DS1672 Maxim, DS1672 Datasheet - Page 7

• Manufacturer Part Number: DS1672
• Description: The DS1672 low-voltage serial timekeeping chip incorporates a 32-bit counter and power-monitoring functions
• Manufacturer: Maxim

PIN DESCRIPTION
Figure 3. Recommended Layout for Crystal
PIN
1, 2
3
4
5
6
7
8
LOCAL GROUND PLANE (LAYER 2)
V
CRYSTAL
NAME
X1, X2
GND
BACKUP
SDA
SCL
RST
V
CC
Connections for Standard 32.768kHz Quartz Crystal. The internal oscillator
circuitry is designed for operation with a crystal having a specified load
capacitance (CL) of 6pF. For more information about crystal selection and
crystal layout considerations, refer to Application Note 58: Crystal
Considerations with Dallas Real-Time Clocks. The DS1672 can also be driven
by an external 32.768kHz oscillator. In this configuration, the X1 pin is
connected to the external oscillator signal and the X2 pin is left unconnected
Battery Input for Any Standard 3V Lithium Cell or Other Energy Source.
Battery voltage must be held between 1.3V and 3.63V for proper operation.
Diodes placed in series between the power source and the V
result in improper operation. If a backup supply is not required, V
be grounded. UL recognized to ensure against reverse charging current when
used in conjunction with a lithium battery (charger disabled). See “Conditions
of Acceptability” at
Ground.
Serial-Data Input/Output. SDA is the input/output pin for the I
interface. The SDA pin is open drain and requires an external pullup resistor.
I
serial interface and requires an external pullup resistor.
Active-Low Reset Output. It functions as a microprocessor reset signal. This
pin is an open-drain output and requires an external pullup resistor.
Power pin for Primary Power Supply. When V
limits, the device is fully accessible and data can be written and read. When
V
2
C Serial-Clock Input. SCL is used to synchronize data movement on the
CC
is below V
GND
X1
X2
PF
, reads and writes are inhibited.
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FUNCTION
CC
is applied within normal
BACKUP
2
C serial
BACKUP
pin may
DS1672
must
.