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  | CY7C1241V18, CY7C1256V18  | ||
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  | CY7C1243V18, CY7C1245V18 | ||
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Pin Definitions (continued) | |||||||||
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  | Pin Name | IO  | 
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  | CQ  | Echo Clock  | Synchronous Echo Clock Outputs. This is a free running clock and is synchronized to the  | 
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  | input clock (K) of the   | 
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  | istics” on page 23. | 
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  | Echo Clock  | Synchronous Echo Clock Outputs. This is a free running clock and is synchronized to the  | 
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  | input clock (K) of the   | 
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  | istics” on page 23.  | 
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  | ZQ  | Input  | Output Impedance Matching Input. This input is used to tune the device outputs to the system  | 
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  | data bus impedance. CQ, CQ, and Q[x:0] output impedance are set to 0.2 x RQ, where RQ is a  | 
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  | resistor connected between ZQ and ground. Alternatively, this pin can be connected directly to  | 
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  | VDDQ, which enables the minimum impedance mode. This pin cannot be connected directly to  | 
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  | GND or left unconnected.  | 
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  | Input  | DLL Turn Off, Active LOW. Connecting this pin to ground turns off the DLL inside the device.  | 
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  | DOFF | ||||||||
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  | The timing in the DLL turned off operation is different from that listed in this data sheet. For  | 
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  | normal operation, this pin can be connected to a pull up through a 10 Kohm or less pull up  | 
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  | resistor. The device behaves in   | 
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  | can be operated at a frequency of up to 167 MHz with   | 
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  | TDO  | Output  | TDO for JTAG. | 
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  | TCK  | Input  | TCK Pin for JTAG. | 
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  | TDI  | Input  | TDI Pin for JTAG. | 
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  | TMS  | Input  | TMS Pin for JTAG. | 
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  | NC  | N/A  | Not Connected to the Die. Can be tied to any voltage level.  | 
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  | NC/72M  | N/A  | Not Connected to the Die. Can be tied to any voltage level.  | 
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  | NC/144M  | N/A  | Not Connected to the Die. Can be tied to any voltage level.  | 
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  | NC/288M  | N/A  | Not Connected to the Die. Can be tied to any voltage level.  | 
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  | VREF  | Input-  | Reference Voltage Input. Static input used to set the reference level for HSTL inputs, outputs,  | 
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  | Reference  | and AC measurement points.  | 
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  | VDD  | Power Supply  | Power Supply Inputs to the Core of the Device. | 
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  | VSS  | Ground  | Ground for the Device. | 
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  | VDDQ  | Power Supply  | Power Supply Inputs for the Outputs of the Device. | 
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Document Number:   | Page 7 of 28  | 
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