JET PROPULSION LABORATORYCalifornia Institute of Technology4800 Oak Grove DrivePasadena, California 91109
10. Work Unit No.
11. Contract or Grant No.NAS7-918
12. Sponsoring Agency Name and Address
NATIONAL AERONAUTICS AND SPACE ADMINISTRATIONWashington, D.C. 20546
13. Type of Report and Period Covered
JPL Publication
14. Sponsoring Agency CodeBW-323-51-43-00-14
15. Supplementary Notes
16. Abstract
During the course of the Jet Propulsion Laboratory's program tostudy radiation-hardened analog-to-digital converters (ADCs), numerousmilestones have been reached in manufacturers' awareness and technology^development and transfer, as well as in user awareness of thesedevelopments.
The testing of ADCs has also continued with twenty differentADCs from seven manufacturers, all tested for total radiation doseand three tested for neutron effects. Results from these tests arereported.
17. Key Words (Selected by Author($))
Space radiationNuclear instrumentationElectronics and electrical engi-
neeringSpacecraft design
18. Distribution Statement
19. Security Classif. (of this report)
Unclassified
20. Security Classif. (of this page)
Unclassified
21. No. of Pages
vi + 23
22. Price
JPL 0184 R9/83
JPL PUBLICATION 85-84
Radiation-Hard Analog-to-DigitalConverters for Space andStrategic Applications
Michael K. GauthierArmando Roberto V. Dantas
November 15, 1985
Prepared for
U.S. Department of the NavyNaval Weapons Support Center
Through an agreement with
National Aeronautics and Space Administration
byJet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena, California
The research described in this publication was carried out by the Jet Propul-sion Laboratory, California Institute of Technology, and was sponsored by theU.S. Department of the Navy, Naval Weapons Support Center, through an agreementwith NASA.
Reference to any specific commercial product, process, or service by trade nameor manufacturer does not necessarily constitute an endorsement by the UnitedStates Government or the Jet Propulsion Laboratory, California Institute ofTechnology.
11
ABSTRACT
During the course of the Jet Propulsion Laboratory's program tostudy radiation-hardened analog-to-digital converters (ADCs), numerous mile-stones have been reached in manufacturers' awareness and technology developmentand transfer, as well as in user awareness of these developments.
The testing of ADCs has also continued with twenty different ADCsfrom seven manufacturers, all tested for total radiation dose and three testedfor neutron effects. Results from these tests are reported.
111
ACKNOWLEDGEMENTS
This research project was carried out under the direction of TomEllis of the Naval Weapons Support Center (NWSC), contract monitor. Gratefulacknowledgement is made for the assistance of: Jack Foster, Dennis Russell,Joe Sunde, and Wes Will of the Boeing Radiation Effects Lab (BREL); Jim Coss,Leroy Craft, Ken Evans, Julian Kalmar, John King (now with Northrop ASD), KeithMartin, and Nancy Mobley of JPL; and special thanks are due to Bill Price, andto the many other individuals who have helped. Without the aid and expertknowledge of all these individuals, this project would not have been as suc-cessfully carried out.
IV
CONTENTS
1. INTRODUCTION 1-1
2. MILESTONES 2-1
2.1 MANUFACTURERS' AWARENESS 2-12.2 IMPROVED HARDNESS 2-12.3 NEW COMPANIES 2-22.4 TECHNOLOGY TRANSFER . . . 2-22.5 THE RADIATION EFFECTS COMMUNITY 2-2
3. CASE HISTORY: SEM ANALYSIS OF THE MICRO NETWORKS MN5214 ADC . . 3-1
3.1 DISCOVERY OF THE PROBLEM 3-13.2 ANALYSIS 3-13.3 RESULTS 3-3
4. RECENT ADC TESTS 4-1
U.I AD573, ANALOG DEVICES, INC 4-14.2 AD574A, ANALOG DEVICES, INC 4-14.3 AD574-MONO, ANALOG DEVICES, INC 4-34.4 AM6108, ADVANCED MICRO DEVICES, INC 4-34.5 AM6112, ADVANCED MICRO DEVICES, INC 4-34.6 AM6148, ADVANCED MICRO DEVICES, INC 4-44.7 HI-574A, HARRIS CORPORATION 4-44.8 HI-674A, HARRIS CORPORATION 4-44.9 MP574, MICROPOWER SYSTEMS, INC 4-54.10 MN5211, MICRO NETWORKS COMPANY 4-54.11 MN5214, MICRO NETWORKS COMPANY 4-54.12 MN5290, MICRO NETWORKS COMPANY 4-64.13 MN90228, MICRO NETWORKS COMPANY 4-6
5. RADIATION EFFECTS ON ADC SEMICONDUCTOR TECHNOLOGIES 5-1
5.1 BI-MOS 5-15.2 BIPOLAR 5-15.3 CMOS 5-15.4 CMOS-RAD HARD 5-15.5 GaAs 5-15.6 I2L 5-45.7 NMOS 5-45.8 PMOS 5-45.9 SOS AND SOI 5-45.10 SOI AND SOI-RAD HARD , 5-4
6. ADC TEST DATA 6-1
7. CONCLUSIONS AND RECOMMENDATIONS 7-1
7.1 CONCLUSIONS 7-17.2 RECOMMENDATIONS 7-1
CONTENTS (Contd)
REFERENCES R-l
Figures
1. Macrophotographs of the MN5211 and MN5214 ADCs 3-22. Radiation analysis of ADC semiconductor technologies 5-3
Tables
1. Radiation hard ADCs 4-22. Comparative analysis of ADC semiconductor technologies 5-23. ADCs tested by JPL 6-2
VI
SECTION 1
INTRODUCTION
Earlier surveys (late 1970s) of available analog-to-digital conver-ters (ADCs) suitable for precision applications showed that none had the propercombination of accuracy and radiation hardness to meet space and/or strategicweapon radiation requirements.
