DS1609 Datasheet, PDF (1/7 Pages) Dallas Semiconductor – Dual Port RAM

DS1609
DS1609
Dual Port RAM
FEATURES
• Totally asynchronous 256–byte dual port memory
• Multiplexed address and data bus keeps pin count
low
• Dual port memory cell allows random access with
minimum arbitration
• Each port has standard independent RAM control sig-
nals
• Fast access time
• Low power CMOS design
• 24–pin DIP or 24–pin SOIC surface mount package
• Both CMOS and TTL compatible
• Operating temperature of –40°C to +85°C
• Standby current of 100 nA @ 25°C makes the device
ideal for battery backup or battery operate applica-
tions.
DESCRIPTION
The DS1609 is a random access 256–byte dual port
memory designed to connect two asyncronous ad-
dress/data buses together with a common memory ele-
ment. Both ports have unrestricted access to all
256 bytes of memory, and with modest system disci-
pline no arbitration is required. Each port is controlled
PIN ASSIGNMENT
PORT A
AD7_A
1
AD6_A
2
AD5_A
3
AD4_A
4
AD3_A
5
AD2_A
6
AD1_A
7
AD0_A
8
WE_A
9
CE_A
10
OE_A
11
GND 12
PORT B
24
V_CC
23
OE_B
22
CE_B
21
WE_B
20
AD0_B
19
AD1_B
18
AD2_B
17
AD3_B
16
AD4_B
15
AD5_B
14
AD6_B
13
AD7_B
DS1609
24–PIN DIP (600 MIL)
See Mech. Drawings
Section
PORT A
AD7_A
1
AD6_A
2
AD5_A
3
AD4_A
4
AD3_A
5
AD2_A
6
AD1_A
7
AD0_A
8
WE_A
9
CE_A
10
OE_A
11
GND
12
PORT B
24
V_CC
23
OE_B
22
CE_B
21
WE_B
20
AD0_B
19
AD1_B
18
AD2_B
17
AD3_B
16
AD4_B
15
AD5_B
14
AD6_B
13
AD7_B
DS1609S
24–PIN SOIC (300 MIL)
See Mech. Drawings
Section
PIN DESCRIPTION
AD0–AD7
– Port address/data
CE
– Port enable
WE
– Write enable
OE
– Output enable
V_CC
GND
– +5 volt supply
– Ground
by three control signals: output enable, write enable,
and port enable. The device is packaged in plastic
24–pin DIP and 24–pin SOIC. Output enable access
time of 50 ns is available when operating at 5 volts.
020499 1/7