DYNEX MA31755

MA31755
MA31755
16-Bit Feedthrough Error Detection
& Correction Unit (EDAC)
Replaces June 1999 version, DS3572-3.0
The MA31755 is a 16 bit Error Detection and Correction
Unit intended for use in high integrity systems for monitoring
and correcting data values retrieved from memory. The EDAC
is placed in the data bus between the processor and the
memory to be protected. Extra check bits added at each
memory location are programmed transparently by the EDAC
during a processor write cycle. The entire checkword and data
combination is verified on read cycles. If any one bit in the
incoming data stream is at fault the EDAC can correct the fault
transparently, presenting the corrected 16-bit value to the
processor. An error in two bits can be detected but cannot be
corrected. Both the correctable and uncorrectable error
conditions are signalled to the system to allow the processor to
take action as required. Parity is passed through the device
unchanged as data bus bit 16.
Tri-statable bus transceivers with a high drive capability
are incorporated at the MD and CB busses which allows the
usual bus driver devices to be removed and reduces the
overall timing overhead imposed on the data bus. Although
designed primarily for MA31750 application, this part may be
used in almost any 16-bit processor system requiring high data
integrity.
DS3572-4.0 January 2000
8
8
VDD
MD[0:16]
VSS
CB[0:5]
MA31755
EDAC
PD[0:16]
XERRN
ENCOR
ENFLG
CERRN
NCERRN
CS0
RDWN
CS1N
CS2N
FEATURES
■ Fast Feedthrough (35ns Detect and Correct Cycle)
Figure 1: Chip Signals
■ 16-Bit Operation with 6 Check Bits
■ Radiation Hard CMOS/SOS Technology
■ Feedthrough Operation
■ Error Corrected/Uncorrected Flags
■ High Drive Capability on Memory Busses
1/13
MA31755
1. PIN DESCRIPTIONS
POWER
VDD x8
VSS x8
Input
Input
-
Supply - 5V nominal (all must be connected)
Circuit 0V reference (all must be connected)
I/O
I/O
I/O
Active High
Active High
Active High
Processor data bus + parity bit (bit 16)
Memory data bus + parity bit (bit 16)
Memory check bit bus
BUSSES
PD[0:16]
MD[0:16]
CB[0:5]
ERROR FLAGS AND CONTROL
CERRN
Output
Active Low
NCERRN
Output
Active Low
XERRN
ENCOR
Input
Input
Active Low
Active High
ENFLG
Input
Active High
Asserted low when a correctable (1 bit) error occurs (ENFLG
must be asserted high)
Asserted low when an uncorrectable error occurs (ENFLG
must be asserted high)
External error feedthrough to NCERRN line.
Enables correction of data when high. Data is passed
through uncorrected when this line is low.
Enables the flagging of incorrect data when high. When this
line is low the two error flag lines are held inactive.
DEVICE AND BUFFER CONTROL
CS2N
CS1N
CS0
RDWN
Input
Input
Input
Input
Active Low
Active Low
Active High
-
Enables device and output buffers.
Enables device and output buffers.
Enables device and output buffers.
High indicates a read cycle, low indicates a write cycle.
2. FUNCTIONAL DESCRIPTION
2.0 GENERAL
2.1 TESTING THE EDAC AND MEMORY SYSTEM
The EDAC is of feedthrough type with 16 data bits, 1 parity
bit and 6 check bits, giving the ability to correct all single bit
errors and detect all double bit errors. Errors in more than two
bits may result in any combination of error flags being raised
and the data may be arbitrarily modified by the correction
circuitry.
The EDAC is placed in the data bus between the processor
and the memory to be protected. It forms the interface
between the 23-bit memory bus and the 17-bit processor bus.
Tri-statable bus transceivers with a high drive capability are
incorporated at both busses.
No specific hardware for testing is provided by the
MA31755 since this would compromise the speed
performance of the part in normal operation. However, it is
possible to fully test the EDAC function and the generation of
the error signals without this. The system should provide a
means by which the check bit memory may be dynamically
write-enabled and disabled - this may be provided by gating
write strobe on the check bit memory with a latched control bit.
By writing first with check bits enabled, then with them
disabled, suitable seed values may be constructed which have
the required pattern of bits to test each feature of the EDAC
operation. A similar approach may be taken when testing the
check bit memory.
By disabling the EDAC (asserting ENCOR low) the
processor may have direct access to the unmodified 17-bit
data from the memory. Suitable test patterns may be applied to
test each memory location as required.
