Multiplier with eight differential LVDS or LVPECL HiPerClockS™ output pairs (pin selectable output type), and uses external feedback for “zero delay” clock regeneration. In PCI Express and Ethernet applications, 100MHz and 125MHz are the most commonly used reference clock frequencies and each of the eight output pairs can be independently set for either 100MHz or 125MHz. With an output frequency range of 98MHz to 165MHz, the device is also suitable for use in a variety of other applications such as Fibre Channel (106.25MHz) and XAUI (156.25MHz). The M-LVDS Input/Output pair is useful in backplane applications when the reference clock can either be local (on the same board as the ICS8743008I) or remote via a backplane connector. In output mode, an input from a local reference clock applied to the CLK/nCLK input pins is translated to M-LVDS and driven out to the MLVDS/nMLVDS pins. In input mode, the internal M_LVDS driver is placed in Hi-Z state using the OE_MLVDS pin and MLVDS/nMLVDS pin then becomes an input (e.g. from a backplane). • Eight differential output pairs with selectable pin type: LVDS or LVPECL. Each output pair is individually selectable for 100MHz or 125MHz (for PCIe and Ethernet applications). • One differential clock input pair CLK/nCLK can accept the following differential input levels: LVPECL, LVDS, M-LVDS, LVHSTL, HCSL • • • • • • • One M-LVDS I/O (MLVDS/nMLVDS) • • • Full 3.3V supply mode -40°C to 85°C ambient operating temperature ICS Input frequency range: 19.6MHz - 165MHz VCO range: 490MHz - 660MHz PCI Express (2.5 Gb/S) and Gen 2 (5 Gb/s) jitter compliant External feedback for “zero delay” clock regeneration RMS phase jitter @ 125MHz (1.875MHz – 20MHz): 0.57ps (typical) Available in lead-free (RoHS 6) packages Pin Assignment nQ1 Q1 VDDO nQ0 Q0 QDIV7 QDIV6 QDIV5 QDIV4 VDDA CLK nCLK PDIV0 PDIV1 The ICS8743008I uses very low phase noise FemtoClock technology, thus making it ideal for such applications as PCI Express Generation 1 and 2 as well as for Gigabit Ethernet, Fibre Channel, and 10 Gigabit Ethernet. It is packaged in a 56-VFQFN package (8mm x 8mm). Output frequency range: 98MHz - 165MHz 56 55 54 53 52 51 50 49 48 47 46 45 44 43 PLL_SEL VDD nc FBO_DIV MR OE0 OE1 OE2 3 4 5 6 7 8 9 10 11 40 39 38 41 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 FBI_DIV0 GND 42 37 36 35 34 33 32 31 30 29 VDDO Q2 nQ2 Q3 nQ3 VDDO Q4 nQ4 Q5 nQ5 FBOUT nFBOUT VDDO Q_TYPE Q6 nQ6 MLVDS nMLVDS GND 1 2 FBI_DIV1 nFBIN FBIN GND QDIV0 QDIV1 QDIV2 QDIV3 Q7 nQ7 nc VDD OE_MLVDS ICS8743008I 56-Lead VFQFN 8mm x 8mm x 0.925mm package body K Package Top View The Preliminary Information presented herein represents a product in pre-production. The noted characteristics are based on initial product characterization and/or qualification. Integrated Device Technology, Incorporated (IDT) reserves the right to change any circuitry or specifications without notice. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 1 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Block Diagram 3 OE2:0 (PU, PU) MR1 (PD) QDIV0 (PD) PDIV1 (PD) PDIV0 (PD) CLK (PD) nCLK (PU/PD) QDIV0 0 ÷4 (default) 1 ÷5 PDIV1:0 00 ÷4 (default) 01 ÷5 10 ÷8 11 ÷1 Q0 nQ0 MR (PD) OE_MLVDS (PU) 0 MLVDS 8 Differential LVPECL or LVDS Pairs nMLVDS PD FBI_DIV1 (PU) VCO 490-660 MHz 1 FBI_DIV0 (PU) FBIN (PD) nFBIN (PU/PD) QDIV7 (PD) FBI_DIV1:0 00 ÷1 01 ÷2 10 ÷4 11 ÷5 (default) QDIV7 0 ÷4 (default) 1 ÷5 nQ7 FBO_DIV (PD) MR1 (PD) PLL_SEL (PU) Q7 FBO_DIV 0 ÷4 (default) 1 ÷5 FBOUT nFBOUT Q_TYPE (PD) MR1 (PD) 1 One master reset pin is used to reset all the internal dividers, but the MR lines are not drawn as all tied together to reduce control line clutter, making the block diagram easier to read PU means internal pull-up resistor on pin (power-up default is HIGH if not externally driven) PD means internal pull-down resistor on pin (power-up default is LOW if not externally driven) IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 2 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Table 1. Pin Descriptions Number Name 1, 7 VDD 2 3 OE_MLVDS MLVDS Type Description Power Core supply pins. Input Active High Output Enable. When HIGH, the M-LVDS output driver is active and provides a buffered copy of reference clock applied the CLK/nCLK input to the MLVDS/nMLVDS output pins. The MLVDS/nMLVDS frequency equals the CLK/nCLK frequency divided by the PDIV Divider value (selectable ÷1, ÷4, ÷5, ÷8). When LOW, the M-LVDS output driver is placed into a Hi-Z state and the MLVDS/nMLVDS pins can accept a differential input. LVCMOS/LVTTL interface levels. Pullup I/O Non-Inverting M-LVDS input/output. The input/output state is determined by the OE_MLVDS pin. When OE_MLVDS = HIGH, this pin is an output and drives the non-inverting M-LVDS output. When OE_MLVDS = LOW, this pin is an input and can accept the following differential input levels: M-LVDS, LVDS, LVPECL, HSTL, HCSL. Inverting M-LVDS input/output. The input/output state is determined by the OE_MLVDS pin. When OE_MLVDS = HIGH, this pin is an output and drives the inverting M-LVDS output. When OE_MLVDS = LOW, this pin is an input and can accept the following differential input levels: M-LVDS, LVDS, LVPECL, HSTL, HCSL. The output driver is always M-LVDS and is not affected by the state of the Q-TYPE pin which affects Q0/nQ0:Q7/nQ7, and FBOUT/nFBOUT. 4 nMLVDS I/O 5, 14, 19 GND Power Power supply ground. PLL select. Determines if the PLL is in bypass or enabled mode (default). In enabled mode, the output frequency = VCO frequency/QDIV divider. In bypass mode, the output frequency = reference clock frequency/ (PDIV*QDIV). LVCMOS/LVTTL interface levels. 