SEMICONDUCTOR DEVICE, MONITORING METHOD FOR VOLTAGE OF INTERNAL POWER SOURCE LINE, AND METHOD FOR DISCRIMINATING TEST MODE

摘要

PROBLEM TO BE SOLVED: To monitor the potential of an internal power source line without probing directly to it.;SOLUTION: A monitor circuit 110 is connected between an external pin EP receiving a signal or the prescribed potential and an internal power source line L2. The monitor circuit 110 comprises N channel MOS transistors QN1-QN3. The transistors QN1-QN3 are connected in series between the external pin EP and the internal power source line L2. Threshold voltage of the transistors QN1-QN3 is assumed to be Vth. First, a standby current flowing through the power source pin receiving the external power source voltage and a ground pin receiving a ground potential is measured. And a potential of the external pin EP is boosted gradually while monitoring a current flowing through the power source pin and the ground pin. If potential of the external pin EP at the time when a current flowing through the power source pin and the ground pin is started to boost is assumed to be VEXT, a potential VINT of the internal power source line L2 is obtained by the equation: VINT=VEXT-3.Vth.;COPYRIGHT: (C)2001,JPO