Rainbow Electronics DS1243Y - Manual

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FEATURES
§ Real time clock keeps track of hundredths of
seconds, seconds, minutes, hours, days, date
of the month, months, and years
§ 8K x 8 NV SRAM directly replaces volatile
static RAM or EEPROM
§ Embedded lithium energy cell maintains
calendar operation and retains RAM data
§ Watch function is transparent to RAM
operation
§ Month and year determine the number of days
in each month; valid up to 2100
§ Lithium energy source is electrically
disconnected to retain freshness until power is
applied for the first time
§ Standard 28–pin JEDEC pinout
§ Full ±10% operating range
§ Operating temperature range 0°C to 70°C
§ Accuracy is better than ±1 minute/month @
25°C
§ Over 10 years of data retention in the absence
of power
§ Available in 120, 150 and 200 ns access time
ORDERING INFORMATION
DS1243Y–XXX
–120 120 ns access
–150 150 ns access
DS1243Y 200 ns access
PIN ASSIGNMENT
PIN DESCRIPTION
A
0
–A
12
– Address Inputs
CE – Chip Enable
GND – Ground
DQ
0
–DQ
7
– Data In/Data Out
V
CC
– Power (+5V)
WE – Write Enable
OE – Output Enable
NC – No Connect
RST – Reset
DESCRIPTION
The DS1243Y 64K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 8192
words by 8 bits) with a built–in real time clock. The DS1243Y has a self–contained lithium energy source
and control circuitry which constantly monitors V
CC
for an out–of–tolerance condition. When such a
condition occurs, the lithium energy source is automatically switched on and write protection is
unconditionally enabled to prevent corrupted data in both the memory and real time clock.
DS1243Y
64K NV SRAM with Phantom Clock
www.dalsemi.com
28-Pin Encapsulated Package
720-Mil Extended
A7
A5
A3
A2
A1
A0
DQ0
DQ1
GND
DQ2
V
CC
WE
NC
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ3
DQ4
1
2
3
4
5
6
7
8
9
10
11
12
14
13
28
27
26
25
24
23
22
21
20
19
18
17
15
16
A12
A6
A4
RST