Analyzing and monitoring aging and performance degradation in fast analog mixed signal converters

Abstract

An integrated circuit (20) includes a digital area (24) including digital circuitry, an analog area (28) including analog circuitry, and an analog-mixed-signal area (32) including at least one signal converter. The integrated circuit further includes a plurality of monitor circuits (36, 40, 44) distributed across the digital area, the analog area, and the analog-mixed-signal area. The monitor circuits are configured to generate measurement data indicative of performance characteristics of the digital circuitry, the analog circuitry, and the at least one signal converter. The integrated circuit further includes a processor (48) configured to receive the measurement data from the plurality of monitor circuits, to estimate a degradation based on the measurement data, and to initiate a responsive action based on the estimated degradation.

Description

[0001] ANALYZING AND MONITORING AGING AND PERFORMANCE DEGRADATION IN FAST ANALOG MIXED SIGNAL CONVERTERS CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application 63 / 778,454, filed March 27, 2025, whose disclosure is incorporated herein by reference.

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates generally to integrated circuit performance monitoring and compensation, and more particularly but not exclusively to systems and methods for analyzing aging effects and performance degradation in analog, digital, and analog-mixed-signal circuits.

[0004] BACKGROUND OF THE INVENTION

[0005] High-speed Application-Specific Integrated Circuits (ASICs) incorporate a variety of circuit types, including digital circuits, analog circuits, and analog-mixed-signal circuits. Digital circuits are typically constructed from PMOS and NMOS transistors arranged in various gate configurations, while analog circuits may include temperature sensors, voltage references, and amplifiers. Analog-mixed-signal circuits, such as high-speed Analog-to-Digital Converters (ADCs) and Digital-to-Analog Converters (DACs), bridge the analog and digital domains by converting signals between these two representations.

[0006] Active components in CMOS and BiCMOS technologies, such as transistors, experience changes in their electrical characteristics over time during operation. Passive components including resistors, capacitors, inductors, and metal interconnects may also exhibit changes in their performance characteristics as the integrated circuit operates over extended periods. These changes can affect various circuit parameters, including threshold voltages, switching speeds, and signal integrity.

[0007] Digital circuits typically rely on timing margins, including setup time and hold time margins, to operate correctly. These timing margins provide tolerance for variations in signal propagation delays and ensure that data is captured reliably by sequential elements such as flip-flops and registers. The timing characteristics of digital circuits can be influenced by operating conditions including temperature, supply voltage, and process variations.

[0008] Analog circuits commonly employ temperature compensation techniques using Proportional To Absolute Temperature (PTAT) and Complementary To Absolute Temperature (CTAT) circuit configurations. PTAT circuits generate outputs that increase with temperature,while CTAT circuits generate outputs that decrease with temperature. By combining these outputs with appropriate scaling factors, designers can create temperature sensors or stable voltage references, such as bandgap references, that maintain relatively constant output across variations in process, temperature, and voltage conditions.

[0009] High-speed ADCs and DACs frequently employ time-interleaved architectures in which multiple lower-speed converter sub-blocks operate in parallel to achieve aggregate conversion rates that exceed the capability of individual converters. For example, an array of Successive Approximation Register (SAR) ADCs operating in a time-interleaved configuration can collectively process high-speed input signals by having each individual ADC convert a different time slice of the input waveform.

[0010] Monitoring the operational status and performance characteristics of integrated circuits can provide information regarding circuit health and operating conditions. Various approaches exist for measuring and tracking circuit parameters, including the use of ring oscillators for characterizing digital circuit timing and the use of reference circuits for monitoring analog performance metrics.

[0011] SUMMARY OF THE INVENTION

[0012] An embodiment of the present invention that is described herein provides an integrated circuit including a digital area including digital circuitry, an analog area including analog circuitry, and an analog-mixed-signal area including at least one signal converter. The integrated circuit further includes a plurality of monitor circuits distributed across the digital area, the analog area, and the analog-mixed-signal area. The monitor circuits are configured to generate measurement data indicative of performance characteristics of the digital circuitry, the analog circuitry, and the at least one signal converter. The integrated circuit further includes a processor configured to receive the measurement data from the plurality of monitor circuits, to estimate a degradation based on the measurement data, and to initiate a responsive action based on the estimated degradation.