6 PLL_SEL Input 8, 26 nc Unused 9 FBO_DIV Input 10 11 12 MR OE0 OE1 Input Input Input Pullup No connect. Pulldown Output Divider Control for the feedback output pair, FBOUT/nFBOUT. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. Pulldown Active High master reset. When logic HIGH, the internal dividers are reset causing the Qx/nQx outputs to drive Hi-Z. Note that assertion of MR overrides the OE[0:2] control pins and all outputs are disabled. When logic LOW, the internal dividers are enabled and the state of the outputs is determined by OE[0:2]. MR must be asserted on power-up to ensure outputs phase aligned. LVCMOS/LVTTL interface levels. Pullup Output Enable. Together with OE1 and OE2, determines the output state of the outputs with the default state: all output pairs switching. When an LVDS or LVPECL output pair is disabled, the disable state is Qx/nQx = Hi-Z. It should also be noted that the feedback output pins (FBOUT/nFBOUT) are always switching and are not affected by the state of OE[2:0]. Refer to table 3B for truth table. LVCMOS/LVTTL Interface levels. Pullup Output Enable. Together with OE0 and OE2, determines the output state of the outputs with the default state: all output pairs switching. When an LVDS or LVPECL output pair is disabled, the disable state is Qx/nQx = Hi-Z. It should also be noted that the feedback output pins (FBOUT/nFBOUT) are always switching and are not affected by the state of OE[2:0]. Refer to table 3B for truth table. LVCMOS/LVTTL Interface levels Continued on next page. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 3 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR Number Name Type PRELIMINARY Description 13 OE2 Input Pullup Output Enable. Together with OE0 and OE1, determines the output state of the outputs with the default state: all output pairs switching. When an HCSL output pair is disabled, the disable state is Qx = LOW, nQx = HI-Z. It should also be noted that the feedback output pins (FBOUT/nFBOUT) are always switching and are not affected by the state of OE[2:0]. Refer to table 3B for truth table. LVCMOS/LVTTL Interface levels 15 FBI_DIV0 Input Pullup Feedback Input Divide Select 0. Together with FB_DIV1, determines the feedback input divider value. LVCMOS/LVTTL interface levels. 16 FBI_DIV1 Input Pullup Feedback Input Divide Select 1. Together with FB_DIV0, determines the feedback input divider value. LVCMOS/LVTTL interface levels. 17 nFBIN Input Pullup/ Pulldown Inverted differential feedback input to phase detector for regenerating clocks with “Zero Delay.” 18 FBIN Input Pulldown Non-inverted differential feedback input to phase detector for regenerating clocks with “Zero Delay.” 20 QDIV0 Input Pulldown Output Divider Control for Q0/nQ0. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 21 QDIV1 Input Pulldown Output Divider Control for Q1/nQ1. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 22 QDIV2 Input Pulldown Output Divider Control for Q2/nQ2. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 23 QDIV3 Input Pulldown Output Divider Control for Q3/nQ3. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 24, 25 Q7/nQ7 Output Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. 27, 28 Q6/nQ6 Output Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. Pulldown Output Type Select. 0 = LVDS outputs (default); 1 = LVPECL outputs on Q0/nQ0:Q7/nQ7, and FBOUT/nFBOUT. The MLVDS/nMLVDS driver is always M-LVDS and is NOT affected by the state of this pin. LVCMOS/LVTTL interface levels. 29 Q_TYPE Input 30, 37, 42, 45 VDDO Power Output supply pins. 31, 32 nFBOUT, FBOUT Output Differential feedback output pair.The feedback ouput pair always switches independent of the output enable settings on the OE[2:0] pins. LVDS or LVPECL interface levels. 33, 34 nQ5/Q5 Output Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. 35, 36 nQ4/Q4 Output Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. 38, 39 nQ3/Q3 Output Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. 40, 41 nQ2/Q2 Output Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. 43, 44 nQ1/Q1 Output Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. Continued on next page. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 4 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR Type PRELIMINARY Number Name Description 46, 47 nQ0/Q0 Output 48 QDIV7 Input Pulldown Output Divider Control for Q7/nQ7. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 49 QDIV6 Input Pulldown Output Divider Control for Q6/nQ6. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 50 QDIV5 Input Pulldown Output Divider Control for Q5/nQ5. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 51 QDIV4 Input Pulldown Output Divider Control for Q4/nQ4. Determines if the output divider = ÷4 (default), or ÷5. LVCMOS/LVTTL interface levels. 52 VDDA Power 53 CLK Input Pulldown Non-inverting differential clock input. Accepts HCSL, LVDS, M-LVDS, HSTL input levels. 54 nCLK Input Pullup/ Pulldown Inverting differential clock input. Accepts HCSL, LVDS, M-LVDS, HSTL input levels. 55 PDIV0 Input Pulldown Input Divide Select 0. Together with PDIV1 determines the input divider value. LVCMOS/LVTTL Interface levels. 