DS1374U-18 Maxim Integrated Products, DS1374U-18 Datasheet - Page 8

• Manufacturer Part Number: DS1374U-18
• Description: Real Time Clock I2C-Compatible 32-Bi t Binary Counter Wat
• Manufacturer: Maxim Integrated Products

Specifications of DS1374U-18

• Function: Clock, Calendar, Elapsed Time Counter, Watchdog Timekeeper
• Supply Voltage (max): 1.89 V
• Supply Voltage (min): 1.71 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Rtc Bus Interface: Serial
• Package / Case: uSOP
• Time Format: Binary

I
Trickle Charger and Reset Input/Output
Figure 4. Functional Diagram
8
μSOP
2
1, 2
10
—
3
4
5
6
7
8
9
C, 32-Bit Binary Counter Watchdog RTC with
_____________________________________________________________________
PIN
5–12
SO
13
14
15
16
—
1
2
3
4
V
V
BACKUP
NAME
X1, X2
BACKUP
GND
SQW
SDA
SDA
N.C.
GND
RST
SCL
V
SCL
V
INT
X1
X2
CC
CC
Connections for a Standard 32.768kHz Quartz Crystal. The internal oscillator circuitry is designed
for operation with a crystal having a specified load capacitance (C
oscillator and can optionally be connected to an external 32.768kHz oscillator. The output of the
internal oscillator, pin X2, is left unconnected if an external oscillator is connected to pin X1.
Connection for a Secondary Power Supply. This supply is used to operate the oscillator and
counters when V
1.3V and 5.5V (-33) for proper operation. This pin can be connected to a primary cell such as a
lithium cell. Additionally, this pin can be connected to a rechargeable cell or a super cap when
used with the trickle-charge feature. UL recognized to ensure against reverse charging when used
with a lithium battery. This pin must be grounded if not used.
Active-Low, Open-Drain Output with a Debounced Pushbutton Input. This pin can be activated by a
pushbutton reset request, a watchdog alarm condition, or a power-fail event. It has an internal 50k
pullup resistor. No external resistors should be connected. If the crystal oscillator is disabled, the
startup time of the oscillator is added to the t
Ground
Serial Data Input/Output. SDA is the input/output for the 2-wire serial interface. The SDA pin is open
drain and requires an external pullup resistor.
Serial Clock Input. SCL is the clock input for the 2-wire serial interface and is used to synchronize
data movement on the serial interface.
Interupt. This pin is used to output the alarm interrupt or the watchdog reset signal. It is active-low
open drain and requires an external pullup resistor.
Square-Wave Output. This pin is used to output the programmable square-wave signal. It is open
drain and requires an external pullup resistor.
DC Power for Primary Power Supply
No Connection. Must be connected to ground.
INTERFACE
CONTROL
TRICKLE
CHARGE
DIVIDER
POWER
CLOCK
2-WIRE
AND
CC
is absent. Supply voltage must be held between 1.3V and 3.7V (-18 and -3) or
32.768kHz
WATCHDOG
4.096kHz
8.192kHz
STAT/CTRL/
COUNTER
TRICKLE
ALARM/
32-BIT
1Hz
MUX
RST
FUNCTION
delay.
DS1374
COUNTER
24-BIT
1Hz/4.096kHz
CONTROL
CONTROL
L
) of 6pF. Pin X1 is the input to the
RST
INT
Pin Description
INT
SQW
RST