Texas Instruments Corporation

Rajendrakumar Joish

Visvesvaraya Appala Pentakota

Shagun Dusad

Jawaharlal Tangudu

Neeraj Shrivastava

Viswanathan Nagarajan

Chandrasekhar Sriram

Himanshu Varshney

Karthik Khanna S

The disclosure provides an amplifier. The amplifier includes a first transistor that receives a first input and generates a first load current. A first output node is coupled to a power supply through a first load resistor. The first load resistor receives the first load current. A first capacitor network is coupled to the first output node and draws a first capacitive current from the first output node. A first current buffer is coupled between the first output node and the first transistor. A current through the first current buffer is a summation of the first load current and the first capacitive current.

Programmable filter in an amplifier

A circuit for digital filtering an analog signal converted to digital, including an analog circuit to generate an analog signal, the analog signal including phase and/or gain errors. An analog-to-digital converter (ADC) to convert the analog signal to a digital signal output to a digital signal path. A frequency-dependent corrector filter included in the digital signal path, and configured as a parameterized filter, the parameterized filter configurable based on the DSA control signal with at least one complex filter parameter for each DSA attenuation step, to correct frequency-dependent errors in phase and/or gain.

Digital filtering for analog gain/phase errors

The disclosure provides an RF receiver. The RF receiver includes an input driver. The input driver receives a coarse signal, and generates an input signal. A digital step attenuator (DSA) is coupled to the input driver and receives the input signal. An analog to digital converter (ADC) is coupled to the DSA. The DSA includes a serial capacitor coupled to the input driver. The DSA also includes a sampling capacitor coupled to the ADC.

Switched capacitor based digital step attenuator

A digital step attenuator (DSA) includes a switch control circuit which receives the attenuated signal output by the DSA from a buffer and generates a tracked control signal for switches within the DSA. Some switch control circuits include a capacitor coupled to receive the buffered signal, a supply voltage, and a switch control logic sub-circuit for each switch. Each switch control logic sub-circuit receives a control signal, for either the gate or the bulk terminal of the switch, and generates the tracked control signal. In other embodiments, switch control circuits include a complementary MOSFET switching device coupled to receive a control signal, and a capacitor coupled to receive the buffered signal, both of which are connected to an output terminal for the tracked control signal. In those embodiments, the DSA includes a switch control circuit for each switch connected to the DSA output.

Continuous time linear capacitive digital step attenuator

Pipelined analog-to-digital converters (ADCs) include a flash ADC that reduces noise tones in power supply current drawn by the flash ADC. A pipelined analog-to-digital converter (ADC) includes a flash ADC and error correction circuitry coupled to the flash ADC. The flash ADC includes a plurality of latched comparators and a plurality of driver circuits. Each of the latched comparators includes an inverting output and a non-inverting output. Each of the driver circuits is coupled to one of the latched comparators, and includes an input terminal and an output terminal. In a first subset of the driver circuits the input terminal is coupled to the inverting output of one of the latched comparators. In a second subset of the driver circuits the input terminal is coupled to the non-inverting output of one of the latched comparators.

Pipelined analog-to-digital converter

The disclosure provides an RF receiver. The RF receiver includes an input driver. The input driver receives a coarse signal, and generates an input signal. A digital step attenuator (DSA) is coupled to the input driver and receives the input signal. An analog to digital converter (ADC) is coupled to the DSA. The DSA includes a sampling capacitor coupled to the ADC. The DSA also includes a time dependent resistor coupled to a source voltage and to the sampling capacitor.

Fast transient settling in a digital step attenuator

The disclosure provides an amplifier. The amplifier includes a first transistor that receives a first input. A second transistor receives a second input. A plurality of impedance networks is coupled between the first transistor and the second transistor. At least one impedance network of the plurality of impedance networks includes a first impedance path and a second impedance path. The first impedance path is activated during single ended operation, and the second impedance path is activated during differential operation.

Programmable impedance network in an amplifier

The disclosure provides a circuit. The circuit includes a gain stage block. The gain stage block is coupled to an input voltage through a first switch. A first capacitor is coupled between the first switch and a ground terminal. A second capacitor is coupled between the first switch and a second switch. A third switch is coupled between the second capacitor and a fixed terminal of the gain stage block.

Switched capacitor gain stage

A programmable (multistep) resistor attenuator architecture (such as for input to a differential amplifier) provides cancellation for harmonic distortion currents. An attenuation node is coupled: (a) to an input node through R; (b) to a virtual ground through kR and a virtual ground switch Swf with on-resistance Rswf; and (c) to a differential ground through mR and a differential ground switch Swp with on-resistance Rswp. Swp can be sized relative to Swf such that a component Ipnf of Ipn through Rswp and mR to the attenuation node, and branching into kR and Rswf, matches (phase/magnitude), a harmonic current Ifn from the virtual ground through Rswf and kR to the attenuation node. Harmonic distortion cancelation at the virtual ground can be based on matching switches Swf and Swp and the resistors R, mR, kR, reducing sensitivity to PVT variations, input frequency and amplitude. The attenuator architecture is extendable to multistage configurations.

Resistor attenuator with switch distortion cancellation

Disclosed examples include a programmable attenuator circuit providing selective cross coupling of impedance components between circuit input nodes and output nodes according to control signals to set or adjust an attenuation value of the attenuator circuit. The attenuator circuit includes a plurality of attenuator impedance components, and a switching circuit to selectively connect at least a first attenuator impedance component between the first input node and the second output node, to selectively connect at least a second attenuator impedance component between the second input node and the first output node, to selectively connect a third attenuator impedance component between the first input node and the first output node, and to selectively connect a fourth attenuator impedance component between the second input node and the second output node.

Programmable step attenuator with cross connection

A circuit includes an amplifier circuit that receives a residue voltage from an output capacitor connected to an output of a digital to analog converter (DAC). The DAC is employed in a pipeline stage of an analog to digital converter (ADC). The amplifier circuit provides a scaled output voltage based on the residue voltage. A sample circuit samples the scaled output voltage during a first portion of a hold phase of the DAC. A discharge circuit supplies the sampled scaled output voltage to the output of the DAC during a second portion of the hold phase of the DAC to mitigate settling time of the DAC.

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Bengaluru, India

Rajendrakumar Joish