CY2308SC-1T

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” on page 3 Multiple low skew outputs Two banks of four outputs, three-stateable by two select inputs 10 MHz to 133 MHz operating range 75 ps typical cycle-to-cycle jitter (15 pF, 66 MHz) Space saving 16-pin 150 mil SOIC package or 16-pin TSSOP 3.3V operation Industrial Temperature available Input Decoding” on page 2”. If all output clocks are not required, Bank B is three-stated. The input clock is directly applied to the output for chip and system testing purposes by the select inputs. 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 table “Select Input Decoding” on page 2. Multiple CY2308 devices accept the same input clock and distribute it in a system. In this case, the skew between the outputs of two devices is less than 700 ps. The CY2308 is available in five different configurations as shown in the table “Available CY2308 Configurations” on page 3. 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 enables the user to obtain 2X and 1X frequencies on each output bank. The exact configuration and output frequencies depend on the output that drives the feedback pin. The CY2308–3 enables 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 is 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 that locks to an input clock presented on the REF pin. The PLL feedback is driven into the FBK pin and obtained from one of the outputs. The input-to-output skew is less than 350 ps and output-to-output skew is less than 200 ps. The CY2308 has two banks of four outputs each that is controlled by the Select inputs as shown in the table “Select Logic Block Diagram /2 REF PLL MUX FBK CLKA1 CLKA2 CLKA3 CLKA4 /2 Extra Divider (–3, –4) Extra Divider (–5H) S2 S1 Select Input Decoding /2 CLKB1 CLKB2 CLKB3 Extra Divider (–2, –3) CLKB4 Cypress Semiconductor Corporation Document Number: 38-07146 Rev. *E • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600 Revised August 03, 2007 [+] Feedback CY2308 Pinouts Figure 1. Pin Diagram - 16 Pin SOIC Top View REF CLKA1 CLKA2 VDD GND CLKB1 CLKB2 S2 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 FBK CLKA4 CLKA3 VDD GND CLKB4 CLKB3 S1 Table 1. Pin Definitions - 16 Pin SOIC Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 REF[1] CLKA1[2] CLKA2 VDD GND CLKB1 S2 [3] [2] [2] Signal 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 [2] [2] Description Input reference frequency, 5V tolerant input CLKB2[2] S1[3] CLKB3[2] CLKB4 GND VDD CLKA3 FBK CLKA4[2] Clock output, Bank A Clock output, Bank A PLL feedback input Select Input Decoding S2 0 0 1 1 S1 0 1 0 1 CLOCK A1–A4 Tri-State Driven Driven [4] CLOCK B1–B4 Tri-State Tri-State Driven[4] Driven Output Source PLL PLL Reference PLL PLL Shutdown Y N Y N Driven 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. Document Number: 38-07146 Rev. *E Page 2 of 15 [+] Feedback CY2308 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 Zero Delay and Skew Control Table 2. REF. Input to CLKA/CLKB Delay Versus Difference in Loading between FBK pin and CLKA/CLKB Pins To close the feedback loop of the CY2308, the FBK pin is driven from any of the eight available output pins. The output driving the FBK pin drives a total load of 7 pF plus any additional load that it drives. The relative loading of this output to the remaining outputs adjusts the input-output delay. This is shown in the Table 2. For applications requiring zero input-output delay, all outputs including the one providing feedback is equally loaded. If input-output delay adjustments are required, use the Zero Delay and Skew Control graph to calculate loading differences between the feedback output and remaining outputs. For zero output-output skew, outputs are loaded equally. For further information on using CY2308, refer to the application note “CY2308: Zero Delay Buffer.” Note 5. Output phase is indeterminant (0° or 180° from input clock). If phase integrity is required, use the CY2308–2. Document Number: 38-07146 Rev. *E Page 3 of 15 [+] Feedback CY2308 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 (MIL-STD-883, Method 3015).................................... >2000V Operating Conditions for 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] Power up time for all VDDs to reach minimum specified voltage (power ramps must be monotonic) Description Min 3.0 0 – – – 0.05 Max 3.6 70 30 15 7 50 Unit V °C pF pF pF ms Electrical Characteristics for 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] Output HIGH Voltage[7] 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) Test Conditions Min – 2.0 – – – 2.4 – – – – – Max 0.8 – 50.0 100.0 0.4 – 12.0 45.0 70.0 (–1H,–5H) 32.0 18.0 Unit V V μA μA V V μA mA mA mA mA Power Down Supply Current REF = 0 MHz Supply Current Note 6. Applies to both Ref Clock and FBK. 7. Parameter is guaranteed by design and characterization. Not 100% tested in production. Document Number: 38-07146 Rev. *E Page 4 of 15 [+] Feedback CY2308 Switching Characteristics for 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