[0013] In some embodiments, the degradation includes one or both of (i) aging and (ii) performance degradation. In some embodiments, the responsive action includes one or both of (i) adjusting an operation of the integrated circuit and (ii) issuing an alert.

[0014] In an example embodiment, the at least one signal converter includes a plurality of converter sub-blocks operating in a time-interleaved configuration, the plurality of monitor circuits includes at least one replica converter structurally matching the converter sub-blocks,and the processor is configured to estimate differential aging among the converter sub-blocks based on measurement data from the at least one replica converter.

[0015] In a disclosed embodiment, the processor is configured to accumulate at least some of the measurement data in a non-volatile memory over multiple operational cycles of the integrated circuit, and to estimate the degradation based on the accumulated measurement data.

[0016] In an example embodiment, the processor is configured to construct a cumulative aging profile based on measurement data collected over multiple operational cycles of the integrated circuit.

[0017] In an embodiment, the processor is configured to apply a predictive aging model to measurement data collected over multiple operational cycles of the integrated circuit, so as to forecast future performance degradation of the integrated circuit.

[0018] There is additionally provided, in accordance with an embodiment that is described herein, a method including receiving measurement data from a plurality of monitor circuits distributed across an integrated circuit that includes a digital area including digital circuitry, an analog area including analog circuitry and an analog-mixed-signal area including at least one signal converter. The measurement data is indicative of performance characteristics of the digital circuitry, the analog circuitry, and the at least one ADC. A degradation is estimated based on the measurement data. A responsive action is initiated based on the estimated degradation.

[0019] The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which:

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Fig. 1 is a block diagram that schematically illustrates an ASIC configured for monitoring aging and performance degradation, in accordance with an embodiment that is described herein;

[0022] Fig. 2 is a graph that schematically illustrates estimation of temperature and generation of reference voltage using PTAT and CTAT characteristics, in accordance with an embodiment that is described herein;

[0023] Fig. 3 is a circuit diagram that schematically illustrates a monitoring circuit within the analog area of the ASIC of Fig. 1, in accordance with an embodiment that is described herein;

[0024] Fig. 4 is a circuit diagram that schematically illustrates a monitoring circuit within the digital area of the ASIC of Fig. 1, in accordance with an embodiment that is described herein;Fig. 5 is a block diagram that schematically illustrates a monitoring circuit for a time-interleaved ADC within the analog-mixed-signal area of the ASIC of Fig. 1, in accordance with an embodiment that is described herein; and

[0025] Fig. 6 is a flow chart that schematically illustrates a method for monitoring and adjusting ASIC operation based on aging and performance degradation, in accordance with an embodiment that is described herein.

[0026] DETAILED DESCRIPTION OF EMBODIMENTS

[0027] OVERVIEW

[0028] High-speed ASICs incorporating digital, analog, and analog-mixed-signal circuits face significant challenges related to the degradation of circuit performance over time. Active components such as CMOS and BiCMOS transistors experience aging effects that alter their electrical characteristics during extended operation, while passive components including resistors, capacitors, inductors, and metal interconnects also exhibit performance changes. These degradation phenomena can compromise the reliability and accuracy of critical circuit functions, potentially leading to unexpected failures without prior warning.

[0029] In digital circuits, aging can reduce setup and hold time margins that are essential for correct operation, leading to timing violations and data errors. In analog circuits, drift in component characteristics can affect the accuracy of temperature sensors, voltage references, and amplifiers. In analog-mixed-signal circuits such as high-speed ADCs and DACs, performance degradation can manifest as reduced conversion accuracy, increased noise, or timing mismatches among parallel converter sub-blocks. Conventional approaches to addressing these issues often lack comprehensive monitoring across all circuit domains within an ASIC, making it difficult to detect and compensate for degradation before critical failures occur.

[0030] Embodiments that are described herein address these challenges by providing a system and method for monitoring aging effects and performance degradation across digital, analog, and analog-mixed-signal areas of an ASIC. In some embodiments, the system includes a plurality of monitor circuits distributed throughout the various functional areas of the ASIC, with each monitor circuit configured to generate measurement data indicative of performance characteristics specific to its respective circuit domain.

