ASM2I99448-32-LT

May 2005 rev 0.3 3.3V/2.5V LVCMOS 1:12 Clock Fanout Buffer Features 12 LVCMOS compatible clock outputs Selectable LVCMOS and differential LVPECL compatible clock inputs Maximum clock frequency of 350MHz Maximum clock skew of 150pS Synchronous output stop in logic low state eliminates output runt pulses High–impedance output control 3.3V or 2.5V power supply Drives up to 24 series terminated clock lines Ambient temperature range –40°C to +85°C 32–Lead LQFP & TQFP packaging Supports clock distribution in networking, ASM2I99448 The ASM2I99448 is specifically designed to distribute LVCMOS compatible clock signals up to a frequency of 350MHz. Each output provides a precise copy of the input signal with a near zero skew. The outputs buffers support driving of 50Ω terminated transmission lines on the incident edge: each output is capable of driving either one parallel terminated or two series terminated transmission lines. Two selectable, independent clock inputs are available, providing support of LVCMOS and differential LVPECL clock distribution systems. The ASM2I99448 CLK_STOP control is synchronous to the falling edge of the input clock. It allows the start and stop of the output clock signal only in a logic low state, thus eliminating potential output runt pulses. Applying the OE control will force the outputs into high–impedance mode. All inputs have an internal pull–up or pull–down resistor preventing unused and open inputs from floating. The device supports a 2.5V or 3.3V power supply and an ambient temperature range of –40°C to +85°C. The ASM2I99448 is pin and function compatible but telecommunication and computing applications Pin and Function compatible to MPC9448 and MPC948 Functional Description The ASM2I99448 is a 3.3V or 2.5V compatible, 1:12 clock fanout buffer targeted for high performance clock tree applications. With output frequencies up to 350 MHz and output skews less than 150 pS, the device meets the needs of most demanding clock applications. performance–enhanced to the MPC948. Alliance Semiconductor 2575, Augustine Drive • Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com Notice: The information in this document is subject to change without notice. May 2005 rev 0.3 Block Diagram Pin Diagram GND VCC ASM2I99448 GND VCC 18 Q4 Q5 Q6 VCC PCLK PCLK CCLK Q0 Q1 Q2 Q3 Q4 Q3 VCC Q2 GND Q1 VCC Q0 GND 25 26 27 28 29 30 31 32 0 1 CLK STOP 24 23 22 21 20 19 Q7 17 16 15 14 GND Q8 VCC Q9 GND Q10 VCC Q11 13 12 11 10 9 8 GND VCC CLK_SEL Q5 Q6 ASM2I99448 VCC CLK_STOP SYNC Q7 Q8 Q9 Q10 1 2 3 4 5 6 7 VCC OE (All input resistors have a value of 25KΩ) Q11 CCLK PCLK CLK_SEL PCLK CLK_STOP VCC OE Table 1. FUNCTION TABLE Control CLK_SEL OE CLK_STOP Default 1 1 1 0 PECL differential input selected Outputs disabled (high-impedance state) 1 1 CCLK input selected Outputs enabled Outputs active Outputs synchronously stopped in logic low state Note: 1. OE=0 will high-impedance tristate all outputs independent on CLK_STOP. 3.3V/2.5V LVCMOS 1:12 Clock Fanout Buffer Notice: The information in this document is subject to change without notice. 