| 摘要 |
<p>PURPOSE:To make the size of an element compact and prevent an increase in a consumed current with an elevation of a power source voltage by uisng a load MOSFET for performing a constant current operation as a load means of a longitudinal type ROM. CONSTITUTION:In a ROM, of plural memory MOSFETM1-3 connected in series, one column is constituted and other column is also constituted of the plural memory MOSFET connected in series. A drain of one end memory MOSFET constituting the respective columns is made an output side and com monly connected to a P channel type load MOSFETQ1. In order to operate this Q1 by a constant current, a constant voltage Vref formed by voltage generat ing circuits Q2-Q6 is supplied to a gate of the Q1. In this case, by voltage of the sum of Vthn of an N-MOSFETQ3 and Vthp of P-MOSFETQ4 and the difference of Vthip of an enhance ment type P-MOSFETQ2 and Vthpd of a depres sion type P-MOSFETQ6, the constant voltage Vref is formed.</p> |