Over the past six years there has been a dramatic increase in thenumber of ADCs available having the proper combination of bits of resolution,accuracy, and operational features to meet space and/or strategic weapon re-quirements, but the problem of radiation hardness remains. During this period,the Jet Propulsion Laboratory (JPL) has been working with the Naval WeaponsSupport Center (NWSC) and the Defense Nuclear Agency (DNA) to research, test,evaluate, and report on the radiation hardness of ADCs.
The objectives of the present study were to categorize and advancethe radiation hardness of existing and future ADCs through system requirement,commercial device, and new ADC concept surveys; total dose and neutron testing/analysis of selected ADCs; and trade-off analysis studies and performances.Emphasis was directed at approaches that could be integrated into a monolithicchip that would have a 1 Mrad(Si) total dose and 10^3 n/cm^ neutronhardness.
Numerous milestones have been reached in ADC hardening, includingraising manufacturers' awareness and improved technology development and trans-fer, as well as user awareness of these developments. The scanning electronmicroscope (SEM)l f2,3,4,5 a(- JPL was used on a few device types to assistmanufacturers in hardness improvement. Increases in device hardness of up to20 times have been achieved by this technique.
During the course of this ongoing program, JPL has radiation hard-ness tested twenty different ADCs from seven different manufacturers for totalradiation dose and three for neutron effects. Many of the previous resultshave been reported on in prior reports and conferences^*'»°. The latestdata^'1-0 has been released this year. This paper summarizes the work com-pleted in this area to date.
1-1
SECTION 2
MILESTONES
JPL conducted their first ADC radiation test in 1978 on the TRW-TDC1001, 8-bit ADC. Since that first test, JPL has continued radiation testingADCs for total radiation dose and neutron effects. The data have been pub-lished in reports2»^»6,10 an(j conference papers^*? and have been included inthe newly established JPL/NASA Electronic Data Bank9, RADATA. Along withradiation effects testing, there have been numerous other ADC related activ-ities, in which JPL was instrumental in initiating and achieving the presentstatus of cooperation towards the development and hardness improvements foundin current ADCs.
2.1 MANUFACTURERS' AWARENESS
In 1981 all known manufacturers of ADCs were contacted for aninitial survey°. Since that time there have been telephone calls and per-sonal visits to key manufacturers. The overall goal was to identify sources ofradiation hardened ADCs, but this also gave JPL the opportunity to inform themanufacturers of the basic requirements for space and strategic weapons, theneed for radiation hardened devices, and what can be done to improve the hard-ness of current and future devices. Although the emphasis was on ADCs, manu-facturers were encouraged to extend the radiation hardening philosophy to theirentire product line. An example of this transfer is the Burr-Brown operationalamplifier, OPA-111, which has been tested with Co-60 gamma rays and 2.5 MeVelectrons to 10 Mrad(Si) and neutrons to >2 x 10^3 n/cm^ with little degra-dation noted.
2.2 IMPROVED HARDNESS
Manufacturers were encouraged to increase the hardness of theirADCs, at little or no cost, through process changes and other hardening tech-niques during periodic redesign, and also to incorporate as many of thehardening design techniques as practical and cost effective when designing anew device.
As an example of improving quality and radiation hardness, thescanning electron microscope (SEM)l»2,3,4,5 at JPL was used to locate radi-ation sensitive components in the Analog Device AD571 and Micro Networks MN5211and MN5214 devices. Increases in device hardness of up to 20 times were madeby the manufacturer from the design and process changes suggested by JPL.
