PRELIMINARY
DS1746/DS1746P
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
Clock registers are accessed identical to the
static RAM. These registers are resident in the
eight top RAM locations.
Century byte register; ie., Y2K compliant
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
Power-fail write protection allows for ±10%
V CC power supply tolerance
Lithium energy source is electrically
disconnected to retain freshness until power is
applied for the first time
DIP Module only
- Standard JEDEC Byte-wide 128k x 8
static RAM pinout
PowerCap Module Board only
- Surface mountable package for direct
connection to PowerCap containing
battery and crystal
- Replaceable battery (PowerCap)
- Power-On Reset Output
- Pin for pin compatible with other densities
of DS174XP Timekeeping RAM
NC
A16
A14
A12
A7
A6
A5
A4
A3
A2
A1
32
31
30
29
28
27
26
25
24
23
22
21
VCC
A15
NC
WE
A13
A8
A9
A11
OE
A10
CE
A0
1
2
3
4
5
6
7
8
9
10
11
12
DQ0
13
20
DQ6
DQ1
DQ2
14
19
DQ5
15
DQ4
GND
16
18
17
DQ7
DQ3
32-PIN ENCAPSULATED
PACKAGE
NC
A15
A16
RST
VCC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
X1
GND VBAT
X2
NC
NC
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
34-PIN POWERCAP MODULE BOARD
(USES DS9034PCX POWERCAP)
1 of 18
021800
