Analog Devices,inc.

Bruce E Amazeen

Gary Carreau

Michael C W Coln

Christopher Peter Hurrell

Michael C Coln

Alain Valentin Guery

Gerald A Miller

Michael Christian Wohnsen Coln

Cathal Murphy

Scott H Wayne

Mark M Martin

Mick Mueck

An amplifier system can include a feedback amplifier circuit having an amplifier, a feedback capacitor connected between an input terminal and an output terminal of the amplifier by at least one first switch, and a reset capacitor connected across the feedback capacitor by at least one second switch and between a pair of reference voltages by at least one third switch. During an input-signal processing phase of operation, a control circuit may close the at least one first switch and open the at least one second switch to electrically connect the feedback capacitor between the input and output terminals to engage feedback processing by the feedback amplifier circuit, and close the third switch to electrically connect the reset capacitor between the first and second voltages to charge the reset capacitor to a selectable voltage difference. During a reset phase of operation, the control circuit may open the at least one third switch, close the at least one second switch and open the at least one first switch to electrically connect the reset capacitor across the feedback capacitor to reset the feedback capacitor using the reset capacitor. The amplifier system can optionally include a plurality of the feedback amplifier circuits.

Reset and resettable circuits

An SAR analog-to-digital converter performs bit decisions in each of a plurality of clock cycles. A sense circuit monitors signals input to a latch within a comparator of the ADC and, when the signals are sufficient to establish a bit decision, the sense circuit terminates a currently active clock cycle causes a bit decision to occur in advance of a normal expiration of the clock cycle. If the signals are insufficient to establish a bit decision prior to a default expiration time of the clock cycle, the clock cycle concludes at the default expiration time.

Self-timed clocked analog to digital converter

A switched-capacitor circuit for use in analog-to-digital conversion samples an input signal with respect to a reference voltage, without having to generate the reference voltage, by using charge redistribution. The switched-capacitor circuit prevents the need to dissipate power while producing the reference voltage. The switched-capacitor circuit is coupled to a comparator and to a logic circuit which provides control signals for switching. The switched-capacitor circuit comprises a plurality of capacitors arranged according to several embodiments.

Method and apparatus for split reference sampling

A SAR converter having enhanced performance by virtue of effectively pre-loading the SAR's most significant bits with a value that makes the associated DAC output almost equal to the signal to be converted. A normal SAR conversion is then completed with the SAR bits that have not been pre-loaded. The value used to pre-load the most significant bits of the SAR is preferably obtained from a low-resolution, high-speed converter, such as a flash. The range of DAC bits used in the normal SAR part of the conversion may be increased such that errors up to a certain magnitude in the high-speed converter can be corrected. A method for performing an enhanced SAR conversion is also described.

Successive approximation analog-to-digital converter with pre-loaded SAR registers

A dual channel ADC uses two digital to analog converters (DACs) and a single comparator to convert two analog input channels. One DAC is used for successive approximation, while the other DAC is used for calibration. The dual channel ADC allows for sampling and conversion of single-ended, pseudo-differential, and fully differential analog input signals while maintaining layout symmetry and reducing crosstalk without substantially increasing circuit area. The single comparator is used for converting both analog input channels. Additional logic (such as switches or digital logic) is used to connect the input sampling capacitors and DACs to the appropriate inputs of the comparator for converting the analog input channels.

Dual channel analog to digital converter

A multi-stage, low-offset, fast-recovery, comparator system and method for: reducing the input offset voltage of the zeroing amplifier by a factor essentially equal to gain of the zeroing amplifier; reducing the input offset voltage of the combined main and zeroing amplifiers by a factor essentially equal to the product of the gains of the main and zeroing amplifiers; and amplifying the input signal to the amplification stage in accordance with the gain of the main amplifier to generate an amplified high-resolution signal.

Multi-stage, low-offset, fast-recovery, comparator system and method

Quasi-differential successive-approximation methods and structures are provided for converting analog signals into corresponding digital signals. These methods and structures realize the signal-to-noise improvements of fully-differential SAR ADCs and the calibration accuracy improvements of pseudo-differential SAR ADCs. Structures of the invention operate in a fully-differential mode to establish more-significant bits of the corresponding digital signals and in a pseudo-differential mode to establish the less-significant bits.

Quasi-differential successive-approximation structures and methods for converting analog signals into corresponding digital signals

A technique for 'marking' integrated-circuit (IC) chips so that, when large lots of the chips are drift-tested at different temperatues, each chip can be identified positively so as to be associated with the test data accumulated for the particular chip. The technique includes forming additional resistors on each IC chip with the resistors connected in series and to a voltage supply. The resistors are timmed at the wafer stage to produce at nodal points between the resistors voltages having magnitudes which uniquely identify each particular chip, thereby to permit part-identified tests to be performed after the chips have been packaged as parts ready for shipment.

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Ipswich, MA, United States of America

Bruce E Amazeen