Manufacturers now provide nine different ADCs which are known to behard to at least 600 krad(Si). With the help of this program, Analog Devices,AMD, and Micro Networks have developed seven of the nine devices.
2-1
2.3 NEW COMPANIES
New companies, previously not ADC manufacturers, are now producingADCs. AMD has three devices which are hard to greater than 600 krad(Si) andPMI has recently announced a new entry into the field, the ADC-910. Thisdevice has not been radiation tested but is expected to be hard to at least500 krad(Si). This estimate is based on the "harder than average" radiationresponse of previously tested PMI devices.9 Linear Technology Corp. is alsoconsidering entering the ADC market.
2.4 TECHNOLOGY TRANSFER
ADC manufacturers in general are not radiation effects experts,although there is usually an individual or a small group within a company witha basic understanding of radiation effects. The major problem for the manufac-turers has been the lack of current information on hardening techniques. In-plant meetings have been held with design, process, and management teams tobring them up-to-date with the latest radiation hardening technology. Thesemeetings have been well received by the companies involved. To date, meetingshave been held with Analog Devices, AMD, Burr-Brown, Harris, Micro Networks,and PMI.
2.5 THE RADIATION EFFECTS COMMUNITY
The JPL program has served the radiation effects community byreporting the latest ADC information through conference papers-^»?, technicalpublications^***, and published test data^'W, including RADATA, the JPL/NASA Electronic Radiation Effects Data Bank9.
2-2
SECTION 3
CASE HISTORY: SEM ANALYSIS OF THE MICRO NETWORKSMN5214 ADC
The purpose of the scanning electron microscope (SEM) analysis wasto locate the sensitive areas which caused the Micro Networks MN5214, a hybrid,12-bit ADC, to show a greater radiation susceptibility than other devices ofthe same type.
3.1 DISCOVERY OF THE PROBLEM
JPL purchased two ADCs, MN5211 and MN5214, from Micro Networks foruse on the Galileo spacecraft program. The devices are similar except for theinput operating range. In fact, the whole MN5210 family of ADCs is so func-tionally similar that the initial radiation tests for these devices were con-ducted on the MN5216. This method was' used because of the lack of availabilityof MN5211 and MN5214 devices and their high unit cost. The tests indicated thedevice was functional to at least 150 krad(Si).
When the initial flight devices were received by JPL, a total doseradiation test was conducted on two samples of each. The devices were irradi-ated at Boeing Radiation Effects Laboratory (BREL) with 2.2 MeV electrons fromtheir Dynamitron. The MN5211 remained functional to at least 600 krad(Si)while the MN5214 failed at 30 krad(Si). The specification limit for thesedevices was 150 krad(Si).
3.2 ANALYSIS
Both device types were delidded and photographed for a visual com-parison. The factory was contacted regarding the "as-built" information. Itwas learned that there were minor differences within each hybrid which wasverified with the photographs (Fig. 1). One of the differences noted was theoperational amplifier (chip #3), which was a 1556. Micro Networks stated thatthe MN5211 contained a Motorola MC1556 while the MN5214 contained a RaytheonRM1556.
3.2.1 SEM Testing
Using a previously developed technique^-»2» 3,4,5^ 30 keV electronsfrom a Cambridge Mark II SEM were used to irradiate samples of the MN5211 andMN5214 while under electrical bias. The flux rates were between 1.5 and 2.9krad(Si)/sec*. Each chip in the hybrid was selectively irradiated, with
A = area irradiated in cm^, I = electron current in Amperes,
rad = 100 ergs/gm, K = an energy dependent absorption constant
3-1
ORIGINAL PAGE fSPC POOR QUALrrv
CHIPS CHIPS
S/N 0039 Log 3720 MN5211/90227Did not fail under irradiation.Chip 3 is Motorola 1556.
S/N 0018 Log 3720 MN5214/90228Failed under irradiation.Chip 3 is Raytheon 1556.
Figure 1. Macrophotographs of the MN5211 and MN5214 ADCs
3-2
the suspected chip exposed last. Electrical parameter measurements were madeon the devices after each exposure. After a total dose of 30 krad(Si) neitherhybrid indicated any sign of degradation.
A second irradiation of 60 krad(Si), or 90 krad(Si) total dose, wasperformed on each hybrid. The MN5211 indicated no sign of degradation; how-ever, the MN5214 indicated a catastrophic failure upon exposure of the lastchip, the operational amplifier (chip #3).
3.2.2 SEM Test Results
The susceptible operational amplifier on the MN5214 was manufacturedby Raytheon and the unaffected counterpart on the MN5211 was manufactured byMotorola. Other differences between the two hybrids, that were noted from astudy of the photographs, did not affect the performance of the ADC under theSEM irradiation of 90 krad(Si) total dose. Barring susceptibility of the other(different) chips on the MN5214, it was concluded that replacement of the Ray-theon operational amplifier with a Motorola version would alleviate the sensi-tivity problem.
