ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR GENERAL DESCRIPTION FEATURES The ICS85320I is a LVCMOS / LVTTL-to-Differential 2.5V / 3.3V LVPECL translator and a memHiPerClockS™ ber of the HiPerClocks™family of High Performance Clocks Solutions from ICS. The ICS85320I has a single ended clock input. The single ended clock input accepts LVCMOS or LVTTL input levels and translates them to 2.5V / 3.3V LVPECL levels. The small outline 8-pin SOIC package makes this device ideal for applications where space, high performance and low power are important. • 1 differential 2.5V/3.3V LVPECL output ICS • LVCMOS/LVTTL CLK input • CLK accepts the following input levels: LVCMOS or LVTTL • Maximum output frequency: 267MHz • Part-to-part skew: 275ps (maximum) • Additive phase jitter, RMS: 0.05ps (typical) • 3.3V operating supply voltage (operating range 3.135V to 3.465V) • 2.5V operating supply voltage (operating range 2.375V to 2.625V) • -40°C to 85°C ambient operating temperature BLOCK DIAGRAM CLK PIN ASSIGNMENT Q nQ nc Q nQ nc 1 2 3 4 8 7 6 5 VCC CLK nc VEE ICS85320I 8-Lead SOIC 3.90mm x 4.92mm x 1.37mm body package M Package Top View 85320AMI www.icst.com/products/hiperclocks.html 1 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR TABLE 1. PIN DESCRIPTIONS Number Name 1, 4, 6 nc Unused Type No connect. Description 2,3 Q, nQ Output Differential output pair. LVPECL interface levels. 5 VEE Power Negative supply pin. 7 CLK Input 8 VCC Power Pullup LVCMOS / LVTTL clock input. Positive supply pin. NOTE: Pullup refers to internal input resistors. See Table 2, Pin Characteristics, for typical values. TABLE 2. PIN CHARACTERISTICS Symbol Parameter CIN Input Capacitance 4 pF RPULLUP Input Pullup Resistor 51 KΩ 85320AMI Test Conditions Minimum www.icst.com/products/hiperclocks.html 2 Typical Maximum Units REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC 4.6V Inputs, VI -0.5V to VCC + 0.5V Outputs, IO Continuous Current Surge Current 50mA 100mA Package Thermal Impedance, θJA 112.7°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 = 3.3V±5% OR 2.5V±5%, TA = -40°C TO 85°C Symbol Parameter Test Conditions VCC Positive Supply Voltage I EE Power Supply Current Minimum Typical Maximum Units 3.135 3.3 3.465 V 2.375 2.5 2.625 V 25 mA Maximum Units TABLE 3B. LVCMOS / LVTTL DC CHARACTERISTICS, VCC = 3.3V±5%, TA = -40°C TO 85°C Symbol Parameter Test Conditions Minimum Typical VIH Input High Voltage CLK 2 VCC + 0.3 V VIL Input Low Voltage CLK -0.3 1.3 V IIH Input High Current CLK VCC = VIN = 3.465V 5 µA IIL Input Low Current CLK VCC = VIN = 3.465V -150 µA TABLE 3C. LVCMOS / LVTTL DC CHARACTERISTICS, VCC = 2.5V±5%, TA = -40°C TO 85°C Symbol Parameter Maximum Units VIH Input High Voltage CLK Test Conditions Minimum 1.6 Typical VCC + 0.3 V VIL Input Low Voltage CLK -0.3 0.9 V IIH Input High Current CLK VCC = VIN = 2.625V 5 µA IIL Input Low Current CLK VCC = VIN = 2.625V -150 µA TABLE 3D. LVPECL DC CHARACTERISTICS, VCC = 3.3V±5% OR 2.5V±5%, TA = -40°C TO 85°C Symbol Parameter Test Conditions Minimum Typical Maximum Units VOH Output High Voltage; NOTE 1 VCC - 1.4 VCC - 0.9 V VOL Output Low Voltage; NOTE 1 VCC - 2.0 VCC - 1.7 V VSWING Peak-to-Peak Output Voltage Swing 0.6 1.0 V NOTE 1: Outputs terminated with 50Ω to VCC - 2V. 85320AMI www.icst.com/products/hiperclocks.html 3 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR TABLE 4A. AC CHARACTERISTICS, VCC = 3.3V±5%, TA = -40°C TO 85°C Symbol Parameter fMAX Output Frequency tPD t sk(pp) Propagation Delay; NOTE 1 Buffer Additive Phase Jitter, RMS; refer to Additive Phase Jitter Section Par t-to-Par t Skew; NOTE 2, 3 tR, tF Output Rise/Fall Time t jit Test Conditions ƒ ≤ 267MHz Integration Range: 12KHz - 20MHz 20% to 80% Minimum Typical 0.8 Maximum Units 267 MHz 1.4 ns 0.05 200 ps 275 ps 700 ps odc Output Duty Cycle 45 55 % NOTE 1: Measured from VCC/2 point of the input to the differential output crossing point. NOTE 2: Defined as skew between outputs on different devices operating at the same supply voltages and with equal load conditions. Using the same type of inputs on each device, the outputs are measured at the differential cross points. NOTE 3: This parameter is defined in accordance with JEDEC