M40SZ100 ST Microelectronics, M40SZ100 Datasheet - Page 3

• Manufacturer Part Number: M40SZ100
• Description: 5V or 3V NVRAM SUPERVISOR FOR LPSRAM
• Manufacturer: ST Microelectronics

SUMMARY DESCRIPTION
The M40SZ100Y/W NVRAM Controller is a self-
contained device which converts a standard low-
power SRAM into a non-volatile memory. A preci-
sion voltage reference and comparator monitors
the V
When an invalid V
tioned chip enable output (E
to write protect the stored data in the SRAM. Dur-
ing a power failure, the SRAM is switched from the
V
external battery for the 16-lead SOIC) to provide
the energy required for data retention. On a sub-
sequent power-up, the SRAM remains write pro-
tected until a valid power condition returns.
The 28-pin, 330 mil SOIC provides sockets with
gold plated contacts for direct connection to a sep-
arate SNAPHAT
The SNAPHAT housing has gold plated pins
which mate with the sockets, ensuring reliable
connection. The housing is keyed to prevent im-
proper insertion. This unique design allows the
SNAPHAT battery package to be mounted on top
Figure 3. Logic Diagram
Note: 1. For 16-pin SOIC package only.
CC
pin to the lithium cell within the SNAPHAT (or
CC
RSTIN
input for an out-of-tolerance condition.
PFI
E
®
CC
housing containing the battery.
M40SZ100W
V CC
M40SZ100Y
V SS
condition occurs, the condi-
V BAT
CON
(1)
) is forced inactive
V OUT
BL
E CON
PFO
RST
AI03933
of the SOIC package after the completion of the
surface mount process which greatly reduces the
board manufacturing process complexity of either
directly soldering or inserting a battery into a sol-
dered holder. Providing non-volatility becomes a
“SNAP.” This feature is also available in the “top-
less” 16-pin SOIC package (MQ).
Insertion of the SNAPHAT housing after reflow
prevents potential battery damage due to the high
temperatures required for device surface-mount-
ing. The SNAPHAT housing is also keyed to pre-
vent reverse insertion.
The 28-pin SOIC and battery packages are
shipped separately in plastic anti-static tubes or in
Tape & Reel form. For the 28-lead SOIC, the bat-
tery/crystal package (e.g., SNAPHAT) part num-
ber is “M4ZXX-BR00SH” (see Table 13, page 17).
Caution: Do not place the SNAPHAT battery top
in conductive foam, as this will drain the lithium
button-cell battery.
Table 1. Signal Names
Note: 1. For SO16 only.
V
RSTIN
E
V
PFO
RST
BAT
V
V
PFI
NC
BL
CON
OUT
E
CC
SS
(1)
Chip Enable Input
Conditioned Chip Enable Output
Reset Output (Open Drain)
Reset Input
Battery Low Output (Open Drain)
Supply Voltage Output
Supply Voltage
Back-up Supply Voltage
Power Fail Input
Power Fail Output
Ground
Not Connected Internally
M40SZ100Y, M40SZ100W
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