19-5503; Rev 9/10
DS1746/DS1746P
Y2K-Compliant, Nonvolatile Timekeeping RAMs
www.maxim-ic.com
FEATURES
PIN CONFIGURATIONS
. Integrated NV SRAM, Real-Time Clock,
Crystal, Power-Fail Control Circuit, and
Lithium Energy Source
. Clock Registers are Accessed Identically to
the Static RAM. These Registers are Resident
in the Eight Top RAM Locations.
. Century Byte Register (i.e., 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
TOP VIEW
N.C.
A16
A14
A12
A7
VCC
A15
N.C.
WE
A13
A8
1
32
31
Maxim
DS1746
2
3
4
30
29
5
6
28
27
A6
A5
A9
A11
7
8
26
25
A4
A3
OE
A10
CE
9
10
24
23
A2
A1
11
12
22
21
DQ7
DQ6
DQ5
DQ4
DQ3
A0
13
14
15
16
20
19
18
17
DQ0
DQ1
DQ2
. Battery Voltage-Level Indicator Flag
. Power-Fail Write Protection Allows for ±10%
GND
V
CC Power Supply Tolerance
Encapsulated DIP
. 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
. Also Available in Industrial Temperature
Range: -40°C to +85°C
N.C.
A15
A16
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
N.C.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Maxim
DS1746P
N.C.
A14
A13
A12
A11
A10
A9
RST
VCC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
A8
A7
A6
A5
A4
A3
A2
A1
A0
DQ2
DQ1
DQ0
GND
X1 GND
VBAT
X2
PowerCap Module Board
(Uses DS9034PCX PowerCap)
. Underwriters Laboratories (UL) recognized
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata.
1 of 16