Abstract: An electrostatic discharge (ESD) protection clamp (21, 21?, 70, 700) for protecting associated devices or circuits (24), comprises a bipolar transistors (21, 21?, 70, 700) in which doping of facing base (75) and collector (86) regions is arranged so that avalanche breakdown occurs preferentially within a portion (84, 85) of the base region (74, 75) of the device (70, 700) away from the overlying dielectric-semiconductor interface (791). Maximum variations (?Vt1)MAX of ESD triggering voltage Vt1 as a function of base-collector spacing dimensions D due, for example, to different azimuthal orientations of transistors (21, 21?, 70, 700) on a semiconductor die or wafer is much reduced. Triggering voltage consistency and manufacturing yield are improved.

Abstract: An electrostatic discharge (ESD) protection device (11, 60, 80) coupled across input-output (I/O) (22) and common (23) terminals of a core circuit (24), comprises, first (70, 90) and second (72, 92) merged bipolar transistors (70, 90; 72, 92). A base (62, 82) of the first (70, 90) transistor serves as collector of the second transistor (72, 92) and the base of the second transistor (72, 92) serves as collector of the first (70, 90) transistor, the bases (62, 82) having, respectively, first width (74, 94) and second width (76, 96). A first resistance (78, 98) is coupled between an emitter (67, 87) and base (62, 82) of the first transistor (70, 90) and a second resistance (79, 99) is coupled between an emitter (68, 88) and base (64, 42) of the second transistor (92, 92). ESD trigger voltage Vt1 and holding voltage Vh can be independently optimized by choosing appropriate base widths (74, 94; 76, 96) and resistances (78, 98; 79, 99).

Abstract: An improved lateral bipolar electrostatic discharge (ESD) protection device (40) comprises a semiconductor (SC) substrate (42), an overlying epitaxial SC layer (44), emitter-collector regions (48, 50) laterally spaced apart by a first distance (52) in the SC layer, a base region (54) adjacent the emitter region (48) extending laterally toward and separated from the collector region (50) by a base-collector spacing (56) that is selected to set the desired trigger voltage Vt1. By providing a buried layer region (49) under the emitter region (48) Ohmically coupled thereto, but not providing a comparable buried layer region (51) under the collector region (50), an asymmetrical structure is obtained in which the DC trigger voltage (Vt1DC) and transient trigger voltage (Vt1TR) are closely matched so that |Vt1TR?Vt1DC|˜0.

Abstract: An electrostatic discharge (ESD) protection clamp (61) for I/O terminals (22, 23) of integrated circuits (ICs) (24) comprises an NPN bipolar transistor (25) coupled to an integrated Zener diode (30). Variations in the break-down current-voltage characteristics (311, 312, 313, 314) of multiple prior art ESD clamps (31) in different parts of the same IC chip is avoided by forming the anode (301) of the Zener (30) in the shape of a base-coupled P+ annular ring (75) surrounded by a spaced-apart N+ annular collector ring (70) for the cathode (302) of the Zener (30).

Abstract: An improved lateral bipolar electrostatic discharge (ESD) protection device (40) comprises a semiconductor (SC) substrate (42), an overlying epitaxial SC layer (44), emitter-collector regions (48, 50) laterally spaced apart by a first distance (52) in the SC layer, a base region (54) adjacent the emitter region (48) extending laterally toward and separated from the collector region (50) by a base-collector spacing (56) that is selected to set the desired trigger voltage Vt1. By providing a buried layer region (49) under the emitter region (48) Ohmically coupled thereto, but not providing a comparable buried layer region (51) under the collector region (50), an asymmetrical structure is obtained in which the DC trigger voltage (Vt1DC) and transient trigger voltage (Vt1TR) are closely matched so that ?Vt1TR?Vt1DC?˜0.

Abstract: An electrostatic discharge (ESD) clamp (41, 51, 61, 71, 81, 91), coupled across input-output (I/O) (22) and common (GND) (23) terminals of a protected semiconductor SC device or IC (24), comprises, an ESD transistor (ESDT) (25) with source-drain (26, 27) coupled between the GND (23) and I/O (22), a first resistor (30) coupled between gate (28) and source (26) and a second resistor (30) coupled between ESDT body (29) and source (26). Paralleling the resistors (30, 32) are control transistors (35, 35?) with gates (38, 38?) coupled to one or more bias supplies Vb, Vb?. The main power rail (Vdd) of the device or IC (24) is a convenient source for Vb, Vb?. When the Vdd is off during shipment, handling, equipment assembly, etc., the ESD trigger voltage Vt1 is low, thereby providing maximum ESD protection when ESD risk is high. When Vdd is energized, Vt1 rises to a value large enough to avoid interference with normal circuit operation but still protect from ESD events.

Abstract: An electrostatic discharge (ESD) protection device (41, 51, 61, 71, 81) coupled across input-output (I/O) (22) and common (23) terminals of a core circuit (24) that it is intended to protect from ESD events, comprises, one or more serially coupled resistor triggered ESD clamp stages (41, 41?, 41?; 71, 71?, 71?), each stage (41, 41+, 41?; 71, 71?, 71?) comprising first (T1, T1?, T1?, etc.) and second transistors (T2, T2?, T2?? etc.) having a common collector (52, 52?, 52?) and first (26, 26?, 26?) and second (36, 36?, 36?) emitters providing terminals (32, 42; 32?, 42?; 32?, 42?) of each clamp stage (41, 41?, 41?; 71, 71?, 71. A first emitter (25) of the first stage (41, 71) couples to the common terminal (23) and a second emitter (42?) of the last stage (41?, 71?) couples to the I/O terminals (22). Zener diode triggers are not used. Integrated external ESD trigger resistors (29, 29?, 29?; 39, 39?, 39?) (e.g.

Abstract: An electrostatic discharge (ESD) protection device (61, 71), coupled across input-output (I/O) (22) and common (23) terminals of a core circuit (24) that it is intended to protect from ESD events, comprises, multiple serially coupled ESD clamp stages (41, 41?), each stage (41, 41?) comprising an interior node (52, 52?) and first (32, 32?) and second terminal (42, 42?) nodes wherein the first terminal node (42) of the first clamp stage (41) is coupled to the common terminal (23) and the second terminal node (42?) of the last clamp stages (41?) is coupled to the I/O terminals (22). A resistance-capacitance ladder (60) is provided in parallel with some of the clamp stages (41, 41?), with a resistance (R1, R2, R3 etc.) coupled to each of the nodes (32, 52, 65 (42; 32?)) of one of the ESD clamp stages (41, 41?) by first terminals thereof and capacitors (C1, C2, etc.) are coupled between second terminals of the resistances (R1, R2, R3 etc.).

Abstract: An electrostatic discharge (ESD) protection clamp (61) for I/O terminals (22, 23) of integrated circuits (ICs) (24) comprises an NPN bipolar transistor (25) coupled to an integrated Zener diode (30). Variations in the break-down current-voltage characteristics (311, 312, 313, 314) of multiple prior art ESD clamps (31) in different parts of the same IC chip is avoided by forming the anode (301) of the Zener (30) in the shape of a base-coupled P+ annular ring (75) surrounded by a spaced-apart N+ annular collector ring (70) for the cathode (302) of the Zener (30).