DRAM
Austin Semiconductor, Inc.
1M x 4 DRAM
DYNAMIC RANDOM-ACCESS
MEMORY
AVAILABLE AS MILITARY
SPECIFICATIONS
• SMD 5962-90847
• MIL-STD-883
SMJ44400
PIN ASSIGNMENT
(Top View)
20-Pin DIP (JD)
(400 MIL)
DQ1
DQ2
W\
RAS\
A9
A0
A1
A2
A3
Vcc
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
Vss
DQ4
DQ3
CAS\
OE\
A8
A7
A6
A5
A4
FEATURES
• Organized 1,048,576 x 4
• Single +5V ±10% power supply
• Enhanced Page-Mode operation for faster memory access
P
Higher data bandwidth than conventional page-mode
parts
P
Random Single-Bit Access within a row with a column
address
• CAS\-Before-RAS\ (CBR) Refresh
• Long Refresh period: 1024-cycle Refresh in 16ms (Max)
• 3-State unlatched Output
• Low Power Dissipation
• All Inputs/Outputs and Clocks are TTL Compatible
• Processing to MIL-STD-883, Class B available
Pin Name
A0 - A9
CAS\
DQ1 - DQ4
OE\
RAS\
W\
Vcc
Vss
Function
Address Inputs
Column-Address Strobe
Data Inputs/Outputs
Output Enable
Row-Address Strobe
Write Enable
5V Supply
Ground
OPTIONS
• Timing
80ns access
100ns access
120ns access
• Package(s)
Ceramic DIP (400mils)
MARKING
-8
-10
-12
The SMJ44400 is offered in a 400-mil, 20-pin ceramic
side-brazed dual-in-line package (JD suffix) that is character-
ized for operation from -55°C to +125°C.
OPERATION
No. 113
Enhanced Page Mode
Enhanced page-mode operation allows faster memory
access by keeping the same row address while selecting
random column addresses. The time for row-address setup
and hold and address multiplex is eliminated. The maximum
number of columns that can be accessed is determined by the
maximum RAS\ low time and the CAS\ page cycle time used.
With minimum CAS\ page cycle time, all 1024 columns
specified by column addresses A0 through A9 can be accessed
without intervening RAS\ cycles.
Unlike conventional page-mode DRAMs, the column-
address buffers in this device are activated on the
(continued)
JD
• Operating Temperature Ranges
Industrial (-40
o
C to +85
o
C)
IT
o
o
Military (-55 C to +125 C)
XT
GENERAL DESCRIPTION
The SMJ44400 is a series of 4,194,304-bit dynamic ran-
dom-access memories (DRAMs), organized as 1,048,576
words of four bits each. This series employs state-of-the-art
technology for high performance, reliability, and low-power
operation.
The SMJ44400 features maximum row access times of
80ns, 100ns, and 120ns. Maximum power dissipation is as
low as 360mW operating and 22mW standby.
All inputs and outputs, including clocks, are compatible
with Series 54 TTL. All addressses and data-in lines are latched
on-chip to simplify system design. Data out is unlatched to
allow greater system flexibility.
SMJ44400
Rev. 1.0 6/01
For more products and information
please visit our web site at
www.austinsemiconductor.com
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
1
DRAM
Austin Semiconductor, Inc.
Enhanced Paga Mode (continued)
falling edge of RAS\. The buffers act as transparent or flow-
through latches while CAS\ is high. The falling edge of CAS\
latches the column addresses. This feature allows the
SMJ44400 to operate at a higher data bandwidth then conven-
tional page-mode parts, since data retrieval begins as soon as
column address is valid rather than when CAS\ goes low. This
performance improvement is referred to as enhanced page
mode. Valid column address can be presented immediately
after row address hold time has been satisfied, usually well in
advance of the maximum (access time from column address)
has been satisfied. In the event that column addresses for the
next cycle are valid at the time CAS\ goes high, access time
for the next cycle is determined by the later occurrence of
t
CAC
or t
CPA
(access time form rising edge of CAS\).
Address (A0-A9)
Twenty address bits are required to decode 1 of 1,048,576
storage cell locations. Ten row-address bits are set up on
inputs A0 through A9 and latched onto the chip by RAS\. The
ten column-address bits are set up on pins A0 through A9 and
latched onto the chip by CAS\. All addresses must be stable
on or before the falling edges of RAS\ and CAS\. RAS\ is
similar to a chip enable in that it activates the sense
amplifiers as well as the row decoder. CAS\ is used as a chip
select, activating the output buffer as well as latching the
address bits into the column-address buffer.
Write Enable (W\)
The read or write mode is selected through W\. A logic
high on the W\ input selects the read mode and a logic low
selects the write mode. The write-enable terminal can be
driven from standard TTL circuits without a pullup resistor.
The data input is disabled when the read mode is selected.