56 PDIV1 Input Pulldown Input Divide Select 1. Together with PDIV0 determines the input divider value. LVCMOS/LVTTL Interface levels. Differential LVDS or LVPECL output pair. The output type is controlled by the Q_TYPE pin as follows: Q_TYPE = 0 LVDS (default); Q_TYPE = 1 LVPECL. Analog supply pin. NOTE: Pullup and Pulldown refer to intenal input resistors. See Table 2, Pin Characteristics, for typical values. Table 2. Pin Characteristics Symbol Parameter Test Conditions CIN Input Capacitance 4 pF RPULLUP Input Pullup Resistor 51 kΩ RPULLDOWN Input Pulldown Resistor 51 kΩ IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 5 Minimum Typical Maximum Units ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Function Tables Table 3A. Common Configuration Table (not exhaustive)NOTE 1 Input Frequency Output Frequency Application Frequency Mult. Factor PDIV FBI_DIV FBO_DIV QDIVx 100MHz 100MHz PCIe Buffer 1 ÷1 ÷1 ÷5 ÷5 125MHz 125MHz PCIe, Ethernet Buffer 1 ÷1 ÷1 ÷4 ÷4 100MHz 125MHz PCIe Multiplier 5/4 ÷1 ÷1 ÷5 ÷4 125MHz 100MHz PCIe Divider 4/5 ÷1 ÷1 ÷4 ÷5 25MHz 100MHz PCIe Multiplier 4 ÷1 ÷4 ÷5 ÷5 25MHz 125MHz PCIe, Ethernet Multiplier 5 ÷1 ÷4 ÷5 ÷4 25MHz 156.25MHz 25/4 ÷1 ÷5 ÷5 ÷4 62.5MHz 125MHz Ethernet Multiplier 2 ÷1 ÷2 ÷4 ÷4 53.125MHz 106.25MHz Fibre Channel Multiplier 2 ÷1 ÷2 ÷5 ÷5 XAUI Multiplier NOTE 1: This table shows more common configurations and is not exhaustive. When using alternate configurations, the designer must ensure the VCO frequency is always within its range of 490MHz – 660MHz. Table 3B. Output Enable Truth Table Inputs State OE2 OE1 OE0 Q[0:7] / nQ[0:7] 0 0 0 Q0/nQ0 switching, Q1/nQ1:Q7/nQ7, disabled (Qx/nQx = Hi-Z) 0 0 1 Q0/nQ0:Q1/nQ1 switching, Q2/nQ2:Q7/nQ7 disabled (Qx/nQx = Hi-Z) 0 1 0 Q0/nQ0:Q2/nQ2 switching, Q3/nQ3:Q7/nQ7 disabled (Qx/nQx = Hi-Z) 0 1 1 Q0/nQ0:Q3/nQ3 switching, Q4/nQ4:Q7/nQ7 disabled (Qx/nQx = Hi-Z) 1 0 0 Q0/nQ0:Q4/nQ4 switching, Q5/nQ5:Q7/nQ7 disabled (Qx/nQx = Hi-Z) 1 0 1 Q0/nQ0:Q5/nQ5 switching, Q6/nQ6:Q7/nQ7 disabled (Qx/nQx = Hi-Z) 1 1 0 Q0/nQ0:Q6/nQ6 switching, Q7/nQ7 disabled (Q7/nQ7 = Hi-Z) 1 1 1 All output pairs switching (default) IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 6 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Absolute Maximum Ratings 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. Item Rating Supply Voltage, VDD 4.6V Inputs, VI -0.5V to VDD + 0.5V Outputs, IO (LVDS) Continuos Current Surge Current 10mA 15mA Outputs, IO (LVPECL) Continuos Current Surge Current 50mA 100mA Package Thermal Impedance, θJA 31.4°C/W (0 mps) Storage Temperature, TSTG -65°C to 150°C DC Electrical Characteristics Table 4A. LVDS Power Supply DC Characteristics, VDD = VDDO = 3.3V ± 5%, TA = -40°C to 85°C Symbol Parameter VDD Core Supply Voltage VDDA Test Conditions Minimum Typical Maximum Units 3.135 3.3 3.465 V Analog Supply Voltage VDD – 0.11 3.3 VDD V VDDO Output Supply Voltage 3.135 3.3 3.465 V IDD Power Supply Current 187 mA IDDA Analog Supply Current 11 mA IDDO Output Supply Current 155 mA Table 4B. LVPECL Power Supply DC Characteristics, VDD = VDDO = 3.3V ± 5%, VEE = 0V, TA = -40°C to 85°C Symbol Parameter VDD Core Supply Voltage VDDA Test Conditions Minimum Typical Maximum Units 3.135 3.3 3.465 V Analog Supply Voltage VDD – 0.11 3.3 VDD V VDDO Output Supply Voltage 3.135 3.3 3.465 V IEE Power Supply Current 230 mA IDDA Analog Supply Current 11 mA IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 7 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Table 4C. LVCMOS/LVTTL DC Characteristics, VDD = VDDO = 3.3V ± 5%, TA = -40°C to 85°C Symbol Parameter VIH VIL IIH IIL Test Conditions Minimum Input High Voltage 3.3V Input Low Voltage 3.3V Typical Maximum Units 2 VDD + 0.3 V -0.3 0.8 V PDIV[0:1], QDIV[0:7], FBO_DIV, MR, Q_TYPE VDD = VIN = 3.465V 150 µA OE_MLVDS, OE[0:2], FBI_DIV[0:1], PLL_SEL VDD = VIN = 3.465V 5 µA PDIV[0:1], QDIV[0:7], FBO_DIV, MR, Q_TYPE VDD = 3.465V, VIN = 0V -5 µA OE_MLVDS, OE[0:2], FBI_DIV[0:1], PLL_SEL VDD = 3.465V, VIN = 0V -150 µA Input High Current Input Low Current Table 4D. Differential DC Characteristics, VDD = VDDO = 3.3V ± 5%, TA = -40°C to 85°C Symbol Parameter Test Conditions IIH Input High Current IIL Input Low Current VPP Peak-to-Peak Voltage; NOTE 1 VCMR Common Mode Input Voltage; NOTE 1, 2 CLK/nCLK, FBIN/nFBIN Minimum Typical VDD = VIN = 3.465V Maximum Units 150 µA CLK, FBIN VDD = 3.465V, VIN = 0V -5 µA nCLK, nFBIN VDD = 3.465V, VIN = 0V -150 µA 0.15 1.3 V GND + 0.5 VDD – 0.85 V NOTE 1: VIL should not be less than -0.3V. NOTE 2: Common mode input voltage is defined as VIH. Table 4E. LVDS DC Characteristics, VDD = VDDO = 3.3V ± 5%, TA = -40°C to 85°C Symbol Parameter Test Conditions Minimum Typical Maximum Units VOD Differential Output Voltage 400 mV ∆VOD VOD Magnitude Change 30 mV VOS Offset Voltage 1.31 V ∆VOS VOS Magnitude Change 95 mV Table 4F. M-LVDS DC Characteristics, VDD = VDDO = 3.3V ± 5%, TA = -40°C to 85°C Symbol Parameter Test Conditions VOD Differential Output Voltage 440 mV ∆VOD VOD Magnitude Change 50 mV VOS Offset Voltage 1.6 V ∆VOS VOS Magnitude Change 50 mV ISC Output Short Circuit Current 48 mA IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 8 Minimum Typical Maximum Units ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Table 4G. LVPECL DC Characteristics, VDD = VDDO = 3.3V ± 5%, VEE = 0V, TA = -40°C to 85°C Symbol Parameter VOH Output High Current; NOTE 1 VOL Output Low Current; NOTE 1 VSWING Peak-to-Peak Output Voltage Swing Test Conditions Minimum Typical Maximum Units VDDO – 1.4 VDDO – 0.9 µA VDDO – 2.0 VDDO – 1.7 µA 0.6 1.0 V NOTE 1: Outputs termination with 50Ω to VDDO – 2V. AC Electrical Characteristics Table 5A. LVDS AC Characteristics, VDD = VDDO = 3.3V ± 5%, TA = -40°C to 85°C Parameter Symbol Test Conditions Minimum Typical 98 Maximum Units 160 MHz fMAX Output Frequency tjit(cc) Cycle-to-Cycle