[0031] In an example implementation, analog monitor circuits utilize PTAT and CTAT circuit configurations to track temperature-dependent voltage characteristics, enabling detection of process drift over time by comparing measured parameters against expected values. In certainembodiments, digital monitor circuits employ ring oscillator configurations with associated logic gates to evaluate timing characteristics such as setup and hold time margins under current operating conditions. In some embodiments, analog-mixed-signal monitor circuits include replica converter sub-blocks that operate in parallel with active converters, enabling continuous performance monitoring without interrupting primary data conversion operations.

[0032] In certain embodiments, a processor receives measurement data from the distributed monitor circuits and estimates degradation based on the collected information. The estimated degradation may be attributed to aging or to performance degradation of any other suitable type. Upon detecting excessive degradation, the processor may initiate a suitable responsive action, e.g., adjust operation of the ASIC or issue an alert.

[0033] The processor may accumulate measurement data in non-volatile memory over multiple operational cycles to construct a cumulative aging profile that tracks performance changes throughout the operational lifetime of the ASIC. In some embodiments, the processor applies a predictive aging model to the accumulated measurement data to forecast future performance degradation and estimate remaining operational time before performance falls below acceptable thresholds.

[0034] The disclosed solution advantageously provides comprehensive coverage for detecting aging-related performance changes across all circuit types present within an ASIC, enabling proactive compensation or alerting before critical failures occur. By distributing monitor circuits throughout the digital, analog, and analog-mixed-signal areas, the ASIC captures degradation information specific to each circuit domain while maintaining minimal overhead on the primary circuit functions. The use of replica converter sub-blocks in time-interleaved ADC configurations enables continuous monitoring with overhead that does not exceed a small fraction of the total converter array. The accumulation of measurement data across power cycles and the application of predictive models enable the ASIC to extend its operational lifetime beyond what would be achievable through reactive correction alone.

[0035] SYSTEM DESCRIPTION

[0036] Fig. 1 is a block diagram that schematically illustrates an ASIC 20 configured for monitoring aging and performance degradation, in accordance with an embodiment that is described herein. ASIC 20 comprises three distinct functional regions: a digital area 24, an analog area 28, and an analog-mixed-signal area 32. Digital area 24 contains digital circuitry constructed from logic gates and sequential elements. Analog area 28 houses analog circuitry including, for example, temperature sensors, voltage references, and amplifiers. Analog-mixed-signal area 32 contains circuits that process both analog and digital signals, such as high-speed ADCs and DACs.

[0037] ASIC 20 comprises a plurality of monitor circuits distributed across the various functional areas to provide comprehensive coverage for detecting performance degradation. One or more digital monitor circuits 36 are positioned within digital area 24 to measure timing characteristics and detect aging effects in the digital circuitry. One or more analog monitor circuits 40 are positioned within analog area 28 to track analog circuit performance by measuring temperature-dependent voltage characteristics and reference voltage stability. In some embodiments, analog monitor circuits 40 are not limited to analog area 28 and may be positioned in other areas of ASIC 20. One or more analog-mixed-signal monitors 44 are located within analog-mixed-signal area 32 to monitor the performance of signal converters and detect degradation in conversion accuracy or timing alignment. In some embodiments, analog-mixed-signal monitor circuits 44 are not limited to analog-mixed-signal area 32 and may be positioned in other areas of ASIC 20.

[0038] A monitor DSP 48 is positioned within digital area 24 and is configured to receive measurement data from digital monitor circuits 36, analog monitor circuits 40, and analog-mixed-signal monitor circuits 44. Monitor DSP 48 processes the collected measurement information to estimate aging and performance degradation across the various circuit domains of ASIC 20. In various embodiments, monitor DSP 48 may comprise a regular controller, an analog controller, or a fully featured DSP. The control circuitry implemented by monitor DSP 48 may be centralized within a single processing block, or may be distributed across multiple processing elements within ASIC 20.

[0039] Based on the estimated degradation, monitor DSP 48 may initiate responsive actions such as adjusting operating parameters of ASIC 20, reconfiguring circuit settings, or issuing alerts to external systems or to a user. Monitor DSP 48 may also accumulate measurement data in non-volatile memory over multiple operational cycles to construct a cumulative aging profile and apply predictive aging models to forecast future performance degradation.

