DS1374_10 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – I2C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output

19-5484; Rev 4; 8/10
I²C, 32-Bit Binary Counter Watchdog RTC with
Trickle Charger and Reset Input/Output
General Description
The DS1374 is a 32-bit binary counter designed to contin-
uously count time in seconds. An additional counter gen-
erates a periodic alarm or serves as a watchdog timer. If
disabled, this counter can be used as 3 bytes of non-
volatile (NV) RAM. Separate output pins are provided for
an interrupt and a square wave at one of four selectable
frequencies. A precision temperature-compensated refer-
ence and comparator circuit monitor the status of V_CC to
detect power failures, provide a reset output, and auto-
matically switch to the backup supply when necessary.
Additionally, the reset pin is monitored as a pushbutton
input for externally generating a reset. The device is pro-
grammed serially through an I²C serial interface.
Portable Instruments
Point-of-Sale Equipment
Medical Equipment
Telecommunications
Applications
Pin Configurations appear at the end of the data sheet.
Features
♦ 32-Bit Binary Counter
♦ Second Binary Counter Provides Time-of-Day
Alarm, Watchdog Timer, or NV RAM
♦ Separate Square-Wave and Interrupt Output Pins
♦ I²C Serial Interface
♦ Automatic Power-Fail Detect and Switch Circuitry
♦ Single-Pin Pushbutton Reset Input/Open-Drain
Reset Output
♦ Low-Voltage Operation
♦ Trickle-Charge Capability
♦ -40°C to +85°C Operating Temperature Range
♦ 10-Pin µSOP, 16-Pin SO
♦ Available in a Surface-Mount Package with an
Integrated Crystal (DS1374C)
♦ Underwriters Laboratories (UL) Recognized
Typical Operating Circuit
RPU = t_r/C_B ^VCC
RPU RPU
V_CC
CPU
INT
RST
N.O.
PUSHBUTTON
RESET
V_CC
CRYSTAL
X1 X2
V_CC
SQW
SCL
SDA
DS1374
INT
RST
V_BACKUP
GND
PRIMARY
BATTERY,
RECHARGEABLE
BATTERY, OR
SUPER CAPACITOR
Ordering Information
PART
TEMP RANGE
VOLTAGE (V)
PIN-PACKAGE
TOP MARK**
DS1374C-18#
-40°C to +85°C
1.8
16 SO (300 mils)
DS1374C-18
DS1374C-3#
-40°C to +85°C
3.0
16 SO (300 mils)
DS1374C-3
DS1374C-33#
-40°C to +85°C
3.3
16 SO (300 mils)
DS1374C-33
DS1374U-18+
-40°C to +85°C
1.8
10 μSOP
DS1374-18
DS1374U-3+
-40°C to +85°C
3.0
10 μSOP
DS1374-3
DS1374U-33+
-40°C to +85°C
3.3
10 μSOP
DS1374-33
#Denotes a RoHS-compliant device that may include lead that is exempt under RoHS requirements. The lead finish is JESD97 category
e3, and is compatible with both lead-based and lead-free soldering processes.
+Denotes a lead(Pb)-free/RoHS-compliant package.
**A "#" anywhere on the top mark denotes a RoHS-compliant package. A “+” anywhere on the top mark denotes a lead(Pb)-free
package.
______________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.