2/13
MA31755
2.2 BUS CONTROL
There are four signals which control the drive status of the EDAC external busses: RDWN, CS2N, CS1N and CS0. The
relationship to each other and to the EDAC busses is shown in Figure 2 below. The timing of these signals is shown in Figures 6
and 7.
RDWN
CS2N
CS1N
CS0
X
X
X
High
Low
High
X
X
Low
Low
X
High
X
Low
Low
X
X
Low
High
High
Bus state
Processor
Memory
Tristate
Tristate
Tristate
Tristate
Tristate
Tristate
Output
Input
Input
Output
Figure 2: Bus Control
2.3 INTERNAL OPERATION
2.3.1 Check Bit Generation
On write cycles the processor data word, PD[0:15], and the processor parity bit ,PD[16], are passed directly to the memory
data bus, MD[0:15], and the memory parity bit, MD[16].
The check bits, CB[0:5], are derived by 6 parity generators operating on sets of 8 bits of the processor data word, PD[0:15], as
shown in Figure 3 below:
CB
Parity
0
1
2
3
4
5
Even
Even
Odd
Odd
Even
Even
PD
15 14
13
X
12
X
X
X
X
X
11
10
9
X
X
X
X
X
X
X
X
X
X
X
X
X
X
8
X
X
7
X
6
X
X
5
X
4
X
X
X
X
X
X
X
X
3
2
X
X
X
X
X
X
X
1
X
X
X
0
X
X
X
X
Figure 3: Check Bit Generation
2.3.2 Syndrome Generation
The syndrome generation logic checks the sense of the check bits with respect to the memory data word. Six 9-input parity
checkers generate the syndrome bits, SY[0:5], according to figure 4 below:
SY
0
1
2
3
4
5
Parity
Even
Even
Odd
Odd
Even
Even
MD
15 14 13
X
X
X
X X
X
X X X
12 11 10
X
X X
X
X
X X
X X
9
X
X
8
X
X
7
X
6
X
X
5
X
4
X
X
X
X
X
X
X
X
3
2
X
X
X
X
X
X
X
X
1
X
X
X
0
X
X
X
CB
0 1
X
X
2
3
4
5
X
X
X
X
Figure 4: Syndrome Generation
If there are no errors in the memory data word, MD[0:15],
or the check bits, CB[0:5], then all of the syndrome bits,
SY[0:5], will be set low.
A single bit error in the memory data word, MD[0:15], will
cause 3 syndrome bits to be set high. However, a single bit
error in the check bits, CB[0:5], will cause only 1 syndrome bit
to be set high. A two bit error in the memory data word and/or
the check bits will cause either 2, 4, 5 or 6 syndrome bits to be
set.
Three or more errors in the memory data word and/or the
check bits will cause an undefined number of syndrome bits to
be set. This will cause the operation of the device in respect of
the states of CERRN, NCERRN and data on the PD bus to be
unpredictable.
3/13
MA31755
2.3.3 Correction
With no syndrome bits set data will pass through from the
MD bus to the PD bus unchanged. When a single bit error
occurs in the memory data word, MD[0:15], the three
syndrome bits which are set identify which data bit is in error.
The correction logic decodes these syndrome bits and will
correct the error provided the correction enable input, ENCOR,
is high.
2.3.4 Flag Generation
The correctable error flag,CERRN, is driven low whenever
1 or 3 syndrome bits are set and flags are enabled (ENFLG=1).
The non-correctable error flag, NCERRN, is driven low
whenever 2, 4, 5 or 6 Syndrome bits are set and flags are
again enabled (ENFLG=1). NCERRN will also be driven low
Check bit
generation
PD[0:16]
Tri-statable
Buffer
Correction
should the external error input, XERRN, be driven low at any
time. Note: this external error feedthrough from XERRN to
NCERRN operates independently of ENFLG and the Chip
Select inputs (CS0, CS1N & CS2N).
Flags are enabled provided the ENFLG input is high and
the device is selected. Note: the flags are not disabled on write
cycles and therefore can indicate errors on write operations
caused by faults on the Memory Data Bus and the Check Bit
Bus.
2.3.5 Internal Structure
Figure 5 below shows the internal block diagram
representing the internal architecture of the MA31755.