3.2.3 Total Dose Testing
Micro Networks agreed to rework the existing MN5214 devices, replac-ing the radiation sensitive Raytheon operational amplifier with the harderMotorola chip. Upon delivery of the rebuilt devices (now identified asMN90228, special build) two sample lots were tested. At 150 krad(Si) alldevices indicated linear degradation similar to the MN5211. Measurements werethen taken after 300 krad(Si) and 600 krad(Si). In the two device typestested, one type showed failures at 600 krad(Si). The other devices, althoughhighly degraded, remained functional.
3.3 RESULTS
The rebuilt MN90228 devices meet the Galileo flight requirements.
Another result is that we have learned the following:
(1) The SEM as a diagnostic tool has been shown to be a highlyreproducible method of locating sensitive areas on integratedcircuits;
(2) The devices tested must be from the same lot as those used inthe system;
(3) There can be large variations in radiation hardness betweenhybrid devices of the same type;
(4) Each component used to build hybrid devices requires a radi-ation hardness analysis, and in some cases actual testing; and
(5) The same type of component made by different manufacturerscan vary widely in radiation hardness.
3-3
SECTION 4
RECENT ADC TESTS
Since the publication of JPL's first ADC report8 in December 1982,there have been thirteen additional ADCs tested for total dose, three of whichwere also tested for neutron effects. A total of five companies' devices arerepresented in JPL's recent ADC test results, listed in Table 1. Brief descrip-tions of the devices follow. This information largely has been taken from themanufacturers' product literature.
4.1 ADS73, ANALOG DEVICES, INC.11
The AD573 is a complete 10-bit, successive approximation ADC con-sisting of a DAG voltage reference, clock, comparator, successive approximationregister (SAR), and three-state output buffers. All components are fabricatedto perform a fully accurate 10-bit conversion in 15 microseconds.
Operating on supplies of +5 V and -12 V to -15 V, the AD573 willaccept analog inputs of 0 to +10 V, unipolar, or -5 V to +5 V, bipolar. Apositive pulse on the CONVERT line initiates the 15-microsecond conversioncycle, and DATA READY indicates completion of the conversion. HIGH BYTE ENABLE(HBE) and LOW BYTE ENABLE (LBE) control three-state output buffers. The AD573interfaces to most popular 8- or 16-bit microprocessors without externalbuffers or peripheral interface adapters. The 10 output data bits can be readas a 10-bit word or as 8- and 12-bit words.
The AD573S guarantees 10-bit accuracy and no missing codes from-55°C to +125°C. The AD573SD/883B is screened in accordance with the Class Brequirements of MIL-STD-883, Method 5004, and is offered in a 20-pin hermet-ically sealed ceramic DIP.
4.2 AD574A, ANALOG DEVICES, INC.11
The AD574A is a complete 12-bit, successive approximation ADC withtri-state output buffer circuitry for direct interface to an 8-, 12- or 16-bitmicroprocessor bus. The AD574A design is implemented with two LSI chips eachcontaining both analog and digital circuitry, resulting in the maximum perfor-mance and flexibility at the lowest cost.
One chip is the high performance AD565A 12-bit DAC and voltagereference. It contains the high speed current output switching circuitry,laser-trimmed thin film resistor network, low temperature coefficient buriedzener reference and the precision input scaling and bipolar offset resistors.The second chip uses the LCI (linear-compatible integrated injection logic)process to provide the low-power I^L, successive approximation register,converter control circuitry, clock, bus interface, and high performance latch-ing comparator. The precision, low-drift comparator is adjusted for initialinput-offset error at the wafer stage by the "Zener-zap" technique, which trimsthe comparator input stage to 1/10 LSB typical error.
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The AD574A is available in six different grades. The AD574AJ, AK,and AL grades are specified for operation over the 0 to + 70°C temperaturerange. The AD574AS, AT, and AU are specified for the -55°C to +125°C range.All grades are packaged in a low-profile, 0.600-inch wide, 28-pin hermeticallysealed ceramic DIP.
4.3 AD574-MONO, ANALOG DEVICES, INC.12
The AD574-MONO is a new monolithic design of the standard 12-bitsuccessive approximation ADC with tri-state output buffer circuitry for directinterface to an 8-, 12- or 16-bit microprocessor bus. The AD574-MONO design isimplemented with a single LSI chip containing both analog and digital circu-itry, resulting in performance and flexibility at the lowest cost.
The operational description is the same as the AD574A, as describedabove in paragraph 4.2.
