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PRELIMINARY
CY2280
100-MHz Pentium(R) II Clock Synthesizer/Driver with Spread Spectrum for Mobile or Desktop PCs
Features
* Mixed 2.5V and 3.3V operation * Clock solution for Pentium(R) II, and other similar processor-based motherboards -- Four 2.5V CPU clocks up to 100 MHz -- Eight 3.3V synch. PCI clocks, one free-running -- Two 3.3V 48-MHz USB clocks -- Three 3.3V Ref. clocks at 14.318 MHz -- Two 2.5V APIC clocks at 14.318 MHz or PCI/2 * EMI control -- Spread spectrum clocking -- Factory-EPROM programmable spread spectrum margin -- Factory-EPROM programmable output drive and slew rate * Factory-EPROM programmable CPU clock frequencies for custom configurations * Available in space-saving 48-pin SSOP package
Functional Description
The CY2280 is a Spread Spectrum clock synthesizer/driver for a Pentium II, or other similar processor-based PC requiring 100-MHz support. All of the required system clocks are provided in a space saving 48-pin SSOP package. The CY2280 can be used with the CY231x for a total solution for systems with SDRAM. The CY2280 provides the option of spread spectrum clocking on the CPU and PCI clocks for reduced EMI. A downspread percentage is introduced when the SEL_SS input is asserted. The device can be run without spread spectrum when the SEL_SS input is deasserted. The percentage of spreading is EPROM-programmable to optimize EMI-reduction. The CY2280 has power-down, CPU stop, and PCI stop pins for power management control. The signals are synchronized on-chip, and ensure glitch-free transitions on the outputs. When the CPU_STOP input is asserted, the CPU clock outputs are driven LOW. When the PCI_STOP input is asserted, the PCI clock outputs (except the free-running PCI clock) are driven LOW. When the PWR_DWN pin is asserted, the reference oscillator and PLLs are shut down, and all outputs are driven LOW.
CY2280 Selector Guide
CY2280 Configuration Options Clock Outputs CPU (66.6, 100 MHz) PCI (CPU/2, CPU/3) USB (48 MHz) APIC (14.318 MHz) APIC (PCI/2) Reference (14.318 MHz) CPU-PCI delay CPU-APIC delay Spread Spectrum (Downspread) -1 4 8 2 2 -3 1.5-4.0 ns -N/A -11S 4 8 2 2 -3 1.5-4.0 ns --0.6% -12S 4 8 2 2 -3 1.5-4.0 ns --1.0% -13S 4 8 2 2 -3 1.5-4.0 ns --1.5% -21S 4 8 2 -2 3 1.5-4.0 ns 2.0-4.5 ns -0.6% -31S 4 8 2 2 -3 0 ns --0.6%
Logic Block Diagram
CPU_STOP XTALIN
XTALOUT
14.318 MHz OSC. CPU PLL Divider STOP LOGIC
-1 -2
APIC [0:1] VDDAPIC REF [0-2] VDDREF CPUCLK [0-3] VDDCPU PCICLK_F
PWR_DWN SEL0 SEL1 SEL100 SEL_SS PCI_STOP
SYS PLL Delay STOP LOGIC
EPROM
VDDPCI PCI [1-7] VDDPCI
USBCLK [0:1] VDDUSB
Pentium is a registered trademark of Intel Corporation.
