M40Z300(2000) Ver la hoja de datos (PDF) - STMicroelectronics
Número de pieza
componentes Descripción
Lista de partido
M40Z300 Datasheet PDF : 16 Pages
| |||
M40Z300, M40Z300W
Table 3. Truth Table
Inputs
Outputs
E
B
A
E1CON
E2CON
E3CON
E4CON
H
X
X
H
H
H
H
L
L
L
L
H
H
H
L
L
H
H
L
H
H
L
H
L
H
H
L
H
L
H
H
H
H
H
L
Table 4. AC Measurement Conditions
Input Rise and Fall Times
≤ 5ns
Input Pulse Voltages
0 to 3V
Input and Output Timing Ref. Voltages
1.5V
DATA RETENTION LIFETIME CALCULATION
Most low power SRAMs on the market today can
be used with the M40Z300/W NVRAM Controller.
There are, however some criteria which should be
used in making the final choice of which SRAM to
use. The SRAM must be designed in a way where
the chip enable input disables all other inputs to
the SRAM. This allows inputs to the M40Z300/W
and SRAMs to be Don’t Care once VCC falls below
VPFD (min). The SRAM should also guarantee
data retention down to VCC = 2.0V. The chip en-
able access time must be sufficient to meet the
system needs with the chip enable propagation
delays included. If the SRAM includes a second
Chip Enable pin (E2), this pin should be tied to
VOUT.
If data retention lifetime is a critical parameter for
the system, it is important to review the data reten-
tion current specifications for the particular
SRAMs being evaluated. Most SRAMs specify a
data retention current at 3.0V. Manufacturers gen-
erally specify a typical condition for room temper-
ature along with a worst case condition (generally
at elevated temperatures). The system level re-
quirements will determine the choice of which val-
ue to use. The data retention current value of the
SRAMs can then be added to the ICCDR value of
Figure 3. AC Testing Load Circuit
DEVICE
UNDER
TEST
333Ω
CL = 50pF
1.73V
CL includes JIG capacitance
AI02393
the M40Z300/W to determine the total current re-
quirements for data retention. The available bat-
tery capacity for the SNAPHAT of your choice can
then be divided by this current to determine the
amount of data retention available (see Table 8).
CAUTION: Take care to avoid inadvertent dis-
charge through VOUT and E1CON-E4CON after bat-
tery has been attached.
For a further more detailed review of lifetime cal-
culations, please see Application Note AN1012.
4/16
Share Link: 