Standard 65. TABLE 4B. AC CHARACTERISTICS, VCC = 2.5V±5%, TA = -40°C TO 85°C Symbol Parameter fMAX Output Frequency tPD t sk(pp) Propagation Delay; NOTE 1 Buffer Additive Phase Jitter, RMS; refer to Additive Phase Jitter Section Par t-to-Par t Skew; NOTE 2, 3 tR, tF Output Rise/Fall Time t jit Test Conditions Minimum ƒ ≤ 267MHz Integration Range: 12KHz - 20MHz 0.8 20% to 80% 200 Typical Maximum Units 215 MHz 1.7 ns 0.05 ps 375 ps 700 ps odc Output Duty Cycle 45 55 % NOTE 1: Measured from VCC/2 point of the input to the differential output crossing point. NOTE 2: Defined as skew between outputs on different devices operating at the same supply voltages and with equal load conditions. Using the same type of inputs on each device, the outputs are measured at the differential cross points. NOTE 3: This parameter is defined in accordance with JEDEC Standard 65. 85320AMI www.icst.com/products/hiperclocks.html 4 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR ADDITIVE PHASE JITTER the 1Hz band to the power in the fundamental. When the required offset is specified, the phase noise is called a dBc value, which simply means dBm at a specified offset from the fundamental. By investigating jitter in the frequency domain, we get a better understanding of its effects on the desired application over the entire time record of the signal. It is mathematically possible to calculate an expected bit error rate given a phase noise plot. The spectral purity in a band at a specific offset from the fundamental compared to the power of the fundamental is called the dBc Phase Noise. This value is normally expressed using a Phase noise plot and is most often the specified plot in many applications. Phase noise is defined as the ratio of the noise power present in a 1Hz band at a specified offset from the fundamental frequency to the power value of the fundamental. This ratio is expressed in decibels (dBm) or a ratio of the power in 0 -10 Input/Output Additive Phase Jitter -20 @ 156.25MHz (12KHz to 20MHz) = 0.05ps typical -30 -40 -50 SSB PHASE NOISE dBc/HZ -60 -70 -80 -90 -100 -110 -120 -130 -140 -150 -160 -170 -180 -190 1k 10k 100k 1M 10M 100M OFFSET FROM CARRIER FREQUENCY (HZ) As with most timing specifications, phase noise measurements have issues. The primary issue relates to the limitations of the equipment. Often the noise floor of the equipment is higher than the noise floor of the device. This is illustrated above. The de- 85320AMI vice meets the noise floor of what is shown, but can actually be lower. The phase noise is dependant on the input source and measurement equipment. www.icst.com/products/hiperclocks.html 5 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR PARAMETER MEASUREMENT INFORMATION 2V 2V V CC Qx SCOPE VCC Qx SCOPE LVPECL LVPECL nQx nQx VEE VEE -0.5V ± 0.125V -1.3V ± 0.165V 2.5V CORE/2.5V OUTPUT LOAD AC TEST CIRCUIT 3.3V CORE/3.3V OUTPUT LOAD AC TEST CIRCUIT Part 1 nQx 80% 80% Qx VSW I N G Part 2 nQy Clock Outputs 20% 20% tF tR Qy t sk(o) PART-TO-PART SKEW OUTPUT RISE/FALL TIME nCLK nQ CLK Q Pulse Width t nQ Q odc = tPD PERIOD t PW t PERIOD PROPAGATION DELAY 85320AMI OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD www.icst.com/products/hiperclocks.html 6 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR APPLICATION INFORMATION TERMINATION FOR 3.3V LVPECL OUTPUTS 50Ω transmission lines. Matched impedance techniques should be used to maximize operating frequency and minimize signal distortion. Figures 1A and 1B 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. 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 3.3V Zo = 50Ω 125Ω FOUT FIN Zo = 50Ω Zo = 50Ω FOUT 50Ω 1 RTT = Z ((VOH + VOL) / (VCC – 2)) – 2 o FIN 50Ω Zo = 50Ω VCC - 2V RTT 84Ω FIGURE 1A. LVPECL OUTPUT TERMINATION 85320AMI 125Ω 84Ω FIGURE 1B. LVPECL OUTPUT TERMINATION www.icst.com/products/hiperclocks.html 7 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. TERMINATION FOR LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR 2.5V LVPECL OUTPUT Figure 2A and Figure 2B 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 2B can be eliminated and the termination is shown in Figure 2C. 2.5V VCC=2.5V 2.5V 2.5V VCC=2.5V R1 250 Zo = 50 Ohm R3 250 + Zo = 50 Ohm + Zo = 50 Ohm - Zo = 50 Ohm 2,5V LVPECL Driv er - R1 50 2,5V LVPECL Driv er R2 62.5 R2 50 R4 62.5 R3 18 FIGURE 2B. 2.5V LVPECL DRIVER TERMINATION EXAMPLE FIGURE 2A. 2.5V LVPECL DRIVER TERMINATION EXAMPLE 2.5V VCC=2.5V Zo = 50 Ohm + Zo = 50 Ohm - 2,5V LVPECL Driv er R1 50 R2 50 FIGURE 2C. 2.5V LVPECL TERMINATION EXAMPLE 85320AMI www.icst.com/products/hiperclocks.html 8 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR APPLICATION SCHEMATIC EXAMPLE Figure 3 shows an example of ICS85320I application schematic. In this example, the device is operated at VCC=3.3V. The decoupling capacitor should be located as close as possible to the power pin. For LVPECL output termination, only two termi- nations examples are shown in this schematic. For more termination approaches, please refer to the LVPECL Termination Application Note. Zo = 50 Ohm Zo = 50 Ohm R2 50 VCC = 3.3V R1 50 U1 1 2 3 4 nc Q nQ nc Vcc Clk nc Vee 8 7 6 5 R3 50 Clk_in 85320 VCC (U1-8) VCC = 3.3V C1 10uf C2 0.1uF R4 133 R6 133 Zo = 50 Ohm + Zo = 50 Ohm - R5 82.5 R7 82.5 Optional Termination FIGURE 3. ICS85320I APPLICATION SCHEMATIC EXAMPLE 85320AMI www.icst.com/products/hiperclocks.html 9 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR POWER CONSIDERATIONS This section provides information on power dissipation and junction temperature for the ICS85320I. Equations and example calculations are also provided. 1. Power Dissipation. The total power dissipation for the ICS85320I 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 * 25mA = 86.6mW Power (outputs)MAX = 30.2mW/Loaded Output pair Total Power_MAX (3.465V, with all outputs switching) = 86.6mW + 30.2mW = 116.6mW 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 103.3°C/W per Table 5 below. Therefore, Tj for an ambient temperature of 85°C with all outputs switching is: 85°C + 0.117W * 103.3°C/W = 97.1°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 5. THERMAL RESISTANCE θJA FOR 8-PIN SOIC, FORCED CONVECTION θJA by Velocity (Linear Feet per Minute) Single-Layer PCB, JEDEC Standard Test Boards Multi-Layer PCB, JEDEC Standard Test Boards 0 200 500 153.3°C/W 112.7°C/W 128.5°C/W 103.3°C/W 115.5°C/W 97.1°C/W NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs. 85320AMI www.icst.com/products/hiperclocks.html 10 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR 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 4. VCC Q1 VOUT RL 50 VCC - 2V FIGURE 4. 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 = V OH_MAX (V CCO_MAX • -V OH_MAX OL_MAX CCO_MAX -V CCO_MAX – 1.0V ) = 1.0V For logic low, VOUT = V (V =V =V CCO_MAX – 1.7V ) = 1.7V OL_MAX 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 OH_MAX ) = [(2V - (V 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 85320AMI www.icst.com/products/hiperclocks.html 11 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR RELIABILITY INFORMATION TABLE 6. θJAVS. AIR FLOW TABLE FOR 8 LEAD SOIC θJA by Velocity (Linear Feet per Minute) Single-Layer PCB, JEDEC Standard Test Boards Multi-Layer PCB, JEDEC Standard Test Boards 0 200 500 153.3°C/W 112.7°C/W 128.5°C/W 103.3°C/W 115.5°C/W 97.1°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 ICS85320I is: 269 85320AMI www.icst.com/products/hiperclocks.html 12 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. PACKAGE OUTLINE - M SUFFIX LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR FOR 8 LEAD SOIC TABLE 7. PACKAGE DIMENSIONS SYMBOL Millimeters MINIMUN N A MAXIMUM 8 1.35 1.75 A1 0.10 0.25 B 0.33 0.51 C 0.19 0.25 D 4.80 5.00 E 3.80 4.00 e 1.27 BASIC H 5.80 6.20 h 0.25 0.50 L 0.40 1.27 α 0° 8° Reference Document: JEDEC Publication 95, MS-012 85320AMI www.icst.com/products/hiperclocks.html 13 REV. A AUGUST 25, 2004 ICS85320I Integrated Circuit Systems, Inc. LVCMOS / LVTTL-TO-DIFFERENTIAL 2.5V / 3.3V LVPECL TRANSLATOR TABLE 8. ORDERING INFORMATION Part/Order Number Marking Package Count Temperature ICS85320AMI 5320AMI 8 lead SOIC 96 per tube -40°C to 85°C ICS85320AMIT 5320AMI 8 lead SOIC on Tape and Reel 2500 -40°C to 85°C The aforementioned trademark, HiPerClockS™ is 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. 85320AMI www.icst.com/products/hiperclocks.html 14 REV. A AUGUST 25, 2004