[0040] Monitor DSP 48 is considered a non-limiting example of a processor. The disclosed techniques can be carried out by any other suitable type of processor. In various embodiments, the functions of monitor DSP 48 may be implemented using suitable hardware, using software, or using a combination of hardware and software elements. The disclosed techniques are not limited to ASICS, and can be used in various other types of integrated circuits. In some embodiments, DSP 48 comprises a general-purpose processor, which is programmed in software to carry out the functions described herein. The software may be downloaded to theprocessor in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and / or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory.

[0041] The configuration of ASIC 20, as illustrated in Fig. 1, is an example configuration that is chosen purely for the sake of conceptual clarity. In alternative embodiments, any other suitable configuration can be used. For example, the ASIC may comprise only a subset of the types of monitor circuits, e.g., only digital monitors 36 and analog-mixed-signal monitors 44.

[0042] ANALOG MONITORING

[0043] Fig. 2 is a graph that schematically illustrates estimation of temperature and generation of reference voltage using PTAT and CTAT characteristics, in accordance with an embodiment that is described herein. The graph depicts voltage V as a function of temperature T, showing relationships between various voltage outputs that may be generated by analog monitor circuits 40.

[0044] A curve 52 represents a PTAT voltage that increases linearly with increasing temperature. A curve 64 represents a CTAT voltage that decreases linearly with increasing temperature. These two fundamental voltage characteristics form the basis for temperature sensing and reference voltage generation within ASIC 20.

[0045] A curve 60 represents the sum of a scaled PTAT voltage and a scaled CTAT voltage, expressed as KlxPTAT+K2*CTAT, where KI and K2 are scaling coefficients. This combined output produces a voltage that varies linearly with temperature and can be used for temperature sensing applications. By monitoring curve 60 over time, analog monitor circuits 40 can track temperature variations and detect drift in the underlying PTAT and CTAT circuit characteristics that may indicate aging effects.

[0046] A curve 56 represents the difference between a scaled PTAT voltage and a scaled CTAT voltage, expressed as K3xPTAT-K4*CTAT, where K3 and K4 are scaling coefficients selected to produce a temperature-independent reference voltage. This output, commonly known as a bandgap voltage, remains substantially constant across temperature variations and provides a stable reference for monitoring process drift and aging effects in analog area 28.

[0047] Fig. 3 is a circuit diagram that schematically illustrates a monitoring circuit within analog area 28 of ASIC 20, in accordance with an embodiment that is described herein. The monitoring circuit implements the PTAT and CTAT voltage generation and processing described above with reference to Fig. 2.The monitoring circuit comprises a PTAT circuit 68 that generates an output voltage VpTAT proportional to absolute temperature, corresponding to curve 52 of Fig. 2. A CTAT circuit 72 generates an output voltage VcTAT that varies inversely with temperature, corresponding to curve 64 of Fig. 2.

[0048] The output of PTAT circuit 68 is provided to a plurality of amplifiers 76 that apply respective gain factors to the VpTAT signal. In the depicted configuration, amplifiers 76 labeled Al and A2 produce scaled outputs Al* VpTAT and A2* VpTAT, respectively. Similarly, the output of CTAT circuit 72 is provided to additional amplifiers 76 labeled A3 and A4, which produce scaled outputs A3* VCTAT and A4* VCTAT, respectively.

[0049] The monitoring circuit further comprises a plurality of differential amplifiers 80 that combine the scaled PTAT and CTAT voltages to produce temperature sensing and reference voltage outputs. A first differential amplifier 80 combines outputs from amplifiers Al and A2 to produce a temperature sensing voltage Vtemp sensl- A second differential amplifier 80 combines outputs from amplifiers A2 and A3 to generate a reference voltage Vreference, which corresponds to curve 56 of Fig. 2 and provides a stable bandgap voltage that remains substantially constant across temperature variations. A third differential amplifier 80 combines outputs from amplifiers A3 and A4 to produce a second temperature sensing voltage Vtemp_sens2- In total, the circuit of Fig. 3 produces seven output voltages: Al* VpTAT, Vtemp sensL A2XVp AT, Vreference, A3xVCTAT, Vtemp_sens2, and A4XVCTAT- The various output voltages of the circuit of Fig. 3 (or digitized values thereof) are typically provided to monitoring DSP 48. By monitoring the temperature sense voltages and / or reference voltage over time, DSP 48 can track temperature variations, detect process drift, and identify aging effects in the analog circuitry. Deviations from expected voltage characteristics may indicate degradation that warrants a responsive action.