Tri-statable
Buffer
MD[0:16]
CB[0:5]
Syndrome
Generation
ENCOR
ENFLG
XERRN
RDWN
CS0
CS1N
CS2N
Buffer
Control
Flags
Generation
Figure 5: Block Diagram of the Internal Architecture of the MA31755
4/13
CERRN
NCERRN
MA31755
3. TIMING DIAGRAMS
PD[0:16]
Data from processor
MD[0:16]
CB[0:5]
Data and check bits to memory
T1
CERRN
NCERRN
T4
Valid Flags
T6
T8
CS0
T9
T10
CS1N
CS2N
RDWN
Figure 6 : Processor Write Timings (ENFLG = 1)
T3
CB[0:5] Check bits from memory
MD[0:16]
Data from memory
T2
PD[0:16]
Valid Data
T4
CERRN
NCERRN
Valid Flags
T6
T8
RDWN
CS0
T5
T7
CS1N
CS2N
Figure 7: Processor Read Timings (ENCOR and ENFLG=1)
5/13
MA31755
XERRN
T13
T13
NCERRN
Figure 8: External Error Feedthrough Timing (ENFLG=X ,CS0=X, CS1N /CS2N=X)
Uncorrected
Data
PD[0:16]
Corrected
Data
CERRN
NCERRN
Uncorrected
Data
Flags Valid
T11
T11
ENFLG
T12
T12
ENCOR
Figure 9: Correction and Error flag enable/disable timings (CS0=1, CS1N/CS2N = 0)
6/13
MA31755
4. AC CHARACTERISTICS
Parameter
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
Description
PD[0:16] to MD[0:16] , CB[0:5] valid
MD[0:16] to PD[0:16] valid
CB[0:5] to PD[0:16] valid
MD[0:16] to CERRN and NCERRN valid
CB[0:5] to CERRN and NCERRN valid
RDWN, CS0 rising to PD[0:16] driven (processor read)
CS1N, CS2N falling to PD[0:16] driven (processor read)
CS0 rising to error flags changing
CS1N, CS2N falling to error flags changing
RDWN, CS0 falling to PD[0:16] Hi-Z
CS1N,CS2N rising to PD[0:16] Hi-Z
CS0 falling to error flags high
CS1N, CS2N rising to error flags high
RDWN, CS1N and CS2N falling to MD[0:16] and CB[0:5]
driven (processor write)
CS0 rising to MD[0:16] and CB[0:5] driven (processor
write)
CS0 falling to MD[0:16] and CB[0:5] Hi-Z
RDWN, CS1N, CS2N rising to MD[0:16] and CB[0:5] Hi-Z
ENFLG to CERRN and NCERRN valid
ENCOR to PD[0:16] valid
XERRN to NCERRN valid
Min
-
Max
25
30
35
40
Units
ns
ns
ns
ns
Notes
CL = 150pF
CL = 50pF
CL = 50pF
CL = 50pF
5
20
ns
CL = 50pF
-
25
ns
CL = 50pF
-
30
ns
CL = 50pF
-
25
ns
CL = 50pF
5
20
ns
CL = 150pF
5
25
ns
CL = 150pF
-
20
20
10
ns
ns
ns
CL = 50pF
CL = 50pF
CL = 50pF
Mil-Std-883, method 5005, subgroups 9, 10, 11
Figure 10: Timing Parameters
5. DC CHARACTERISTICS AND RATINGS
Symbol
VDD
VI
TA
TS
Description
Supply voltage
Input voltage
Operating temperature
Storage temperature
Min.
-0.5
-0.3
-55
-65
Max.
7
VDD+0.3
+125
+150
Units
V
V
oC
oC
Figure 11: Absolute Maximum Ratings
Note: Stresses above those listed may cause permanent
damage to the device. This is a stress rating only and
functional operation of the device at these conditions, or
at any other condition above those indicated in the
operations section of this specification, is not implied.
Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Parameter
VOH
Description
Output high voltage
Min
Vdd- 0.5
Max
-
Unit
V
VOL
Output low voltage
-
Vss+0.5
V
Notes
IOH = 15mA on MD[0:16] / CB[0:5]
IOH = 5mA on other outputs.
IOL = -15mA on MD[0:16] / CB[0:5]
IOL = -5mA on other outputs.
VIH
Input high voltage
Vdd-1.5
V
VIL
Input low voltage
Vss+1.5 V
IIL, IIH (Note 1) Input current high/low
10
uA
IOZ (Note 1)
Output tri-state leakage 0.1
mA
VO = 0 to VDD
ISS
Standby current
10
mA
IDD
Operating current
100
mA
Conditions VDD = 4.5 to 5.5V, TA = -55 to +125°C
Mil-Std-883, method 5005, subgroups 1, 2, 3
Note 1: Worst case at TA = +125°C, guaranteed but not tested at TA = -55°C.
