M4T28-BR12SH, M4T32-BR12SH
SUMMARY DESCRIPTION
®
The M4TXX-BR12SH SNAPHAT top is a detach-
able lithium power source for ST’s non-volatile
The SNAPHAT top contains both the battery and
crystal and is designed to be “snapped on” after
the SOIC is surface mounted on the PC board.
Thus the two piece solution prevents the battery
and crystal from being exposed to the high tem-
peratures of the surface mount process.
®
TIMEKEEPER surface-mount SOIC (MH) pack-
age (28- and 44-pin).
Figure 2. Logic Diagram
Table 1. Signal Names
X1
X2
V
Crystal Input
Crystal Output
Negative Voltage
Positive Voltage
X1
X2
BAT–
V
BAT+
SNAPHAT
V
V
BAT+
BAT–
AI02528
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