This document presents the results of a heavy-ion test program carried out on the Linear Technology LT1668 16-bit 50 Msps DAC (LTC1668IG) to identify single-event effects. In particular, it was studied the detection of single-event latch-up (SEL), single-event upsets (SEU), and single-event transients (SET) due to heavy-ions radiation. The tests were performed at the heavy-ion facility Tandem-ALPI at INFN Legnaro National Laboratory (Italy) in February 2021 and June 2022 for a total irradiation time of ~51 hours

Cotta Ramusino, Angelo

Della Torre, Stefano

Galli, Luca

Limonta, Andrea

Malaguti, Roberto

Nicolò, Donato

Signorelli, Giovanni

Silvestrin, Luca

Spinella, Franco

Tartari, Andrea

Tessaro, Mario

Wyss, Jeffery

Zannoni, Mario

English

Open Access Repository

ISTITUTO NAZIONALE DI FISICA NUCLEARESezione di Milano–BicoccaINFN-23-32 MIBDecember 19, 2023Heavy-ion test report of LTC1668 DACLiteBIRD-NOTE-84A. Cotta Ramusino8, S. Della Torre2, L. Galli4, A. Limonta1,2, R. Malaguti8,D. Nicolò3,4, G. Signorelli4, L. Silvestrin5,6, F. Spinella4, A. Tartari3,4,M. Tessaro5,6, J. Wyss6,7 and M. Zannoni1,21) Dipartimento di Fisica dell’Università di Milano Bicocca,2) INFN, Sez. di Milano Bicocca, Milano, Italy3) Dipartimento di Fisica dell’Università di Pisa and 4) INFN, Sez. di Pisa, Pisa, Italy,5) Dipartimento di Fisica dell’Università di Padova and 6) INFN, Sez. di Padova, Padova, Italy7) Dipartimento di Ingegneria Civile e Meccanica, Università di Cassino, Italy8) INFN Sez. di Ferrara, Ferrara, ItalyAbstractThis document presents the results of a heavy-ion test program carried out on the LinearTechnology LT1668 16-bit 50 Msps DAC (LTC1668IG) to identify single-event effects.In particular, it was studied the detection of single-event latch-up (SEL), single-event up-sets (SEU), and single-event transients (SET) due to heavy-ions radiation. The tests wereperformed at the heavy-ion facility Tandem-ALPI at INFN Legnaro National Laboratory(Italy) in February 2021 and June 2022 for a total irradiation time of ∼51 hours.PACS:61.80.-x, 61.80.JhPublished byLaboratori Nazionali di FrascatiContents1 Applicable and reference documents 31.1 Applicable documents . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 Reference documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Device Information 42.1 Description of LTC1668 . . . . . . . . . . . . . . . . . . . . . . . . . . 42.2 Component schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Sample identification 54 Test set-up 64.1 Test facility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.1.1 Beamline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.1.2 Test chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.1.3 Beam quality control and dosimetry . . . . . . . . . . . . . . . . 64.2 Test system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.3 Test principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Test condition 96 Test Results 126.1 Dosimetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 Conclusion 1621 Applicable and reference documents1.1 Applicable documentsnone1.2 Reference documents1. ESCC Basic Specification no. 251002. ECSS-Q-ST-60-15C Space product assurance — Radiation assurance for EEE com-ponents3. ECSS-E-ST-10-04C Description of space environment.4. LiteBIRD note 056: “Guidelines for radiation test on the ground”5. Radiation tolerance tests for DAC LTC1668 (companion paper)6. J. Wyss et al, “SIRAD: an irradiation facility at the LNL Tandem accelerator forradiation damage studies on semiconductor detectors and electronic devices andsystems”, Nucl. Instr. Meth. A 462 (2001) 42632 Device Information2.1 Description of LTC1668Part description: LTC1668IG 16-bit, 50Msps DACManufacturer: Linear TechnologyPackage: 28-pin SSOPTechnology: BiCMOSSamples used: Tested four samples out of a batch of ten.2.2 Component schematicsWe reported in the draw below the schematic of the device under test.43 Sample identificationDie area: 2 mm × 2.95 mm = 5.9 mm254 Test set-up4.1 Test facility4.1.1 BeamlineThe SEE experiment was