4.4 AM6108, ADVANCED MICRO DEVICES, INC.13
The AM6108 is a monolithic, high-speed, microprocessor-compatibleADC that converts analog input signals into an 8-bit digital output code inless than 1 microsecond. The digital output code is selected by the user aseither a two's complement or offset binary. Due to the high-speed conversion,"WAIT" states are no longer necessary for most microprocessor-based data con-version/acquisition systems or instrumentation.
The AM6108 consists of an 8-bit DAC, high-speed comparator, SAR,2.5 V reference and control logic. The 2.5 V reference is implemented util-izing the band-gap voltage of silicon. The digital outputs are tri-statebuffers with the standard TTL levels for logic 1 and 0, which allows the userto conveniently interface with the microprocessor data bus. Internal scalingresistors enable the AM6108 to handle input signal ranges of 0 to +5 V, and 0to +10 V with the device operating at ±5 V supplies.
The AM6108DM guarantees 8-bit accuracy and no missing codes from-55°C to +125°C and is offered in a 28 pin hermetic package.
4.5 AM6112, ADVANCED MICRO DEVICES, INC.14
The AM6112 is the first monolithic microprocessor-compatible, 12-bithigh-speed ADC. The AM6112 high-speed ADC contains a precision reference, DAC,comparator, SAR, scale resistors, tri-state output buffers, and comprehensivecontrol logic, enabling the device to be interfaced with a variety of micro-processors. The AM6112 is capable of completing a 12-bit conversion in underthree microseconds and can operate with input voltage ranges of 0 to +10 V, 0to +5 V, and ±5 V without external components.
The AM6112 has four modes of operation, two for microprocessors, onefor DMA, and a "stand-alone" mode. These modes are software programmable,except for the stand-alone, which is pin selectable. The AM6112 is easilyinterfaced with 8- and 16-bit microprocessors. It is guaranteed monotonicwith no missing codes over the full operating range of -55°C to +125°C, and ispackaged in a 24-pin hermetic DIP.
4-3
4.6 AM6148, ADVANCED MICRO DEVICES, INC.15
The AM6148 is a microprocessor-compatible ADC, and is the firstmonolithic high-speed 8-bit ADC to include a precision reference, DAC, com-parator, SAR, scale resistors, tri-state output buffers, and control logic.The AM6148 is capable of completing an 8-bit conversion in under one micro-second and can operate with input voltage ranges of 0 to +10 V, 0 to +5 V, and±5 V without external components. With appropriate external resistors, theuser can program the device to operate on other input signal ranges (2 or3 precision resistors are required). Full 8-bit performance is guaranteed overtemperature. The device has tri-state outputs for bus compatibility and 2status outputs - one a standard TTL signal and the other available as a statusoutput on the data bus.
The AM6148 is useful in microprocessor-based systems or can be usedin a stand-alone mode. The conversion time is short enough to allow mostmicroprocessors to accept data immediately after requesting a conversion. TheAM6148 is the same as the AM6108 except some of the pins, including datastatus, positive reference, and the inventing comparator input, have beendeleted. The AM6148 is guaranteed for 8-bit accuracy and no missing codes from-55°C to +125°C and is offered in a 24-pin hermetic package.
4.7 HI-574A, HARRIS CORPORATION16
The HI-574A is a complete 12-bit ADC including a +10 V reference,clock, tri-state outputs and a digital interface for microprocessor control.Successive approximation conversion is performed by two monolithic dice housedin a 28-pin package. The bipolar analog die features the Harris dielectricisolation process, which provides enhanced AC performance and freedom fromlatch-up.
The voltage comparator features high power supply ripple rejectionplus a high-speed current-mode latch, and provides precise decisions down to0.1 LSB of input overdrive. Noise has been reduced by a factor of 2 by usingcurrent instead of voltage for transmission of signals between the analog anddigital ICs, and the clock oscillator is current-controlled for excellent tem-perature stability. The oscillator is trimmed for a nominal conversion timeof 20 ±1 us.
The HI-574A offers standard unipolar and bipolar input ranges, andis laser trimmed for specified linearity, gain and offset accuracy. The buriedzener reference circuit is trimmed for minimum temperature coefficient. Powerrequirements are +5 V and ±12 V to ±15 V, with typical dissipation of 515 mW.All models are packaged in a 28-pin side-brazed, ceramic DIP. MIL-STD-883Method 5004, Class B screening is available.
4.8 HI-674A, HARRIS CORPORATION17
The HI-674A is a complete 12-bit ADC including a +10 V reference,clock, tri-state outputs and a digital interface for microprocessor control.This ADC is a higher speed (nominal conversion time of 12 + us) version ofthe HI-574A, as described above in paragraph 4.7.