Cypress Semiconductor Corporation
*
3901 North First Street
*
San Jose
*
CA 95134
* 408-943-2600 December 24, 1998
CY2280
Pin Configurations
REF0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 48 47 46 45 44 43 42 48-pin SSOP (Top View) 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 VDDREF REF2 VDDAPIC APIC0 APIC1 VSS RESERVED VDDCPU CPUCLK0 CPUCLK1 VSS VDDCPU CPUCLK2 CPUCLK3 VSS AVDD VSS PCI_STOP CPU_STOP PWR_DWN N/C SEL0 SEL1 SEL100 REF0 REF1 VSS XTALIN XTALOUT VSS PCICLK_F PCICLK1 VDDPCI PCICLK2 PCICLK3 VSS PCICLK4 PCICLK5 VDDPCI PCICLK6 PCICLK7 VSS AVDD VSS VDDUSB USBCLK0 USBCLK1 VSS 1 2 3 4 5 6 7 48-pin SSOP (Top View) 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 VDDREF REF2 VDDAPIC APIC0 APIC1 VSS RESERVED VDDCPU CPUCLK0 CPUCLK1 VSS VDDCPU CPUCLK2 CPUCLK3 VSS AVDD VSS PCI_STOP CPU_STOP PWR_DWN CY2280-11S SEL_SS SEL0 SEL1 SEL100
REF1 VSS XTALIN XTALOUT VSS PCICLK_F PCICLK1 VDDPCI PCICLK2 PCICLK3 VSS PCICLK4 PCICLK5 VDDPCI PCICLK6 PCICLK7 VSS AVDD VSS VDDUSB USBCLK0 USBCLK1 VSS
CY2280-1
CY2280-12S CY2280-13S CY2280-21S CY2280-31S
Pin Summary
Name VDDPCI VDDUSB VDDREF VDDAPIC VDDCPU AVDD VSS XTALIN[1] XTALOUT
[1]
Pins 15, 9 21 48 46 41, 37 33, 19 4 5 31 30 29 28 28 27 26 25 40, 39, 36, 35 8, 10, 11, 13, 14, 16, 17 7 45, 44 1, 2, 47 22, 23 42
Description 3.3V Digital voltage supply for PCI clocks 3.3V Digital voltage supply for USB clocks 3.3V Digital voltage supply for REF clocks 2.5V Digital voltage supply for APIC clocks 2.5V Digital voltage supply for CPU clocks Analog voltage supply, 3.3V Reference crystal input Reference crystal feedback Active LOW control input to stop PCI clocks Active LOW control input to stop CPU clocks Active LOW control input to power down device Spread spectrum select input (-11S, -12S, -13S, -21S, -31S options) Spread spectrum select input (-1 option) CPU frequency select input, bit 0 (see Function Table) CPU frequency select input, bit 1 (see Function Table) CPU frequency select input, selects between 100 MHz and 66.6 MHz (see Function Table) CPU clock outputs PCI clock outputs, at one-half or one-third the CPU frequency of 66.6 MHz or 100 MHz respectively Free-running PCI clock output APIC clock outputs 3.3V Reference clock outputs USB clock outputs Reserved
3, 6, 12, 18, 20, 24, 32, 34, 38, 43 Ground
PCI_STOP CPU_STOP PWR_DWN SEL_SS N/C SEL0 SEL1 SEL100 CPUCLK[0:3] PCICLK[1:7] PCICLK_F APIC[0:1] REF[0:2] USBCLK[0:1] RESERVED
Note: 1. For best accuracy, use a parallel-resonant crystal, CLOAD = 18 pF.
