fax id: 3516 1CY 7B9 92 0 CY7B9910 CY7B9920 Low Skew Clock Buffer Features • • • • • • • • • Block Diagram Description All outputs skew <100 ps typical (250 max.) 15- to 80-MHz output operation Zero input to output delay 50% duty-cycle outputs Outputs drive 50Ω terminated lines Low operating current 24-pin SOIC package Jitter: <200 ps peak to peak, <25 ps RMS Compatible with Pentium™-based processors Phase Frequency Detector and Filter These two blocks accept inputs from the reference frequency (REF) input and the feedback (FB) input and generate correction information to control the frequency of the Voltage-Controlled Oscillator (VCO). These blocks, along with the VCO, form a Phase-Locked Loop (PLL) that tracks the incoming REF signal. VCO The VCO accepts analog control inputs from the PLL filter block and generates a frequency. The operational range of the VCO is determined by the FS control pin. Functional Description The CY7B9910 and CY7B9920 Low Skew Clock Buffers offer low-skew system clock distribution. These multiple-output clock drivers optimize the timing of high-performance computer systems. Eight individual drivers can each drive terminated transmission lines with impedances as low as 50Ω while delivering minimal and specified output skews and full-swing logic levels (CY7B9910 TTL or CY7B9920 CMOS). The completely integrated PLL allows “zero delay” capability. External divide capability, combined with the internal PLL, allows distribution of a low-frequency clock that can be multiplied by virtually any factor at the clock destination. This facility minimizes clock distribution difficulty while allowing maximum system clock speed and flexibility. Test Mode The TEST input is a three-level input. In normal system operation, this pin is connected to ground, allowing the CY7B9910/CY7B9920 to operate as explained above. (For testing purposes, any of the three-level inputs can have a removable jumper to ground, or be tied LOW through a 100Ω resistor. This will allow an external tester to change the state of these pins.) If the TEST input is forced to its MID or HIGH state, the device will operate with its internal phase-locked loop disconnected, and input levels supplied to REF will directly control all outputs. Relative output to output functions are the same as in normal mode. Logic Block Diagram Pin Configuration TEST PHASE FREQ DET FB REF Voltage FILTER Controlled SOIC Top View Oscillator FS REF VCCQ FS NC VCCQ VCCN Q0 Q1 GND Q2 Q3 VCCN Q0 Q1 Q2 Q3 Q4 Q5 1 24 2 23 3 22 4 21 5 20 6 7 7B9910 7B9920 19 18 8 17 9 16 10 15 11 14 12 13 GND TEST NC GND VCCN Q7 Q6 GND Q5 Q4 VCCN FB Q6 Q7 7B9910–1 7B9910–2 Pentium is a trademark of Intel Corporation. Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600 November 1994 – Revised July 7, 1997 CY7B9910 CY7B9920 Pin Definitions Signal Name I/O Description REF I Reference frequency input. This input supplies the frequency and timing against which all functional variation is measured. FB I PLL feedback input (typically connected to one of the eight outputs). FS[9,10,11] I Three-level frequency range select. TEST I Three-level select. See Test Mode section. Q[0..7] O Clock outputs. VCCN PWR Power supply for output drivers. VCCQ PWR Power supply for internal circuitry. GND PWR Ground. Maximum Ratings Static Discharge Voltage ........................................... >2001V (per MIL-STD-883, Method 3015) (Above which the useful life may be impaired. For user guidelines, not tested.) Latch-Up Current ..................................................... >200 mA Storage Temperature .................................–65°C to +150°C Operating Range Ambient Temperature with Power Applied.............................................