[0050] DIGITAL MONITORING

[0051] Fig. 4 is a circuit diagram that schematically illustrates a monitoring circuit within digital area 24 of ASIC 20 of Fig. 1, in accordance with an embodiment that is described herein. The monitoring circuit employs a ring oscillator configuration with associated logic gates to evaluate timing characteristics of the digital circuitry.The monitoring circuit comprises a chain of inverters 84, labeled Inv#l through Inv#101, connected in series to form a ring oscillator. Each inverter 84 receives an input from the preceding inverter and provides an output to the subsequent inverter, creating an oscillating signal that propagates through the chain. The oscillation frequency of this ring oscillator is dependent on the propagation delay of each inverter 84, which in turn is affected by operating conditions including temperature, supply voltage, and process variations, as well as aging effects that accumulate over time.

[0052] The monitoring circuit further comprises a plurality of XOR gates 88, labeled XOR #1 through XOR #100, arranged to compare signal timing at different points along the inverter chain. Each XOR gate 88 receives two inputs: one input from the output of Inv#l and another input from the output of a corresponding inverter in the chain. For example, XOR #1 receives inputs from Inv#l and Inv#2, XOR #2 receives inputs from Inv#l and Inv#3, and this pattern continues through XOR #100, which receives inputs from Inv#l and Inv#101. This configuration enables measurement of timing relationships between signals at different stages of the inverter chain.

[0053] A digital analysis circuit 92 receives outputs from the inverter chain, the XOR gates 88, and an external clock signal. Digital analysis circuit 92 processes these signals to evaluate setup and hold time margins under current operating conditions. By comparing the oscillation frequency of the ring oscillator against a known reference clock frequency, digital analysis circuit 92 can calculate operating conditions and detect changes in timing characteristics that may indicate aging or performance degradation.

[0054] The outputs of digital analysis circuit 92 are provided to monitor DSP 48, which uses this information in conjunction with data from analog monitor circuits 40 and analog-mixed-signal monitor circuits 44 to estimate overall degradation of ASIC 20. Changes in the measured timing characteristics over time may indicate aging effects in the digital circuitry that warrant adjustment of operating parameters or issuance of an alert.

[0055] The configuration of the digital monitoring circuit, as illustrated in Fig. 4, is an example configuration that is chosen purely for the sake of conceptual clarity. In alternative embodiments, any other suitable configuration can be used. For example, the number of inverters 84 and XOR gates 88 may be varied depending on the desired measurement resolution and circuit area constraints. Other types of logic gates, e.g., OR, AND or higher-complexity logic functions, can be used instead of or in addition to XOR gates 88. Digital analysis circuit 92 may implement various signal processing techniques for extracting timing information from the monitored signals.In some embodiments, digital monitor circuits 36 comprise more complex designs that mirror the actual digital design of ASIC 20, in addition to or instead of ring oscillator configurations, to more accurately reflect the aging behavior of the operational digital circuitry.

[0056] ANALOG-MIXED-SIGNAL MONITORING

[0057] Fig. 5 is a block diagram that schematically illustrates a monitoring circuit for a time-interleaved ADC within analog-mixed-signal area 32 of ASIC 20 of Fig. 1, in accordance with an embodiment that is described herein. The monitoring circuit enables continuous performance monitoring of high-speed analog-to-digital conversion without interrupting primary data conversion operations.

[0058] In the present example, the time-interleaved ADC comprises a plurality of ADCs 96, labeled ADC #1 through ADC #128, arranged in a time-interleaved configuration to achieve a high aggregate conversion rate. A time interleaver 100 receives input high-speed analog data and distributes time-sliced portions of the input signal to the respective ADCs 96. Each ADC 96 converts its assigned time slice and produces a corresponding digital data output, with the collective outputs forming the aggregate digital data output of the time-interleaved ADC. Each ADC 96 operates at a conversion rate that is slower than the input high-speed analog data rate by a factor corresponding to the number of parallel ADCs.

[0059] A clock generation circuit 104 receives a high-speed clock input and generates coordinated timing signals for the various components within analog-mixed-signal area 32. Clock generation circuit 104 provides clock signals to time interleaver 100 to synchronize the distribution of input data across the parallel ADC channels.