4-4
4.9 MP574, MICROPOWER SYSTEMS, INC.18
The MP574 is a complete 12-bit, successive approximation ADC withtri-state output buffers for direct interface to 8- or 16-bit microprocessorbuses. The MP574 is implemented with advanced bipolar and CMOS LSI chipsresulting in maximum performance at lowest cost. The SAR, 12-bit decoded D/A,control logic, switches and buffers are fabricated using CMOS processing forlowest power, while a unique comparator, reference and required amplifiers arefabricated using linear bipolar processes for maximum speed and reduced offsetand drift over temperature.
The MP574 is offered in a 28 pin hermetically sealed package foruse over a wide temperature range and for MIL-STD-883 requirements. The lowercost proprietary commercial package is offered for applications not requiringthe wider temperature exposure.
The MP574 is available in 6 product grades. The MP574J, K and Lare specified for a temperature range of 0°C to +70°C while the MP574S, T andU are specified over the MIL temperature range -55°C to +125°C. The MP574 isalso available with full MIL-STD-883 screening, processed in accordance withMethod 5008.
4.10 MN5211, MICRO NETWORKS COMPANY19
The MN5211 device is a high-speed, 12-bit, successive approximationADC in the industry standard 24 pin dual-in-line package. Conversion time is13 usec and all specifications are met with a 1-MHz clock. Functional lasertrimming of the highly stable thin-film resistor networks results in adjustment-free devices that are extremely accurate and highly stable. Zero error, forexample, is guaranteed to be better than ±0.025% FSR at +25°C and better than±0.05% FSR over the entire operating temperature range. All units are fullyspecified and 100% tested for linearity and accuracy at their operating temper-ature extremes as well as at room temperature.
The input voltage range is -5 V to +5 V and has an internal 6.3 Vreference. The linearity is ±1/2 LSB and no missing codes are guaranteed overthe entire operating temperature range.
The MN5211 may be procured for operation over the full -55°C to+125°C military temperature range or the 0°C to +70°C commercial temperaturerange. In addition, high-reliability processing, screening, and qualificationaccording to Method 5008 of MIL-STD-883 are available.
4.11 MN5214, MICRO NETWORKS COMPANY19
The MN5214 device is a high-speed, 12-bit, successive approximationADC in the industry standard 24-pin dual-in-line packages. Conversion time is13 psec and all specifications are met with a 1 MHz clock. This ADC is sim-ilar to the MN5211, as described above in paragraph 4.10, except it uses a-10.000 V external reference for improved overall accuracy.
4-5
4.12 MN5290, MICRO NETWORKS COMPANY19
The MN5290 is a high-performance, dual-in-line package, 16-bit ADCspecifically designed for use in military/aerospace and industrial applica-tions that demand fully guaranteed high-resolution performance over extendedoperating temperature ranges. These successive approximation ADCs exploit thestability and tracking advantages of both SiCr and NiCr thin-film resistortechnologies. Fully assembled devices are functionally laser trimmed beforeand after a proprietary resistor stabilization process for temperature sta-bility. There are 4 models in the MN5290 family. All operate from -55°C to+1258C, and each guarantees no missing codes.
This device is complete with internal clock and reference and has 6user-selectable input ranges. Output data is straight binary coded for uni-polar input ranges and offset binary coded for bipolar input ranges and isavailable in either serial or parallel format. Conversion time is 40 usecmaximum.
4.13 MN90228, MICRO NETWORKS COMPANY20*21
The MN90228 is very similar to the MN5214 as described above in par-agraph 4.11, except it was custom built to JPL specifications.
4-6
SECTION 5
RADIATION EFFECTS ON ADC SEMICONDUCTOR TECHNOLOGIES
A comparison of the various ADC semiconductor fabrication technol-ogies to their radiation hardness in various radiation environments is given inTable 2 and Fig. 2. The radiation hardening of these technologies ranges fromvery soft to very hard and varies from environment to environment.
5.1 BI-MOS
Bi-MOS technology is a combination of I^L and CMOS on the samechip for optimization of the analog and digital circuits and provides all theadvantages of I^L and radiation-hardened CMOS (when made with the radiation-hardened CMOS process).
5.2 BIPOLAR
The current bipolar technology is overall one of the most radiation-hard technologies for semiconductor devices. A number of ADC devices are cur-rently available in bipolar technology.
5.3 CMOS
Standard CMOS (complementary metal oxide semiconductor) is a populartechnology but it is radiation-soft. Many ADCs have been designed in CMOS.
5.4 CMOS-RAD HARD
Radiation-hardened CMOS processes are as hard as the hardest bipolarprocesses. Sandia Laboratory is using this radiation-hardened process forADCs.
5.5 GaAs
GaAs may be a good technology for future devices. It is very hardin ionizing radiation environments but does suffer from bulk damage problems.Therefore, GaAs devices will not have the surface leakage problems of manybipolar devices but will have a sensitivity to electron, proton, neutron, andheavy ion damage, which is similar to the bipolar device sensitivity.