–55°C to +125°C Range Supply Voltage to Ground Potential ............... –0.5V to +7.0V Commercial DC Input Voltage............................................ –0.5V to +7.0V Industrial Ambient Temperature VCC 0°C to +70°C 5V ± 10% –40°C to +85°C 5V ± 10% Output Current into Outputs (LOW) ............................. 64 mA Electrical Characteristics Over the Operating Range CY7B9910 Parameter Description Test Conditions VCC = Min., IOH = –16 mA Min. Max. CY7B9920 Min. Max. 2.4 Unit VOH Output HIGH Voltage V VOL Output LOW Voltage VIH Input HIGH Voltage (REF and FB inputs only) 2.0 VCC VCC – 1.35 VCC V VIL Input LOW Voltage (REF and FB inputs only) –0.5 0.8 –0.5 1.35 V VIHH Three-Level Input HIGH Voltage (Test, FS)[1] Min. ≤ VCC ≤ Max. VCC – 1V VCC VCC – 1V VCC V VIMM Three-Level Input MID Voltage (Test, FS)[1] Min. ≤ VCC ≤ Max. VCC/2 – 500 mV VCC/2 + 500 mV VCC/2 – 500 mV VCC/2 + 500 mV V VILL Three-Level Input LOW Voltage (Test, FS)[1] Min. ≤ VCC ≤ Max. 0.0 1.0 0.0 1.0 V IIH Input HIGH Leakage Current (REF and FB inputs only) VCC = Max., VIN = Max. 10 µA IIL Input LOW Leakage Current (REF and FB inputs only) VCC = Max., VIN = 0.4V IIHH Input HIGH Current (Test, FS) VIN = VCC IIMM Input MID Current (Test, FS) VIN = VCC/2 IILL Input LOW Current (Test, FS) VIN = GND VCC = Min., IOH =–40 mA VCC –0.75 VCC = Min., IOL = 46 mA 0.45 V VCC = Min., IOL = 46 mA 0.45 10 –500 200 –50 50 –200 2 µA –500 –50 200 µA 50 µA –200 µA CY7B9910 CY7B9920 Electrical Characteristics Over the Operating Range (continued) CY7B9910 Parameter Description Test Conditions Min. CY7B9920 Max. Min. Max. Unit –250 N/A mA mA IOS Output Short Circuit Current[2] VCC = Max., VOUT = GND (25°C only) ICCQ Operating Current Used by Internal Circuitry VCCN = VCCQ = Max., Com’l All Input Mil/Ind Selects Open 85 85 90 90 ICCN Output Buffer Current per Output Pair[3] VCCN = VCCQ = Max., IOUT = 0 mA Input Selects Open, fMAX 14 19 mA PD Power Dissipation per Output Pair[4] VCCN = VCCQ = Max., IOUT = 0 mA Input Selects Open, fMAX 78 104[5] mW Capacitance[6] Parameter CIN Description Input Capacitance Test Conditions TA = 25°C, f = 1 MHz, VCC = 5.0V Max. Unit 10 pF Notes: 1. These inputs are normally wired to V CC, GND, or left unconnected (actual threshold voltages vary as a percentage of VCC). Internal termination resistors hold unconnected inputs at VCC/2. If these inputs are switched, the function and timing of the outputs may glitch and the PLL may require an additional tLOCK time before all data sheet limits are achieved. 2. Tested one output at a time, output shorted for less than one second, less than 10% duty cycle. Room temperature only. CY7B9920 outputs are not short circuit protected. 3. Total output current per output pair can be approximated by the following expression that includes device current plus load current: CY7B9910: ICCN = [(4 + 0.11F) + [((835 – 3F)/Z) + (.0022FC)]N] x 1.1 CY7B9920: ICCN = [(3.5+ .17F) + [((1160 – 2.8F)/Z) + (.0025FC)]N] x 1.1 Where F = frequency in MHz C = capacitive load in pF Z = line impedance in ohms N = number of loaded outputs; 0, 1, or 2 FC = F < C 4. Total power dissipation per output pair can be approximated by the following expression that includes device power dissipation plus power dissipation due to the load circuit: CY7B9910: PD = [(22 + 0.61F) + [((1550 – 2.7F)/Z) + (.0125FC)]N] x 1.1 CY7B9920: PD = [(19.25+ 0.94F) + [((700 + 6F)/Z) + (.017FC)]N] x 1.1 See note 3 for variable definition. 5. CMOS output buffer current and power dissipation specified at 50-MHz reference frequency. 