| 摘要 |
PURPOSE: A pattern selecting apparatus is provided to increase a frequency of a pattern data applied to an each pin of the device to be tested without increasing the frequency of the pattern data produced by a pattern producer. CONSTITUTION: A pattern selecting apparatus comprises the k number of pattern selecting circuit(20-1)-(20-k). A pattern datas(Q1)-(Qk) are applied to an each pin of a memory device through a pin electronic circuit from each of the pattern selecting circuit(20-1)-(20-k). A different property of the pattern data is assigned to a signals(S1-1)-(S1-q). Each pattern selecting block maintains an n number of a pattern selecting data in a register so as to choose the pattern data. A clock is applied to a signal(S31-1)-(S31-m) by enabling one of the signals(S4-1)-(S4-n), and the pattern selecting data which is time-divisioned on a signal(S5) is set up as a register. Each pattern selecting block outputs the pattern data as a signal(S7-1)-(S7-m) by selecting and changing the n kinds of pattern selecting data according to a signal(S2). One of signal(S6-1)-(S6-m) switched to m times frequency of the pattern data is high leveled, and choose one of the signal(S7-1)-(S7-m) with an AND gate(31-1)-(31-m). A multiplexed signal(S9-1) with an OR gate(32) is outputted to a certain pin of the device to be tested.
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