DS1249W_10 Datasheet, PDF (6/8 Pages) Dallas Semiconductor – 3.3V 2048kb Nonvolatile SRAM

POWER-DOWN/POWER-UP CONDITION
DS1249W
SEE NOTE 11
POWER-DOWN/POWER-UP TIMING
PARAMETER
SYMBOL
V_CC Fail Detect to CE and WE Inactive
t_PD
V_CC Slew from V_TP to 0V
t_F
V_CC Slew from 0V to V_TP
t_R
V_CC Valid to CE and WE Inactive
t_PU
V_CC Valid to End of Write Protection
t_REC
MIN
150
150
TYP
(T_A: See Note 10)
MAX UNITS NOTES
1.5
µs
11
µs
µs
2
ms
125
ms
PARAMETER
Expected Data-Retention Time
SYMBOL MIN TYP
t_DR
10
MAX
(T_A = +25°C)
UNITS NOTES
years
9
WARNING:
Under no circumstance are negative undershoots, of any amplitude, allowed when device is in battery
backup mode.
NOTES:
1. WE is high for a read cycle.
2. OE = V_IH or V_IL. If OE = V_IH during write cycle, the output buffers remain in a high impedance state.
3. t_WP is specified as the logical AND of CE and WE . t_WP is measured from the latter of CE or WE
going low to the earlier of CE or WE going high.
4. t_DS is measured from the earlier of CE or WE going high.
5. These parameters are sampled with a 5pF load and are not 100% tested.
6. If the CE low transition occurs simultaneously with or latter than the WE low transition in Write
Cycle 1, the output buffers remain in a high-impedance state during this period.
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