Method for testing semiconductor integrated circuit device, voltage drop power supply circuit suitable for the method, and semiconductor integrated circuit device having the voltage drop circuit

A voltage drop power supply circuit for a semiconductor integrated circuit device, comprising:

• first means for generating a constant internal power supply voltage from an external power supply voltage in accordance with a first characteristic line defining a relationship between the external power supply voltage and the internal power supply voltage and for applying the constant internal power supply voltage to internal circuits of the semiconductor integrated circuit device;
• and
• second means for generating a burn-in voltage from the external power supply voltage having a level higher than that used in the normal operation in accordance with a second characteristic line defining a relationship between the external power supply voltage and the internal power supply line and for applying the burn-in voltage to the internal circuits when a burn-in test is carried out for the semiconductor integrated circuit device,
• the second characteristic line crossing the first characteristic line at an intermediate point between lower and upper limit voltages defined by the first characteristic line,
• the burn-in voltage being greater than the internal power supply voltage used in the normal operation.

A semiconductor integrated circuit device comprising:

• first internal circuits operating with an external power supply voltage;
• second internal circuits operating with a constant internal power supply voltage obtained by dropping the external power supply voltage;
• first means for generating the constant internal power supply voltage from the external power supply voltage in accordance with a first characteristic line defining a relationship between the external power supply voltage and the internal power supply voltage and for applying the constant internal power supply voltage to the second internal circuits of the semiconductor integrated circuit device;
• and
• second means for generating a burn-in voltage from the external power supply voltage having a level higher than that used in the normal operation in accordance with a second characteristic line defining a relationship between the external power supply voltage and the internal power supply line and for applying the burn-in voltage to the second internal circuits when a burn-in test is carried out for the semiconductor integrated circuit device,
• the second characteristic line crossing the first characteristic line at an intermediate point between lower and upper limit voltages defined by the first characteristic line,
• the burn-in voltage being greater than the internal power supply voltage used in the normal operation.