CDC586PAH

CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 3.3-V PHASE-LOCK-LOOP CLOCK DRIVER WITH 3-STATE OUTPUTS • FEATURES • • • • • • Low Output Skew for Clock-Distribution and Clock-Generation Applications Operates at 3.3-V VCC Distributes One Clock Input to 12 Outputs Two Select Inputs Configure Up to Nine Outputs to Operate at One-Half or Double the Input Frequency No External RC Network Required External Feedback Pin (FBIN) Is Used to Synchronize the Outputs to the Clock Input • • • • • Application for Synchronous DRAM, High-Speed Microprocessor TTL-Compatible Inputs and Outputs Outputs Drive Parallel 50-Ω Terminated Transmission Lines State-of-the-Art EPIC-IIB™ BiCMOS Design Significantly Reduces Power Dissipation Distributed VCC and Ground Pins Reduce Switching Noise Packaged in 52-Pin Thin Quad Flat Package GND SEL1 SEL0 AGND FBIN AGND AV CC CLKIN NC AV CC OE TEST CLR PAH PACKAGE (TOP VIEW) 1 52 51 50 49 48 47 46 45 44 43 42 41 40 39 2 38 3 37 4 36 5 35 6 34 7 33 8 32 9 31 10 30 11 29 12 28 13 27 14 15 16 17 18 19 20 21 22 23 24 25 26 VCC 4Y3 GND VCC 4Y2 GND VCC 4Y1 GND GND VCC 3Y3 GND GND 2Y2 VCC GND 2Y3 VCC GND GND 3Y1 VCC GND 3Y2 VCC GND 1Y1 VCC GND 1Y2 VCC GND 1Y3 VCC GND GND 2Y1 VCC NC – No internal connection DESCRIPTION The CDC586 is a high-performance, low-skew, low-jitter clock driver. It uses a phase-lock loop (PLL) to precisely align, in both frequency and phase, the clock output signals to the clock input (CLKIN) signal. It is specifically designed for use with popular microprocessors operating at speeds from 50 MHz to 100 MHz or down to 25 MHz on outputs configured as half-frequency outputs. The CDC586 operates at 3.3-V VCC and is designed to drive a properly terminated 50-W transmission line. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. EPIC-IIB is a trademark of Texas Instruments. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 1993–2004, Texas Instruments Incorporated CDC586 SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 www.ti.com The feedback input (FBIN) is used to synchronize the output clocks in frequency and phase to CLKIN. One of the twelve output clocks must be fed back to FBIN for the PLL to maintain synchronization between the CLKIN input and the outputs. The output used as the feedback pin is synchronized to the same frequency as the CLKIN input. The Y outputs can be configured to switch in phase and at the same frequency as CLKIN. Select inputs (SEL1, SEL0) configure up to nine Y outputs, in banks of three, to operate at one-half or double the CLKIN frequency, depending on which pin is fed back to FBIN (see Table 1 and Table 2). All output signal duty cycles are adjusted to 50%, independent of the duty cycle at CLKIN. Output-enable (OE) is provided for output control. When OE is high, the outputs are in the high-impedance state. When OE is low, the outputs are active. TEST is used for factory testing of the device and can be used to bypass the PLL. TEST should be strapped to GND for normal operation. Unlike many products containing PLLs, the CDC586 does not require external RC networks. The loop filter for the PLL is included on chip, minimizing component count, board space, and cost. Because it is based on PLL circuitry, the CDC586 requires a stabilization time to achieve phase lock of the feedback signal to the reference signal. This stabilization time is required following power up and application of a fixed-frequency, fixed-phase signal at CLKIN, as well as following any changes to the PLL reference or feedback signals. Such changes occur upon change of the select inputs, upon enabling of the PLL via TEST, and upon enable of all outputs via OE. The CDC586 is characterized for operation from 0°C to 70°C. DETAILED DESCRIPTION OF OUTPUT CONFIGURATIONS The voltage-controlled oscillator (VCO) used in the CDC586 PLL has a frequency range of 100 MHz to 200 MHz, twice the operating frequency range of the CDC586 outputs. The output of the VCO is divided by two and by four to provide reference frequencies with a 50% duty cycle of one-half and one-fourth the VCO frequency. SEL0 and SEL1 select which of the two signals are buffered to each bank of device outputs. One device output must be externally wired to FBIN to complete the PLL. The VCO operates such that the frequency and phase of this output match that of the CLKIN signal. In the case that a VCO/2 output is wired to FBIN, the VCO must operate at twice the CLKIN frequency, resulting in device outputs that operate at either the same or one-half the CLKIN frequency. If a VCO/4 output is wired to FBIN, the device outputs operate at twice or the same frequency as the CLKIN frequency. 2 CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 Output Configuration A Output configuration A is valid when any output configured as a 1x frequency output in Table 1 is fed back to FBIN. The input frequency range for CLKIN is 50 MHz to 100 MHz when using output configuration A. Outputs configured as 1/2x outputs operate at half the CLKIN frequency, while outputs configured as 1x outputs operate at the same frequency as CLKIN. Table 1. Output Configuration A (1) INPUTS SEL0 L L None All L H 1Yn 2Yn, 3Yn, 4Yn H L 1Yn, 2Yn 3Yn, 4Yn H H 1Yn, 2Yn, 3Yn 4Yn SEL1 (1) OUTPUTS 1/2x FREQUENCY 1x FREQUENCY n = 1, 2, 3 Output Configuration B Output configuration B is valid when any output configured as a 1x frequency output in Table 2 is fed back to FBIN. The input frequency range for CLKIN is 25 MHz to 50 MHz when using output configuration B. Outputs configured as 1x outputs operate at the CLKIN frequency, while outputs configured as 2x outputs operate at double the frequency of CLKIN. Table 2. Output Configuration B (1) INPUTS SEL1 (1) OUTPUTS SEL0 1x FREQUENCY 2x FREQUENCY L L All None L H 1Yn 2Yn, 3Yn, 4Yn H L 1Yn, 2Yn 3Yn, 4Yn H H 1Yn, 2Yn, 3Yn 4Yn n = 1, 2, 3 3 CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 FUNCTIONAL BLOCK DIAGRAM OE 42 CLR FBIN 40 48

































