AK49256S_09 Datasheet, PDF (1/2 Pages) ACCUTEK MICROCIRCUIT CORPORATION – Dynamic Random Access Memory

ACCUTEK
MICROCIRCUIT CORPORATION
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.
AK49256S / AK49256G
262,144 Word by 9 Bit MOS
Dynamic Random Access Memory
Front View
30-Pin SIM
1
30
30-Pin SIP
1
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 D₉ and Q₉
· 3.15 Watt active and 205 mW standby (max)
· Operating free air temperature 0⁰C to 70⁰C
· Upward compatible with AK491024, AK591024, AK594096 and
AK5916384
· Functionally and Pin compatible with AK59256A
PIN NOMENCLATURE
PIN ASSIGNMENT
FUNCTIONAL DIAGRAM
A0 - A8
DQ1 - DQ8
Address Inputs
Data In / Data Out
PIN #
1
2
SYMBOL
Vcc
CAS
PIN #
16
17
SYMBOL
DQ5
A8
D9
Q9
CAS, PCAS
Data In 9
3
4
Data Out 9
5
Column Address Strobe ₆
DQ!
18
NC
A0
19
NC
A1
20
DQ6
DQ2
21
WE
RAS
WE
Vcc
Row Address Strobe
7
A2
22
Vss
Write Enable
5v Supply
8
A3
23
DQ7
9
Vss
24
NC
10
DQ3
25
DQ8
Vss
Ground
NC
No Connect
11
A4
26
Q9
12
A5
27
RAS
13
DQ4
28
PCAS
MODULE OPTIONS
14
A6
29
D9
15
A7
30
Vcc
Leadless SIM: AK49256S
Leaded SIP: AK49256G