1/7November 1999
M4TXX-BR12SH
TIMEKEEPER SNAPHAT (Battery & Crystal)
■Provides BatteryBackup PowerforNon-Volatile
TIMEKEEPERs and Controllers in the
SNAPHAT SOIC Package
■Removable Battery Avoids Heat Associated
with Surface Mount Process
■Snaps Directly onto Surface-Mounted
SNAPHAT SOIC
■Choice of Battery Capacities
– M4T28-BR12SH = 48 mAh
– M4T32-BR12SH = 120 mAh
■Keyed Insertion to Insure Proper Assembly
■Removable for Replacement and Proper
Disposal
■Available in Tubes or Tape & Reel
■For Use with the 28 and 44 pin SOIC Versions
of the TIMEKEEPER Product Families
DESCRIPTION
The M4Txx-BR12SH SNAPHAT top is a detach-
able lithium power source for ST’s non-volatile
TIMEKEEPER surface mount SOIC (MH) pack-
age (28 and 44 pin).
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 avoids the battery and
crystal fromhaving to be exposed to the high tem-
peratures of the surface mount process.
SNAPHAT (SH)
Battery & Crystal
Figure 1. Logic Diagram
AI02528
SNAPHAT
VBAT– VBAT+
X1 X2
M4TXX-BR12SH
2/7
MECHANICAL INFORMATION
Electrical connectionto the SOIC is made through
four pins that connect to the fourpress fitted sock-
ets at each end of the SOIC. Critical contact
points between the pins and sockets are gold-plat-
ed to resist oxidation. Internally,each socket con-
tains six independent contact fingers to form
redundant connections between the two compo-
nents. These sockets were designed with high
point contact force to provide the lowest possible
contact resistance. The SNAPHAT top also incor-
porates four molded-in retaining clips which hold
onto the ends of the SOIC insuring mechanical
and electrical connection even under severe me-
chanical shock andvibration. Thecombined SOIC
and SNAPHAT assembly can sustain shock levels
in excess of 100 g without separating. This pack-
age also passes variable frequency testing in ac-
cordance with MIL-STD-883, method 2007.2,
condition A.
Figure 2 illustrates the affect of repeated insertion
and extraction of the SNAPHAT top to the SOIC.
The force required to extract the SNAPHAT, and
then to re-insert it, reduces each time. After three
or four extractions, though, the reduction starts to
become unnoticeable, and the force required
remains at a fairly constant figure. Typically,
though, the SNAPHAT will only need to be
extracted and re-inserted once in its lifetime.
BATTERY CHARACTERISTICS
Figure 3 illustrates the lithium coin cell discharge
rate for a given load. This demonstrates the char-
Figure 2. SNAPHAT Insertion/Extraction Forces
AI02526
0
2.5
5
Force (pounds)
123 6
Number of Extractions
45 7
7.5
10
12.5
5
7.5
20
9810
Average Insertion
Force
Average Extraction Force
Table 1. Description
Parameter Value
Operating
Temperature 1=0to70°C
6 = –40 to 85 °C
Storage
Temperature –40 to 85 °C
Nominal Crystal
Frequency 32.768 kHz
Load Capacitance 12.5 pF
Nominal
Battery Voltage 2.8 V
Nominal
Battery Capacity 48 mAh M4T28
120 mAh M4T32
Battery Chemistry Li(CF)x
acteristically flat voltage level supplied by the bat-
tery until very near the end of its life. These
discharge levels have been greatly accelerated in
comparison to the normal, actual usage.
UL RECOGNITION
The M4Txx-BR12SH has been recognized by Un-
derwriters Laboratories under their Component
Recognition Program and carries U.L. File Num-
ber E89556.
3/7
M4TXX-BR12SH
BATTERY LIFE
For information on Data RetentionLife and Battery
Storage Life, please refer to the Application Note
AN1012.
