Datasheet

DS1251/DS1251P
11 of 20
PHANTOM CLOCK AC ELECTRICAL CHARACTERISTICS
(T
A
= Over the operating range.) (5V)
10BPARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Read Cycle Time t
RC
65 ns
CE Access Time t
CO
55 ns
OE Access Time t
OE
55 ns
CE to Output Low-Z t
COE
5 ns
OE to Output Low-Z t
OEE
5 ns
CE to Output High-Z t
OD
25 ns 5
OE to Output High-Z t
ODO
25 ns 5
Read Recovery t
RR
10 ns
Write Cycle Time t
WC
65 ns
Write Pulse Width t
WP
55 ns 3
Write Recovery t
WR
10 ns 10
Data Setup Time t
DS
30 ns 4
Data Hold Time t
DH
0 ns 4
CE Pulse Width t
CW
60 ns
RST Pulse Width t
RST
65 ns
POWER-DOWN/POWER-UP TIMING
(T
A
= Over the operating range.) (3.3V)
11BPARAMETER SYMBOL MIN TYP MAX UNITS NOTES
CE at V
IH
before Power-Down t
PD
0
µs
V
CC
Slew from V
PF(MAX)
to
V
PF(MIN)
(CE at V
PF
)
t
F
300
µs
V
CC
Slew from V
PF(MIN)
to V
SO
t
FB
10
µs
V
CC
Slew from V
PF(MAX)
to
V
PF(MIN)
(CE at V
PF
)
t
R
0
µs
CE at V
IH
after Power-Up t
REC
1.5 2.5 ms
(T
A
= +25°C)
4BPARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Expected Data Retention Time t
DR
10 years 9
Warning: Under no circumstances are negative undershoots of any amplitude allowed when device
is in battery-backup mode.