CYW137OXCT

W137 FTG for Mobile 440BX & Transmeta’s Crusoe CPU Features • Maximized EMI suppression using Cypress’s Spread Spectrum Technology • Two copies of CPU output • Six copies of PCI output (Synchronous w/CPU output) • One 48-MHz output for USB support • One selectable 24 /48 MHz output • Two Buffered copies of 14.318 MHz input reference signal • Supports 100 MHz or 66 MHz CPU operation • Power management control input pins • Available in 28-pin SSOP (209 mils) and 28-pin TSSO (173 mils) • SS function can be disabled • See W40S11-02 for 2 SDRAM DIMM support CPU0:1 Cycle to Cycle Jitter: ..................................... 200 ps PCI_F, PCI1:5 Output to Output Skew:....................... 500 ps PCI_F, PCI1:5 Cycle to Cycle Jitter: .......................... 250 ps CPU to PCI Output Skew:................1.5–4.0 ns (CPU Leads) Output Duty Cycle:..................................................... 45/55% PCI_F, PCI Edge Rate: .............................................. >1 V/ns CPU_STOP#, OE, SPREAD#, SEL48#, PCI_STOP#, PWR_DWN# all have a 250-kW pull-up resistor. Table 1. Pin Selectable Frequency SEL100/66# 0/1 0 1 OE 0 1 1 CPU Hi-Z 66.6 MHz 100 MHz PCI Hi-Z 33.3 33.3 Spread% Don’t Care See Table 2 See Table 2 Key Specifications Supply Voltages:........................................ VDDQ3 = 3.3V±5% VDDQ2 = 2.5V±5% CPU0:1 Output to Output Skew: ................................. 175 ps Table 2. Spread Spectrum Feature SPREAD# 0 1 Spread Profile –0.5% (down spread) 0% (spread disabled) Block Diagram of the anchored frame as Pin Configuration Rev 1.0, November 24, 2006 2200 Laurelwood Road, Santa Clara, CA 95054 Tel:(408) 855-0555 Fax:(408) 855-0550 Page 1 of 8 www.SpectraLinear.com W137 Pin Definitions Pin Name CPU0:1 Pin No. 24, 23 Pin Type O Pin Description CPU Clock Outputs 0 and 1. These two CPU clock outputs are controlled by the CPU_STOP# control pin. Output voltage swing is controlled by voltage applied to VDDQ2. Frequency is selected per Table 1. PCI Bus Clock Outputs 1 through 5. These five PCI clock outputs are controlled by the PCI_STOP# control pin. Output voltage swing is controlled by voltage applied to VDDQ3. Frequency is selected per Table 1. Fixed PCI Clock Output. Unlike PCI1:5 outputs, this output is not controlled by the PCI_STOP# control pin; it cannot be forced LOW by PCI_STOP#. Output voltage swing is controlled by voltage applied to VDDQ3. Frequency is selected per Table 1. CPU_STOP# Input. When brought LOW, clock outputs CPU0:1 are stopped LOW after completing a full clock cycle (2–3 CPU clock latency). When brought HIGH, clock outputs CPU0:1 start with a full clock cycle (2–3 CPU clock latency). PCI_STOP# Input. The PCI_STOP# input enables the PCI1:5 outputs when HIGH and causes them to remain at logic 0 when LOW. The PCI_STOP# signal is latched on the rising edge of PCI_F. Its effect takes place on the next PCI_F clock cycle. I/O Dual-Function REF0 and SEL48# Pin. Upon power-up, the state of SEL48# is latched. The state is set by either a 10K resistor to GND or to VDD. A 10K resistor to GND causes pin 14 to provide a 48-MHz clock. If the pin is strapped to VDD, pin 14 will provide a 24-MHz clock. After 2 ms, the pin becomes a high-drive output that produces a copy of 14.318 MHz. I/O Dual-Function REF1 and SPREAD# Pin. Upon power-up, the state of SPREAD# is latched. The state is set by either a 10K resistor to GND or to VDD. A 10K resistor to GND enables Spread Spectrum function. If the pin is strapped to VDD, Spread Spectrum is disabled. After 2 ms, the pin becomes a high-drive output that produces a copy of 14.318 MHz. I/O Dual-Function 24 MHz or 48 MHz Output and Output Enable Input. Upon power-up, the state of pin 14 is latched. The state is set by either a 10K resistor to GND or to VDD. A 10K resistor to GND latches OE LOW, and all outputs are tri-stated. If the pin is strapped to VDD, OE is latched HIGH and all outputs are active. After 2 ms, the pin becomes an output whose frequency is set by the state of pin 27 on power-up. 48 MHz Output. Fixed 48 MHz USB output. Output voltage swing is controlled by voltage applied to VDDQ3. Frequency Selection Input. Select power-up default CPU clock frequency as shown in Table 1. Crystal Connection or External Reference Frequency Input. This pin can either be used as a connection to a crystal or to a reference signal. Crystal Connection. An input connection for an external 14.318 MHz crystal. If using an external reference, this pin must be left unconnected. Power Down Control. When this input is LOW, device goes into a low-power standby condition. All outputs are held LOW. CPU and PCI clock outputs are stopped LOW after completing a full clock cycle (2–3 CPU clock cycle latency). When brought HIGH, CPU and PCI outputs start with a full clock cycle at full operating frequency (3 ms maximum latency). Power Connection. Connected to 3.3V. Power Connection. Power supply for CPU0:1 output buffers. Connected to 2.5V. Ground Connection. Connect all ground pins to the common system ground plane. PCI1:5 5, 6, 9, 10, 11 O PCI_F 4 O CPU_STOP# 18 I PCI_STOP# 20 I REF0/SEL48# 27 I/O REF1/SPREAD# 26 I/O 24/48MHz/OE 14 I/O 48MHz SEL100/66# X1 X2 PWR_DWN# 13 16 2 3 17 O I I I I VDDQ3 VDDQ2 GND 8, 12, 19, 28 25 1, 7, 15, 21, 22 P P G Rev 1.0, November 24, 2006 Page 2 of 8 W137 Overview The W137 was developed to meet the Intel® Mobile Clock specification for the BX chipset, including Super I/O and USB support. The W40S11-02 is the Intel-defined companion part used for driving 2 SDRAM DIMM modules. Please see that data sheet for additional information. Cypress’s proprietary spread spectrum frequency synthesis technique is a feature of the CPU and PCI outputs. When enabled, this feature reduces the peak EMI measurements of not only the output signals and their harmonics, but also of any other clock signals that are properly synchronized to them. The –0.5% modulation profile matches that defined as acceptable in Intel’s clock specification. Upon W137 power-up, the first 2 ms of operation are used for input logic selection. During this period the output buffers are tri-stated, allowing the output strapping resistor on each l/O pin to pull the pin and its associated capacitive clock load to either a logic HIGH or logic LOW state. At the end of the 2-ms period, the established logic 0 or 1 condition of each l/O pin is then latched. Next, the output buffers are enabled, which converts both l/O pins into operating clock outputs. The 2-ms timer is started when VDD reaches 2.0V. The input latches can only be reset by turning VDD off and then back on again. It should be noted that the strapping resistors have no significant effect on clock output signal integrity. The drive impedance of the clock output is