GENERAL NOTES
To remove the SNAPHAT top for replacement, a
DIP/IC extractor tool should be used.
Caution: To avoid draining battery do NOT place
SNAPHAT pins in a conductive foam.
Caution: To avoid damaging SNAPHAT sockets
do NOT wave solder SOIC.
For battery disposal information, seeon the webat
www.rayovac.com.
Figure 3. Battery Discharge Rates
AI02519
0
1.0
1.5
2.0
2.5
3.0
3.5
Voltage (V)
LOAD CHARACTERISTICS
Temp: 20°C
1000 2000 3000 4000 5000 6000
Duration (hrs.)
(B)
15kΩ30kΩ50kΩ100kΩ
0
1.0
1.5
2.0
2.5
3.0
3.5
Voltage (V)
LOAD CHARACTERISTICS
Temp: 20°C
200 400 600 1200 1600 1800
Duration (hrs.)
(A)
100kΩ
800 1000 1400 2000
15kΩ30kΩ
Figure 4. DIP Extractor Tool
AI02527
M4TXX-BR12SH
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Table 2. Ordering Information Scheme
For further information on any aspect of this device, please contact the STMicroelectronics Sales Office
nearest to you.
Example: M4T28-BR12 SH 1
Product Family
M4T = SNAPHAT Battery & Crystal
Battery Voltage & Capacity
28-BR12 = BR1225, 3 V,48 mAh
32-BR12 = BR1632, 3 V,120 mAh
Package
SH = SNAPHAT
Temperature Range
1=0to70°C
6=–40to85°C
5/7
M4TXX-BR12SH
Figure 5. M4T28-BR12SH - TIMEKEEPER 4-pin SNAPHAT Housing for 48 mAh Battery & Crystal,
Package Outline
Drawing is not to scale.
SHTK-A
A1 A
D
E
eA
eB
A2
BL
A3
Table 3. M4T28-BR12SH - TIMEKEEPER 4-pin SNAPHAT Housing for 48 mAh Battery & Crystal,
Package Mechanical Data
Symb mm inches
Typ Min Max Typ Min Max
A 9.78 0.385
A1 6.73 7.24 0.265 0.285
A2 6.48 6.99 0.255 0.275
A3 0.38 0.015
B 0.46 0.56 0.018 0.022
D 21.21 21.84 0.835 0.860
E 14.22 14.99 0.560 0.590
eA 15.55 15.95 0.612 0.628
eB 3.20 3.61 0.126 0.142
L 2.03 2.29 0.080 0.090
M4TXX-BR12SH
6/7
Figure 6. M4T32-BR12SH - TIMEKEEPER 4-pin SNAPHAT Housingfor 120mAh Battery & Crystal,
Package Outline
Drawing is not to scale.
SHTK-A
A1 A
D
E
eA
eB
A2
BL
A3
Table 4. M4T32-BR12SH - TIMEKEEPER 4-pin SNAPHAT Housing for 120 mAh Battery & Crystal,
Package Mechanical Data
Symb mm inches
Typ Min Max Typ Min Max
A 10.54 0.415
A1 8.00 8.51 0.315 0.335
A2 7.24 8.00 0.285 0.315
A3 0.38 0.015
B 0.46 0.56 0.018 0.022
D 21.21 21.84 0.835 0.860
E 17.27 18.03 0.680 0.710
eA 15.55 15.95 0.612 0.628
eB 3.20 3.61 0.126 0.142
L 2.03 2.29 0.080 0.090
7/7
M4TXX-BR12SH
If you have any questions or suggestions concerning the matters raised in this document, please send
them to the following electronic mail addresses:
apps.nvram@st.com
(for application support)
ask.memory@st.com
(for general enquiries)
Please rememberto include your name, company, location, telephone number and fax number.
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of useofsuch information norfor any infringement of patents or other rights of third parties which may result from itsuse. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in lifesupport devices or systems without express written approval of STMicroelectronics.
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