Hysteresis reduced sense amplifier and method of operation
AssigneeMotorola, Inc.
InventorsSteven C. Sullivan, Perry H. Pelley, George P. Hoekstra
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Abstract
A sense amplifier (40) uses a body shorting device (60) to selectively electrically short circuit the bodies of two transistors (44, 48) that function as a differential sensing pair. Equalization of charge injected into the bodies functions to minimize offset voltage between the two bodies. The body shorting device selectively shorts the bodies in response to a body control signal after a sense operation and after asserting a precharging signal to initiate precharging of the sense amplifier's outputs.
Claims20
Sense amplifier circuitry, comprising:
- a plurality of body isolated transistors coupled to provide differential sensing;
- and
- control circuitry having a first terminal coupled to a first body portion of one of the plurality of body isolated transistors, a second terminal coupled to a second body portion of another one of the plurality of body isolated transistors, and a third terminal for receiving a body control signal, the control circuitry selectively coupling the first and second body portions in response to the body control signal.
Sense amplifier circuitry, comprising:
- a first input/output node for receiving a first input signal;
- a first isolated body transistor coupled to the first input/output node;
- a second input/out put node for receiving a second input signal;
- a second isolated body transistor cross-coupled to the first isolated body transistor and coupled to the second input/output node, the first isolated body transistor and the second isolated body transistors coupled to provide an amplified output signal at the first input/output node and the second input/output node;
- and
- a body shorting device coupled between the first isolated body transistor and the second isolated body transistor, the body shorting device being responsive to a body control signal, wherein the body shorting device selectively electrically short circuits a body portion of the first isolated body transistor to a body portion of the second isolated body transistor.
Sense amplifier circuitry, comprising:
- a cross-coupled differential sensing pair of isolated body transistors, each of the pair of isolated body transistors having a body portion to provide body portions susceptible to mismatched charges;
- and
- control circuitry for distributing the mismatched charges of the body portions between each of the pair of isolated body transistors.
A method for operating a sense amplifier having a first input/output node, a second input/output node, a first isolated body transistor cross coupled to a second isolated body transistor to provide differential sensing at the first and second input/output nodes, the first isolated body transistor having a first body voltage and the second isolated body transistor having a second body voltage, the method comprising:
- sensing a read access to the sense amplifier;
- asserting a precharge signal;
- in response to asserting the precharge signal, precharging the first and second input/output nodes to a predetermined voltage level, wherein the first body voltage reaches a first voltage level and the second voltage reaches a second voltage level, different from the first voltage level;
- asserting a body control signal after asserting the precharge signal;
- and
- in response to asserting the body control signal, connecting a body portion of the first isolated body transistor to a body portion of the second isolated body transistor.
Dependencies are inferred from the claim text.