CMOS output stages, electrostatic discharge (ESD) protection circuits and input bus-keeper functions are provided that block dc and ac leakage paths within inactive powered-down integrated circuits used in redundant high-reliability system configurations employing cold-sparing to provide backup circuitry. These circuits and methods avoid both undesirable power consumption in a cold-spared backup unit and loading of connected active units when powered down, without compromising performance or functionality of the backup unit when in its active powered state. Inputs and outputs using an analog majority voting principle to implement in-circuit redundancy for on-chip fault tolerance are also provided, incorporating the low-leakage principles of the invention for low power dissipation when powered down. Such on-chip redundancy can harden an IC against various faults, such as single-event effects in high-radiation environments, while maintaining the other advantages in a cold-sparing system.

A transmitter includes a driver circuit configured to drive a channel connected to a first node by controlling a turn-on impedance of a pull-up path, a turn on impedance of a pull-down path, or both according to a plurality of control signals; an encoder configured to generate the plurality of control signals according to a multi-bit data and a calibration signal; and a calibration circuit configured to generate the calibration signal including calibration information corresponding to the plurality of control signals, wherein the encoder determines activation and magnitude of each of the plurality of control signals according to the multi-bit data and the calibration information.

The present disclosure describes embodiments of a write assist circuit. The write assist circuit can include a control circuit and a voltage generator. The control circuit can be configured to receive memory address information associated with a memory write operation for memory cells. The voltage generator can be configured to provide a reference voltage to one or more bitlines coupled to the memory cells. The voltage generator can include two capacitive elements, where during the memory write operation, (i) one of the capacitive elements can be configured to couple the reference voltage to a first negative voltage, and (ii) based on the memory address information, both capacitive elements can be configured to cumulatively couple the reference voltage to a second negative voltage that is lower than the first negative voltage.

A transmitter includes a driver circuit configured to drive a channel connected to a first node by controlling a turn-on impedance of a pull-up path, a turn on impedance of a pull-down path, or both according to a plurality of control signals; an encoder configured to generate the plurality of control signals according to a multi-bit data and a calibration signal; and a calibration circuit configured to generate the calibration signal including calibration information corresponding to the plurality of control signals, wherein the encoder determines activation and magnitude of each of the plurality of control signals according to the multi-bit data and the calibration information.

According to one embodiment, in a semiconductor device, the first pull-up circuit is connected to a third node and to a fourth node. The third node is a node between a drain of the first transistor with a first conductivity type and a source of the second transistor with the first conductivity type. The fourth node is a node between a drain of the third transistor with the first conductivity type, and a source of the fourth transistor with the first conductivity type and a source of the fifth transistor with the first conductivity type. The first pull-down circuit is connected to a fifth node and to a sixth node. The fifth node is a node between a drain of the first transistor with a second conductivity type and a source of the second transistor with the second conductivity type. The sixth node is a node between a drain of the third transistor with the second conductivity type and a source of the fourth transistor with the second conductivity type and a source of the fifth transistor with the second conductivity type.

According to one embodiment, in a semiconductor device, the first pull-up circuit is connected to a third node and to a fourth node. The third node is a node between a drain of the first transistor with a first conductivity type and a source of the second transistor with the first conductivity type. The fourth node is a node between a drain of the third transistor with the first conductivity type, and a source of the fourth transistor with the first conductivity type and a source of the fifth transistor with the first conductivity type. The first pull-down circuit is connected to a fifth node and to a sixth node. The fifth node is a node between a drain of the first transistor with a second conductivity type and a source of the second transistor with the second conductivity type. The sixth node is a node between a drain of the third transistor with the second conductivity type and a source of the fourth transistor with the second conductivity type and a source of the fifth transistor with the second conductivity type.

A write assist circuit can include a control circuit and a voltage generator. The control circuit can be configured to receive memory address information associated with a memory write operation for memory cells. The voltage generator can be configured to provide a reference voltage to one or more bitlines coupled to the memory cells. The voltage generator can include two capacitive elements, where during the memory write operation, (i) one of the capacitive elements can be configured to couple the reference voltage to a first negative voltage, and (ii) based on the memory address information, both capacitive elements can be configured to cumulatively couple the reference voltage to a second negative voltage that is lower than the first negative voltage.

According to one embodiment, in a semiconductor device, the first pull-up circuit is connected to a third node and to a fourth node. The third node is a node between a drain of the first transistor with a first conductivity type and a source of the second transistor with the first conductivity type. The fourth node is a node between a drain of the third transistor with the first conductivity type, and a source of the fourth transistor with the first conductivity type and a source of the fifth transistor with the first conductivity type. The first pull-down circuit is connected to a fifth node and to a sixth node. The fifth node is a node between a drain of the first transistor with a second conductivity type and a source of the second transistor with the second conductivity type. The sixth node is a node between a drain of the third transistor with the second conductivity type and a source of the fourth transistor with the second conductivity type and a source of the fifth transistor with the second conductivity type.

A write assist circuit can include a control circuit and a voltage generator. The control circuit can be configured to receive memory address information associated with a memory write operation for memory cells. The voltage generator can be configured to provide a reference voltage to one or more bitlines coupled to the memory cells. The voltage generator can include two capacitive elements, where during the memory write operation, (i) one of the capacitive elements can be configured to couple the reference voltage to a first negative voltage, and (ii) based on the memory address information, both capacitive elements can be configured to cumulatively couple the reference voltage to a second negative voltage that is lower than the first negative voltage.

The present disclosure describes embodiments of a write assist circuit. The write assist circuit can include a control circuit and a voltage generator. The control circuit can be configured to receive memory address information associated with a memory write operation for memory cells. The voltage generator can be configured to provide a reference voltage to one or more bitlines coupled to the memory cells. The voltage generator can include two capacitive elements, where during the memory write operation, (i) one of the capacitive elements can be configured to couple the reference voltage to a first negative voltage, and (ii) based on the memory address information, both capacitive elements can be configured to cumulatively couple the reference voltage to a second negative voltage that is lower than the first negative voltage.