Figure 12: Operating Electrical Characteristics
7/13
MA31755
Subgroup
Definition
1
Static characteristics specified in Figure 12 at +25°C
2
Static characteristics specified in Figure 12 at +125°C
3
Static characteristics specified in Figure 12 at -55°C
7
Functional characteristics specified at +25°C
8A
Functional characteristics specified at +125°C
8B
Functional characteristics specified at -55°C
9
Switching characteristics specified in Figure 10 at +25°C
10
Switching characteristics specified in Figure 10 at +125°C
11
Switching characteristics specified in Figure 10 at -55°C
Figure 13: Definition of Subgroups
6. APPLICATIONS INFORMATION
To memory system
CONTROL
VDD
PWRDN
INT02N
INT08N
INT10N
INT11N
INT13N
INT15N
IOI1N
IOI2N
MA31750
RDYN
CLK
TCLK
ABN
DPARN
DTON
CONREQN
RESETN
GND
RDYN
PD[0:16]
VDD0-3
PD[0:16]
RDWN
MD[0:16]
CB[0:5]
MA31755
SUREN
TGON
INTAKN
NPU
ILLADN
CS2N
CS1N
XERRN
CS0
CERRN
NCERRN
VSS0-3
Figure 14: Basic System Diagram for the MA31755 with the MA31750
8/13
MD[0:16]
CB[0:5]
RDWN
ENMDN
ENPDN
AS[0-3]
PS[0-3]
PB[0-3]
REQN
GRANTN
LOCKN
RESETN
A[0-15]
ASTB
ASTB
DSN
DSN
M/ION
M/ION
RDWN
R/WN
O/IN
O/IN
RDN
RDN
WRN
WRN
MPROEN
PEN
EXADEN
FLT7N
SYSFN
CLK
TCLK
A[0-15]
D[0-16]
XERRN
MA31755
7. PACKAGING
The device will be supplied in a 68-pin PGA for development with a 68-pin flatpack option for flight parts.
1
Pin A1 Index
0.100
2
3
4
5
TOP
VIEW
0.900
±0.010
BOTTOM
VIEW
1.060 sq
±0.020
6
7
8
9
10
A
B
C
D
E
F
G
H
J
K
0.050
±0.010
0.105 max
XG451 Outline
0.045 ±0.005
0.018
±0.002
0.180 ±0.010
Figure 15: Dimensioned Drawing for the 68-pin PGA Package
Pin
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
Function
CB05
NCERRN
RDWN
PD16
PD14
VDD
PD13
PD11
PD10
PD08
CB03
GND
CERRN
XERRN
PD15
GND
PD12
PD09
GND
PD06
Pin
C1
C2
C3
C8
C9
C10
D1
D2
D9
D10
E1
E2
E9
E10
F1
F2
F9
F10
G1
G2
Function
CB02
CB04
VDD
VDD
PD07
PD04
CB00
CB01
PD05
PD03
GND
NC
PD02
PD01
VDD
NC
GND
VDD
MD16
MD14
Pin
G9
G10
H1
H2
H3
H8
H9
H10
J1
J2
J3
J4
J5
J6
J7
J8
J9
J10
K1
K2
Function
CS0
PD00
MD15
MD12
VDD
VDD
ENFLG
CS1N
MD13
GND
MD10
MD07
GND
MD05
MD02
MD00
GND
CS2N
MD11
MD09
Pin
K3
K4
K5
K6
K7
K8
K9
K10
Function
MD08
MD06
VDD
NC
MD04
MD03
MD01
ENCOR
Figure 16: Pinout for the 68-pin PGA Package
9/13
MA31755
Ref
Millimetres
Inches
Min.
Nom.
Max.
Min.
Nom.
Max.
