DS1337C Maxim, DS1337C Datasheet - Page 7

• Manufacturer Part Number: DS1337C
• 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

CLOCK ACCURACY
The accuracy of the clock is dependent upon the accuracy of the crystal and the accuracy of the match between
the capacitive load of the oscillator circuit and the capacitive load for which the crystal was trimmed. Crystal
frequency drift caused by temperature shifts creates additional error. External circuit noise coupled into the
oscillator circuit can result in the clock running fast.
crystal and oscillator from noise. Refer to Application Note 58: Crystal Considerations with Dallas Real-Time
Clocks for detailed information.
Figure 1. Typical PC Board Layout for Crystal
DS1337C ONLY
The DS1337C integrates a standard 32,768Hz crystal in the package. Typical accuracy at nominal V
is approximately +10ppm. Refer to Application Note 58 for information about crystal accuracy vs. temperature.
OPERATING MODES
The amount of current consumed by the DS1337 is determined, in part, by the I
operation. The following table shows the relationship between the operating mode and the corresponding I
parameter.
Operating Mode
I
I
I
I
Oscillator Disabled
2
2
2
2
C Interface Active
C Interface Inactive
C Interface Inactive
C Interface Inactive
LOCAL GROUND PLANE (LAYER 2)
NOTE: AVOID ROUTING SIGNALS IN THE CROSSHATCHED
AREA (UPPER LEFT-HAND QUADRANT) OF THE PACKAGE
UNLESS THERE IS A GROUND PLANE BETWEEN THE SIGNAL
LINE AND THE PACKAGE.
CRYSTAL
V
1.8V ≤ V
1.8V ≤ V
1.3V ≤ V
1.3V ≤ V
CC
CC
CC
CC
CC
GND
X1
X2
≤ 5.5V
≤ 5.5V
≤ 1.8V
≤ 1.8V
Power
Data Retention
(I
I
I
Timekeeping (I
CC
CC
CCTDDR
Active (I
Standby (I
7 of 16
Figure 1
)
CCA
CCS
)
CCTOSC
shows a typical PC board layout for isolating the
)
)
DS1337 I
2
C interface and oscillator
2
C Serial Real-Time Clock
CC
and +25°C
CC