When W\ goes low prior to CAS\ (early write), data out
reamins in the high-impedance state for the entire cycle
permitting a write operation independent of the state of OE\.
This permits early-write operation to be completed with OE\
grounded.
Data In/Out (DQ1 - DQ4)
The high-impedance output buffer provides direct TTL
compatibility (no pullup resistor required) with a fanout of
two Series 54 TTL loads. Data out is the same polarity as data
in. The output is in the high-impedance (floating) state until
CAS\ and OE\ are brought low. In a read cycle the output
becomes valid after all access times are satisfied. The output
remains valid while CAS\ and OE\ are low. CAS\ or OE\ going
high returns it to the high-impedance state.
SMJ44400
Output Enable (OE\)
OE\ controls the impedance of the output buffers. When
OE\ is high, the buffers remain in the high-impedance state.
Bringing OE\ low during a normal cycle activates the output
buffers, putting them in the low-impedance state. It is
necessary for both RAS\ and CAS\ to be brought low for the
output buffers to go into the low-impedance state. Once in
the low-ompedance state, they remain in the low-impedance
state until either OE\ or CAS\ is brought high.
Refresh
A refresh operation must be performed at least once every
16ms to retain data. This can be achieved by strobing each of
the 1024 rows (A0-A9). A normal read or write cycle
refreshes all bits in each row that is selected. A RAS\-only
operation can be used by holding CAS\ at the high (inactive)
level, conserving power as the output buffer remains in the
high-impedance state. Externally generated addresses must
be used for a RAS\-only refresh. Hidden refresh can be
performed while maintaining valid data at teh output pin. This
is accomplished by holding CAS\ at V
IL
after a read operation
and cycling RAS\ after a specified precharge period, similar
to a RAS\-only refresh cycle. The external address is ignored
during the hidden refresh cycles.
CAS\-before-RAS\ (CBR) and hidden refresh
CBR refresh is utilized by bringing CAS\ low earlier than
RAS\ (see parameter t
CSR
) and holding it low after RAS\ falls
(see parameter t
CSR
). For successive CBR refresh cycles,
CAS\ can remain low while cycling RAS\. The external
address is ignored and the refresh address is generated
internally. During CBR refresh cycles the outputs remain in
the high-impedance state.
Hidden refresh can be performed while maintaining valid
data at the output pins. Thsi is accomplished by holding CAS\
at VIL after a read operation. RAS\ is cycled after the
specified read cycle parameters are met. Hidden refresh can
also be used in conjuction with an early-write cycle. CAS\ is
maintained at VIL while RAS\ is cycled, once all the specified
early-write parameters are met. Externally generated
addresses must be used to specify the location to be accessed
during the initial RAS\ cycle of a hidden refresh operation.
Subsequent RAS\ cycles (refresh cycles) use the internally-
generated addresses and the external address is ignored.
Power Up
To achieve proper device operation, an initial pause of
200µs followed by a minimum of eight initialization cycles is
(continued)
SMJ44400
Rev. 1.0 6/01
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
2
DRAM
Austin Semiconductor, Inc.
Power Up (continued)
required after full Vcc level is achieved. These eight initial-
ization cycles need to include at least one refresh (RAS\-only
or CBR) cycle.
Test Mode
An industry standard Design For Test (DFT) mode is
incorporated in the SMJ44400. A CBR with W\ low (WCBR)
cycle is used to enter test mode. In the test mode, data is
SMJ44400
written into and read from eight sections of the array in
parallel. All data is written into the array through DQ1. Data
is comparted upon reading and if all bits are equal, all DQ pins
go high. If any one bit is different, all the DQ pins go low.
Any combination read, write, read-write, or page-mode can
be used in the test mode. The test mode function reduces test
times by enabling the 1M x 4-bit DRAM to be tested as if it
were a 512K DRAM where column address 0 is not used. A
RAS\-only or CBR refresh cycle is used to exit the DFT mode.
LOGIC SYMBOL
1
RAM 1024K x 4
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
6
7
8
9
11
12
13
14
15
5
20D10/21D0
A
0
1 048 575
RAS\
4
20D19/21D9
C20[Row]
G23/[Refresh Row]
24[Power Down]
C21[Column]
G24
CAS\
17
&
23C22
24,25EN
3
W\
16
OE\
23,21D
G25
DQ1
1
2
DQ2
18
DQ3
19
DQ4
A, 22D
26
A, Z26
1. This symbol is in accordance with ANSI/IEEE Std. 91-1984 and IEC Publication 617-12. The pinouts illustrated are for the JD package.
SMJ44400
Rev. 1.0 6/01
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
3
DRAM
Austin Semiconductor, Inc.