A
-
-
2.72
-
-
0.107
A1
1.83
-
2.24
0.072
-
0.088
b
0.41
-
0.51
0.016
-
0.020
c
0.20
-
0.30
0.008
-
0.012
D1, D2
23.88
-
24.51
0.940
-
0.960
e
-
2.54
-
-
0.050
-
j1
-
1.02
-
-
0.040
-
j2
-
0.51
-
-
0.020
-
L
10.16
-
10.54
0.400
-
0.415
Z
1.65
-
2.16
0.065
-
0.085
XG540
A
A1
c
L
D1
j1
Z
Pin 1
b
D2
Top View
e
j2
Figure 17: Dimensioned Drawing for the 68-pin Flatpack Package Topbraze
10/13
VDD
MD11
MD9
MD10
MD8
MD7
GND
MD6
NC
VDD
MD5
MD4
MD3
MD1
MD2
MD0
GND
MA31755
26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
27
GND
ENCOR
28
8
MD12
ENFLG
29
7
MD13
CS2N
30
6
MD14
CS1N
31
5
MD15
CS0
32
4
MD16
PD0
33
3
NC
GND
34
VDD
PD1
35
2
1
VDD
GND
68
NC
PD2
37
67
CB0
PD3
38
66
CB1
PD4
39
65
CB2
PD5
40
64
CB3
VDD
TOP VIEW
Pin 1
Index
36
GND
CERRN
NCERRN
RDWN
XERRN
PD16
PD15
VDD
PD14
GND
VDD
PD13
61
43
44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
PD12
CB5
GND
PD9
CB4
62
PD10
PD11
63
42
PD8
41
VDD
PD6
PD7
Figure 18: Pinout for the 68-pin Flatpack Package
11/13
MA31755
8. RADIATION TOLERANCE
8.1 TOTAL DOSE RADIATION TESTING
For product procured to guaranteed total dose radiation
levels, each wafer lot will be approved when all sample
devices from each lot pass the total dose radiation test.
The sample devices will be subjected to the total dose
radiation level (Cobalt-60 Source), defined by the ordering
code, and must continue to meet the electrical parameters
specified in the data sheet. Electrical tests, pre and post
irradiation, will be read and recorded.
Dynex Semiconductor can provide radiation testing
compliant with Mil-Std-883 test method 1019, Ionizing
Radiation (Total Dose).
Total Dose (Function to specification)*
5x105 Rad(Si)
Transient Upset (Stored data loss)
1x1011 Rad(Si)/sec
Transient Upset (Survivability)
>1x1012 Rad(Si)/sec
Neutron Hardness (Function to specification)
>1x1015 n/cm2
Single Event Upset**
<1x10-10 Errors/bit day
Latch Up
Not possible
* Other total dose radiation levels available on request
** Worst case galactic cosmic ray upset - interplanetary/high altitude orbit
Figure 19: Radiation Hardness Parameters
9. ORDERING INFORMATION
Unique Circuit Designator
Radiation Tolerance
S
R
Q
MAx31755xxxxx
Radiation Hard Processing
100 kRads (Si) Guaranteed
300 kRads (Si) Guaranteed
Package Type
A
F
QA/QCI Process
(See Section 9 Part 4)
Test Process
(See Section 9 Part 3)
Pin Grid Array
Flatpack (Solder Seal)
Assembly Process
(See Section 9 Part 2)
Reliability Level
For details of reliability, QA/QC, test and assembly
options, see ‘Manufacturing Capability and Quality
Assurance Standards’ Section 9.
12/13
L
C
D
E
B
S
Rel 0
Rel 1
Rel 2
Rel 3/4/5/STACK
Class B
Class S
MA31755
http://www.dynexsemi.com
e-mail: [email protected]
HEADQUARTERS OPERATIONS
DYNEX SEMICONDUCTOR LTD
Doddington Road, Lincoln.
Lincolnshire. LN6 3LF. United Kingdom.
Tel: 00-44-(0)1522-500500
Fax: 00-44-(0)1522-500550
DYNEX POWER INC.
Unit 7 - 58 Antares Drive,
Nepean, Ontario, Canada K2E 7W6.
Tel: 613.723.7035
Fax: 613.723.1518
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© Dynex Semiconductor 2000 Publication No. DS3572-4 Issue No. 4.0 January 2000
TECHNICAL DOCUMENTATION – NOT FOR RESALE. PRINTED IN UNITED KINGDOM
Datasheet Annotations:
Dynex Semiconductor annotate datasheets in the top right hard corner of the front page, to indicate product status. The annotations are as follows:Target Information: This is the most tentative form of information and represents a very preliminary specification. No actual design work on the product has been started.
Preliminary Information: The product is in design and development. The datasheet represents the product as it is understood but details may change.
Advance Information: The product design is complete and final characterisation for volume production is well in hand.
No Annotation: The product parameters are fixed and the product is available to datasheet specification.
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