DESCRIPTION
The Accutek AK49256 high density memory modules is a random
access memory organized in 256K x 9 bit words. The assembly
consists of nine standard 256K x 1 DRAMs in plastic leaded chip
carriers (PLCC) mounted on the front side of a printed circuit board.
The module can be configured as a leadless 30 pad SIM or a leaded
30 pin SIP. This packaging approach provides a 6 to 1 density in-
crease over standard DIP packaging.
The operation of the AK49256 is identical to nine 256K x 1 DRAMs.
For the lower eight bits data input is tied to the data output and
brought out separately for each device, with common RAS and CAS
control. This common I/O feature dictates the use of early-write cy-
cles to prevent contention of D and Q. Since the Write-Enable (WE)
signal must always go low before CAS in a write cycle, Read-Write
and Read-Modify-Write operation is not possible. For the ninth bit,
the data input (D9) and the data output (Q9) pins are brought out
separately and controlled by a separate PCAS for that bit. Bit nine is
generally used for parity.
FEATURES
·262,144 by 9 bit organization
·Optional 30 Pad leadless SIM (Single In-Line Module) or 30
Pin leaded SIP (Single In-Line Package)
·JEDEC standard pinout
·Common CAS and RAS control for the lower eight bits
·Separate PCAS control for D9and Q9
·3.15 Watt active and 205 mW standby (max)
·Operating free air temperature 00Cto70
0C
·Upward compatible with AK491024, AK591024, AK594096
and AK5916384
·Functionally and Pin compatible with AK59256A
Accutek
Microcircuit
Corporation
AK49256S / AK49256G
262,144 Word by 9 Bit MOS
Dynamic Random Access Memory
130
1
Front View
30-Pin SIM
30-Pin SIP
PIN NOMENCLATURE
A0-A
8Address Inputs
DQ1-DQ
8Data In / Data Out
D9Data In 9
Q9Data Out 9
CAS, PCAS Column Address Strobe
RAS Row Address Strobe
WE Write Enable
Vcc 5v Supply
Vss Ground
NC No Connect
MODULE OPTIONS
Leadless SIM: AK49256S
Leaded SIP: AK49256G
PIN ASSIGNMENT
PIN # SYMBOL PIN # SYMBOL
1 Vcc 16 DQ5
2 CAS 17 A8
3 DQ! 18 NC
4A019NC
5 A1 20 DQ6
6 DQ2 21 WE
7 A2 22 Vss
8 A3 23 DQ7
9 Vss 24 NC
10 DQ3 25 DQ8
11 A4 26 Q9
12 A5 27 RAS
13 DQ4 28 PCAS
14 A6 29 D9
15 A7 30 Vcc
FUNCTIONAL DIAGRAM
ORDERING INFORMATION
PART NUMBER CODING INTERPRETATION
Position 12345678
1 Product
AK = Accutek Memory
2 Type
4 = Dynamic RAM
5 = CMOS Dynamic RAM
6 = Static RAM
3 Organization/Word Width
1 = by 1 16 = by 16
4 = by 4 32 = by 32
8 = by 8 36 = by 36
9 = by 9
4 Size/Bits Depth
64 = 64K 4096 = 4 MEG
256 = 256K 8192 = 8 MEG
1024 = 1 MEG 16384 = 16 MEG
5 Package Type
G = Single In-Line Package (SIP)
S = Single In-Line Module (SIM)
D = Dual In-Line Package (DIP)
W = .050 inch Pitch Edge Connect
Z = Zig-Zag In-Line Package (ZIP)
6 Special Designation
P = Page Mode
N = Nibble Mode
K = Static Column Mode
W = Write Per Bit Mode
V = Video Ram
7 Separator
- = Commercial 00Cto+70
0C
M = Military Equivalent Screened
(-550C to +1250C)
I = Industrial Temperature Tested
(-450Cto+85
0C)
X = Burned In
8 Speed (first two significant digits)
DRAMS SRAMS
50 = 50 nS 8 = 8 nS
60 = 60 nS 10 = 10 nS
70 = 70 nS 12 = 12 nS
80 = 80 nS 15 = 15 nS
130
3.525
3.475
0.100
TYP
0.325
0.275
0.100
T.P.
3.100
3.090
0.024
0.016
0.425
0..375
.100
.060
0.685
0.635
1
0.685
0.635
0.100
TYP
0.100
TYP
0.200"
MAX
0.053
0.047
ACCUTEK MICROCIRCUIT CORPORATION
BUSINESS CENTER at NEWBURYPORT
2 NEW PASTURE ROAD, SUITE 1
NEWBURYPORT, MA 01950-4054
VOICE: 978-465-6200 FAX: 978-462-3396
Email: sales@accutekmicro.com
Internet: www.accutekmicro.com
Accutek reserves the right to make changes in specifications at any
time and without notice. Accutek does not assume any responsibil-
ity for the use of any circuitry described; no circuit patent licenses
are implied. Preliminary data sheets contain minimum and maxi-
mum limits based upon design objectives, which are subject to
change upon full characterization over the specific operating condi-
tions.
MECHANICAL DIMENSIONS
Inches
The numbers and coding on this page do not include all variations
available but are show as examples of the most widely used variations.
Contact Accutek if other information is required.
EXAMPLES:
AK49256SP-10
256K x 9, 100 nSEC DRAM 30 pin SIM Configuration, Page Mode
AK49256GK-80
256K x 9, 80 nSEC DRAM 30 pin SIP Configuration, Static Column Mode
