DESCRIPTION
The Accutek AK58256AG/AS high density memory module is a
random access memory organized in 256K x 8 bit words. The
assembly consists of two 256K x 4 DRAMs in surface mount
packages mounted to 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 better
than 6 to 1 density increase over standard DIP packaging.
The operation of the AK58256 is identical to two 256K x 4
DRAMs. The data input/output is brought out separately for
each 256K x 4 device, with common RAS, CAS and WE control.
The OE pins are tied to Vss which dictates the use of early-write
cycles 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.
FEATURES
·262,144 x 8 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, RAS and WE control for eight DQ lines
·Separate CAS control for one separate pair of D and Q lines
·1024 refresh cycles/16ms, A0to A8
·Power:
.99 Watt Max Active (60 nS)
.88 Watt Max Active (70 nS)
.77 Watt Max Active (80 nS)
.65 Watt Max Active (100 nS)
11 mWatt standby (max)
·Operating free air temperature: 00to 700C
·Upward compatible with AK581024, AK584096 and
AK5816384
·Functionally and Pin compatible with AK48256
·Available with access times of 60 to 100 nS
Accutek
Microcircuit
Corporation
AK58256AG / AK58256AS
262,144 x 8 bit CMOS
Dynamic Random Access Memory
130
+ +
1
++
Front View
30-Pin SIM
30-Pin SIP
PIN NOMENCLATURE
DQ1-DQ
8Data In / Data Out
A0-A
8Address Inputs
CAS Column Address Strobe
RAS Row Address Strobe
WE Write Enable
Vcc 5v Supply
Vss Ground
NC No Connect
MODULE OPTIONS
Leadless SIM: AK58256AS
Leaded SIP: AK58256AG
PIN ASSIGNMENT
PIN # SYMBOL PIN # SYMBOL
1 Vcc 16 DQ5
2 CAS 17 A8
3 DQ1 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 NC
12 A5 27 RAS
13 DQ4 28 NC
14 A6 29 NC
15 A7 30 Vcc
FUNCTIONAL DIAGRAM
*
A0 - A8
DQ1
DQ2
DQ3
DQ4
RAS
CAS
WE
OE
*
*
*
A0 - A8
DQ1
DQ2
DQ3
DQ4
RAS
CAS
WE
OE
*
*
*
+
WE
+
+
CAS
RAS
A0 - A8 +
*
*
*
*
+
+
+
+
*
*
*
+
+
+
*
+
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
DQ8
*
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
60 = 60 nS 8 = 8 nS
70 = 70 nS 12 = 12 nS
80 = 80 nS 15 = 15 nS
10 = 100 nS 20 = 20 nS
12 = 120 nS 70 = 70 nS
15 = 150 nS 85 = 85 nS
The numbers and coding on this page do not include all variations
available, but are shown as examples of the most widely used vari-
ations. Contact Accutek if other information is required.
130
++
1
++
0.200"
MAX
0.053
0.047
3.510
3.490
0.260
0.240
0.085
0.075
0.325
0.275
0.100
T.P.
0.100
TYP
0.505
0.495
3.110
3.090
0.100
T.P.
0.024
0.016
0.100
TYP
0.515
0.505
3.245
3.225
0.410
0.390
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
EXAMPLES:
AK58256ASP-60
256K x 8, Dynamic RAM, Leadless SIM, Page Mode, Commercial,
60 nSEC Access Time
AK58256AGK-70
256K x 8, Dynamic RAM, Leaded SIP, Static Column Mode
Commercial, 70 nSEC AccessTime
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