 
 Phase-Lock Loop CLKIN TEST SEL0 45
2 

 

 

 CLR
2 41 50 SEL1 51 



  


  

 One of Four Identical Outputs – 1Yn Select Logic 1Y1–1Y3 One of Four Identical Outputs – 2Yn 2Y1–2Y3 One of Four Identical Outputs – 3Yn 3Y1–3Y3 One of Four Identical Outputs – 4Yn 4Y1–4Y3 4 CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 Terminal Functions TERMINAL NAME NO. I/O DESCRIPTION CLKIN 45 I Clock input. CLKIN is the clock signal distributed by the CDC586 clock-driver circuit. CLKIN provides the reference signal to the integrated PLL that generates the clock output signals. CLKIN must have a fixed frequency and fixed phase for the PLL to obtain phase lock. Once the circuit is powered up and a valid CLKIN signal is applied, a stabilization time is required for the PLL to phase lock the feedback signal to its reference signal. CLR 40 I CLR is used for testing purposes only. FBIN 48 I Feedback input. FBIN provides the feedback signal to the internal PLL. FBIN must be hardwired to one of the 12 clock outputs to provide frequency and phase lock. The internal PLL adjusts the output clocks to obtain zero phase delay between FBIN and CLKIN. OE 42 I Output enable. OE is the output enable for all outputs. When OE is low, all outputs are enabled. When OE is high, all outputs are in the high-impedance state. Since the feedback signal for the PLL is taken directly from an output terminal, placing the outputs in the high-impedance state interrupts the feedback loop; therefore, when a high-to-low transition occurs at OE, enabling the output buffers, a stabilization time is required before the PLL obtains phase lock. SEL1, SEL0 51, 50 I Output configuration select. SEL0 and SEL1 select the output configuration for each output bank (e.g., 1×, 1/2×, or 2×). (see Table 1 and Table 2). TEST 41 I TEST is used to bypass the PLL circuitry for factory testing of the device. When TEST is low, all outputs operate using the PLL circuitry. When TEST is high, the outputs are placed in a test mode that bypasses the PLL circuitry. TEST should be strapped to GND for normal operation. 1Y1-1Y3 2Y1-2Y3 3Y1-3Y3 2, 5, 8 12, 15, 18 22, 25, 28 O Output ports. These outputs are configured by SEL1 and SEL0 to transmit one-half or one-fourth the frequency of the VCO. The relationship between the CLKIN frequency and the output frequency is dependent on SEL1 and SEL0 and the frequency of the output being fed back to FBIN. The duty cycle of the Y output signals is nominally 50% independent of the duty cycle of CLKIN. O Output ports. 4Y1-4Y3 transmit one-half the frequency of the VCO regardless of the state of SEL1 and SEL0. The relationship between the CLKIN frequency and the output frequency is dependent on the frequency of the output being fed back to FBIN. The duty cycle of the Y output signals is nominally 50% independent of the duty cycle of CLKIN. 4Y1-4Y3 32, 35, 38 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) UNIT VCC Supply voltage range VI (2) Input voltage range VO (2) Voltage range applied to any output in the high state or power-off state IO Current into any output in the low state, 64 mA IIK(VI < 0) Input clamp current, -20 mA IOK(VO < 0) Output clamp current, Maximum power dissipation at TA = 55°C (in still air) Tstg (1) (2) (3) Storage temperature range -0.5 V to 4.6 V -0.5 V to 7 V -0.5 V to VCC + 0.5 V -50 mA (3) 1.2 W -65°C to 150°C Stresses beyond those listed under "absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed. The maximum package power dissipation is calculated using a junction temperature of 150°C and a board trace length of 750 mils. For more information, see the Package Thermal Considerations application note in the ABT Advanced BiCMOS Technology Data Book, literature number SCBD002. 5 CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 RECOMMENDED OPERATING CONDITIONS (1) MIN MAX VCC Supply voltage 3 3.6 VIH High-level input voltage 2 VIL Low-level input voltage VI Input voltage IOH High-level output current IOL Low-level output current TA Operating free-air temperature (1) UNIT V V 0.8 0 0 V 5.5 V -32 mA 32 mA 70 °C Unused inputs must be held high or low. ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range (unless otherwise noted) PARAMETER VIK VOH TA = 25°C MIN VCC = 3 V, II = -18 mA VCC = MIN to MAX (1), IOH = -100 µA VCC-0.2 VCC = 3 V, IOH = -32 mA 2 MAX -1.2 0.2 IOL = 32 mA 0.5 VCC = 0, VI = 3.6 V ±10 VCC = 3.6 V, VI = VCC or GND IOZH VCC = 3.6 V, VO = 3 V IOZL VCC = 3.6 V, VO = 0 ICC VCC = 3.6 V, IO = 0, VI = VCC or GND II VCC = 3 V UNIT V V IOL = 100 µA VOL (1) TEST CONDITIONS ±1 V µA 10 µA -10 µA Outputs high 1 Outputs low 1 Outputs disabled 1 mA Ci VI = VCC or GND 4 pF Co VO = VCC or GND 8 pF For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. TIMING REQUIREMENTS over recommended ranges of supply voltage and operating free-air temperature MIN fclock Clock frequency VCO is operating at four times the CLKIN frequency 25 50 VCO is operating at double the CLKIN frequency 50 100 40% 60% Input clock duty cycle Stabilization time (1) (1) 6 MAX After SEL1, SEL0 50 After OE↓ 50 After power up 50 After CLKIN 50 UNIT MHz µs Time required for the integrated PLL circuit to obtain phase lock of its feedback signal to its reference signal. For phase lock to be obtained, a fixed-frequency, fixed-phase reference signal must be present at CLKIN. Until phase lock is obtained, the specifications for propagation delay and skew parameters given in the switching characteristics table are not applicable. CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 SWITCHING CHARACTERISTICS over recommended ranges of supply voltage and operating free-air temperature, CL = 30 pF (see Figure 3) FROM (INPUT) PARAMETER (1) and Figure 1 through TO (OUTPUT) MIN MAX UNIT 100 MHz Y 45% 55% CLKIN↑ Y 500 +500 ps CLKIN↑ Y 200 ps 0.5 ns fmax Duty cycle tphase error (2) Jitter(pk-pk) tsk(o) (2) tsk(pr) (1) (2) (2) 1 ns tr 1.4 ns tf 1.4 ns The specifications for parameters in this table are applicable only after any appropriate stabilization time has elapsed. The propagation delay, tphase error, is dependent on the feedback path from any output to FBIN. The tphase error, tsk(o), and tsk(pr) specifications are valid only for equal loading of all outputs. PARAMETER MEASUREMENT INFORMATION 3V Input 1.5 V 0V From Output Under Test CL = 30 pF (see Note A) 1.5 V tphase error 500 Ω 2V 0.8 V Output LOAD CIRCUIT FOR OUTPUTS tr VOH 2V 1.5 V 0.8 V VOL tf VOLTAGE WAVEFORMS PROPAGATION DELAY TIMES A. CL includes probe and jig capacitance. B. The outputs are measured one at a time with one transition per measurement. C. All input pulses are supplied by generators having the following characteristics: PRR≤ 100 MHz, ZO = 50 Ω, tr≤ 2.5 ns, tf ≤ 2.5 ns. Figure 1. Load Circuit and Voltage Waveforms 7 CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 PARAMETER MEASUREMENT INFORMATION (continued) CLKIN tphase error 1 Outputs Operating at 1/2 CLKIN Frequency tphase error 2 tphase error 3 Outputs Operating at CLKIN Frequency A. B. tphase error 4 tphase error 7 tphase error 5 tphase error 8 tphase error 6 tphase error 9 Output skew, tsk(o), is calculated as the greater of: • The difference between the fastest and slowest of tphase error n (n = 1, 2, . . . 6) • The difference between the fastest and slowest of tphase error n (n = 7, 8, 9) Process skew, tsk(pr), is calculated as the greater of: • The difference between the maximum and minimum tphase identical operating conditions. • The difference between the maximum and minimum tphase identical operating conditions. error n (n = 1, 2, . . . 6) across multiple devices under error n (n = 7, 8, 9) across multiple devices under Figure 2. Waveforms for Calculation of tsk(o) 8 CDC586 www.ti.com SCAS336E – FEBRUARY 1993 – REVISED APRIL 2004 PARAMETER MEASUREMENT INFORMATION (continued) CLKIN tphase error 10 Outputs Operating at CLKIN Frequency tphase error 11 tphase error 12 tphase error 13 Outputs Operating at 2X CLKIN Frequency tphase error 14 tphase error 15 A. Output skew, tsk(o), is calculated as the greater of: B. Process skew, tsk(pr), is calculated as the greater of: • • The difference between the fastest and slowest of tphase error n (n = 10, 11, . . . 15) The difference between the maximum and minimum tphase under identical operating conditions. error n (n = 10, 11, . . . 15) across multiple devices Figure 3. Waveforms for Calculation of tsk(o) and tsk(pr) 9 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. 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