CY2308SI-1

1CY2308 CY2308 3.3V Zero Delay Buffer Features • Zero input-output propagation delay, adjustable by capacitive load on FBK input • Multiple configurations, see “Available CY2308 Configurations” table • Multiple low-skew outputs — Output-output skew less than 200 ps — Device-device skew less than 700 ps — Two banks of four outputs, three-stateable by two select inputs • 10-MHz to 133-MHz operating range • Low jitter, less than 200 ps cycle-cycle (–1, –1H, –4, –5H) • Space-saving 16-pin 150-mil SOIC package or 16-pin TSSOP • 3.3V operation • Industrial Temperature available The CY2308 has two banks of four outputs each, which can be controlled by the Select inputs as shown in the table “Select Input Decoding.” If all output clocks are not required, Bank B can be three-stated. The select inputs also allow the input clock to be directly applied to the output for chip and system testing purposes. The CY2308 PLL enters a power-down state when there are no rising edges on the REF input. In this mode, all outputs are three-stated and the PLL is turned off, resulting in less than 50 µA of current draw. The PLL shuts down in two additional cases as shown in the “Select Input Decoding” table. Multiple CY2308 devices can accept the same input clock and distribute it in a system. In this case, the skew between the outputs of two devices is guaranteed to be less than 700 ps. The CY2308 is available in five different configurations, as shown in the “Available CY2308 Configurations” table on page 2. The CY2308–1 is the base part, where the output frequencies equal the reference if there is no counter in the feedback path. The CY2308–1H is the high-drive version of the –1, and rise and fall times on this device are much faster. The CY2308–2 allows the user to obtain 2X and 1X frequencies on each output bank. The exact configuration and output frequencies depends on which output drives the feedback pin. The CY2308–3 allows the user to obtain 4X and 2X frequencies on the outputs. The CY2308–4 enables the user to obtain 2X clocks on all outputs. Thus, the part is extremely versatile, and can be used in a variety of applications. The CY2308–5H is a high-drive version with REF/2 on both banks. Functional Description The CY2308 is a 3.3V Zero Delay Buffer designed to distribute high-speed clocks in PC, workstation, datacom, telecom, and other high-performance applications. The part has an on-chip PLL which locks to an input clock presented on the REF pin. The PLL feedback is required to be driven into the FBK pin, and can be obtained from one of the outputs. The input-to-output skew is guaranteed to be less than 350 ps, and output-to-output skew is guaranteed to be less than 200 ps. Block Diagram /2 REF Pin Configuration PLL MUX FBK CLKA1 CLKA2 CLKA3 CLKA4 REF CLKA1 CLKA2 VDD GND CLKB1 CLKB2 S2 /2 Extra Divider (–3, –4) Extra Divider (–5H) SOIC Top View 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 S2 S1 FBK CLKA4 CLKA3 VDD GND CLKB4 CLKB3 S1 Select Input Decoding /2 CLKB1 CLKB2 CLKB3 Extra Divider (–2, –3) CLKB4 Cypress Semiconductor Corporation Document #: 38-07146 Rev. *C • 3901 North First Street • San Jose • CA 95134 • 408-943-2600 Revised June 16, 2004 CY2308 Pin Description Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 REF [1] Signal CLKA1[2] CLKA2 VDD GND CLKB1[2] CLKB2 S2[3] S1 [3] [2] [2] [2] Description Input reference frequency, 5V tolerant input Clock output, Bank A Clock output, Bank A 3.3V supply Ground Clock output, Bank B Clock output, Bank B Select input, bit 2 Select input, bit 1 Clock output, Bank B Clock output, Bank B Ground 3.3V supply Clock output, Bank A Clock output, Bank A PLL feedback input CLKB3 GND VDD CLKB4[2] CLKA3[2] CLKA4[2] FBK Select Input Decoding S2 0 0 1 1 S1 0 1 0 1 CLOCK A1–A4 Three-State Driven Driven [4] CLOCK B1–B4 Three-State Three-State Driven[4] Driven Output Source PLL PLL Reference PLL PLL Shutdown Y N Y N Driven Available CY2308 Configurations Device CY2308–1 CY2308–1H CY2308–2 CY2308–2 CY2308–3 CY2308–3 CY2308–4 CY2308–5H Feedback From Bank A or Bank B Bank A or Bank B Bank A Bank B Bank A Bank B Bank A or Bank B Bank A or Bank B Bank A Frequency Reference Reference Reference 2 X Reference 2 X Reference 4 X Reference 2 X Reference Reference /2 Bank B Frequency Reference Reference Reference/2 Reference Reference or Reference[5] 2 X Reference 2 X Reference Reference /2 Notes: 1. Weak pull-down. 2. Weak pull-down on all outputs. 