DESCRIPTION
The Accutek AK59256A high density memory modules is a random
access memory organized in 256K x 9 bit words. The assembly
consists of two 256K x 4 and one 256K x 1 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 den-
sity increase over standard DIP packaging.
The operation of the AK59256A is identical to two 256K x 4 DRAMs
plus one 256K x 1 DRAM. For the lower eight bits data input is tied
to data output and 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 conten-
tion 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
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 x 9 bit organization
·Optional 30 Pad SIM (Single In-Line Module) or 30 Pin leaded
SIP (Single In-Line Package)
·JEDEC standard pinout
·Common CAS, RAS and WE control for the lower eight bits
·Separate PCAS control for D9and Q9
·Power:
1.26 Watt Max Active (70 nSEC)
1.10 Watt Max Active (80 nSEC)
.935 Wat Max Active (100 nSEC)
22 mWatt Standby (Max)
·Operating free air temperature: 0oto 70oC
·Upward compatible with AK491024, AK591024, AK594096
and AK5916384
·Functionally and Pin compatible with AK49256
·Available with access times of 60 nSEC to 100 nSEC
Accutek
Microcircuit
Corporation
AK59256AS / AK59256AG
262,144 Word by 9 bit, CMOS
Dynamic Random Access Memory
130
+ +
1
++
Front View
30-Pin SIM
30-Pin SIP
PIN NOMENCLATURE
DQ1-DQ
8Data In / Data Out
D9Data In
Q9Data Out
A0-A
9Address Inputs
CAS, PCAS Column Address Strobe
RAS Row Address Strobe
WE Write Enable
Vcc 5v Supply
Vss Ground
NC No Connect
MODULE OPTIONS
Leadless SIM: AK59256AS
Leaded SIP: AK59256AG
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 Q9
12 A5 27 RAS
13 DQ4 28 PCAS
14 A6 29 D9
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
*
*
*
A0 - A8
D
RAS
CAS
WE
Q
*
*
*
+
WE
+
+
CAS
RAS
A0 - A8 +
*
*
*
*
+
+
+
+
*
*
*
+
+
+
*
+
*
+
*
+
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
DQ8
D9
Q9
*
+
PCAS
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
++
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
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:
AK59256AGP-60
256K x 9, 60 nSEC, DRAM, SIP Configuration, 30 Pin, Page Mode
AK59256ASP-70
256K x 9, 70 nSEC, DRAM, SIM Configuration, 30 Pin, Page Mode
