Abstract: A device (16) for preventing an input signal (V.sub.I) applied to a terminal (12) of an integrated circuit from damaging a section (18) of the circuit contains a regular enhancement-mode insulated-gate FET (Q1 or Q2), a resistor (R1 or R2) that enables the regular FET to act temporarily like a "floating-gate" FET, and a thick-oxide insulated-gate FET (Q3).
Type:
Grant
Filed:
October 11, 1985
Date of Patent:
November 22, 1988
Assignee:
North American Philips Corporation, Signetics Division
Abstract: Gate sidewall spacers are created by a two-step procedure in fabricating a field-effect transistor using a protective material such as silicon nitride to prevent gate-electrode oxidation. In the first step, a layer (32) of insulating material is conformally deposited and then substantially removed except for small spacer portions (34) adjoining the sidewalls of a doped non-monocrystalline semiconductor layer (20A) destined to become the gate electrode (36). The second step consists of performing an oxidizing heat treatment to increase the thickness of the spacer portions. No significant gate dielectric encroachment occurs. Also, the spacers achieve a profile that substantially avoids electrical shorts.
Type:
Grant
Filed:
October 5, 1987
Date of Patent:
November 22, 1988
Assignee:
North American Philips Corporation, Signetics Division
Abstract: A switching device (22) responsive to an input voltage V.sub.A is powered by low and high internal supply voltages V.sub.L and V.sub.H. The device changes state as V.sub.A -V.sub.L passes a threshold voltage V.sub.T. After the device makes a desired change of state in response to rising V.sub.A, a hysteresis circuit (24) temporarily decreases V.sub.T below that which would otherwise be present. Likewise, after the device makes a desired change of state in the opposite direction when V.sub.A is falling, the hysteresis circuit temporarily decreases V.sub.T. In both cases, V.sub.T later automatically returns to its original value. This dynamic hysteresis prevents spikes in V.sub.L and V.sub.H from causing undesired changes in state.
Type:
Grant
Filed:
November 25, 1986
Date of Patent:
April 26, 1988
Assignee:
North American Philips Corporation, Signetics Division
Abstract: A double-ended code converter (10) contains three or more like-configured amplifiers (T.sub.O -T.sub.M+1). Each has a first flow electrode (E1), a second flow electrode (E2), and a control electrode (CE) for receiving a signal to control charge carriers moving from the first electrode to the second. The first electrodes are coupled to a circuit supply (12) which may be a current source or a voltage supply. The second electrodes are selectively coupled to one or the other of a pair of lines (L.sub.B and L.sub.BN) which are coupled to respective load elements (14.sub.B and 14.sub.BN) to provide a pair of complementary signals (V.sub.B and V.sub.BN).
Type:
Grant
Filed:
September 12, 1986
Date of Patent:
April 12, 1988
Assignee:
North American Philips Corporation, Signetics Division