FUNCTIONAL BLOCK DIAGRAM
RAS\
CAS\
W\
OE\
Timeing and Control
SMJ44400
A0
A1
Column
Address
Buffers
A9
2
8
Column Decode
Sense Amplifiers
128K Array
128K Array
R
128K Array
128K Array
O
W
D
E
C
O
D
E
R
128K Array
10
128K Array
16
16
16
Row
Address
Buffers
16
I/O
Buffers
4 of 16
Selection
Data
In
Reg.
4
Data
Out
Reg.
4
10
2
ABSOLUTE MAXIMUM RATINGS*
Voltage on Vcc Supply Relative to Vss...............-1V to +7.0V
Voltage Range on Any Pin Relative to Vss.........-1V to +7.0V
Short Circuit Output Current (per I/O)….......................50mA
Power Dissipation.................................................................1W
Storage Temperature Range..........................-65°C to +150°C
Operating Temperature Range......................-55°C to +125°C
*Stresses greater than those listed under "Absolute
Maximum Ratings" may cause permanent damage to the
device. This is a stress rating only and functional opera-
tion of the device at these or any other conditions above
those indicated in the operation section of this specifica-
tion is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect reliability.
** Junction temperature depends upon package type,
cycle time, loading, ambient temperature and airflow.
RECOMMENDED OPERATING CONDITIONS
SYM
DESCRIPTION
MIN
4.5
2.4
-1
-55
125
1
NOM
5
MAX
5.5
6.5
0.8
UNIT
V
V
V
°C
°C
V
CC
Supply Voltage
V
IH
High-Level Input Voltage
V
IL
Low-Level Input Voltage
T
A
T
C
Minimum Operating Temperature
Maximum Operating Case Temperature
1. The algebraic convention, where the more negative (less positive) limit is designated as minimum, is used for logic-voltage levels only.
SMJ44400
Rev. 1.0 6/01
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
4
DRAM
Austin Semiconductor, Inc.
SYM
V
OH
PARAMETER
High-level output voltage
TEST CONDITIONS
I
OH
= -5mA
I
OL
= 4.2mA
V
CC
= 5.5V, V
I
= 0V to 6.5V, All
other pins = 0V to V
CC
V
CC
= 5.5V, V
O
= 0V to V
CC,
CAS\ High
V
CC
= 5.5V, Minimum cycle
After 1 memory cycle,
RAS\ and CAS\ High,
V
IH
= 2.4V
V
CC
= 5.5V, Minimum cycle,
RAS\ cycling,
CAS\ High (RAS\ only),
RAS\ Low after CAS\ Low (CBR)
V
CC
= 5.5V, t
PC
= minimum,
RAS\ Low, CAS\ cycling
SMJ44400
ELECTRICAL CHARACTERISTICS AND RECOMMENDED OPERATING CONDITIONS
(-55
o
C<T
A
<125
o
C or -40
o
C to +85
o
C; Vcc = 5V +10%)
-8
-10
-12
MIN MAX MIN MAX MIN MAX UNIT
2.4
2.4
2.4
V
0.4
±10
±10
85
4
0.4
±10
±10
80
4
0.4
±10
±10
70
4
V
µA
µA
mA
mA
V
OL
Low-level output voltage
I
I
I
O
Input current (leakage)
Output current (leakage)
I
CC1
Read - or write-cycle current
1
I
CC2
Standby current
I
CC3
Average refresh current
1
(RAS\ only, or CBR\)
85
75
65
mA
I
CC4
Average page current
2
50
40
35
mA
CAPACITANCE (f = 1MHz)
3
SYM
C
i(A)
C
i(RC)
C
i(W)
C
O
PARAMETER
Input capacitance, address inputs
Input capacitance, strobe inputs
Input capacitance, write-enable inputs
Output capacitance
MAX
7
10
10
10
UNIT
pF
pF
pF
pF
SWITCHING CHARACTERISTICS
(-55
o
C<T
A
<125
o
C or -40
o
C to +85
o
C; Vcc = 5V +10%)
SYM
t
AA
t
CAC
t
CPA
t
RAC
t
OEA
t
OFF
t
OEZ
PARAMETERS
Access time from column address
Access time from CAS\ low
Access time from column precharge
Access time from RAS\ low
Access time from OE\ low
Output disable time after CAS\ High
Output disable tiem after OE\ High
4
4
-8
MAX
40
20
45
80
20
20
20
-10
MAX
45
25
50
100
25
25
25
-12
MAX
55
30
55
120
30
30
30
UNIT
ns
ns
ns
ns
ns
ns
ns
NOTES:
1. Measured with a maximum of one address change while RAS\ = V
IL
.
2. Measured with a maximum of one address change while CAS\ = V
IH
.
3. V
CC
= 5V ±0.5V and the bias on the pins under test is 0V. Capacitance is sampled only at initial design and after any major change.
4. t
OFF
and t
OEZ
are specified when the output is no longer driven. The outputs are disabled by bringing either OE\ or CAS\ High.
SMJ44400
Rev. 1.0 6/01
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
5
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