performed with the Tandem-ALPI beam at INFN Legnaro Na-tional Laboratories (Italy) with a cocktail of ions ranging in LET from 12,5 MeV cm2/mgto 82.5 MeV cm2/mg. Among the ions that can be accelerated by the facility, four ionshave been used (Cl-35, Ni-58, Ag-107, and I-127) to span the desired LET range in thebeam time allocated. Moreover, the devices under test have been rotated through severalangles to increase the Effective LET1.Ion Energy (MeV) Range in Si (µm) LET in Si (MeV cm2 /mg)35Cl 160*, 171** 46, 49.71 13.05, 12.6858Ni 220 37.03 29.3679Br 228 31.2 41.96107Ag 266 29.03 58.39127I 249*, 276** 27.74, 29.53 63.66, 65.37*Energy value of the beam during the 2022 campaign**Energy value of the beam during the 2021 campaign4.1.2 Test chamberIrradiation is performed in a vacuum chamber equipped with a movable and tiltable stagethat allows the alignment of the DUT with the ion beam. The position and tilt of the DUTare monitored with a CCD camera looking inside the vacuum through a set of mirrors. Alaser beam is used to align the various DUTs with the beam. At the same time, dedicatedsoftware allows recording the encoder data to re-position all DUTs correctly after thevacuum chamber has been closed. Vacuum feedthroughs (high-density and coaxial) areavailable to carry the signals out of the chamber. A picture of the test chamber with ourdetectors installed is shown in Figure 1.4.1.3 Beam quality control and dosimetryThe DUT region is surrounded by four PIN diodes that count the number of impingingions during irradiation to estimate the received flux. A second set of four PIN diodescan be placed in place of the DUT at any time to cross-check the total flux. The beamhomogeneity is guaranteed by de-focusing the beam. A flux of 103 to 105 ions/cm2/secis available. A beam blocker ensures the correct timing of the irradiation of the DUTs.The real-time ion flux and the total fluence are recorded by the system and stored togetherwith the accelerator parameters.1L. Silvestrin et al., “Status and prospects of the SIRAD irradiation facility for radiation effects stud-ies at LNL,” 2013 14th European Conference on Radiation and Its Effects on Components and Systems(RADECS), 2013, pp. 1-4, DOI: 10.1109/RADECS.2013.6937371.6Figure 1: Test chamber at LNL SIRAD facility with the board hosting 4 DUTs installed.4.2 Test systemThe testing apparatus is based on an ArriaV GX FPGA (a GEMROC board that wasdeveloped within the framework of the BESIII experiment) that operates at 166 MHz. It iscoupled with customized transition boards that facilitate the interface between the currentoutput of the LTC1668 and the input ADCs. The system implements the high-resolutionreadout of four independent currents/voltages at 24 bits at 26kHz, and a lower-resolutionreadout of device currents and temperatures. This high-resolution, slow ADC, is used todetect SEL and SEU. The transition boards send a copy of each of the four DAC outputsto a digital scope read out at 50 MHz to detect transients (SET). The 16-bit digital scopefeatures a sampling rate of 62.5 MS/s, with a maximum temporal resolution of 16 ns/bin.The system allowed us to be sensitive to 15 bits out of 16 with the high resolution, low-speed ADC, while 10 bits out of 16 with the low resolution, high-speed one.4.3 Test principleThe LTC1668 has been tested with a ±5V power supply. During irradiation the contentsof the irradiation registers were frozen, i.e. the input of the DAC was held constant,the CLK was stopped, and the output was digitized at 24 bits with a 16kHz rate. Thelatch-up was identified by monitoring the positive and negative current drawn by theDUT. The typical behavior of the DUT current is shown in Figure 3. During normaloperation, the DUT draws Ip = 32 mA and In = 2.7 mA. A sudden current increase wasattributed to a latch-up. At this point, the current was monitored and recorded for a few7Figure 2: Schematics of the test set-upseconds, after which the DUT was switched off, waited for 10 to 20 seconds accordingto the test conditions, and switched on again. The setup allowed