Accutek
Microcircuit
Corporation
AK58256AG / AK58256AS
262,144 x 8 bit CMOS
Dynamic Random Access Memory
DESCRIPTION
Front View
30-Pin SIM
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.
+
+
30
1
30-Pin SIP
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.
+
+
1
FEATURES
· Power:
· 262,144 x 8 bit organization
.99 Watt Max Active (60 nS)
· Optional 30 Pad leadless SIM (Single In-Line Module) or 30
Pin leaded SIP (Single In-Line Package)
.88 Watt Max Active (70 nS)
.77 Watt Max Active (80 nS)
.65 Watt Max Active (100 nS)
11 mWatt standby (max)
· 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, A0 to A8
· Operating free air temperature: 00 to 700C
· Upward compatible with AK581024, AK584096 and
AK5816384
· Functionally and Pin compatible with AK48256
· Available with access times of 60 to 100 nS
PIN NOMENCLATURE
PIN ASSIGNMENT
FUNCTIONAL DIAGRAM
PIN #
1
SYMBOL
Vcc
CAS
DQ1
A0
PIN #
SYMBOL
DQ5
A8
DQ1 - DQ8
A0 - A8
CAS
Data In / Data Out
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Address Inputs
Column Address Strobe
Row Address Strobe
Write Enable
2
3
NC
A0 - A8
+
A0 - A8
RAS
CAS
WE
4
NC
RAS
RAS
CAS
WE
+
+
+
*
*
*
5
A1
DQ6
WE
Vss
DQ7
NC
WE
6
DQ2
A2
DQ1
DQ2
DQ3
DQ4
DQ1 +
*
7
Vcc
5v Supply
DQ2
DQ3
DQ4
+
+
+
*
*
*
8
A3
Vss
Ground
OE
*
9
Vss
DQ3
A4
NC
No Connect
10
11
12
13
14
15
DQ8
NC
A5
RAS
NC
A0 - A8
RAS
CAS
WE
MODULE OPTIONS
*
*
*
DQ4
A6
NC
Leadless SIM: AK58256AS
Leaded SIP: AK58256AG
DQ1
DQ2
DQ3
DQ4
A7
Vcc
DQ5 +
*
DQ6
DQ7
DQ8
+
+
+
*
*
*
OE
*