DS32KHZSLASHDIP datasheet(6/10 Pages) DALLAS

6 / 10 page

DS32kHz

6 of 10

Figure 2. Block Diagram

OPERATION

The DS32kHz module contains a crystal and an IC. While powered, the DS32kHz peridocially measures the

temperature and adjusts the crystal load to compensate.

The DS32kHz is designed to operate in two modes. In the dual-supply mode, a comparator circuit, powered by VCC,

monitors the relationship between the VCC and VBAT input levels. When VCC drops below a certain level compared to

VBAT, the device switches over to VBAT (Figure 3A). This mode uses VCC to conserve the battery connected to VBAT

while VCC is applied.

In the single-supply mode, VCC is grounded and the unit is powered by VBAT. Current consumption is less than that

of VCC, because the comparator circuit is unpowered (Figure 3B).

Figure 3A shows how the DS32kHz should be connected when using two power supplies. VCC should be between

4.5V and 5.5V and VBAT should be between 2.7V and 3.3V. Figure 3B shows how the DS32kHz can be used when

only a single-supply system is available. VCC should be grounded and VBAT should then be held between 2.7V and

5.5V. The VBAT pin should be connected directly to a battery. Figure 3C shows a single supply mode where VCC is

held at +5V. See the frequency stability versus operating voltage for information about frequency error versus

supply voltage.

Figure 3. Power-Supply Connections

DS32KHZ/DIP Datasheet(PDF) 6 Page - Dallas Semiconductor