[0060] In the embodiment of Fig. 5, analog-mixed-signal monitoring circuit 44 comprises two replica ADCs 108, shown as ADC #0 and ADC #129, which structurally match (e.g., are identical to) ADCs 96 used for primary data conversion. A time interleaver 112 receives input analog sensing data and routes this data to replica ADCs 108. The input analog sensing data comprises analog signals that are known or that represent system status, and may include analog outputs from analog monitor circuits 40. Time interleaver 112 performs smart switching between different analog inputs to route them to replica ADCs 108. Clock generation circuit 104 also provides coordinated clock signals to time interleaver 112 to ensure synchronized operation with the primary conversion channels.

[0061] Replica ADCs 108 produce digital sensing data outputs that are routed to monitor DSP 48 for aging characterization and performance monitoring purposes. Because replica ADCs108 are structurally identical to ADCs 96 and operate under the same clock and environmental conditions, their performance characteristics reflect the aging and degradation experienced by the primary converter array. By comparing the performance of replica ADCs 108 against expected values or against each other, monitor DSP 48 can estimate differential aging among the converter sub-blocks and detect degradation in conversion accuracy or timing alignment. Having multiple replica ADCs 108 enables measurement and cancellation of mismatching and other impairments among the converter sub-blocks.

[0062] In practical implementations, all ADCs are implemented using high-speed switching, and this switching results in degradation of transistor performance due to aging effects. The digital sensing data from replica ADCs 108 enables calibration of timing and voltages across the complete ADC array, optimization of operation of the complete ADC array, and tracking of aging of the ADC array over time.

[0063] The use of replica ADCs 108 positioned at the ends of the converter array enables continuous monitoring with overhead that does not exceed a small fraction of the total converter array. This configuration allows analog-mixed-signal monitor circuits 44 to track performance degradation without consuming conversion cycles from the primary ADCs 96, thereby maintaining uninterrupted high-speed data conversion throughput.

[0064] The configuration of the time-interleaved ADC, and its monitoring circuit using replica ADCs 108, as illustrated in Fig. 5, is an example configuration that is chosen purely for the sake of conceptual clarity. In alternative embodiments, any other suitable configuration can be used. For example, the time-interleaved ADC may comprise any other suitable number of ADCs 96. As another example, the monitoring circuit may comprise more than two replica ADCs 108, or a single replica ADC 108.

[0065] The description of Fig. 5 refers to a time-interleaved ADC, by way of example. In alternative embodiments, the disclosed technique can be used in a similar manner to monitor a time-interleaved DAC that comprises a plurality of DAC blocks, using one or more replica DACs.

[0066] DIFFERENTIAL AGING ESTIMATION

[0067] In some embodiments, the time-interleaved ADC of Fig. 5 comprises N active SAR-ADC circuits (e.g., ADCs 96) connected in a time-interleaved parallel configuration, where N is an integer greater than one. The N active SAR-ADC circuits collectively operate at an aggregate output data rate equal to N times the individual conversion rate of each active SAR-ADC circuit. Each of the N active SAR-ADC circuits is structurally and operationally identical to the others.

[0068] At least one replica SAR-ADC circuit (e.g., replica ADC 108) matches (e.g., is structurally identical to) each of the N active SAR-ADC circuits. The at least one replica SAR-ADC circuit operates concurrently and continuously with the N active SAR-ADC circuits without interrupting the aggregate data conversion output. The at least one replica SAR-ADC circuit receives as input a copy of the same analog input signal provided to the N active SAR-ADC circuits, or alternatively receives known reference signals. The at least one replica SAR-ADC circuit routes its digital output to control circuitry (e.g., monitor DSP 48) for aging characterization and performance monitoring, with the routed output not forming part of the aggregate data conversion output.

[0069] Comparison logic within monitor DSP 48 compares performance metrics of the at least one replica SAR-ADC circuit against corresponding metrics of the N active SAR-ADC circuits to detect differential aging. The total monitoring overhead introduced by the at least one replica SAR-ADC circuit, expressed as a ratio of replica circuits to total SAR-ADC circuits in the array, does not exceed 1 / N.

[0070] The description above refers to a time-interleaved ADC, by way of example. In alternative embodiments, the disclosed technique can be used in a similar manner to monitor a time-interleaved DAC that comprises a plurality of DAC blocks, using one or more replica DACs.

