DS3231MZ+ MAXIM [Maxim Integrated Products], DS3231MZ+ Datasheet - Page 9

• Manufacturer Part Number: DS3231MZ+
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 4. Single Supply (V
Figure 5. Single Supply (V
Figure 6. Dual Power Supply
Table 1. Power Control
CONFIGURATION
Dual Supply
V
(Figure 4)
(Figure 5)
(Figure 6)
V
BAT
CC
Only
Only
CONDITION
CC
BAT
V
V
V
V
+3.3V
+3.3V
EOSC = 0
EOSC = 1
V
V
V
CC
CC
CC
CC
CC
CC
CC
Only)
Only)
V
V
V
> V
< V
> V
< V
BAT
BAT
BAT
PF
PF
PF
PF
V
V
CC
CC
> V
< V
I/O ACTIVE
BAT
BAT
±5ppm, I
I
I
I
BATA
CCA
CCA
I
I
BATA
CCA
The temperature sensor, oscillator, and digital adjust-
ment controller logic form the highly accurate time base.
The controller reads the output of the on-board tempera-
ture sensor and adjusts the final 1Hz output to maintain
the required accuracy. The device is trimmed at the
factory to maintain a tight accuracy over the operating
temperature range. When the device is powered by V
the adjustment occurs once a second. When the device
is powered by V
10s to conserve power. Adjusting the 1Hz time base less
often does not affect the device’s long-term timekeeping
accuracy. The device also contains an Aging Offset reg-
ister that allows a constant offset (positive or negative) to
be added to the factory-trimmed adjustment value.
The DS3231M can be configured to operate on a single
power supply (using either V
supply configuration, which provides a backup supply
source to keep the timekeeping circuits alive during
absence of primary system power.
Figure 4 illustrates a single-supply configuration using
V
the RST output is asserted (active low). Temperature
conversions are executed once per second.
Figure 5 illustrates a single-supply configuration using
V
is disabled and is held at ground through the connection
of the internal pullup resistor. Temperature conversions
are executed once every 10s.
Figure 6 illustrates a dual-supply configuration, using
the V
V
power-selection function is provided by a temperature-
compensated voltage reference and a comparator circuit
that monitors the V
V
than V
CC
BAT
BAT
PF
, the device is powered by V
only, with the V
only, with the V
CC
supply for backup power. In this configuration, the
V
V
PF
CC
CC
2
supply for normal system operation and the
but greater than V
> V
< V
C Real-Time Clock
I/O INACTIVE
BAT
BAT
I
BAT
BATDR
I
I
I
BATT
CCS
CCS
BAT
Power-Supply Configurations
CC
, the adjustment occurs once every
CC
High-Accuracy Time Base
input grounded. When V
level. When V
input grounded. The RST output
I
I
BATT
CCS
BAT
CC
, the device is powered
or V
CC
. When V
CC
BAT
Disabled (Low)
Inactive (High)
Inactive (High)
Active (Low)
Active (Low)
is greater than
) or in a dual-
RST
CC
CC
is less
< V
CC
PF
9
,
,