CDP1822C/3
High-Reliability CMOS
256-Word x 4-Bit LSI Static RAM
March 1997
Features
Description
• For Applications in Aerospace, Military, and Critical
Industrial Equipment
The CDP1822C/3 is a 256 word by 4-bit random access
memory designed for use in memory systems where high
speed, low operating current, and simplicity in use are
desirable. The CDP1822 features high speed and excellent
noise immunity. It has separate data inputs and outputs and
utilizes a single power supply of 4V to 6.5V.
• Interfaces Directly with CDP1802 Microprocessor
• Very Low Operating Current
- At V
= 5V and Cycle Time = 1µs . . . . . . 4mA (Typ)
DD
Two Chip Select inputs simplify system expansion. An output
Disable control provides Wire-OR-capability and is also
useful in common Input/Output systems. The Output Disable
input allows this RAM to be used in common data Input/Out-
put systems by forcing the output into a high impedance
state during a write operation independent of the Chip Select
input condition. The output assumes a high impedance state
when the Output Disable is at high level or when the chip is
deselected by CS1 and/or CS2.
• Static CMOS Silicon-On-Sapphire Circuitry
- CD4000 Series Compatible
• Industry Standard Pinout
• Two Chip Select Inputs - Simple Memory Expansion
• Memory Retention for Standby. . . . . . . . . . . . . 2V (Min)
Battery Voltage
• Single Power Supply Operation . . . . . . . . . . 4V to 6.5V
The high noise immunity of the CMOS technology is
preserved in this design. For TTL interfacing at 5V operation,
excellent system noise margin is preserved by using an
external pull-up resistor at each input.
• High Noise Immunity 30% of V . . . . . . . . . 4V to 6.5V
DD
• Output Disable for Common I/O Systems
• Three-State Data Output for Bus Oriented Systems
• Separate Data Inputs and Outputs
• Latch-Up-Free Transient Radiation Tolerance
Ordering Information
PART
PACKAGE
SBDIP
TEMP. RANGE
NUMBER
PKG. NO.
o
o
-55 C to +125 C CDP1822CD3
D22.4A
Pinout
CDP1822C/3 (SBDIP)
OPERATIONAL MODES
INPUTS
TOP VIEW
CHIP
CHIP
22
V
DD
A3
A2
A1
A0
A5
A6
A7
1
2
SELECT SELECT OUTPUT READ/
21 A4
1
2
DISABLE WRITE
3
MODE
Read
(CS1)
(CS2)
(OD)
(R/W)
OUTPUT
Read
20
19
18
17
16
15
14
13
12
R/W
4
CS1
O. D.
CS2
DO4
DI4
0
0
0
1
1
1
0
0
1
1
0
0
5
Write
Data In
6
Write
High
Impedance
7
8
Standby
Standby
1
X
X
X
0
X
X
1
X
X
X
High
Impedance
V
SS
9
DI1
DO3
DI3
High
Impedance
10
11
DO1
DI2
DO2
Output
X
High
Disable
Impedance
Logic 1 = High, Logic 0 = Low, X = Don’t Care
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
File Number 2981.1
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