2 of 15 May 2005 rev 0.3 Table 2. PIN CONFIGURATION Pin# 4,3 2 1 5 6 31,29,27,25,23,21,19,17,15,13,11,9 8,12,16,20,24,28,32 7,10,14,18,22,26,30 ASM2I99448 Pin Name PCLK, PCLK CCLK CLK_SEL CLK_STOP OE Q0 – Q11 GND VCC I/O Input Input Input Input Input Output Supply Supply Type LVPECL LVCMOS LVCMOS LVCMOS LVCMOS LVCMOS Ground VCC Function LVPECL Clock Inputs Alternative clock signal input Clock input select Clock output enable/disable Output enable/disable (high–impedance tristate) Clock output Negative power supply (GND) for I/O and core. Positive power supply for I/O and core. All VCC pins must be connected to the positive power supply for correct operation Table 3. ABSOLUTE MAXIMUM RATINGS1 Symbol VCC VIN VOUT IIN IOUT TStor Supply Voltage DC Input Voltage DC Output Voltage DC Input Current DC Output Current Storage Temperature Range –65 Parameter Min –0.3 –0.3 –0.3 Max 3.9 VCC + 0.3 VCC + 0.3 ±20 ±50 125 Unit V V V mA mA °C Note: 1. These are stress ratings only and are not implied for functional use. Exposure to absolute maximum ratings for prolonged periods of time may affect device reliability. 3.3V/2.5V LVCMOS 1:12 Clock Fanout Buffer Notice: The information in this document is subject to change without notice. 3 of 15 May 2005 rev 0.3 Table 4. GENERAL SPECIFICATIONS Symbol VTT MM HBM LU CPD CIN ASM2I99448 Characteristic Output Termination Voltage ESD Protection (Machine Model) ESD Protection (Human Body Model) Latch–up Immunity Power Dissipation Capacitance Input Capacitance Min 200 2000 200 Typ VCC÷2 Max Unit V V V mA Condition 10 4.0 pF pF Per Output Inputs Table 5. DC CHARACTERISTICS (VCC = 3.3V ± 5%, TA = –40°C to +85°C) Symbol VIH VIL VPP VCMR1 IIN VOH VOL ZOUT ICCQ 4 Characteristic Input HIGH Voltage Input LOW Voltage Peak–to–Peak Input Voltage Common Mode Range Input Current 2 Min 2.0 –0.3 PCLK PCLK 250 1.1 2.4 Typ Max VCC + 0.3 0.8 VCC – 0.6 300 0.55 0.30 Unit V V mV V µA V V V Ώ mA Condition LVCMOS LVCMOS LVPECL LVPECL VIN = VCC or GND IOH = –24mA3 IOL = 24mA3 IOL = 12mA All VCC Pins Output HIGH Voltage Output LOW Voltage Output Impedance Maximum Quiescent Supply Current 17 2.0 Note: 1. VCMR (DC) is the crosspoint of the differential input signal. Functional operation is obtained when the crosspoint is within the VCMR range and the input swing lies within the VPP (DC) specification. 2. Input pull-up / pull-down resistors influence input current. 3. The ASM2I99448 is capable of driving 50Ω transmission lines on the incident edge. Each output drives one 50Ω parallel terminated transmission line to a termination voltage of VTT. Alternatively, the device drives up to two 50Ω series terminated transmission lines (for VCC=3.3V) or one 50Ω series terminated transmission line (for VCC=2.5V). 4. ICCQ is the DC current consumption of the device with all outputs open and the input in its default state or open. 3.3V/2.5V LVCMOS 1:12 Clock Fanout Buffer Notice: The information in this document is subject to change without notice. 4 of 15 May 2005 rev 0.3 Table 6. AC CHARACTERISTICS (VCC = 3.3V ± 5%, TA = –40°C to +85°C)1 Symbol fref fMAX VPP 2 VCMR ASM2I99448 Characteristics Input Frequency Maximum Output Frequency Peak-to-peak input voltage Common Mode Range Reference Input Pulse Width CCLK Input Rise/Fall Time Propagation delay Output Disable Time Output Enable Time Setup time CCLK to CLK_STOP PCLK to CLK_STOP PCLK to any Q CCLK to any Q PCLK PCLK Min 0 0 400 1.3 1.4 1.6 1.3 Typ Max 350 350 1000 VCC-0.8 1.03 3.6 3.3 11 11 Unit MHz MHz mV V nS nS nS nS nS nS nS nS nS nS pS nS pS pS % nS Condition LVPECL LVPECL 0.8 to 2.0V tP, REF tr, tf tPLH/HL tPLH/HL tPLZ, HZ tPZL, LZ tS 0.0 0.0 1.0 1.5 150 2.0 300 400 45 0.1 50 55 1.0 tH tsk(O) tsk(PP) tSK(P) DCQ tr, tf Hold time Output-to-output Skew Device-to-device Skew 4 Output pulse skew Output Duty Cycle Output Rise/Fall Time CCLK to CLK_STOP PCLK to CLK_STOP PCLK or CCLK to any Q Using CCLK Using PCLK fQ