Jitter; NOTE 1 25 ps tsk(o) Output Skew; NOTE 2 60 ps 125MHz, Integration Range: 1.875MHz – 20MHz 0.60 ps tjit(Ø) RMS Phase Jitter (Random); NOTE 3 100MHz, Integration Range: 1.875MHz – 20MHz 0.66 ps tj Phase Jitter Peak-to-Peak; NOTE 4 125MHz, (1.2MHz – 21.9MHz), 106 samples 13.49 ps tREFCLK_HF_RMS Phase Jitter RMS; NOTE 5 125MHz 1.29 ps tR / tF Output Rise/Fall Time 20% to 80% 600 ps odc Output Duty Cycle 50 % NOTE 1: This parameter is defined in accordance with JEDEC Standard 65. NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at the differential cross points. NOTE 3: Please refer to the Phase Noise plots. NOTE 4: RMS jitter after applying system transfer function. See IDT Application Note PCI Express Reference Clock Requirements. Maximum limit for PCI Express is 86ps peak-to-peak. NOTE 5: RMS jitter after applying system transfer function. The pole frequencies for H1 and H2 for PCIe Gen 2 are 8-16MHz and 5-16MHz. See IDT Application Note PCI Express Reference Clock Requirements. Maximum limit for PCI Express Generation 2 is 3.1ps rms. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 9 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Table 5B. LVPECL AC Characteristics, VDD = VDDO = 3.3V ± 5%, VEE = 0V, TA = -40°C to 85°C Parameter Symbol fMAX Output Frequency tjit(cc) Cycle-to-Cycle Jitter; NOTE 1 tsk(o) Output Skew; NOTE 2 tjit(Ø) tj RMS Phase Jitter (Random); NOTE 3 Phase Jitter Peak-to-Peak; NOTE 4 tREFCLK_HF_RMS Phase Jitter RMS; NOTE 5 tR / tF Output Rise/Fall Time odc Output Duty Cycle Test Conditions Minimum Typical 98 Maximum Units 160 MHz 25 ps 60 ps 125MHz, Integration Range: 1.875MHz – 20MHz 0.57 ps 100MHz, Integration Range 1.875MHz – 20MHz 0.64 ps 125MHz, (1.2MHz – 21.9MHz), 106 samples 13.49 ps 125MHz 1.29 ps 20% to 80% 600 ps 50 % NOTE 1: This parameter is defined in accordance with JEDEC Standard 65. NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at the differential cross points. NOTE 3: Please refer to the Phase Noise plots. NOTE 4: RMS jitter after applying system transfer function. See IDT Application Note PCI Express Reference Clock Requirements. Maximum limit for PCI Express is 86ps peak-to-peak. NOTE 5: RMS jitter after applying system transfer function. The pole frequencies for H1 and H2 for PCIe Gen 2 are 8-16MHz and 5-16MHz. See IDT Application Note PCI Express Reference Clock Requirements. Maximum limit for PCI Express Generation 2 is 3.1ps rms. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 10 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Typical LVDS Phase Noise at 125MHz ➝ 125MHz RMS Phase Jitter (Random) 1.875MHz to 20MHz = 0.60ps (typical) Raw Phase Noise Data ➝ ➝ Noise Power dBc Ethernet Filter Phase Noise Result by adding an Ethernet filter to raw data Offset Frequency (Hz) Typical LVDS Phase Noise at 100MHz ➝ 100MHz RMS Phase Jitter (Random) 1.875MHz to 20MHz = 0.66ps (typical) Raw Phase Noise Data ➝ ➝ Noise Power dBc Hz 10Gb Ethernet Filter Phase Noise Result by adding a 10Gb Ethernet filter to raw data Offset Frequency (Hz) IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 11 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Typical LVPECL Phase Noise at 125MHz ➝ 125MHz RMS Phase Jitter (Random) 1.875MHz to 20MHz = 0.57ps (typical) Noise Power dBc Ethernet Filter Raw Phase Noise Data ➝ ➝ Phase Noise Result by adding an Ethernet filter to raw data Offset Frequency (Hz) Typical LVPECL Phase Noise at 100MHz ➝ 100MHz RMS Phase Jitter (Random) 1.875MHz to 20MHz = 0.64ps (typical) Raw Phase Noise Data ➝ ➝ Noise Power dBc 10Gb Ethernet Filter Phase Noise Result by adding a 10Gb Ethernet filter to raw data Offset Frequency (Hz) IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 12 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Parameter Measurement Information SCOPE 3.3V±5% POWER SUPPLY + Float GND – VDDO V SCOPE Qx VDD, DDA 3.3V±5% POWER SUPPLY + Float GND – LVDS nQx VDD, VDDO Qx VDDA M-LVDS nQx 3.3V M-LVDS Output Load AC Test Circuit 3.3V LVDS Output Load AC Test Circuit 2V 2V VDD VDD, VDDO V DDA Qx SCOPE nCLK V V Cross Points PP CMR CLK LVPECL nQx VEE GND -1.3V±0.165V 3.3V LVPECL Output Load AC Test Circuit 3.3V LVPECL Output Load AC Test Circuit nQ0:Q7 nFBOUT nQx Qx Q0:Q7, FBOUT tcycle n ➤ ➤ nQy ➤ tcycle n+1 ➤ tjit(cc) = |tcycle n – tcycle n+1| 1000 Cycles Qy tsk(o) Output Skew IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 13 Cycle-to-Cycle Jitter ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Parameter Measurement Information, continued nQ0:Q7, nFBOUT 80% 80% nQ0:Q7 nFBOUT VOD 80% 80% VSW I N G Q0:Q7, FBOUT 20% 20% Q0:Q7 FBOUT VOS tF tR GND LVPECL Output Rise/Fall Time LVDS Output Rise/Fall Time Phase Noise Plot Noise Power nQ0:Q7, nFBOUT Q0:Q7, FBOUT tF tR 20% 20% t PW t odc = PERIOD t PW Phase Noise Mask x 100% t PERIOD f1 Offset Frequency f2 RMS Jitter = Area Under the Masked Phase Noise Plot LVPECL/LVDS Output Duty Cycle/Pulse Width/Period RMS Phase Jitter VDD VDD out LVDS ➤ out ➤ out ➤ DC Input LVDS 100 VOS/∆ VOS ➤ VOD/∆ VOD out ➤ DC Input ➤ Offset Voltage Setup IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 14 Differential Output Voltage Setup ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Parameter Measurement Information, continued VDD VDD out M-LVDS ➤ out ➤ DC Input ➤ out M-LVDS 100 100 ➤ VOD/∆ VOD VOS/∆ VOS out ➤ DC Input ➤ M-LVDS Offset Voltage Setup M-LVDS Differential Output Voltage Setup 20 0 -3dB 1.2MHz Mag (dB) -20 -3dB 21.9MHz -40 -60 -80 -100 104 105 106 107 108 Frequency (Hz) H3(s) * (H1(s) – H2(s)) Composite PCIe Transfer Function IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 15 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Application Information Overview The is a high performance FemtoClock Zero Delay Buffer/ Multiplier/Divider which uses external feedback for accurate clock regeneration and low static and dynamic phase offset. It can be used in a number different ways: • Backplane clock multiplier. Many backplane clocks are relatively low frequency because of heavy electrical loading. The ICS8743008I can multiply a low frequency backplane clock (e.g. 25MHz) to an appropriate reference clock frequency for PCIe, Ethernet, 10G Ethernet: 100MHz, 125MHz, 156.25MHz. The device can also accept a high frequency local reference (100MHz or 125 MHz, for example) and divide the frequency down to 25MHz M-LVDS to drive a backplane. • PCIe frequency translator for PCIe add-in cards. In personal computers, the PCIe reference clock is 100MHz, but some 2.5G serdes used in PCI Express require a 125MHz reference. The ICS8743008I can perform the 100MHz → 125MHz and 125MHz → 100MHz frequency translation for a PCI Express add-in card while delivering low dynamic and static phase offset. • General purpose, low phase noise Zero Delay Buffer Configuration Notes and Examples When configuring the output frequency, the main consideration is keeping the VCO within its range of 490MHz - 660MHz. The designer must ensure that the VCO will always be within its allowed range for the expected input frequency range by using the appropriate choice of feedback output and input dividers. There are two input modes for the device. In the first mode, a reference clock is provided to the CLK/nCLK input and this reference clock is divided by the value of the PDIV divider (selectable ÷1, ÷4, ÷5, ÷8). In the second mode, a reference clock is provided to the MLVDS/ nMLVDS input pair. OE_MLVDS determines the input mode. When OE_MLVDS = HIGH (default), the M-LVDS driver is active and provides an M-LVDS output to the MLVDS/nMLVDS pins and also the reference to the phase detector via the PDIV divider. When OE_MLVDS is LOW, the internal M-LVDS driver is in Hi-Z state and the MLVDS/nMLVDS pin pair becomes an input and the reference clock applied to this input is applied to the phase detector. MLVDS/nMLVDS Output Mode OE_MLVDS = HIGH (default) VCO frequency = CLK/nCLK frequency * FBI_DIV * FBO_DIV/ (PDIV value) Allowed VCO frequency = 490MHz – 660MHz Output frequency = VCO frequency/QDIVx value = CLK/nCLK freq. * FBI_DIV * FBO_DIV/(PDIV*QDIVx) IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 16 Example: a frequency synthesizer provides a 125MHz reference clock to CLK/nCLK input. The ICS8743008I must provide a 25MHz M-LVDS clock to the backplane and also provide two local clocks: one 100MHz LVDS output to an ASIC and one 125MHz output to the PCI Express serdes. Solution. Since only two outputs are needed, the two unused outputs can be disabled. Set OE[2:0] = 001b so that only Q0/nQ0 and Q1/nQ1 are switching. Since a 25MHz backplane clock is needed from a 125MHz reference clock, set PDIV = ÷5 and OE_MLVDS = HIGH to enable the M-LVDS driver. 25MHz is applied to the MLVDS/nMLVDS pins and to the phase detector input. Set FBO_DIV = 4 and FBI_DIV = 5 which makes the VCO run at 500MHz (25MHz * 4 * 5 = 500MHz). Set QDIV0 = 0 (÷4) for 125MHz output and QDIV1 = 1 (÷5) for 100MHz output. To figure out what pins must pulled up or down externally with resistors, check the internal pullup or pulldown resistors on each pin in the pin description table or on the block diagram. PDIV[1:0] defaults to 00/÷4 and we need 01/÷5. So PDIV1 can be left floating (it has an internal pulldown resistor) and PDIV0 must be driven or pulled up via external pullup resistor to HIGH state. OE_MLVDS defaults to Logic 1 (active) and this is what we need, so that pin can be left floating. The FBO_DIV and FB_IN dividers default to the desired values, so their respective control pins can be left floating (FBO_DIV and FBI_DIV[1:0]). QDIV0 needs to be ÷4, which is a default value so this pin can be left floating. QDIV1 must be HIGH for ÷5, so this pin must be pulled high or driven high externally. OE[2:0] = 001, so OE0 can Float and OE[2:1] must be pulled Low. MLVDS/nMLVDS Input Mode OE_MLVDS = LOW VCO frequency = MLVDS/nMLVDS freq. * FBI_DIV * FBO_DIV Output frequency = VCO frequency/QDIVx value = MLVDS/nMLVDS freq. * FBI_DIV * FBO_DIV/(QDIVx) Example - backplane: The 8743008I sits on a backplane card and must multiply a 25MHz reference that comes from the backplane into one 125MHz reference clock for a gigabit Ethernet serdes and one 100MHz reference clock for a PCI Express serdes. Solution. Since only two outputs are needed, the two unused outputs can be disabled. Set OE2:0 = 001b so that only Q0/nQ0 and Q1/nQ1 are switching. Set OE_MLVDS = 0 so the internal M-LVDS driver is in a Hi-Z state, allowing the MLVDS/nMLVDS pins to function as an input for the 25MHz clock reference. Set FBO_DIV = 4 and FBI_DIV = 5 which makes the VCO run at 500MHz (25MHz * 4 * 5 = 500MHz). Set QDIV0 = 0 (÷4) for 125MHz output and QDIV1 = 1 (÷5) for 100MHz output. To figure out what pins must pulled up or down externally with resistors, check the internal pullup or pulldown resistors on each pin in the pin description table or on the block diagram. PDIV[1:0] defaults to 00/÷4 and we need 01/÷5. So PDIV1 can be left floating (it has an internal pulldown resistor) and PDIV0 must be driven or pulled up ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR via external pullup resistor