DS32KHZ View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated
Part Name
Description
Manufacturer
DS32KHZ Datasheet PDF : 8 Pages
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Figure 4. Power-Supply Connections
4.5V - 5.5V
Vcc
2.7V - 3.3V
Vbat
GND
Vcc
2.7V - 5.5V
32.768kHz out
Vbat
GND
32.768kHz out
DS32kHz
4.5V - 5.5V
Vcc
Vbat
GND
32.768kHz out
A
B
C
Figure 5 illustrates how a standard 32.768kHz crystal and the DS32kHz should be connected to address the
interchangeable option. Using this connection scheme and the recommended layout provides a solution, which
requires no hardware modifications. Only one device should be used at a time, and both layouts should be located
very close together if the recommended layout is not used.
The DS32kHz ICC and IBAT currents are specified with no output loads. Many RTC oscillator circuits use a quartz
crystal or resonator. Driving the oscillator circuit with the rail-to-rail output of the DS32kHz can increase the ICC and
IBAT currents significantly and increase the current consumption of the RTC as well. Figure 6 shows one circuit that
can be used to reduce the current consumption of a DS32kHz and an RTC. The values of R1 and C1 may vary
depending on the RTC used. However, values of 1.0MΩ and 100pF are recommended as a starting point. R2 is
used to shift the input waveform to the proper level. The recommended value for R2 is 33kΩ.
Figure 5. DS32kHz Connections
VCC
32kHz out
VBAT DS32kHz
32.768 Hz
X1 or Xin
RTC
X2 or Xout
VCC
VBAT
A PC board can be laid out so that the RTC can use either the DS32kHz or a crystal
Figure 6. DS32kHz and RTC Connections
VCC
VCC
R1 C1
1MΩ 100pF
VBAT
DS32kHz
X1
R2
33kΩ
VBAT
X2 RTC
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