2
CY2280
Function Table (-11S, -12S, -13S, -31S Options)
SEL100 SEL1 SEL0 0 0 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 1 0 1 0 1 1 0 1 0 1 SEL_SS[2] N/A N/A N/A 0 (downspread) 1 (no spread) N/A N/A N/A 0 (downspread) CPU/PCI Ratio 2 2 2 2 2 3 3 3 3 CPUCLK Hi-Z Reserved Reserved PCICLK_F PCICLK Hi-Z Reserved Reserved REF Hi-Z 14.318 MHz 14.318 MHz 14.318 MHz 14.318 MHz TCLK[3] 14.318 MHz 14.318 MHz 14.318 MHz Hi-Z 14.318 MHz 14.318 MHz 14.318 MHz 14.318 MHz TCLK[3] 14.318 MHz 14.318 MHz 14.318 MHz APIC USBCLK Hi-Z 48 MHz 48 MHz 48 MHz 48 MHz TCLK/2 48 MHz 48 MHz 48 MHz
66.66 MHz 33.33 MHz 66.66 MHz 33.33 MHz TCLK/2 Reserved Reserved 100 MHz TCLK/6 Reserved Reserved 33.33 MHz
Function Table (-21S Option)
SEL100 SEL1 SEL0 0 0 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 1 0 1 0 1 1 0 1 0 1 SEL_SS[2] N/A N/A N/A 0 (downspread) 1 (no spread) N/A N/A N/A 0 (downspread) CPU/PCI Ratio 2 2 2 2 2 3 3 3 3 CPUCLK Hi-Z Reserved Reserved PCICLK_F PCICLK Hi-Z Reserved Reserved REF Hi-Z 14.318 MHz 14.318 MHz 14.318 MHz 14.318 MHz TCLK[3] 14.318 MHz 14.318 MHz 14.318 MHz Hi-Z Reserved Reserved 16.67 MHz 16.67 MHz TCLK/12[3] Reserved Reserved 16.67 MHz APIC USBCLK Hi-Z 48 MHz 48 MHz 48 MHz 48 MHz TCLK/2 48 MHz 48 MHz 48 MHz
66.66 MHz 33.33 MHz 66.66 MHz 33.33 MHz TCLK/2 Reserved Reserved 100 MHz TCLK/6 Reserved Reserved 33.33 MHz
Actual Clock Frequency Values
Clock Output CPUCLK CPUCLK USBCLK Target Frequency Actual Frequency (MHz) (MHz) 66.67 100 48.0 66.654 99.77 48.008 PPM -195 -2346 167
Power Management Logic
CPU_STOP X 0 0 1 1 PCI_STOP X 0 1 0 1 0 1 1 1 1 PWR_DWN CPUCLK Low Low Low Running Running PCICLK Low Low Running Low Running PCICLK_F Low Running Running Running Running Other Clocks Low Running Running Running Running Osc. Off PLLs Off
Running Running Running Running Running Running Running Running
Notes: 2. Target frequency is modulated by percentage shown (max.) when SEL_SS = 0. 3. TCLK supplied on the XTALIN pin in Test Mode.
3
CY2280
Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.) Supply Voltage ..................................................-0.5 to +7.0V Input Voltage .............................................. -0.5V to VDD+0.5 Storage Temperature (Non-Condensing) ... -65C to +150C Max. Soldering Temperature (10 sec) ...................... +260C Junction Temperature ............................................... +150C Package Power Dissipation .............................................. 1W Static Discharge Voltage ........................................... >2000V (per MIL-STD-883, Method 3015, like VDD pins tied together)
Operating Conditions[4]
Parameter AVDD, VDDPCI, VDDUSB, VDDREF VDDCPU VDDAPIC TA CL Description Analog and Digital Supply Voltage CPU Supply Voltage APIC Supply Voltage Operating Temperature, Ambient Max. Capacitive Load on CPUCLK PCICLK APIC, REF USB Reference Frequency, Oscillator Nominal Value 14.318 Min. 3.135 2.375 2.375 0 Max. 3.465 2.625 2.625 70 20 30 20 20 14.318 MHz Unit V V V C pF
f(REF)
Electrical Characteristics Over the Operating Range
Parameter VIH VIL VOH VOL VOH Description High-level Input Voltage Low-level Input Voltage High-level Output Voltage
[6]
Test Conditions Except Crystal Inputs[5] Except Crystal Inputs
[5]
Min. Max. Unit 2.0 0.8 IOH = 12 mA CPUCLK IOH = 18 mA APIC IOL = 12 mA IOL = 18 mA CPUCLK APIC 2.4 V 2.0 0.4 V V V V
VDDCPU = VDDAPIC = 2.375V
Low-level Output Voltage[6] VDDCPU = VDDAPIC = 2.375V
High-level Output Voltage[6] VDDPCI, AVDD, VDDREF, VDDUSB = 3.135V IOH = 14.5 mA PCICLK IOH = 16 mA USBCLK IOH = 16 mA REF Low-level Output Voltage
[6]
VOL
VDDPCI, AVDD, VDDREF, VDDUSB= 3.135V IOL = 9.4 mA PCICLK IOL = 9 mA IOL = 9 mA USBCLK REF -10 -10
0.4V
V
IIH IIL IOZ IDD25 IDD25 IDD33 IDDS
Input High Current Input Low Current Output Leakage Current Power Supply Current for 2.5V Clocks[6] Power Supply Current for 2.5V Clocks[6] Power Supply Current for 3.3V Clocks[6] Power-down Current[6]
VIH = V DD VIL = 0V Three-state VDDCPU = 2.625V, VIN = 0 or V DD, Loaded Outputs, CPU = 66.6 MHz VDDCPU = 2.625V, VIN = 0 or VDD, Loaded Outputs, CPU = 100 MHz VDD = 3.465V, VIN = 0 or VDD, Loaded Outputs Current draw in powerdown state
+10 10 +10 70 100 170 500
A A A mA mA mA A
Notes: 4. Electrical parameters are guaranteed with these operating conditions. 5. Crystal Inputs have CMOS thresholds. 6. Parameter is guaranteed by design and characterization. Not 100% tested in production.