to HIGH state. OE_MLVDS defaults to Logic 1(active) and this is what we need, so that pin can be left floating. The FBO_DIV and FB_IN dividers default to the desired values, so their respective control pins can be left floating PRELIMINARY (FBO_DIV and FBI_DIV1:0). QDIV0 needs to be ÷4, which is a default value so this pin can be left floating. QDIV1 must be HIGH for ÷5, so this pin must be pulled high or driven high externally. OE[2:0] = 001, so OE0 can Float and OE[2:1] must be pulled Low Master Master Clock Clock Card Card 25 25 MHz MHz ICS8743008I ICS8743008I CLK CLK MLVDS MLVDS 100 100 MHz MHz LVDS LVDS ÷4 ÷4 CLK nCLK nMLVDS MLVDS SSC SSC Synthesizer Synthesizer ICS841S32I ICS841S32I 100 100 MHz MHz LVDS LVDS FPGA FPGA FemtoClock FemtoClock VCO VCO 125 125 MHz MHz LVDS LVDS PCIe PCIe Serdes Serdes Slave Slave synthesizer synthesizer Off Off or or output output disabled disabled Backplane Backplane Slave Slave Clock Clock Card Card 25 25 MHz MHz MLVDS MLVDS ICS8743008I ICS8743008I CLK CLK SSC SSC Synthesizer Synthesizer ICS841S32I ICS841S32I ÷4 ÷4 CLK nCLK 100 100 MHz MHz LVDS LVDS FPGA FPGA FemtoClock FemtoClock VCO VCO 125 125 MHz MHz LVDS LVDS PCIe PCIe Serdes Serdes Figure 1. Example Backplane Application Bold lines indicate active clock path This example shows a case where each card may be dynamically configured as a master or slave card, hence the need for an ICS8743008I and ICS841402I on each card. On the master timing card, the ICS841402I provides a 100MHz reference to the ICS8743008I CLK/nCLK input. The M-LVDS pair on the ICS8743008I is configured as an output (OE_MLVDS = Logic 1) and the internal divider is set to ÷4 to generate 25MHz M-LVDS to the backplane. The 25MHz clock is also used as a reference to the FemtoClock PLL which multiplies to a VCO frequency of 500MHz. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 17 Each of the eight output pairs may be individually set for ÷4 or ÷5 for 125MHz or 100MHz operation respectively and in this example, one output pair is set to 100MHz for the FPGA and another output pair is set to 125MHz for the PCI Express serdes. For the slave card, the M-LVDS pair is configured as an input (OE_MLVDS = LOW) and the FemtoClock PLL multiplies this reference frequency to 500MHz VCO frequency and the output dividers are set to provide 100MHz to the FPGA and 125MHz to the PCI Express Serdes as shown. ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Power Supply Filtering Technique As in any high speed analog circuitry, the power supply pins are vulnerable to random noise. To achieve optimum jitter performance, power supply isolation is required. The ICS8743008I provides separate power supplies to isolate any high switching noise from the outputs to the internal PLL. VDD, VDDA and VDDO should be individually connected to the power supply plane through vias, and 0.01µF bypass capacitors should be used for each pin. Figure 2 illustrates how a 10Ω resistor along with a 10µF and a 0.01µF bypass capacitor should be connected to each VDDA pin. 3.3V VDD .01µF 10Ω .01µF 10µF VDDA Figure 2. Power Supply Filtering Wiring the Differential Input to Accept Single Ended Levels Figure 3 shows how the differential input can be wired to accept single ended levels. The reference voltage V_REF = VDD/2 is generated by the bias resistors R1, R2 and C1. This bias circuit should be located as close as possible to the input pin. The ratio of R1 and R2 might need to be adjusted to position the V_REF in the center of the input voltage swing. For example, if the input clock swing is only 2.5V and VDD = 3.3V, V_REF should be 1.25V and R2/R1 = 0.609. VDD R1 1K Single Ended Clock Input CLK V_REF nCLK C1 0.1u R2 1K Figure 3. Single-Ended Signal Driving Differential Input IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 18 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Differential Clock Input Interface The CLK /nCLK accepts LVDS, LVPECL, LVHSTL, SSTL, HCSL and other differential signals. Both VSWING and VOH must meet the VPP and VCMR input requirements. Figures 4A to 4E show interface examples for the HiPerClockS CLK/nCLK input driven by the most common driver types. The input interfaces suggested here are examples only. Please consult with the vendor of the driver component to confirm the driver termination requirements. For example, in Figure 4A, the input termination applies for IDT HiPerClockS open emitter LVHSTL drivers. If you are using an LVHSTL driver from another vendor, use their termination recommendation. 3.3V 3.3V 3.3V 1.8V Zo = 50Ω Zo = 50Ω CLK CLK Zo = 50Ω nCLK Zo = 50Ω nCLK HiPerClockS Input LVHSTL R1 50 IDT HiPerClockS LVHSTL Driver HiPerClockS Input LVPECL R2 50 R1 50 R2 50 R2 50 Figure 4A. HiPerClockS CLK/nCLK Input Driven by an IDT Open Emitter HiPerClockS LVHSTL Driver Figure 4B. HiPerClockS CLK/nCLK Input Driven by a 3.3V LVPECL Driver 3.3V 3.3V 3.3V R3 125 3.3V R4 125 3.3V Zo = 50Ω Zo = 50Ω CLK CLK R1 100 Zo = 50Ω nCLK HiPerClockS Input LVPECL R1 84 R2 84 Figure 4C. HiPerClockS CLK/nCLK Input Driven by a 3.3V LVPECL Driver 2.5V Zo = 50Ω nCLK Receiver LVDS Figure 4D. HiPerClockS CLK/nCLK Input Driven by a 3.3V LVDS Driver 3.3V *R3 33 Zo = 50Ω CLK Zo = 50Ω nCLK HCSL *R4 33 R1 50 R2 50 HiPerClockS Input *Optional – R3 and R4 can be 0Ω Figure 4E. HiPerClockS CLK/nCLK Input Driven by a 3.3V HCSL Driver IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 19 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY VFQFN EPAD Thermal Release Path In order to maximize both the removal of heat from the package and