6. Applies to REF and FB inputs only. Tested initially and after any design or process changes that may affect these parameters. AC Test Loads and Waveforms 5V R1 CL R2 3.0V R1=130 R2=91 CL = 50 pF (CL = 30pF for –5 and – 2 devices) (Includes fixture and probe capacitance) 2.0V Vth =1.5V 0.8V 0.0V 2.0V Vth =1.5V 0.8V ≤1ns ≤1ns 7B9910–3 7B9910–4 TTL AC Test Load (CY7B9910) TTL Input Test Waveform (Cy7B9910) VCC VCC R1 CL R1=100 R2=100 CL = 50 pF (CL =30 pF for –5 and – 2devices) (Includes fixture and probe capacitance) R2 80% Vth = VCC/2 20% 0.0V ≤ 3ns 7B9910–5 80% Vth = VCC/2 20% ≤ 3ns 7B9910–6 CMOS Input Test Waveform (CY7B9920) CMOS AC Test Load (CY7B9920) 3 CY7B9910 CY7B9920 Switching Characteristics Over the Operating Range[7] CY7B9910–2[8] Parameter fNOM Description Operating Clock Frequency in MHz Min. Typ. CY7B9920–2[8] Max. Min. FS = LOW[9, 10] 15 30 15 Typ. Max. Unit 30 MHz FS = MID[9, 10] 25 50 25 50 FS = HIGH[9, 10, 11] 40 80 40 80[12] tRPWH REF Pulse Width HIGH 5.0 5.0 ns tRPWL REF Pulse Width LOW 5.0 5.0 ns [13, 14] tSKEW Zero Output Skew (All Outputs) tDEV Device-to-Device Skew[14, 15] tPD Propagation Delay, REF Rise to FB Rise tODCV Output Duty Cycle Variation tORISE Output Rise Time[17, 18] 0.1 0.25 0.1 0.75 [16] Time[17, 18] tOFALL Output Fall tLOCK PLL Lock Time[19] tJR Cycle-to-Cycle Output Jitter Peak to Peak Description Operating Clock Frequency in MHz ns 0.0 +0.25 –0.25 0.0 +0.25 ns –0.65 0.0 +0.65 –0.65 0.0 +0.65 ns 0.15 1.0 1.2 0.5 2.0 2.5 ns 0.15 1.0 1.2 0.5 2.0 2.5 ns 0.5 0.5 ms 200 200 ps 25 25 ps CY7B9910–5 Parameter ns 0.75 –0.25 RMS fNOM 0.25 Min. Typ. CY7B9920–5 Max. Min. FS = LOW[9, 10] 15 30 15 Typ. Max. Unit 30 MHz FS = MID[9, 10] 25 50 25 50 FS = HIGH[9, 10, 11] 40 80 40 80[12] tRPWH REF Pulse Width HIGH 5.0 5.0 ns tRPWL REF Pulse Width LOW 5.0 5.0 ns Outputs)[13, 14] tSKEW Zero Output Skew (All tDEV Device-to-Device Skew[8, 15] tPD Propagation Delay, REF Rise to FB Rise –0.5 0.0 +0.5 –0.5 tODCV Output Duty Cycle Variation[16] –1.0 0.0 +1.0 –1.0 0.15 1.0 1.5 0.15 1.0 1.5 Output Rise tOFALL Output Fall Time[17, 18] tJR PLL Lock 0.5 0.25 0.5 ns 1.0 ns 0.0 +0.5 ns 0.0 +1.0 ns 0.5 2.0 3.0 ns 0.5 2.0 3.0 ns 0.5 0.5 ms 200 200 ps 25 25 ps 1.0 Time[17, 18] tORISE tLOCK 0.25 Time[19] Cycle-to-Cycle Output Jitter Peak to Peak[8] RMS[8] Notes: 7. Test measurement levels for the CY7B9910 are TTL levels (1.5V to 1.5V). Test measurement levels for the CY7B9920 are CMOS levels (VCC/2 to VCC/2). Test conditions assume signal transition times of 2ns or less and output loading as shown in the AC Test Loads and Waveforms unless otherwise specified. 8. Guaranteed by statistical correlation. Tested initially and after any design or process changes that may affect these parameters. 9. For all three-state inputs, HIGH indicates a connection to VCC, LOW indicates a connection to GND, and MID indicates an open connection. Internal termination circuitry holds an unconnected input to VCC/2. 10. The level to be set on FS is determined by the “normal” operating frequency (fNOM) of the VCO (see Logic Block Diagram). The frequency appearing at the REF and FB inputs will be fNOM when the output connected to FB is undivided. The frequency of the REF and FB inputs will be fNOM/X when the device is configured for a frequency multiplication by using external division in the feedback path of value X. 11. When the FS pin is selected HIGH, the REF input must not transition upon power-up until V CC has reached 4.3V. 12. Except as noted, all CY7B9920–2 and –5 timing parameters are specified to 80-MHz with a 30-pF load. 13. tSKEW is defined as the time between the earliest and the latest output transition among all outputs when all are loaded with 50 pF and terminated with 50Ω to 2.06V (CY7B9910) or VCC/2 (CY7B9920). 14. tSKEW is defined as the skew between outputs. 15. tDEV is the output-to-output skew between any two outputs on separate devices operating under the same conditions (VCC, ambient temperature, air flow, etc.). 16. tODCV is the deviation of the output from a 50% duty cycle. 