Abstract: An electronic circuit comprises a digital-to-analog converter (DAC) core circuit having a current source device and a digital input bit. An isolation circuit is also provided and is connected to the DAC core circuit. The isolation circuit is configured to selectively provide a source bias signal to the current source device. The isolation circuit also is configured to isolate the source bias signal from the current source device based on a state of the digital input bit.

Abstract: An electronic circuit comprises a digital-to-analog converter (DAC) core circuit having a current source device and a digital input bit. An isolation circuit is also provided and is connected to the DAC core circuit. The isolation circuit is configured to selectively provide a source bias signal to the current source device. The isolation circuit also is configured to isolate the source bias signal from the current source device based on a state of the digital input bit.

Abstract: An apparatus and method for self-testing a DDR memory interface are disclosed. In one aspect, a built-in-self-test (BIST) memory interface circuit includes a signal multiplier for receiving a first clock signal from a tester and outputs a multiplied clock signal. A first multiplexer is used for selecting between a test mode and a normal operating mode and provides an output signal. A delay magnitude generator is coupled to the signal multiplier to receive the multiplied clock signal and provides a second clock signal and a phase control signal. A plurality of digitally controlled delay line blocks are used for each receiving the second clock signal and the phase control signal and outputting a phase shifted data strobe output signal in response to receiving an internal data strobe input signal. A second multiplexer selects one of the internal data strobe input signals and a third multiplexer selects the phase shifted data strobe output signal that corresponds to the selected internal data strobe input signal.

Abstract: An apparatus and method for self-testing a DDR memory interface are disclosed. In one aspect, a built-in-self-test (BIST) memory interface circuit includes a signal multiplier for receiving a first clock signal from a tester and outputs a multiplied clock signal. A first multiplexer is used for selecting between a test mode and a normal operating mode and provides an output signal. A delay magnitude generator is coupled to the signal multiplier to receive the multiplied clock signal and provides a second clock signal and a phase control signal. A plurality of digitally controlled delay line blocks are used for each receiving the second clock signal and the phase control signal and outputting a phase shifted data strobe output signal in response to receiving an internal data strobe input signal. A second multiplexer selects one of the internal data strobe input signals and a third multiplexer selects the phase shifted data strobe output signal that corresponds to the selected internal data strobe input signal.

Abstract: An apparatus and method for self-testing a DDR memory interface are disclosed. In one aspect, a built-in-self-test (BIST) memory interface circuit includes a signal multiplier for receiving a first clock signal from a tester and outputs a multiplied clock signal. A first multiplexer is used for selecting between a test mode and a normal operating mode and provides an output signal. A delay magnitude generator is coupled to the signal multiplier to receive the multiplied clock signal and provides a second clock signal and a phase control signal. A plurality of digitally controlled delay line blocks are used for each receiving the second clock signal and the phase control signal and outputting a phase shifted data strobe output signal in response to receiving an internal data strobe input signal. A second multiplexer selects one of the internal data strobe input signals and a third multiplexer selects the phase shifted data strobe output signal that corresponds to the selected internal data strobe input signal.

Abstract: An apparatus and method for self-testing a DDR memory interface are disclosed. In one aspect, a built-in-self-test (BIST) memory interface circuit includes a signal multiplier for receiving a first clock signal from a tester and outputs a multiplied clock signal. A first multiplexer is used for selecting between a test mode and a normal operating mode and provides an output signal. A delay magnitude generator is coupled to the signal multiplier to receive the multiplied clock signal and provides a second clock signal and a phase control signal. A plurality of digitally controlled delay line blocks are used for each receiving the second clock signal and the phase control signal and outputting a phase shifted data strobe output signal in response to receiving an internal data strobe input signal. A second multiplexer selects one of the internal data strobe input signals and a third multiplexer selects the phase shifted data strobe output signal that corresponds to the selected internal data strobe input signal.

Abstract: An apparatus and method for self-testing a DDR memory interface are disclosed. In one aspect, a built-in-self-test (BIST) memory interface circuit includes a signal multiplier for receiving a first clock signal from a tester and outputs a multiplied clock signal. A first multiplexer is used for selecting between a test mode and a normal operating mode and provides an output signal. A delay magnitude generator is coupled to the signal multiplier to receive the multiplied clock signal and provides a second clock signal and a phase control signal. A plurality of digitally controlled delay line blocks are used for each receiving the second clock signal and the phase control signal and outputting a phase shifted data strobe output signal in response to receiving an internal data strobe input signal. A second multiplexer selects one of the internal data strobe input signals and a third multiplexer selects the phase shifted data strobe output signal that corresponds to the selected internal data strobe input signal.

Abstract: An apparatus and method for self-testing a DDR memory interface are disclosed. In one aspect, a built-in-self-test (BIST) memory interface circuit comprises a signal multiplier for receiving a first clock signal from a tester and outputs a multiplied clock signal. A first multiplexer is used for selecting between a test mode and a normal operating mode and provides an output signal. A delay magnitude generator is coupled to the signal multiplier to receive the multiplied clock signal and provides a second clock signal and a phase control signal. A plurality of digitally controlled delay line blocks are used for each receiving the second clock signal and the phase control signal and outputting a plurality of sequential input/output bit-pair signals corresponding to an internal data strobe input signal and a phase shifted data strobe output signal respectively.

Abstract: An apparatus and method for self-testing a DDR memory interface are disclosed. In one aspect, a built-in-self-test (BIST) memory interface circuit comprises a signal multiplier for receiving a first clock signal from a tester and outputs a multiplied clock signal. A first multiplexer is used for selecting between a test mode and a normal operating mode and provides an output signal. A delay magnitude generator is coupled to the signal multiplier to receive the multiplied clock signal and provides a second clock signal and a phase control signal. A plurality of digitally controlled delay line blocks are used for each receiving the second clock signal and the phase control signal and outputting a plurality of sequential input/output bit-pair signals corresponding to an internal data strobe input signal and a phase shifted data strobe output signal respectively.