the distinction betweenthe transient errors (glitch at the device output) and the permanent errors (Single EventUpset in the device registers). A static digital input has been applied during the irradiation(about mid-scale, DUT output=2V). With this setup, we have been able to test the 15(9) most significant bits out of the 16-bit device resolution for SEU (SET) respectively.Upsets or transients are identified by changes in DAC output: SEU is defined as a definitechange of output, identified using the high-resolution, low-speed, DAC; SEL is definedas glitches in the output observed with the lower resolution, high-speed, ADC. The datastream of the high-resolution ADC is written to a file which is eventually analyzed offline,while the digital-scope-based high-speed DAQ is triggered whenever the DAC level exitsa window centered around the mean output voltage. Since the average output level canchange following SEUs, the average level is continuously monitored by a moving-averagealgorithm, which also computes the signal RMS. A transient is triggered whenever thesignal exits a 5σ window centered around the moving average. A 2240 µs sample istherefore recorded to disk.8InegIposlatch-up  detectedDUT OFFDUT ONDUT ONlatch-up  detected ……Figure 3: Typical behaviour of positive and negative current of LTC1668 during irradia-tion.5 Test conditionEach DUT received, at the end of the campaign, a minimum irradiation fluence of ∼7.5 × 105 cm−2 from at least two different ions covering a LET range from 12 to 85MeV cm2 mg−1 (see section 6.1). The flux was kept constant in the range 3 × 104 to4 × 104 cm−2s−1. We monitored positive and negative currents, reference voltage, andDUT temperature. The DUTs were tested at room temperature, i.e. the temperature theyreached in the vacuum when switched on. This turned out to be in the range of 28 to35 ◦C (see Figure 4). Trigger follows different strategies according to the different SEEobserved. A typical sequence of data acquisition with both SELs and SEUs visible ispresented in Figure 5.SELA latch-up was triggered with the following parameters:• Negative or positive threshold 40 mA;• Temperature threshold 50◦C;• Hold time ∼4 sec (the time before switching off the DUT);• Detector re-armed after 10 sec.9Figure 4: Typical temperature of a DUT during the test. The DUT is switched on at t=0.Typical running procedure: SELDAC outputcurrentzoomSwitch-off  DUTSwitch-on  DUTwaitlatch-upsingle-event upsetsCount  = # of SELFigure 5: Typical sequence of data acquisition during one test run.10Figure 6: Examples of transient events recorded during the test.SEUThe DAC pattern was alternatively programmed with the content 0xA5A5 or 0x5A5A, forwhich the output of the DAC was set at the mid-range of the high-resolution ADC. Heavy-ion Event Upsets were recognized offline by analyzing the DAC output data stream andidentifying the sudden changes in the DAC level. The RMS of the 24-bit ADC readoutwas ∼100 ADC counts while the total span of the DAC as recorded by the ADC was∼0x61A800 corresponding to 23 bits. We were then effectively sensitive to 15 out of 16bits of the DAC.SETSingle Event Transients are detected using a 16-bit digital scope receiving one copy ofthe DAC output. The trigger logic is set when the DAC signal exceeds a window of ±5σon a moving baseline (calculated using the first 512 pre-trigger samples, corresponding to8.192µs). With this exit window trigger, we could detect both positive and negative ex-cursions. With these settings, we were sensitive also to SEUs, SELs, and spurious events.Data were re-processed offline to eliminate spurious triggers and to classify different typesof transients. We found that, during the acquisition time, a high number of short transientevents were triggered. These events are probably due to the tails of the noise distribution,which increase in the harsh environment of the experimental cavity. Since we are inter-ested in long transients only, during the offline analysis we reject all events shorter than80 ns (corresponding to 5 samples). Examples of SET