17. Specified with outputs loaded with 30 pF for the CY7B99X0–2 and –5 devices and 50 pF for the CY7B99X0–7 devices. Devices are terminated through 50Ω to 2.06V (CY7B9910) or VCC/2 (CY7B9920). 18. tORISE and tOFALL measured between 0.8V and 2.0V for the CY7B9910 or 0.8VCC and 0.2VCC for the CY7B9920. 19. tLOCK is the time that is required before synchronization is achieved. This specification is valid only after VCC is stable and within normal operating limits. This parameter is measured from the application of a new signal or frequency at REF or FB until t PD is within specified limits. 4 CY7B9910 CY7B9920 Switching Characteristics Over the Operating Range[7] (continued) CY7B9910–7 Parameter fNOM Description Min. [9, 10] Operating Clock Frequency in MHz FS = LOW FS = MID[9, 10] [9, 10, 11] FS = HIGH Typ. CY7B9920–7 Max. Min. 15 30 25 40 Typ. Max. Unit 15 30 MHz 50 25 50 80 40 80[12] tRPWH REF Pulse Width HIGH 5.0 5.0 ns tRPWL REF Pulse Width LOW 5.0 5.0 ns tSKEW Zero Output Skew (All Outputs) [13, 14] 0.3 [8, 15] 0.75 0.3 ns 1.5 ns tDEV Device-to-Device Skew tPD Propagation Delay, REF Rise to FB Rise –0.7 0.0 +0.7 –0.7 0.0 +0.7 ns tODCV Output Duty Cycle Variation[16] –1.2 0.0 +1.2 –1.2 0.0 +1.2 ns 0.15 1.5 2.5 0.5 3.0 5.0 ns 0.15 1.5 2.5 0.5 3.0 5.0 ns tORISE tOFALL Output Rise Output Fall Time[17, 18] Time[17, 18] Time[19] tLOCK PLL Lock tJR Cycle-to-Cycle Output Jitter tJR 1.5 0.75 0.5 0.5 ms Peak to Peak[8] 200 200 ps RMS[8] 25 25 ps AC Timing Diagrams tREF tRPWL tRPWH REF tPD tODCV tODCV FB Q tSKEW tSKEW tJR OTHER Q 7B9910–8 5 CY7B9910 CY7B9920 REF LOAD Z0 FB REF FS SYSTEM CLOCK LOAD Q0 Q1 Z0 Q2 Q3 LOAD Q4 Q5 Z0 Q6 Q7 LOAD TEST Z0 7B9910–9 Figure 1. Zero-Skew and/or Zero-Delay Clock Driver Operational Mode Descriptions nated transmission lines (with impedances as low as 50 ohms), allows efficient printed circuit board design. Figure 1 shows the device configured as a zero-skew clock buffer. In this mode the 7B9910/9920 can be used as the basis for a low-skew clock distribution tree. The outputs are aligned and may each drive a terminated transmission line to an independent load. The FB input can be tied to any output and the operating frequency range is selected with the FS pin. The low-skew specification, coupled with the ability to drive termi- Figure 2 shows the CY7B9910/9920 connected in series to construct a zero-skew clock distribution tree between boards. Cascaded clock buffers will accumulate low-frequency jitter because of the non-ideal filtering characteristics of the PLL filter. It is not recommended that more than two clock buffers be connected in series. LOAD REF Z0 FB SYSTEM CLOCK REF FS LOAD Z0 Q0 Q1 Q2 Q3 LOAD Q4 Q5 Z0 Q6 Q7 FB REF FS TEST Z0 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 LOAD LOAD TEST 7B9910–10 Figure 2. Board-to-Board Clock Distribution 6 CY7B9910 CY7B9920 Ordering Information Accuracy (ps) 250 500 750 Ordering Code CY7B9910–2SC CY7B9920–2SC CY7B9910–5SC CY7B9910–5SI CY7B9920–5SC CY7B9920–5SI CY7B9910–7SC CY7B9910–7SI CY7B9920–7SC CY7B9920–7SI Package Name S13 S13 S13 S13 S13 S13 S13 S13 S13 S13 Package Type 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC 24-Lead Small Outline IC Operating Range Commercial Commercial Industrial Commercial Industrial Commercial Industrial Commercial Industrial Document #: 38–00437–B Package Diagram 24-Lead (300-Mil) Molded SOIC S13 © Cypress Semiconductor Corporation, 1997. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress Semiconductor product. Nor does it convey or imply any license under patent or other rights. Cypress Semiconductor does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress Semiconductor products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress Semiconductor against all charges.