Texas Instruments Corporation

Tanmay Neema

Gautam Salil Nandi

Atul Kumar Agrawal

Rishubh Khurana

Deepak Kumar Meher

Kanak Chandra Das

Siddharth Malhotra

Rajavelu Thinakaran

In described examples, an R2R digital-to-analog converter includes multiple arms and a voltage regulator. Respective arms include an arm switch with a p-channel MOSFET (PFET) switch and an n-channel MOSFET (NFET) switch. The voltage regulator includes a differential amplifier, a p-ladder that includes N cascade-coupled PFETS and has first and second ends, an n-ladder that includes y×N cascade-coupled NFETS and has first and second ends, a first resistor (resistance R), and a second resistor (resistance y×R). The first p-ladder end is coupled to a first terminal of the first resistor. The second terminal of the first resistor is coupled to an input of the differential amplifier and a first terminal of the second resistor. A second terminal of the second resistor is coupled to the first n-ladder end. An output of the differential amplifier is coupled to the second n-ladder end and provides a gate voltage of the NFET switch.

Voltage regulator for switch control

The techniques and circuits, described herein, include solutions for error compensation in source measurement units (SMUs). An example SMU is capable of both sourcing current to a device under test (DUT) and measuring current through the DUT. An SMU may include a sensing resistor coupled in series with the DUT. A voltage across the sensing resistor may be measured by a current sensing amplifier in order to determine the output current through the DUT. In practice, the resistance of the sensing resistor may vary depending on manufacturing tolerances, etc. A gain of the current sensing amplifier may be calibrated in order to compensate for sensing resistor variance, which increases the accuracy with which current to the DUT can be sourced and measured.

Force/measure current gain trimming

In described examples, a digital-to-analog converter includes an output, multiple most significant bit (MSB) connector resistors each having a resistance R−ΔR, multiple least significant bit (LSB) connector resistors each having a resistance R, and multiple binary arm resistors each having a resistance 2R. The MSB connector resistors are coupled in a series beginning with the output and ending with a first one of the LSB connector resistors, and the LSB connector resistors are coupled in a series beginning with the first LSB connector resistor. A terminal of one of the binary arm resistors is coupled to an ending of the LSB connector resistor series, and a terminal of each of different remaining ones of the binary arm resistors is coupled between a different pair of the MSB and/or LSB connector resistors.

Digital-to-analog converter with digitally controlled trim

In described examples, a digital-to-analog converter (DAC) includes an output, a ground, a reference voltage terminal, an input code terminal, multiple switches, multiple resistors, and a controller. The switches couple to the reference voltage terminal when activated and to the ground when deactivated. The resistors are variously coupled between corresponding ones of the switches and the output, so that activating the switches causes the DAC to output an output voltage. The controller is coupled to the input code terminal and coupled to control the switches. The controller generates an output code based on an input code in response to at least one differential nonlinearity error greater than one least significant bit voltage. The input code corresponds to a first ideal output voltage, the output code corresponds to a second, different ideal output voltage. The controller generates an output voltage by controlling the switches using the output code.

An integrated circuit includes a power-on reset (POR) circuit and a digital logic circuit. The POR has first and second control outputs. The POR circuit is configured to generate a first control signal on the first control output responsive to a supply voltage on the supply voltage node exceeding a first threshold voltage and is configured to generate a second control signal on the second control output responsive to the supply voltage exceeding a second threshold voltage. The digital logic circuit has a first control input coupled to the first control output of the POR circuit and has a second control input coupled to the second control output of the POR circuit. The digital logic circuit is configured to initiate a first read transaction responsive to assertion of the first control signal and to initiate a second read transaction responsive to assertion of the second control signal.

Power-on reset circuit

An integrated circuit includes a digital-to-analog converter (DAC) core including a plurality of thermometric arms and an R-2R ladder, the DAC core to convert a DAC code to an analog signal. The integrated circuit includes additional components as well. A differential non-linearity (DNL) calibration circuit outputs DNL coefficients based on the DAC code. A memory stores a value indicative of a product of a resistor temperature coefficient (TC) and a resistor self-heating coefficient (SHC). A current DAC (IDAC) couples to the R-2R ladder. A self-heating calibration circuit generates a self-heating trim code based on the value from the memory. An adder adds a value indicative of the DNL coefficients with the self-heating trim code to generate an IDAC trim code and provides the IDAC trim code to the IDAC to trim the R-2R ladder.

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Indore, India

Tanmay Neema