4
CY2280
Switching Characteristics[6, 7]
Parameter t1 t2 Output All CPUCLK, APIC Description Output Duty Cycle
[8]
Test Conditions t1 = t1A / t1B Between 0.4V and 2.0V -1,-11S, -12S,-13S, -21S only -31S only -1,-11S, -12S,-13S, -21S only -31S only
Min. 45 1.0
Typ. 50
Max. 55 4.0
Unit % V/ns
CPU and APIC Clock Rising and Falling Edge Rate PCI Clock Rising and Falling Edge Rate
0.8 1.0
4.0 4.0
V/ns V/ns
t2
PCICLK
Between 0.4V and 2.4V
0.9 0.5
4.0 2.0 1.6
V/ns V/ns ns
t2 t3
USBCLK, REF CPUCLK
USB, REF Rising and Falling Edge Rate CPU Clock Rise Time
Between 0.4V and 2.4V Between 0.4V and 2.0V -1,-11S, -12S,-13S, -21S only -31S only -1,-11S, -12S,-13S, -21S only -31S only
0.4
0.4 0.4
2.0 1.6
ns ns
t4
CPUCLK
CPU Clock Fall Time
Between 2.0V and 0.4V
0.4 100 1.5
2.0 175 4.0
ns ps ns
t5 t6
CPUCLK CPUCLK, PCICLK
CPU-CPU Clock Skew CPU-PCI Clock Skew[9]
Measured at 1.25V Measured at 1.25V for 2.5V clocks, and at 1.5V for 3.3V clocks Measured at 1.5V Measured at 1.25V for 2.5V clocks Measured at 1.25V Measured at 1.25V -1,-11S, -12S,-13S, -21S only -31S only -21S only 2.0 -1,-11S, -12S,-13S, -21S only -31S only
-1
1 250 4.5 100 200 175 250
ns ps ns ps ps
t7 t8 t9 t10
PCICLK, PCICLK CPUCLK, APIC APIC CPUCLK
PCI-PCI Clock Skew CPU-APIC Clock Skew [10] APIC-APIC Clock Skew Cycle-Cycle Clock Jitter
250 250
350 500 3
ps ps ms
t11 t12
PCICLK CPUCLK, PCICLK
Cycle-Cycle Clock Jitter Power-up Time
Measured at 1.5V CPU, PCI clock stabilization from power-up
Notes: 7. All parameters specified with loaded outputs. 8. Duty cycle is measured at 1.5V when VDD = 3.3V. When VDD = 2.5V, duty cycle is measured at 1.25V. 9. PCI lags CPU for -11S, -12S, -13S, -14S, -21S options. 10. APIC lags CPU for -21S option.
