bq4285E/L
Power-Down/Power-Up Timing—bq4285L (T = T
)
OPR
A
Symbol
Parameter
Minimum
300
Typical
Maximum
Unit
Conditions
tF
tR
VCC slew from 2.7V to 0V
VCC slew from 0V to 2.7V
-
-
-
-
µs
µs
100
Internal write-protection
period after VCC passes VPFD
on power-up.
tCSR
CS at VIH after power-up
20
-
200
ms
-
0
-
VBC > VPFD
VBC < VPFD
Write-protect time for ex-
ternal RAM
tWPT
10
16
30
µs
Time during which external
SRAM is write-protected after
VCC passes VPFD on power-up.
tCER
tCSR
tCSR
Chip enable recovery time
-
ms
Chip enable propagation
delay to external SRAM
tCED
-
9
15
ns
Caution: Negative undershoots below the absolute maximum rating of -0.3V in battery-backup mode
may affect data integrity.
Power-Down/Power-Up Timing—bq4285L
23
TI [ TEXAS INSTRUMENTS ]
