DS1743/DS1743P
Y2KC Nonvolatile Timekeeping RAM
www.dalsemi.com
FEATURES
PIN ASSIGNMENT
ꢀ
Integrated NV SRAM, real time clock, crystal, power-
fail control circuit and lithium energy source
NC
A12
A7
A6
A5
A4
A3
A2
A1
1
2
3
4
5
6
7
8
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC
ꢀ
Clock registers are accessed identical to the static
RAM. These registers are resident in the eight top
RAM locations.
Century byte register
Totally nonvolatile with over 10 years of operation in
the absence of power
BCD coded century, year, month, date, day, hours,
minutes, and seconds with automatic leap year
compensation valid up to the year 2100
Battery voltage level indicator flag
WE
CE2
A8
A9
A11
OE
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
A10
CE
9
A0
10
11
12
13
14
DQ7
DQ6
DQ5
DQ4
DQ3
DQ0
DQ1
DQ2
GND
ꢀ
ꢀ
Power-fail write protection allows for ±10% VCC
power supply tolerance
28-Pin Encapsulated Package
(700-mil Extended)
ꢀ
ꢀ
Lithium energy source is electrically disconnected to
retain freshness until power is applied for the first time
DIP Module only
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
NC
NC
NC
NC
A12
A11
A10
A9
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
NC
NC
NC
–
Standard JEDEC bytewide 8k x 8 static RAM
pinout
RST
VCC
WE
OE
CE
ꢀ
PowerCap Module Board only
–
Surface mountable package for direct connection
to PowerCap containing battery and crystal
A8
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
A7
A6
A5
A4
A3
A2
A1
A0
–
–
–
Replaceable battery (PowerCap)
Power-On Reset Output
Pin for pin compatible with other densities of
DS174XP Timekeeping RAM
VBAT X2
X1 GND
19
18
34-Pin Powercap Module Board
(Uses DS9034PCX Powercap)
ORDERING INFORMATION
DS1743P-XXX (5V)
PIN DESCRIPTION
-70
70 ns access
100 ns access
A0-A12
- Address Input
-100
CE
- Chip Enable
blank 28-pin DIP Module
CE2
- Chip Enable 2 (DIP
Module only)
- Output Enable
P
34-pin PowerCap Module
board*
OE
WE
- Write Enable
- Power Supply Input
- Ground
- Data Input/Output
- No Connection
- Power-On Reset Output
(PowerCap Module board only)
- Crystal Connection
- Battery Connection
*DS1743WP-XXX
(3.3V)
-120
-150
VCC
120 ns access
150 ns access
GND
DQ0-DQ7
NC
blank 28-pin DIP Module
P
34-pin PowerCap Module
board*
RST
*DS9034PCX (PowerCap) Required:
X1, X2
VBAT
(must be ordered separately)
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