events measured during the test arereported in Figure 6.116 Test ResultsThe irradiation test was performed in two separate periods in February 2021 and June2022 for a total irradiation time of ∼51 hours. The complete campaign involves 96runs, considering both data acquisitions and instrument calibrations. To compute the SEEcross-sections, the number of observed events was normalized to the acquisition lifetimeand taking into account the effective flux in the tilted situation. The so-obtained valueswere fitted using the Weibull function:σ(L) = σf[1− e−(L−Lthw)s](1)Where L is the LET of incident particle, Lth is the threshold value for producing the singleevent effect, σf is the cross-section plateau value for high LET, w and s are parametersdescribing the transition smoothness from threshold to high LET plateau. Results arepresented in Figures 8 (SEL), 8 (SEL), and 9 (SET). For SET analysis, we discard thetime in which the system was in Latch-up. Furthermore, we notice that the fast SETacquisition was affected by dead times (probably associated with data dump from theoscilloscope RAM to the computer storage disk), which occurred unpredictably. Thecombined effect was a systematic uncertainty that we couldn’t properly assess. The runin which this problem has been identified was excluded from the analysis. Furthermore,for the same reason, we also excluded runs at high LET (i.e. the ones with a greaternumber of SELs) with less than 2 SET occurrences. This also explains why data pointsare sparser and more scattered in Figure 9 than in Fig. 8 and 7. Nevertheless, a thresholdvalue of LET, together with plateau values of σ(L) never exceeding 2× 10−4 cm2, can beneatly spotted. The fit proposed in Fig. 9 was evaluated with an iterative procedure where,at first, all parameters of the Weibull function were free; then we fix w and s parameterswhile performing again the fit and exploring the 2σ band. In the same figure, we define asthe safety threshold the result of the Weibull fit considering σf and Lth values in the worst2σ case. Using the computed cross-section, we estimated the number of events per deviceper day (see table 1) that could be statistically experienced during the on-orbit operationsfor three different conditions: i) during a solar minimum, ii) during a solar maximum, andiii) during the worst day. The three cases cover respectively: i) the pessimistic scenario(i.e. the highest galactic cosmic rays flux intensity), ii) the optimistic scenario (i.e. thelowest galactic cosmic rays flux intensity), and, finally, iii) the scenario for 18 hours ofexposure at the most intense SEP registered. This estimation was done using CRÈME2software, a set of online tools for SEE rate prediction developed in collaboration withNASA. The computed fluences in the three scenarios are then transported through 100mils of aluminum to account for the effects due to standard shielding. Finally, the Direct-2Tylka et al (1997) ”CREME96: A Revision of the Cosmic Ray Effects on Micro-Electronics Code”,IEEE Trans. Nucl. Sci., vol. 44, no. 6, pp. 2150-2160, Dec. 1997. [online] available athttps://creme.isde.vanderbilt.edu/ [Oct. 2023]12SEL SEU SET(safety threshold)Solar minimum 5.37× 10−5 8.41× 10−5 5.28× 10−5[SEE/device/day] (2.83× 10−4)Solar Maximum 1.92× 10−5 3.04× 10−5 3.36× 10−5[SEE/device/day] (1.05× 10−4)SEP WORST-DAY 4.02× 10−1 6.49× 10−1 7.25× 10−1[SEEs/device in 18 hours] (2.33)Table 1: Number of SEE/device/day in case of a parallelepiped with X = 2.00 mm, Y =2.95 mm, and Z = 1 µm. In the SET column, we report in parenthesis the value using thesafety threshold cross-section. For the SEP worst day the number of SEE is evaluated foran exposition of 18 hours.Ionization-heavy-ion-Induced SEE was evaluated using the HUP module that calculatesdirect-ionization rates using the integral rectangular parallelepiped (IRPP) method3.6.1 DosimetryIn table 2 we evaluate the total ionizing dose (TID) received during the test through theequation:D = F · LET · 1.6 · 10−5. (2)Where D is the deposited dose in rad, F is the fluence measured in the