Datasheet

DS1554 256k, Nonvolatile, Y2K-Compliant Timekeeping RAM
16 of 18
POWER-UP/DOWN CHARACTERISTICS—3.3V
(V
CC
= 3.3V 10%, T
A
= Over the operating range.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CE or WE at V
IH
, Before
Power-Down
t
PD
0
s
V
CC
Fall Time: V
PF(MAX)
to V
PF(MIN)
t
F
300
s
V
CC
Rise Time: V
PF(MIN)
to V
PF(MAX)
t
R
0
s
V
PF
to
RST
High
t
REC
40 200 ms
Expected Data-Retention Time
(Oscillator On)
t
DR
(Notes 6, 7) 10 years
Figure 9. Power-Up/Down Waveform Timing (3.3V Device)
CAPACITANCE
(T
A
= +25°C)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Capacitance on All Input Pins C
IN
(Note 1) 14 pF
Capacitance on IRQ/FT, RST,
and DQ Pins
C
IO
(Note 1) 10 pF