Except for speed, ADCs made of GaAs may not be any better than high-quality bipolar silicon devices.
5-1
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5-2
i 1 SOME PARAMETERDEGRADATIONS
GZZZJ MILD DEGRADATIONOF PARAMETERS,
SOME FAILURES
^ MOST PARAMETERS SHOWEXTENSIVE DEGRADATIONOR TOTAL PARTS FAILURE
(a) TECHNOLOGY
BI-MOS (|2UCMOS)
81 -POLAR
CMOS
CMOS (RAD HARD)
GaAs
12L
NMOS
PMOS
SOS/SOI
SOS/SOI (RAD HARD)
101 102 103 104 105 105 107 108 IO9 1010 1011
TOTAL DOSE, rad (Si)
(b) TECHNOLOGY
BI-MOS (|2UCMOS)
61 -POLAR
CMOS
CMOS (RAD HARD)
GaAs
I2L
NMOS
PMOS
SOS/SOI
SOS/SOI (RAD HARD)
c= - 77K ^^m^^
103 104 IO5 106 107 1
DOSE RATE, rad (Si)/sec
10' 1010 1011 1012 1013
(c) TECHNOLOGY
BI-MOS (|2L CMOS)
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CMOS (RAD HARD)
GaAs
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PMOS
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NEUTRON, n/cm
Figure 2. Radiation analysis of ADC semiconductor technologies:(a) total dose, (b) dose rate, and (c) neutron
5-3
5.6 I2L
(integrated injection logic) is an overall radiation-hardtechnology incorporating high speed, small size, and low power.
5.7 NMOS
NMOS (N-type MOS) technology is very soft and shows little promiseof being hardened.
5.8 PMOS
PMOS (P-type MOS) technology, like NMOS, is very soft and showslittle promise of being hardened.
5.9 SOS AND SOI
SOS and SOI (silicon-on-sapphire and silicon-on-insulator) is softto total dose but hard to other environments. Currently there is developmentwork going on in the area of SOI, but little of it is directly related to ADCs.
5.10 SOI AND SOI-RAD HARD
Recent developments of radiation-hardened CMOS SOS and SOI have in-creased the total dose hardness to the same levels as radiation-hardened CMOS.
SECTION 6
ADC TEST DATA
For immediate needs in a radiation environment, there are a numberof choices depending on the bit-resolution required by the system. Table 3lists all ADCs tested by JPL to date.
8-bit; For 8-bit applications, the AMD AM6108 and AM6148 should beconsidered. Radiation tests of these devices indicate that they are hard toat least 600 krad(Si). This device family has also been neutron tested to1 x 1Q13 n/cm2 with little parameter degradation.
10-bit; Those with applications requiring a 10-bit ADC should con-sider the ADI AD571, which has been radiation tested and is hard to at least75 krad(Si), although the latest date codes (1981) tested indicated the deviceswere hard to 300 krad(Si).
12-bit; Designers requiring a 12-bit ADC should consider the AD574-MONO or the AM6112. The AD574-MONO is a new monolithic design of the oldAD574, and has a radiation hardness of at least 1 Mrad(Si).
The AM6112 has been neutron tested to 1 x 1013 n/cm2 with littledegradation. In total dose the device is hard to at least 600 krad(Si).
16-bit; When a 16-bit ADC is required, consideration should begiven to the Micro Networks MN5290. This device has been radiation tested andis hard to at least 1 Mrad(Si).
'Unless otherwise noted, each is a monolithic chip.*These devices were radiation tested using Co-60 gamma rays; all other deviceswere tested using the Dynamitron, 2.5 MeV electrons, as the radiation source.
6-2
Table 3. ADCs tested by JPL (Continued)
TotalDate Power, Speed, Dose Neutron,
Part No. Code Mfg Process Bits mW ys krad(Si) n/cm^ Remarks'
MN90228MP574
8141(85x)
MN5290 8419
MNC BipolarMPS CMOS/
BipolarMNC Bipolar
1212
600135
3.025
60050
16 830 35 >1000
HybridHybrid
Hybrid
'Unless otherwise noted, each is a monolithic chip.
6-3
SECTION 7
CONCLUSIONS AND RECOMMENDATIONS
7.1 CONCLUSIONS
The objectives of this study have been met with new analog to dig-ital converters complying with space and/or strategic weapon requirements beingdeveloped. Bit configuration and operating speed have been improved and con-figurations with optimized special features to ease equipment design and oper-ation are being developed. Current and potential technologies are being evalu-ated and processes are being developed to optimize performance and comply withspace and/or strategic radiation hardening requirements. It is intended thatthese devices will be suitable for a wide range of equipment and systems appli-cations.
