Samsung Electronics Co., Ltd.

Yong-Bo Park

Hyung-kyu Lim

Hee-Choul Park

Byeong-Yun Kim

Hyung-Kyu Lim

An internal power voltage generating circuit of a semiconductor memory device may be constructed with a voltage sensing circuit (100) and a reference voltage controller (300) providing an internal power voltage int. V.sub.CC of a given reference voltage amplitude V.sub.ref and an external power voltage amplitude ext. V.sub.CC. Thus, when a high voltage over an operating voltage of a chip is applied to a pad (10) of the chip, the internal power voltage is raised to the level of the external power voltage. Therefore, when stress is added to the chip during a 'burn-in-test', the defective chip is easily detected. Consequently, the reliability of those semiconductor memory devices subjected to post-manufacturing testing can be improved.

Electrically programmable internal power voltage generating circuit

A circuit for generating an internal voltage to be supplied to memory elements of a semiconductor memory chip during normal operation and for providing an external voltage to the memory elements during a burn-in test operation. The circuit may be constructed with a driver circuit (50) which receives an external voltage and is controlled to generate the internal voltage. A comparator (300) compares the internal voltage to a first reference voltage to produce a control signal G2 to control the driver circuit (50). An external voltage detector (100) compares a second reference voltage to the external voltage to generate control signal B2. A driver control circuit (200) is enabled by control signal B2, if the external voltage is less than the second reference voltage, to pass control signal G2 to the driver circuit and thereby enable generation of the internal voltage to be equal to, or less than, the operating voltage of the semiconductor memory chip. The driver control circuit is disabled by control signal B2 if the external voltage is greater than the second reference voltage, thereby preventing the control signal G2 of the comparator from controlling conduction by the driver circuit (50) to enable output of the external voltage exhibiting an elevated amplitude to the memory elements for burn-in test operation.

Internal voltage generating circuit

A data output buffer suitable for use in a semiconductor memory device includes a first input circuit coupled to a first data signal and a first control signal, e.g., an output enable signal, and a second input circuit coupled to a second data signal which is the inverse of the first data signal and the first control signal. The data output buffer also includes a pull-up circuit responsive to the output of the first input circuit for selectively raising the data output node to a high voltage level, e.g., Vcc, and a pull-down circuit responsive to the output of the second input circuit for selectively lowering the data output node to a low voltage level, e.g., Vss. The data output buffer further includes a preset circuit comprised of a first preset control circuit responsive to the output of the first input circuit and a second control signal, e.g., an inverse output enable signal, for selectively raising the data output node from the low voltage level to an intermediate voltage level, e.g., 1/2 Vcc, and a second preset control circuit responsive to the output of the second input circuit and the second control signal for selectively lowering the data output node from the high voltage level to the intermediate voltage level. The preset control circuit advantageously operates to maintain the data output node at the intermediate voltage level during active states of the output enable signal without generating any DC current, thereby eliminating the noise and reliability problems of presently available data output buffers.

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Suwon, South Korea

Yong-Bo Park