M48T02_03 Datasheet, PDF (11/19 Pages) STMicroelectronics – 5.0V, 16 Kbit (2Kb x 8) TIMEKEEPER® SRAM

M48T02, M48T12
Figure 10. Power Down/Up Mode AC Waveforms
VCC
VPFD (max)
VPFD (min)
VSO
tF
tPD
tFB
INPUTS
RECOGNIZED
tDR
tRB
DON'T CARE
tR
NOTE
tREC
RECOGNIZED
OUTPUTS
VALID
HIGH-Z
VALID
(PER CONTROL INPUT)
(PER CONTROL INPUT)
AI00606
Note: Inputs may or may not be recognized at this time. Caution should be taken to keep E high as V_CC rises past V_PFD (min). Some systems
may perform inadvertent WRITE cycles after VCC rises above VPFD (min) but before normal system operations begin. Even though a
power on reset is being applied to the processor, a reset condition may not occur until after the system clock is running.
Table 9. Power Down/Up AC Characteristics
Symbol
Parameter⁽¹⁾
Min
Max
Unit
t_PD
E or W at V_IH before Power Down
0
µs
t_F(2)
V_PFD (max) to V_PFD (min) V_CC Fall Time
300
µs
t_FB(3)
V_PFD (min) to V_SS V_CC Fall Time
10
µs
t_R
V_PFD (min) to V_PFD (max) V_CC Rise Time
0
µs
t_RB
V_SS to V_PFD (min) V_CC Rise Time
1
µs
t_REC
E or W at V_IH before Power Up
2
ms
Note: 1. Valid for Ambient Operating Temperature: T_A = 0 to 70°C; V_CC = 4.75 to 5.5V or 4.5 to 5.5V (except where noted).
2. VPFD (max) to VPFD (min) fall time of less than tF may result in deselection/write protection not occurring until 200µs after VCC pass-
es V_PFD (min).
3. VPFD (min) to VSS fall time of less than tFB may cause corruption of RAM data.
Table 10. Power Down/Up Trip Points DC Characteristics
Symbol
Parameter^(1,2)
Min
Typ
Max
Unit
V_PFD Power-fail Deselect Voltage
M48T02
4.5
4.6
4.75
V
M48T12
4.2
4.3
4.5
V
V_SO
Battery Back-up Switchover Voltage
3.0
V
t_DR(3)
Expected Data Retention Time
10
Note: 1. All voltages referenced to VSS.
2. Valid for Ambient Operating Temperature: T_A = 0 to 70°C; V_CC = 4.75 to 5.5V or 4.5 to 5.5V (except where noted).
3. At 25°C; VCC = 0V.
YEARS
11/19