ADC development is evolving in two directions: (1) the standardmonolithic ADC, and (2) the monolithic ADC with extended features, whichincludes the ability to interface directly with the microprocessor bus. Thissecond type will eventually evolve into the "smart ADC," which will havevarious microprocessor functions (RAM, ROM, etc.) on the chip.
There are individual applications best served by each type of ADCchip but both types are being developed and have been monitored during thisstudy. The primary concern for the immediate future is the monolithic ADC, butthis study has not overlooked the requirements for, and development of, the"smart ADC."
7.2 RECOMMENDATIONS
Application and design engineers with immediate needs now haveseveral choices of ADCs which may meet their requirements. The AMD AM6108 andAM6148 should be considered for 8-bit applications, the ADI AD571 for 10-bitapplications, the ADI AD574-MONO and AMD AM6112 for 12-bit applications, andthe Micro Networks MN5290 for 16-bit applications. These are all monolithicdevices except for the MN5290 and are hard to at least 300 krad(Si). Increasedhardness may be obtained on these devices by "tweaking" the manufacturing pro-cess. With vendor cooperation, process variations may be made that willimprove the typical hardness of the devices by a factor of two to four times.
To continue the development of radiation hardened ADCs, it is recom-mended that:
(1) Meetings, conferences, and workshops be conducted on radiationhardening of ADCs, in order to define relevant research andestablish communications between cooperating laboratories,researchers and industry;
(2) Further development of faster radiation hardened ADCs, whichhave higher bit resolution, use less power and include addi-tional functional elements such as microprocessor control,on-board RAM and ROM, and internal programmability, should beencouraged.
7-1
(3) ADC designers should be encouraged to apply radiation harden-ing techniques, whenever cost effective, during new ADCdevelopment, redesign, or when process changes are made;
(4) Radiation tests of candidate ADC devices as well as newdesigns, processes, and technologies be continued; and
(5) The interface between ADC users and manufacturers becontinued and increased.
7-2
REFERENCES
1. A. G. Stanley and M. K. Gauthier, "SEM Analysis of Ionizing RadiationEffects in Linear Circuitry," IEEE Transactions on Nuclear Science NS-24,No. 6 (December 1977).
2. M. K. Gauthier and J. D. Ferret, "Investigation of Total Dose DegradationMechanisms of an Analog-to-Digital Converter (AD571)" Final Report,900-972, Revised-second printing, Jet Propulsion Laboratory, Pasadena,February 1981 (internal report).
3. M. K. Gauthier, J. Perret, and K. C. Evans, "SEM Analysis of IonizingRadiation Effects in an Analog to Digital Converter (AD571)," IEEETransactions on Nuclear Science NS-28, No. 6 (Dec. 1981).
4. M. K. Gauthier and A. G. Stanley, "Methods for Analyzing RadiationSensitivity of Integrated Circuits," U.S. Patent 4,172,228, October 23,1979.
5. C. G. Thomas and K. C. Evans, "The SEM as a Diagnostic Tool for RadiationHardness Design of Microcircuits," Scanning Electron Microscopy, Vol. I(1979) pp. 735-9.
6. W. E. Price, K. E. Martin, D. K. Nichols, M. K. Gauthier, and S. F.Brown, "Total-Dose Radiation Effects Data for Semiconductor Devices,Volume II," JPL Pub. No. 81-66, Jet Propulsion Laboratory, Pasadena,December 1, 1981.
7. M. K. Gauthier, J. J. King, D. K. Nichols, and R. L. Weesner, "FutureRadiation Hardened Analog to Digital Converters," GOMAC-82 ConferenceDigest of Papers, Government Micro-Electronics Conference, New York,November 1982.
8. M. K. Gauthier, "New Technologies for Radiation-Hardening Analog-to-Digital Converters,"JPL Pub. No. 82-105, Jet Propulsion Laboratory,Pasadena, December 31, 1982.
9. RADATA, JPL/NASA Radiation Effects Electronic Data Bank, Jet PropulsionLaboratory, Pasadena, CA.
10. K. E. Martin, M. K. Gauthier, J. R. Coss, A. R. V. Dantas, andW. E. Price, "Total - Dose Radiation Effects Data for SemiconductorDevices, 1985 Supplement, Volume II," JPL Pub 85-43, Jet PropulsionLaboratory, Pasadena, December 1985.
11. Data-Acquisition Databook 1982, Analog Devices, Inc. (1980), pp. 11-31through 11-37, Wilmington, Mass.
12. Personal communications with Mark Skillings, Product MarketingSpecialist - Converters, Analog Devices Semiconductors, Wilmington, Mass.01887 (October 1985).
