m40z300 STMicroelectronics, m40z300 Datasheet - Page 5

• Manufacturer Part Number: m40z300
• Description: Nvram Controller For Up To Eight Lpsram
• Manufacturer: STMicroelectronics

1
Caution:
Description
The M40Z300/W NVRAM SUPERVISOR is a self-contained device which converts a
standard low-power SRAM into a non-volatile memory. A precision voltage reference and
comparator monitors the V
When an invalid V
E4
failure, the SRAM is switched from the V
provide the energy required for data retention. On a subsequent power-up, the SRAM
remains write protected until a valid power condition returns.
The 28-pin, 330mil SOIC provides sockets with gold plated contacts for direct connection to
a separate SNAPHAT housing containing the battery. The SNAPHAT housing has gold
plated pins which mate with the sockets, ensuring reliable connection. The housing is keyed
to prevent improper insertion. This unique design allows the SNAPHAT battery package to
be mounted on top 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 soldered holder. Providing non-volatility becomes a
“SNAP.” The 16-pin SOIC provides battery pins for an external user-supplied battery.
Insertion of the SNAPHAT housing after reflow prevents potential battery damage due to the
high temperatures required for device surface-mounting. The SNAPHAT housing is also
keyed to prevent 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 battery/crystal package (e.g., SNAPHAT) part
number is “M4ZXX-BR00SH” (see
Do not place the SNAPHAT battery top in conductive foam, as this will drain the lithium
button-cell battery.
CON
) are forced inactive to write-protect the stored data in the SRAM. During a power
CC
condition occurs, the conditioned chip enable outputs (E1
CC
input for an out-of-tolerance condition.
Table 13 on page
CC
pin to the lithium cell within the SNAPHAT
23).
CON
to
®
to
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