3. Weak pull-ups on these inputs. 4. Outputs inverted on 2308–2 and 2308–3 in bypass mode, S2 = 1 and S1 = 0. 5. Output phase is indeterminant (0° or 180° from input clock). If phase integrity is required, use the CY2308–2. Document #: 38-07146 Rev. *C Page 2 of 14 CY2308 Zero Delay and Skew Control REF. Input to CLKA/CLKB Delay v/s Difference in Loading between FBK pin and CLKA/CLKB Pins To close the feedback loop of the CY2308, the FBK pin can be driven from any of the eight available output pins. The output driving the FBK pin will be driving a total load of 7 pF plus any additional load that it drives. The relative loading of this output (with respect to the remaining outputs) can adjust the inputoutput delay. This is shown in the graph above. For applications requiring zero input-output delay, all outputs including the one providing feedback should be equally loaded. If input-output delay adjustments are required, use the above graph to calculate loading differences between the feedback output and remaining outputs. For zero output-output skew, be sure to load outputs equally. For further information on using CY2308, refer to the application note “CY2308: Zero Delay Buffer.” Maximum Ratings Supply Voltage to Ground Potential ...............–0.5V to +7.0V DC Input Voltage (Except Ref) .............. –0.5V to VDD + 0.5V DC Input Voltage REF ........................................... –0.5 to 7V Storage Temperature.................................. –65°C to +150°C Junction Temperature...................................................150°C Static Discharge Voltage (per MIL-STD-883, Method 3015) ............................. >2000V Operating Conditions for CY2308SC-XX Commercial Temperature Devices Parameter VDD TA CL CIN tPU Supply Voltage Operating Temperature (Ambient Temperature) Load Capacitance, below 100 MHz Load Capacitance, from 100 MHz to 133 MHz Input Capacitance[6] 0.05 Power-up time for all VDDs to reach minimum specified voltage (power ramps must be monotonic) Description Min. 3.0 0 Max. 3.6 70 30 15 7 50 Unit V °C pF pF pF ms Note: 6. Applies to both Ref Clock and FBK. Document #: 38-07146 Rev. *C Page 3 of 14 CY2308 Electrical Characteristics for CY2308SC-XX Commercial Temperature Devices Parameter VIL VIH IIL IIH VOL VOH IDD (PD mode) IDD Description Input LOW Voltage Input HIGH Voltage Input LOW Current Input HIGH Current Output LOW Voltage [7] Test Conditions Min. 2.0 Max. 0.8 Unit V V µA µA V V VIN = 0V VIN = VDD IOL = 8 mA (–1, –2, –3, –4) IOL = 12 mA (–1H, –5H) IOH = –8 mA (–1, –2, –3, –4) IOH = –12 mA (–1H, –5H) Unloaded outputs, 100-MHz REF, Select inputs at VDD or GND Unloaded outputs, 66-MHz REF (–1, –2, –3, –4) Unloaded outputs, 33-MHz REF (–1, –2, –3, –4) 2.4 50.0 100.0 0.4 Output HIGH Voltage[7] Power Down Supply Current REF = 0 MHz Supply Current 12.0 45.0 70.0 (–1H,–5H) 32.0 18.0 µA mA mA mA mA Note: 7. Parameter is guaranteed by design and characterization. Not 100% tested in production. Document #: 38-07146 Rev. *C Page 4 of 14 CY2308 Switching Characteristics for CY2308SC-XX Commercial Temperature Devices [8] Parameter t1 t1 t1 Name Output Frequency Output Frequency Output Frequency Duty Cycle[7] = t2 ÷ t1 (–1, –2, –3, –4, –1H, –5H) Duty Cycle[7] = t2 ÷ t1 (–1, –2, –3, –4, –1H, –5H) t3 t3 t3 t4 t4 t4 t5 Rise Time[7] (–1, –2, –3, –4) Rise Time[7] (–1, –2, –3, –4) Rise Time[7] (–1H, –5H) Fall Time[7] (–1, –2, –3, –4) Fall Time[7] (–1, –2, –3, –4) Fall Time[7] (–1H, –5H) Output to Output Skew on same Bank (–1, –2, –3, –4)[7] Output to Output Skew (–1H, –5H) Test Conditions 30-pF load, All devices 20-pF load, –1H, –5H devices[9] 15-pF load, –1, –2, –3, –4 devices Measured at 1.4V, FOUT = 66.66 MHz 30-pF load Measured at 1.4V, FOUT