DS1337 Maxim, DS1337 Datasheet - Page 6

• Manufacturer Part Number: DS1337
• Description: The DS1337 serial real-time clock is a low-power clock/calendar with two programmable time-of-day alarms and a programmable square-wave output
• Manufacturer: Maxim

BLOCK DIAGRAM
DETAILED DESCRIPTION
The Block Diagram shows the main elements of the DS1337. As shown, communications to and from the DS1337
occur serially over an I
implementing a START condition and providing a device identification code, followed by data. Subsequent
registers can be accessed sequentially until a STOP condition is executed. The device is fully accessible through
the I
The DS1337 maintains the time and date when V
OSCILLATOR CIRCUIT
The DS1337 uses an external 32.768kHz crystal. The oscillator circuit does not require any external resistors or
capacitors to operate.
shows a functional schematic of the oscillator circuit. The startup time is usually less than 1 second when using a
crystal with the specified characteristics.
Table 1. Crystal Specifications*
*The crystal, traces, and crystal input pins should be isolated from RF generating signals. Refer to
Application Note 58: Crystal Considerations for Dallas Real-Time Clocks for additional specifications.
Nominal Frequency
Series Resistance
Load Capacitance
"C" version only
2
PARAMETER
C interface whenever V
SDA
SCL
X1
X2
INTERFACE AND
2
Table 1
C
C
SERIAL BUS
C bus. The DS1337 operates as a slave device on the serial bus. Access is obtained by
L
L
REGISTER
ADDRESS
SYMBOL
ESR
CC
C
f
O
L
is between 5.5V and 1.8V. I
specifies several crystal parameters for the external crystal. The Block Diagram
MIN
1Hz/4.096kHz/8.192kHz/32.768kHz
32.768
CC
TYP
CONTROL
DS1337
6
LOGIC
is as low as 1.3V.
6 of 16
1Hz
MAX
2
C operation is not guaranteed when V
50
UNITS
kHz
k
pF
USER BUFFER
CHARGE, AND
CLOCK AND
REGISTERS
REGISTERS
CALENDAR
CONTROL
(7 BYTES)
TRICKLE
ALARM,
BUFFER
MUX/
DS1337 I
2
C Serial Real-Time Clock
N
N
CC
SQW/INTB
INTA
is below 1.8V.