Continuing development and expansion of a series of P-channel MOSFET circuits in flight data systems is reported. Using hybrid thick film techniques, these circuits evolved into bugs with more than 1000 transistors on a chip. A proposed data system for Helios satellite will have approximately 130 bugs and a semiconductor count of more than 100,000, will weigh less than 1 N and use less than 1.2 W

Trainor, J. H.

English

NASA Technical Reports Server

82 GODDARD SPACEFLIGHT CENTER
FLIGHT DATA SYSTEMS USING LSI P-CHANNEL MOSFETS
James H. Trainor
For a number of years, we have carried out a research and development
program concerned with the general improvement of space flight signal and
data processing systems for experiments. We are concerned with com-
ponents; linear circuitry; digital circuitry; and special effects due to noise
suppression, radiation damage, and so on. For instance, as a result of our
efforts, there is now available on the GSFC Preferred Parts List a line of
very low power, complementary bipolar circuitry using hybrid thick-f'dm
techniques.
For the last two years, we have been helping to support the continuing
development and expansion of a series of P-channel MOSFET circuits which
had its beginnings in the IMP program. The GSFC engineers primarily
responsible are Hosea White and Don Lokerson. The commercial manufac-
turer of these custom devices is American Micro-Systems Inc. (AMI).
The evolution of these circuits from discrete devices to the present LSI
devices, or bugs, some of which have more than 1000 transistors on a chip,
and the effects this advanced circuitry has had on experiment and spacecraft
design are really astounding. Figure 1 tells a qualitative story using the IMP
program as an example. Across the top of the figure, data flow is traced
from the experiment sensors through the data system to the transmitter,
function by function. Four spacecraft examples are shown with light gray
denoting the experiment contribution or responsibility and dark gray
denoting the spacecraft data system responsibility. The vertical extent in a
given block is intended to indicate the relative functional complexity.
Several features are to be noted:
(1) As one has learned more about what is going on in space, the sensor
systems and their immediate electronics have become far more sophisticated
and complex.
https://ntrs.nasa.gov/search.jsp?R=19720018124 2020-03-17T03:53:49+00:00Z
TECHNOLOGYACCOMPLISHMENTS,1970 83
(2) OnIMPI, a largeincreasein sophisticatedanalogprocessingwas
noted,aswasadramaticincreasein thedemandsandabilitiesofthedigital
system.
(3) OnIMPH andIMPJ,moreusefulMOSFETbugswereavailable,
andthespacecraftengineerswereableto simplifytheexperimentseven
more.
(4) It is interestingto notethatif wewereto includetheproposed
IMPKK' here,or PioneerF andPioneerG, or HeliosA andHeliosB
experiments,forinstance,thepicturewouldchangemarkedly.Muchofthe
darkgraywouldbelightgraybecauseasophisticatedsetofbugsorcircuits
isavailable.Experimenterscanbuildtheirownsophisticatedspecialpurpose
datasystem,andthespacecraftwill revertbacktocentralfunctionstypical
ofIMPDandIMPE,forinstance.
Figure2 addsfurtherdetailto whatI havebeensaying.Horizontally,
yearsfrom1960to 1971areplotted,andseveralsatellitemilestonesare
shown.The left ordinate gives the number of cans, flatpacs, or bugs in the
data system and is to be used with the circular data points and the thin
narrow curve. The right ordinate gives the number of semiconductor devices
in the system and is to be used with the diamond-shaped data points and the
heavy curve.
The can count increased rapidly at first, to approximately 1000 to
1500 devices, but has since decreased. The number of semiconductors has
increased by more than three orders of magnitude. The IMP I data and
encoding system has approximately 328,000 semiconductors, and IMP H
will have approximately 500,000. In this time, there has been an evolution
from discrete transistors to several transistors in a can to MSI to LSI. The
spacecraft capability and complexity have increased markedly, but because
of parallel data paths and the high reliability of these parts, the reliability is
probably much higher. Currently, the IMP program has shown greater than
700 X l06 device-hours in orbit with an absolute maximum of 2 device
failures.
Previously, I had referred to the next step in this evolution being
experiments having their own extensive data systems. At least three
experiments on Pioneer F and Pioneer G are using these devices, and we are
also using them on Helios A and Helios B and expect to use them on HEAO.
84 GODDARD SPACE FLIGHT CENTER
For Helios, our experiment data system will use approximately 130 bugs
and have a semiconductor count of greater than 100,000. It will weigh less
than 1 N and use less than 1.2 W. This system probably will use more
transistors than all the rest of the spacecraft combined.
Table 1 is a summary showing the size of the family available, the part
numbers, and GSFC drawing numbers. In addition to funding the TREE and
PHA bugs, an additional LSI bug is now being funded which will be called
the Helios bug. Up to 12 bits can be entered, either serially or in parallel,
and then shifted out. The availability of a family of low weight, very low
power, very reliable parts that are also low cost ('$150 per bug with NASA
specifications) is a major advance.
S_NSOI_ SlG_At SI_;_II eA'_rt
PROJECT [LECTROIIICS"_ COMMIIIITIO)I"P _ON'_SlO__ STOkX_t
IMPO IE
IMPF &G
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") .;QMMUlA1_OI_ '') 1:0011_ "_MOOULATOR
f
IMP EYE EXPERIMENT aJUA SYSTlll
IMPH & I
EXPERIMEN'_
DATASYSTEM
RELATW[
FUNCTIONAL
COMPLEXITY
Figure 1-Spacecraft data flow.
TECHNOLOGY ACCOMPLISHMENTS, 1970 85
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300 en 31-l,10 BIT LOG
COMP AND PHASE
BLOCKS-Ip~500 MOS IN
900 BUGS
Figure 2-Evolution of encoding system.
86 GODDARD SPACE FLIGHT CENTER
Table 1 -MOSFET block part numbers and drawing numbers.
BLOCK
Logic Block
Logic Block
Logic Block
Binary Block
ATXC Floator Block
ATX Registors Block
10 Channel Switch
Universal 4 Bit
HOS Commutator
Outside World 4 Bit
MOs Commutator
16 Bit SR with
Storage
MARS BUG
TREE BUG
F_ BUG
HELIOS BUG
PHASE I BLOCKS
SC-1128B
SC-1129B
SC-1173B
SC-I149B
PHASE III BLOCKS
C-1275
C- 1276
S- 1304
S- 1304
S-1307
PHASE IV BLOCKS
C-1308
C-1375
C- 1487
C- 1652
GSFC DRAWING #
GD-I154-025
(2 sheets)
G?-1154-042
(9 sheets)
GD-I154-044
GD-I154-043
GD-I154-048
GE-1281-452
GE-1154-047
GE-1281-454
GE-1281-455
GE-1281-456


Flight data systems using LSI P-channel MOSFETS

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