Rainbow Electronics DS1374 - Manual

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 I
2 C™ serial interface.
Applications
Portable Instruments
Point-of-Sale Equipment
Medical Equipment
Telecommunications
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
♦ I
2 C 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 Laboratory (UL) Recognized
DS1374
I
2
C, 32-Bit Binary Counter Watchdog RTC with
Trickle Charger and Reset Input/Output
______________________________________________ Maxim Integrated Products 1
Ordering Information
DS1374
X1 X2
CRYSTAL
V CC
V CC
SQW
SCL
SDA
INT
RST
INT
RST
GND
V BACKUP
V CC
V CC
N.O.
PUSHBUTTON
RESET
PRIMARY
BATTERY,
RECHARGEABLE
BATTERY, OR
SUPER CAPACITOR
CPU
RPU
RPU = t r /C B
RPU
Typical Operating Circuit
Rev 1; 9/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART TEMP RANGE
PIN-
PACKAGE
TOP MARK
DS1374U-18 -40°C to +85°C 10 µSOP DS1374-18
DS1374U-3 -40°C to +85°C 10 µSOP DS1374-3
DS1374U-33 -40°C to +85°C 10 µSOP DS1374-33
DS1374C-18 -40°C to +85°C 16 SO, 0.300" DS1374C-18
DS1374C-3 -40°C to +85°C 16 SO, 0.300" DS1374C-3
DS1374C-33 -40°C to +85°C 16 SO, 0.300" DS1374C-33
I 2 C is a trademark of Philips Corp. Purchase of I 2 C compo-
nents of Maxim Integrated Products, Inc., or one of its subli-
censed Associated Companies, conveys a license under the
Philips I
2 C Patent Rights to use these components in an I 2 C
system, provided that the system conforms to the I 2 C Standard
Specification as defined by Philips.
Pin Configurations appear at the end of the data sheet.