5
CY2280
Switching Waveforms
Duty Cycle Timing
t1A OUTPUT t1B
All Outputs Rise/Fall Time
VDD OUTPUT 0V t2 t3 t2 t4
CPU-CPU Clock Skew
CPUCLK
CPUCLK t5
CPU-PCI Clock Skew
CPUCLK
PCICLK t6
PCI-PCI Clock Skew
PCICLK
PCICLK t7
CPU-APIC Clock Skew (-21S only)
CPUCLK
APIC t8
6
CY2280
Switching Waveforms (continued)
APIC-APIC Clock Skew
APIC
APIC t9
CPU_STOP
CPUCLK (Internal) PCICLK (Internal) PCICLK
(Free-Running)
CPU_STOP CPUCLK (External)
PCI_STOP
CPUCLK (Internal) PCICLK (Internal) PCICLK
(Free-Running)
PCI_STOP PCICLK (External)
PWR_DOWN
CPUCLK (Internal) PCICLK (Internal) PWR_DWN CPUCLK (External) PCICLK (External) VCO Crystal Shaded section on the VCO and Crystal waveforms indicates that the VCO and crystal oscillator are active, and there is a valid clock.
7
CY2280
SPREAD SPECTRUM CLOCKING
Spread Spectrum Disabled
Spread Spectrum Enabled
Amplitude (dB)
Frequency (MHz)
Description Modulation Frequency Down Spread Margin at the Fundamental Frequency Down Spread Margin at the Fundamental Frequency Down Spread Margin at the Fundamental Frequency Down Spread Margin at the Fundamental Frequency Configuration All (except -1) -11S, -31S -12S -13S -21S CPU, PCI CPU, PCI CPU, PCI CPU, PCI, APIC Outputs Min. 30.0 0.0 0.0 0.0 0.0 Max. 33.0 -0.6 -1.0 -1.5 -0.6 Unit kHz % % % %
8
CY2280
Application Information
Clock traces must be terminated with either series or parallel termination, as they are normally done.
Application Circuit
Summary
* A parallel-resonant crystal should be used as the reference to the clock generator. The operating frequency and CLOAD of this crystal should be as specified in the data sheet. Optional trimming capacitors may be needed if a crystal with a different CLOAD is used. Footprints must be laid out for flexibility. * Surface mount, low-ESR, ceramic capacitors should be used for filtering. Typically, these capacitors have a value of 0.1 F. In some cases, smaller value capacitors may be required. * The value of the series terminating resistor satisfies the following equation, where Rtrace is the loaded characteristic impedance of the trace, Rout is the output impedance of the clock generator (specified in the data sheet), and Rseries is the series terminating resistor. Rseries > Rtrace - Rout * Footprints must be laid out for optional EMI-reducing capacitors, which should be placed as close to the terminating resistor as is physically possible. Typical values of these capacitors range from 4.7 pF to 22 pF. * A Ferrite Bead may be used to isolate the Board VDD from the clock generator VDD island. Ensure that the Ferrite Bead offers greater than 50 impedance at the clock frequency, under loaded DC conditions. Please refer to the application note "Layout and Termination Techniques for Cypress Clock Generators" for more details. * If a Ferrite Bead is used, a 10 F-22 F tantalum bypass capacitor should be placed close to the Ferrite Bead. This capacitor prevents power supply droop during current surges.
9
CY2280
Test Circuit
VDDPCI, VDDCORE, VDDUSB, VDDREF
3, 6, 12, 18, 20, 24, 32, 34, 38, 43 9, 15, 19, 21, 33, 48 0.1 F CY2280
VDDCPU, VDDAPIC 37, 41, 46 0.1 F
OUTPUTS CLOAD
Notes: Each supply pin must have an individual decoupling capacitor All capacitors must be placed as close to the pins as is possible.
Ordering Information
Ordering Code CY2280PVC-1 CY2280PVC-11S CY2280PVC-12S CY2280PVC-13S CY2280PVC-14S CY2280PVC-21S CY2280PVC-31S Document #: 38-00694-C Package Name O48 O48 O48 O48 O48 O48 O48 Package Type 48-Pin SSOP 48-Pin SSOP 48-Pin SSOP 48-Pin SSOP 48-Pin SSOP 48-Pin SSOP 48-Pin SSOP Operating Range Commercial Commercial Commercial Commercial Commercial Commercial Commercial
10
CY2280
Package Diagram
48-Lead Shrunk Small Outline Package O48
51-85061-B
(c) Cypress Semiconductor Corporation, 1998. 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.

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