[0071] CUMULATIVE AND PREDICTIVE AGING PROFILES

[0072] The cumulative and predictive aging profile techniques described in this section are applicable to any of the monitoring configurations described herein, including analog monitor circuits 40, digital monitor circuits 36, and analog-mixed-signal monitor circuits 44. In some embodiments, monitor DSP 48 aggregates measurement data from the various distributed monitor circuits to construct comprehensive aging profiles for ASIC 20.

[0073] In certain embodiments, monitor DSP 48 stores a time-stamped performance record comprising measurement data obtained from analog monitor circuits 40, analog-mixed-signal monitor circuits 44, and digital monitor circuits 36 into a Non-Volatile Memory (NVM) coupled to or integrated within ASIC 20. The storing occurs at predetermined intervals during ASIC operation and upon each controlled shutdown of ASIC 20.

[0074] Upon each power-up initialization of ASIC 20, monitor DSP 48 retrieves the time-stamped performance record from the non-volatile memory. Monitor DSP 48 computes acumulative aging profile by comparing current performance measurements obtained during the power-up initialization against corresponding measurements retrieved from the time-stamped performance record, and by quantifying a performance delta representing accumulated aging across one or more prior operational periods.

[0075] Monitor DSP 48 generates adjusted performance parameters for ASIC 20 based on the cumulative aging profile. The adjusted performance parameters account for total accumulated aging of ASIC 20 over its entire operational lifetime to date. The cumulative aging profile is preserved across power cycles ("operational cycles") such that aging state information is not lost upon power interruption. Monitor DSP 48 applies the adjusted performance parameters to ASIC 20 at each power-up initialization prior to commencement of normal ASIC operation.

[0076] In some embodiments, monitor DSP 48 applies a predictive aging model to a timeseries of performance measurements accumulated over a plurality of operational cycles of ASIC 20. The predictive aging model identifies a rate-of-degradation trend by fitting the timeseries of performance measurements to a degradation function. The predictive aging model extrapolates a projected future performance value at one or more predetermined future time points based on the identified rate-of-degradation trend. The predictive aging model computes a projected time-to-threshold value representing an estimated remaining operational time until the projected future performance value is predicted to fall below a predefined minimum acceptable performance threshold.

[0077] Monitor DSP 48 compares the projected time-to-threshold value against a predefined safety margin. When the projected time-to-threshold value is less than or equal to the predefined safety margin, monitor DSP 48 proactively initiates at least one corrective action. The corrective action is selected from the group consisting of reducing a clock frequency of at least one circuit block within ASIC 20; increasing a supply voltage or adjusting power levels applied to at least one circuit block within ASIC 20 to compensate for threshold voltage drift; reconfiguring one or more operating parameters of ASIC 20 to redistribute computational load away from degraded circuit elements; and generating a predictive failure alert to an external system indicating projected remaining operational lifetime.

[0078] The proactive corrective action is initiated before actual performance degradation of ASIC 20 reaches the minimum acceptable performance threshold, thereby extending the operational lifetime of ASIC 20 beyond what would be achievable through reactive correction alone.METHOD DESCRIPTION

[0079] Fig. 6 is a flow chart that schematically illustrates a method for monitoring and adjusting ASIC operation based on aging and performance degradation, in accordance with an embodiment that is described herein. The method may be performed by monitor DSP 48 in conjunction with the various monitor circuits distributed throughout ASIC 20.

[0080] At a monitoring stage 116, measurement data is received from monitor circuits positioned in analog area 28, digital area 24, and analog-mixed-signal area 32 of ASIC 20. The measurement data may comprise, for example, temperature-dependent voltage characteristics from analog monitor circuits 40, timing characteristics from digital monitor circuits 36, and conversion performance data from analog-mixed-signal monitor circuits 44.

[0081] At an estimation stage 124, monitor DSP 48 estimates aging and performance degradation based on the measurement data collected from the various monitor circuits. Monitor DSP 48 may compare current measurement values against baseline values established during initial operation, track trends in the measurement data over time, or apply predictive aging models to forecast future performance degradation, for example.

