| 摘要 |
PROBLEM TO BE SOLVED: To provide an impedance adjusting device for performing termination operations with an accurate impedance value even in a small area. SOLUTION: The impedance adjusting device includes: a comparison unit 410 configured to compare a reference voltage VREF with the voltage of a calibration node ZQ; a counting unit 420 configured to count an impedance code PCODE <0:N> in response to comparison results UP/DOWN by the comparison unit 410; a reference impedance unit 430 having an impedance value determined according to the impedance code PCODE and connected to the calibration node ZQ; a storage unit 440 configured to store the comparison results by the comparison unit 410 when the generation of the impedance code PCODE has been completed; and a termination unit configured to terminate a given pad with a plurality of parallel resistors 611 to 615 configured to be turned on/off in response to the impedance code PCODE <0:N> and a resistor 616 configured to be turned on/off in response to a signal TRIM stored in the storage unit 440. COPYRIGHT: (C)2011,JPO&INPIT
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