the electrical performance, a land pattern must be incorporated on the Printed Circuit Board (PCB) within the footprint of the package corresponding to the exposed metal pad or exposed heat slug on the package, as shown in Figure 5. The solderable area on the PCB, as defined by the solder mask, should be at least the same size/shape as the exposed pad/slug area on the package to maximize the thermal/electrical performance. Sufficient clearance should be designed on the PCB between the outer edges of the land pattern and the inner edges of pad pattern for the leads to avoid any shorts. While the land pattern on the PCB provides a means of heat transfer and electrical grounding from the package to the board through a solder joint, thermal vias are necessary to effectively conduct from the surface of the PCB to the ground plane(s). The land pattern must be connected to ground through these vias. The vias act as “heat pipes”. The number of vias (i.e. “heat pipes”) are PIN PIN PAD SOLDER application specific and dependent upon the package power dissipation as well as electrical conductivity requirements. Thus, thermal and electrical analysis and/or testing are recommended to determine the minimum number needed. Maximum thermal and electrical performance is achieved when an array of vias is incorporated in the land pattern. It is recommended to use as many vias connected to ground as possible. It is also recommended that the via diameter should be 12 to 13mils (0.30 to 0.33mm) with 1oz copper via barrel plating. This is desirable to avoid any solder wicking inside the via during the soldering process which may result in voids in solder between the exposed pad/slug and the thermal land. Precautions should be taken to eliminate any solder voids between the exposed heat slug and the land pattern. Note: These recommendations are to be used as a guideline only. For further information, please refer to the Application Note on the Surface Mount Assembly of Amkor’s Thermally/Electrically Enhance Leadfame Base Package, Amkor Technology. EXPOSED HEAT SLUG GROUND PLANE THERMAL VIA SOLDER PIN LAND PATTERN (GROUND PAD) PIN PAD Figure 5. P.C. Assembly for Exposed Pad Thermal Release Path – Side View (drawing not to scale) IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 20 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY 3.3V LVDS Driver Termination A general LVDS interface is shown in Figure 6. 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 50Ω 3.3V LVDS Driver + R1 100Ω – 50Ω 100Ω Differential Transmission Line Figure 6. Typical LVDS Driver Termination 3.3V M-LVDS Driver Termination A general M-LVDS interface is shown in Figure 7 In a 100Ω differential transmission line environment, M-LVDS drivers require a matched load termination of 100Ω across near the receiver input. For a multiple M-LVDS outputs buffer, if only partial outputs are used, it is recommended to terminate the unused outputs. 3.3V 50Ω 3.3V LVDS Driver + R2 100Ω R1 100Ω – 50Ω 100Ω Differential Transmission Line Figure 7. Typical M-LVDS Driver Termination IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 21 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Termination for 3.3V LVPECL Outputs 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 50Ω transmission lines. Matched impedance techniques should be used to maximize operating frequency and minimize signal distortion. Figures 8A and 8B 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 = 50Ω 125Ω FOUT FIN Zo = 50Ω Zo = 50Ω FOUT 50Ω RTT = 125Ω 1 Z ((VOH + VOL) / (VCC – 2)) – 2 o FIN 50Ω Zo = 50Ω VCC - 2V RTT Figure 8A. 3.3V LVPECL Output Termination 84Ω 84Ω Figure 8B. 3.3V LVPECL Output Termination Recommendations for Unused Input and Output Pins Inputs: Outputs: LVCMOS Control Pins LVPECL Outputs 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. All unused LVPECL outputs can be left floating. We recommend that there is no trace attached. Both sides of the differential output pair should either be left floating or terminated. CLK/nCLK Inputs LVDS Outputs For applications not requiring the use of the differential input, both CLK and nCLK can be left floating. Though not required, but for additional protection, a 1kΩ resistor can be tied from CLK to ground. 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. M-LVDS Outputs MLVDS/nMLVDS Inputs For applications not requiring the use of the differential input, both MLVDS and nMLVDS can be left floating. Though not required, but for additional protection, a 1kΩ resistor can be tied from MLVDS to ground. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 22 All unused M-LVDS output pairs can be either left floating or terminated with 100Ω across. If they are left floating, there should be no trace attached. ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Power Considerations – LVPECL Outputs This section provides information on power dissipation and junction temperature for the ICS8743008I, for all outputs that are configured to LVPECL. Equations and example calculations are also provided. 