DS1339 Maxim, DS1339 Datasheet - Page 8

• Manufacturer Part Number: DS1339
• Description: The DS1339 serial real-time clock (RTC) is a low-power clock/date device with two programmable time-of-day alarms and a programmable square-wave output
• Manufacturer: Maxim

PIN DESCRIPTION
TYPICAL OPERATING CIRCUIT
µSOP
—
1
2
3
4
5
6
7
8
VCC
CPU
PIN
RPU
4–13
SO
14
15
16
—
—
1
2
3
RPU
VCC
SQW/INT
V
NAME
GND
SDA
BACKUP
N.C.
SCL
6
5
V
X1
X2
CRYSTAL
1
CC
X1
SCL
SDA
DS1339
X2
2
GND
SQW/INT
Connections for Standard 32.768kHz Quartz Crystal. The internal oscillator
circuitry is designed for operation with a crystal having a specified load
capacitance (C
DS1339. In this configuration, the X1 pin is connected to the external oscillator
signal and the X2 pin is left unconnected.
For more information about crystal selection and crystal layout considerations,
refer to Application Note 58: Crystal Considerations with Dallas Real-Time
Clocks.
Secondary Power Supply. Supply voltage must be held between 1.3V and 3.7V
for proper operation. This pin can be connected to a primary cell, such as a
lithium button cell. Additionally, this pin can be connected to a rechargeable cell
or a super cap when used in conjunction with the trickle-charge feature. Diodes
should not be placed in series between the backup source and the V
or improper operation will result. If a backup supply is not required, V
be grounded. UL recognized to ensure against reverse charging current when
used with a lithium cell. For more information, visit www.maxim-ic.com/qa/info/ul.
Ground. DC power is provided to the device on these pins.
Serial Data Input/Output. SDA is the input/output pin for the I
The SDA pin is an open-drain output and requires an external pullup resistor.
The pull up voltage may be up to 5.5V regardless of the voltage on V
Serial Clock Input. SCL is used to synchronize data movement on the I
interface. The pull up voltage may be up to 5.5V regardless of the voltage on
V
Square-Wave/Interrupt Output. Programmable square-wave or interrupt output
signal. The SQW/INT pin is an open-drain output and requires an external pullup
resistor. The pull up voltage may be up to 5.5V regardless of the voltage on V
If not used, this pin may be left unconnected.
Primary Power Supply. When voltage is applied within normal limits, the device
is fully accessible and data can be written and read. When a backup supply is
connected and V
and alarm functions operate when the device is powered by V
No Connection. These pins are unused and must be connected to ground.
V
4
BACKUP
VCC
VCC
CC
8
.
7
3
i
L
) of 6pF. An external 32.768kHz oscillator can also drive the
CC
is below V
8 of 20
PF
, reads and writes are inhibited. The timekeeping
FUNCTION
DS1339 I
2
C Serial Real-Time Clock
2
C serial interface.
CC
or V
BACKUP
BACKUP
BACKUP
CC
2
.
C serial
.
input,
must
CC
.