[0082] At an action stage 220, monitor DSP 48 initiates suitable responsive actions based on the estimated aging and performance degradation. The responsive actions may include adjusting operating parameters of ASIC 20, such as modifying clock frequencies, adjusting power levels, or reconfiguring circuit settings. Alternatively or additionally, the responsive actions may include issuing alerts to external systems or to a user to indicate that performance has degraded beyond acceptable thresholds. In some embodiments, monitor DSP 48 reports on system status either constantly during operation or on demand in response to external queries.

[0083] ***

[0084] The various ASIC and circuit configurations illustrated in Figs. 1-5 are example configurations that are chosen purely for the sake of conceptual clarity. In alternative embodiments, any other suitable configuration can be used. Elements that are not mandatory for understanding of the disclosed techniques have been omitted from the figure for the sake of clarity.

[0085] It will be appreciated that the embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art. Documents incorporated byreference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.

Claims

CLAIMS1. An integrated circuit, comprising:a digital area comprising digital circuitry;an analog area comprising analog circuitry;an analog-mixed-signal area comprising at least one signal converter;a plurality of monitor circuits distributed across the digital area, the analog area, and the analog-mixed-signal area, the plurality of monitor circuits configured to generate measurement data indicative of performance characteristics of the digital circuitry, the analog circuitry, and the at least one signal converter; anda processor configured to receive the measurement data from the plurality of monitor circuits, to estimate a degradation based on the measurement data, and to initiate a responsive action based on the estimated degradation.

2. The integrated circuit according to claim 1, wherein the degradation comprises one or both of (i) aging and (ii) performance degradation.

3. The integrated circuit according to claim 1, wherein the responsive action comprises one or both of (i) adjusting an operation of the integrated circuit and (ii) issuing an alert.

4. The integrated circuit according to any of claims 1-3, wherein the at least one signal converter comprises a plurality of converter sub-blocks operating in a time-interleaved configuration, wherein the plurality of monitor circuits comprises at least one replica converter structurally matching the converter sub-blocks, and wherein the processor is configured to estimate differential aging among the converter sub-blocks based on measurement data from the at least one replica converter.

5. The integrated circuit according to any of claims 1-3, wherein the processor is configured to accumulate at least some of the measurement data in a non-volatile memory over multiple operational cycles of the integrated circuit, and to estimate the degradation based on the accumulated measurement data.

6. The integrated circuit according to any of claims 1-3, wherein the processor is configured to construct a cumulative aging profile based on measurement data collected over multiple operational cycles of the integrated circuit.

7. The integrated circuit according to any of claims 1-3, wherein the processor is configured to apply a predictive aging model to measurement data collected over multipleoperational cycles of the integrated circuit, so as to forecast future performance degradation of the integrated circuit.

8. A method, comprising:receiving measurement data from a plurality of monitor circuits distributed across an integrated circuit that includes a digital area comprising digital circuitry, an analog area comprising analog circuitry and an analog-mixed-signal area comprising at least one signal converter, the measurement data indicative of performance characteristics of the digital circuitry, the analog circuitry, and the at least one ADC;estimating a degradation based on the measurement data; andinitiating a responsive action based on the estimated degradation.

9. The method according to claim 8, wherein the degradation comprises one or both of (i) aging and (ii) performance degradation.

10. The method according to claim 8, wherein the responsive action comprises one or both of (i) adjusting an operation of the integrated circuit and (ii) issuing an alert.

11. The method according to any of claims 8-10, wherein the at least one signal converter comprises a plurality of converter sub-blocks operating in a time-interleaved configuration, wherein the plurality of monitor circuits comprises at least one replica converter structurally matching the converter sub-blocks, and wherein estimating the degradation comprises estimating differential aging among the converter sub-blocks based on measurement data from the at least one replica converter.

12. The method according to any of claims 8-10, wherein receiving the measurement data comprises accumulating at least some of the measurement data in a non-volatile memory over multiple operational cycles of the integrated circuit, and wherein estimating the degradation comprises estimating the degradation based on the accumulated measurement data.

13. The method according to any of claims 8-10, wherein estimating the degradation comprises constructing a cumulative aging profile based on measurement data collected over multiple operational cycles of the integrated circuit.

14. The method according to any of claims 8-10, wherein estimating the degradation comprises applying a predictive aging model to measurement data collected over multiple operational cycles of the integrated circuit, so as to forecast future performance degradation of the integrated circuit.

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