1. Power Dissipation. The total power dissipation for the ICS8743008I 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. NOTE: Please refer to Section 3 for details on calculating power dissipated in the load. • Power (core)MAX = VDD_MAX * IEE_MAX = 3.465V * 230mA = 796.95mW • Power (outputs)MAX = 30mW/Loaded Output pair If all outputs are loaded, the total power is 8 * 30mW = 240mW Total Power_MAX (3.465V, with all outputs switching) = 796.95mW + 240mW = 1036.95mW 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 HiPerClockS 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 no air flow and a multi-layer board, the appropriate value is 31.4°C/W per Table 6 below. Therefore, Tj for an ambient temperature of 85°C with all outputs switching is: 85°C + 1.037W * 31.4°C/W = 117.6°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. Table 6. Thermal Resistance θJA for 40 Lead VFQFN, Forced Convection θJA by Velocity Meters per Second Multi-Layer PCB, JEDEC Standard Test Boards 0 1 2.5 31.4°C/W 27.5°C/W 24.6°C/W IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 23 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY 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 9. VDDO Q1 VOUT RL 50Ω VDDO - 2V Figure 9. LVPECL Driver Circuit and Termination To calculate worst case power dissipation into the load, use the following equations which assume a 50Ω load, and a termination voltage of VDDO – 2V. • For logic high, VOUT = VOH_MAX = VDDO_MAX – 0.9V (VDDO_MAX – VOH_MAX) = 0.9V • For logic low, VOUT = VOL_MAX = VDDO_MAX – 1.7V (VDDO_MAX – VOL_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 = [(VOH_MAX – (VDDO_MAX – 2V))/RL] * (VDDO_MAX – VOH_MAX) = [(2V – (VDDO_MAX – VOH_MAX))/RL] * (VDDO_MAX – VOH_MAX) = [(2V – 0.9V)/50Ω] * 0.9V = 19.8mW Pd_L = [(VOL_MAX – (VDDO_MAX – 2V))/RL] * (VDDO_MAX – VOL_MAX) = [(2V – (VDDO_MAX – VOL_MAX))/RL] * (VDDO_MAX – VOL_MAX) = [(2V – 1.7V)/50Ω] * 1.7V = 10.2mW Total Power Dissipation per output pair = Pd_H + Pd_L = 30mW IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 24 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Power Considerations – LVDS Outputs This section provides information on power dissipation and junction temperature for the ICS8743008I. Equations and example calculations are also provided. 1. Power Dissipation. The total power dissipation for the ICS8743008I is the sum of the core power plus the analog 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 * (187mA + 11mA) = 686.07mW • Power (outputs)MAX = VDDO_MAX * IDDO_MAX = 3.465V * 155mA = 537.08mW Total Power_MAX = 686.07mW + 537.08mW = 1223.15mW • 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 HiPerClockS 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 no air flow and a multi-layer board, the appropriate value is 31.4°C/W per Table 7 below. Therefore, Tj for an ambient temperature of 85°C with all outputs switching is: 85°C + 1.223W * 31.4°C/W = 123.4°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. Table 7. Thermal Resistance θJA for 40 Lead VFQFN, Forced Convection θJA by Velocity Meters per Second Multi-Layer PCB, JEDEC Standard Test Boards 0 1 2.5 31.4°C/W 27.5°C/W 24.6°C/W IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 25 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Reliability Information Table 8. θJA vs. Air Flow Table for a 56 Lead VFQFN θJA vs. Air Flow Meters per Second Multi-Layer PCB, JEDEC Standard Test Boards 0 1 2.5 31.4°C/W 27.5°C/W 24.6°C/W Transistor Count The transistor count for ICS8743008I is: 4893 Package Outline and Package Dimensions Package Outline - K Suffix for 56 Lead VFQFN (Ref.) S eating Plan e N &N Even (N -1)x e (R ef.) A1 Ind ex Area A3 N L N e (Ty p.) 2 If N & N 1 Anvil Singula tion are Even 2 OR E2 (N -1)x e (Re f.) E2 2 To p View b A (Ref.) D Chamfer 4x 0.6 x 0.6 max OPTIONAL e N &N Odd 0. 08 C D2 2 Th er mal Ba se D2 C Table 9. Package Dimensions JEDEC Variation: VJJD-2/-5 All Dimensions in Millimeters Symbol Minimum Maximum N 56 A 0.80 1.00 A1 0 0.05 A3 0.25 Ref. b 0.18 0.30 14 ND & NE D&E 8.00 Basic D2 & E2 2.75 6.80 e 0.50 Basic L 0.30 0.50 NOTE: The following package mechanical drawing is a generic drawing that applies to any pin count VFQFN package. This drawing is not intended to convey the actual pin count or pin layout of this device. The pin count and pinout are shown on the front page. The package dimensions are in Table 8 below Reference Document: JEDEC Publication 95, MO-220 IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 26 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Ordering Information Table 10. Ordering Information Part/Order Number 8743008DKILF 8743008DKILFT Marking ICS8743008DIL ICS8743008DIL Package “Lead-Free” 56 Lead VFQFN “Lead-Free” 56 Lead VFQFN Shipping Packaging Tray 1000 Tape & Reel Temperature -40°C to 85°C -40°C to 85°C NOTE: Parts that are ordered with an "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant. While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology (IDT) assumes no responsibility for either its use or for the 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 IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support devices or critical medical instruments. IDT™ / ICS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR 27 ICS8743008DKI REV. A AUGUST 25, 2008 ICS8743008I FEMTOCLOCKS™ LVDS/LVPECL ZERO DELAY BUFFER/CLOCK GENERATOR PRELIMINARY Contact Information: www.IDT.com www.IDT.com Sales Technical Support 800-345-7015 (inside USA) +408-284-8200 (outside USA) Fax: 408-284-2775 www.IDT.com/go/contactIDT [email protected] +480-763-2056 Corporate Headquarters Integrated Device Technology, Inc. 6024 Silver Creek Valley Road San Jose, CA 95138 United States 800-345-7015 (inside USA) +408-284-8200 (outside USA) © 2008 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT and the IDT logo are trademarks of Integrated Device Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered trademarks used to identify products or services of their respective owners. Printed in USA