AN1011

Battery status for NVRAMs and serial RTCs

Doc ID 6254 Rev 4

5/11

Battery status for NVRAMs and serial RTCs

For the devices listed in Table 1 and 2, the battery can be internal or external to the IC

package. In the external cases, the battery will either be a user-supplied battery or it may

be incorporated into ST's SNAPHAT package which mates to the underlying IC as depicted

in Figure 6 on page 6.

Figure 4 shows the CAPHAT IC package with the battery integrated with the IC. In this

package, the battery is encapsulated within the device.

Figure 5 is representative of several IC packages all of which use a customer-supplied,

external battery. None of these device types include the battery in the IC package.

Figure 6 on page 6 shows ST's SNAPHAT SOH28 (SOIC) package with mating SNAPHAT

battery top. Here, there is no battery in the IC package. Instead, it is a separate,

removable/replaceable unit stacked on top of the IC which reduces board space.

Figure 4.

CAPHAT IC package

Figure 5.

External battery, user supplied

CAPHAT and

Hybrid DIPs:

Internal battery

encapsulated in

device package

External,

user supplied

battery

Serial RTC