6
TD220102.eps
V
CC
CE
CON
t
PF
t
FS
4.75
V
PFD
4.25
V
SO
t
WPT
V
OHB
CE
Power-Down Timing
Power-Fail Control
(TA = T
OPR
)
Symbol Parameter Minimum Typical Maximum Unit Notes
t
PF
V
CC
slew, 4.75V to 4.25V 300 - -
µ
s
t
FS
V
CC
slew, 4.25V to V
SO
10 - -
µ
s
t
PU
V
CC
slew, 4.25V to 4.75V 0 - -
µ
s
t
CED
Chip-enable propagation
delay
- 7 10 ns
t
CER
Chip-enable recovery 40 80 120 ms
Time during which SRAM is
write-protected after V
CC
passes V
PFD
on power-up.
t
WPT
Write-protect time 40 100 150
µ
s
Delay after V
CC
slews down
past V
PFD
before SRAM is
write-protected.
Note: Typical values indicate operation at T
A
= 25°C.
Caution: Negative undershoots below the absolute maximum rating of -0.3V in battery-backup mode
may affect data integrity.
Oct. 1998 D
bq2201