plane normal tothe beam in cm−2 and LET is the linear energy transfer expressed in MeV cm2mg−1.This formula assumes that the energy lost by the incoming particle is fully absorbed bythe medium. For instance, the medium is supposed to be thick enough to fully absorbthe kinetic energy of emitted delta rays and the particle energy is almost constant whiletraversing the absorber.3This method is compliant to ECSS guidelines — ECSS-E-HB-10-12A Space engineering — Calcula-tion of radiation and its effects and margin policy handbook (2010)13Figure 7: Single-Event Latch-up cross-section measurement for three samples ofLTC1668, along with the Weibull function describing the data set.Figure 8: Single-Event Upsets cross-section measurement for three samples of LTC1668,along with the Weibull function describing the data set.14DUT Ions Energy [MeV] Total Fluence [cm−2] Ionizing Dose [rad]DUT0 Cl-35 171 6.09E+07 1.46E+04DUT0 Ni-58 220 5.29E+07 2.74E+04DUT0 Ag-107 266 4.96E+06 4.76E+03DUT0 I-127 276 7.49E+05 7.84E+02TOTAL 1.19E+08 4.68E+04DUT1 Cl-35 160 5.91E+07 1.37E+04DUT1 Cl-35 171 6.02E+07 1.44E+04DUT1 Ni-58 220 2.44E+07 1.38E+04DUT1 Br-79 228 3.19E+06 2.30E+03DUT1 Ag-107 266 1.17E+07 1.24E+04DUT1 I-127 249 1.19E+07 1.27E+04DUT1 I-127 276 4.60E+05 4.81E+02TOTAL 1.70E+08 6.94E+04DUT2 Cl-35 160 3.84E+06 9.34E+03DUT2 Cl-35 171 4.80E+07 1.22E+04DUT2 Br-79 228 6.69E+05 5.19E+02DUT2 Ag-107 266 8.14E+06 8.79E+03DUT2 I-127 249 4.23E+06 5.04E+03TOTAL 9.94E+07 3.58E+04DUT3 Cl-35 160 4.53E+07 1.15E+04DUT3 Br-79 228 9.13E+05 7.31E+02DUT3 I-127 249 3.00E+06 3.64E+03TOTAL 4.92E+07 1.59E+04Table 2: Heavy Ions Fluence and Ionizing dose absorbed by DUTs during the test period15Figure 9: Single-Event Transient cross-section measurement for three samples ofLTC1668, along with the Weibull function describing the data set.7 ConclusionWe tested the 16-bit DAC LTC1668 from Linear Technology at room temperature undera beam of different ions spanning LET range from 12 to 80 MeV cm2 mg−1. The SEEtest on the LTC1668 shows that the device is sensitive toSEL: SELs have been observed at LET> 14 MeV cm2 mg−1. SEL has a relatively lowcross-section but cannot be considered as a rare event, therefore a suitable SELcircumvention circuitry should be implemented.SEU: A significant number of SEUs is observed, which induces the wrong output value.The output should be reset after reprogramming the DAC registers.SET: Numerous SETs were observed with different time characteristics and populations.They show up as a blend of short (< 1µs) and long (> 1µs) pulses. Overall, thecross-section of transient events exhibits a threshold around 10 MeV cm2 mg−1,reaching rapidly a plateau value ≤ 2× 10−4 cm2.16Appendix: Total Irradiation Dose testA preliminary total irradiation dose test was performed on a sample of LTC1668 at thegELBE facility in Dresden. In the gELBE facility photons are produced by bremsstrahlungby 17 MeV electrons hitting a 12.4 µm niobium foil, at a current of 600 µA. The energyspectrum of the photon is shown in Figure 10, and the dose rate is up to 18 krad/hour.The sample was placed in the irradiated area and a 1 MHz sinusoid spanning the fullFigure 10: Photon spectrum at the gELBE facility and photon fluence in the experimentalarea.DAC range was generated and recorded every 30 seconds. A 10-hour acquisition wasperformed, the sample being irradiated for 6.5 hours, during which the dose was moni-tored with a calibrated rad FET. The total dose on the DAC was found to be 70 krad. Nosignificant decrease in amplitude nor difference in the acquired waveforms and Fouriertransforms were observed. Figure 11 shows the amplitude variation as a function of thetime during irradiation.Figure 11: Amplitude of the 1 MHz sinusoid as a function of the time during irradiation17

Heavy-ion test report of LTC1668 DAC - LiteBIRD-NOTE-84

https://www.openaccessrepository.it/record/143515/files/LiteBIRD-Note-084-LTC1668_Internal_Note.pdf

Heavy-ion test report of LTC1668 DAC - LiteBIRD-NOTE-84

Abstract

Similar works

Full text

Available Versions

Open Access Repository